// whatsapp_test.cpp: validates detz's native WhatsApp implementation against
// golden vectors captured from the real Baileys client (tests/whatsapp_data,
// copied from jfelipesjc/wa-go, MIT). No network; these are offline byte-exact
// checks of the wire codec, crypto, Noise handshake and Signal session. The
// live pairing/send paths need a phone and are not covered here. See
// docs/whatsapp.md.
#include <unistd.h>

#include <cstdio>
#include <cstdlib>
#include <filesystem>
#include <fstream>
#include <functional>
#include <map>
#include <memory>
#include <string>

#include "json.h"
#include "wa_binary.h"
#include "wa_cert.h"
#include "wa_client.h"
#include "wa_consts.h"
#include "wa_crypto.h"
#include "wa_device.h"
#include "wa_iq.h"
#include "wa_keepalive.h"
#include "wa_noise.h"
#include "wa_proto.h"
#include "wa_signal.h"
#include "wa_appstate.h"
#include "wa_consts.h"
#include "wa_jid.h"
#include "wa_lidmap.h"
#include "wa_media.h"
#include "wa_pair_events.h"
#include "wa_pairing.h"
#include "wa_passkey.h"
#include "wa_qr_channel.h"
#include "wa_mediaconn.h"
#include "wa_mediaerror.h"
#include "wa_mediatype.h"
#include "wa_sticker.h"
#include "wa_receiver.h"
#include "wa_store.h"
#include "wa_tokens_data.h"
#include "wa_vcf.h"
#include "sqldb.h"

using namespace detz::wa;
using detz::json::Value;

static int g_fail = 0;
static void check(bool ok, const std::string& name) {
  std::printf("  %s %s\n", ok ? "ok  " : "FAIL", name.c_str());
  if (!ok) g_fail++;
}

static Bytes fromhex(const std::string& h) {
  Bytes b;
  for (size_t i = 0; i + 1 < h.size(); i += 2) b.push_back((uint8_t)std::stoi(h.substr(i, 2), nullptr, 16));
  return b;
}
static std::string tohex(const Bytes& b) {
  std::string s;
  char t[3];
  for (auto c : b) {
    std::snprintf(t, 3, "%02x", c);
    s += t;
  }
  return s;
}
static Bytes b64(const std::string& in) {
  static const std::string T = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  Bytes out;
  int val = 0, bits = -8;
  for (char c : in) {
    if (c == '=') break;
    auto p = T.find(c);
    if (p == std::string::npos) continue;
    val = (val << 6) | (int)p;
    bits += 6;
    if (bits >= 0) {
      out.push_back((uint8_t)((val >> bits) & 0xff));
      bits -= 8;
    }
  }
  return out;
}
static std::string slurp(const std::string& p) {
  std::ifstream f(p);
  return std::string((std::istreambuf_iterator<char>(f)), std::istreambuf_iterator<char>());
}
static std::array<uint8_t, 32> a32(const Bytes& b) {
  std::array<uint8_t, 32> a{};
  for (size_t i = 0; i < 32 && i < b.size(); ++i) a[i] = b[i];
  return a;
}
static SignalKey sk33(const Bytes& b) {
  SignalKey k{};
  for (size_t i = 0; i < 33 && i < b.size(); ++i) k[i] = b[i];
  return k;
}
static WaCrypto::KeyPair kpair(const Value& o) {
  WaCrypto::KeyPair k;
  k.priv = a32(fromhex(o.get("priv").str()));
  Bytes pb = fromhex(o.get("pub").str());
  k.pub = a32(Bytes(pb.begin() + (pb.size() == 33 ? 1 : 0), pb.end()));
  return k;
}

static const char* DIR = nullptr;
static std::string path(const std::string& f) { return std::string(DIR) + "/" + f; }

// ---- crypto (RFC vectors + XEdDSA) ----
static void test_crypto() {
  std::printf("[crypto]\n");
  Bytes ikm(22, 0x0b), salt;
  for (int i = 0; i < 13; i++) salt.push_back(i);
  Bytes info;
  for (int i = 0xf0; i <= 0xf9; i++) info.push_back(i);
  check(tohex(WaCrypto::hkdf_sha256(ikm, salt, info, 42)) ==
            "3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865",
        "HKDF-SHA256 RFC 5869 case 1");
  check(tohex(WaCrypto::pbkdf2_sha256(Bytes{'p', 'a', 's', 's', 'w', 'o', 'r', 'd'}, Bytes{'s', 'a', 'l', 't'}, 1, 32)) ==
            "120fb6cffcf8b32c43e7225256c4f837a86548c92ccc35480805987cb70be17b",
        "PBKDF2-SHA256");
  auto a = WaCrypto::generate_x25519(), b = WaCrypto::generate_x25519();
  check(WaCrypto::x25519(a.priv, b.pub) == WaCrypto::x25519(b.priv, a.pub), "X25519 DH agreement");
  bool xok = true;
  for (int i = 0; i < 64; ++i) {
    auto kp = WaCrypto::generate_x25519();
    Bytes m = WaCrypto::random_bytes(1 + i);
    auto sig = WaCrypto::xeddsa_sign(kp.priv, m);
    if (!WaCrypto::xeddsa_verify(kp.pub, m, sig)) xok = false;
    sig[i % 64] ^= 1;
    if (WaCrypto::xeddsa_verify(kp.pub, m, sig)) xok = false;
  }
  check(xok, "XEdDSA sign/verify roundtrip + tamper (64 keys)");
}

// ---- binary codec ----
static void test_codec() {
  std::printf("[codec]\n");
  std::ifstream f(path("codec_battery.jsonl"));
  std::string line;
  int n = 0, ok = 0;
  std::function<WaNode(const Value&)> build = [&](const Value& t) -> WaNode {
    WaNode node(t.get("tag").str());
    for (const auto& m : t.get("attrs").members()) node.attrs[m.first] = m.second.str();
    const Value& c = t.get("content");
    if (c.is_string())
      node.content = fromhex(c.str());
    else if (c.is_array()) {
      WaNode::Children ch;
      for (const auto& e : c.items()) ch.push_back(build(e));
      node.content = ch;
    }
    return node;
  };
  std::function<bool(const WaNode&, const WaNode&)> eq = [&](const WaNode& x, const WaNode& y) -> bool {
    if (x.tag != y.tag || x.attrs != y.attrs || x.content.index() != y.content.index()) return false;
    if (auto* a = x.bytes()) return *a == *y.bytes();
    if (auto* a = x.children()) {
      auto* b = y.children();
      if (a->size() != b->size()) return false;
      for (size_t i = 0; i < a->size(); ++i)
        if (!eq((*a)[i], (*b)[i])) return false;
    }
    return true;
  };
  while (std::getline(f, line)) {
    if (line.empty()) continue;
    ++n;
    Value v = Value::loads(line);
    WaNode want = build(v.get("decoded_tree"));
    WaNode got = WaBinary::decode(WaBinary::unpack(fromhex(v.get("encoded_hex").str())));
    Bytes re = WaBinary::encode(got);
    Bytes framed;
    framed.push_back(0);
    framed.insert(framed.end(), re.begin(), re.end());
    WaNode got2 = WaBinary::decode(WaBinary::unpack(framed));
    if (eq(got, want) && eq(got2, want)) ++ok;
  }
  check(ok == n && n == 19, "codec battery " + std::to_string(ok) + "/" + std::to_string(n) + " (decode + re-encode)");
}

// ---- ClientPayload byte-exact ----
static void test_client_payload() {
  std::printf("[proto]\n");
  Value d = Value::loads(slurp(path("client_payload.json")));
  const Value& fl = d.get("fields");
  const Value& ua = fl.get("userAgent");
  const Value& dp = fl.get("devicePairingData");
  WaClientPayload p;
  p.has_passive = true;
  p.has_user_agent = true;
  auto& u = p.user_agent;
  u.app_version.has = true;
  u.app_version.primary = ua.get("appVersion").get("primary").as_int();
  u.app_version.secondary = ua.get("appVersion").get("secondary").as_int();
  u.app_version.tertiary = ua.get("appVersion").get("tertiary").as_int();
  p.has_web_info = true;
  p.has_connect = true;
  WaDevicePairingData pd;
  pd.e_regid = b64(dp.get("eRegid").str());
  pd.e_keytype = b64(dp.get("eKeytype").str());
  pd.e_ident = b64(dp.get("eIdent").str());
  pd.e_skey_id = b64(dp.get("eSkeyId").str());
  pd.e_skey_val = b64(dp.get("eSkeyVal").str());
  pd.e_skey_sig = b64(dp.get("eSkeySig").str());
  pd.build_hash = b64(dp.get("buildHash").str());
  pd.device_props = b64(dp.get("deviceProps").str());
  p.pairing = pd;
  p.has_pull = true;
  check(tohex(p.encode()) == d.get("payloadHex").str(), "ClientPayload byte-exact (registration)");
}

// ---- Noise handshake ----
static void test_noise() {
  std::printf("[noise]\n");
  Value d = Value::loads(slurp(path("noise.json")));
  auto ephPriv = a32(fromhex(d.get("ephemeralKeyPriv").str()));
  auto ephPub = a32(fromhex(d.get("ephemeralKeyPub").str()));
  auto stPriv = a32(fromhex(d.get("authStaticKeyPriv").str()));
  auto stPub = a32(fromhex(d.get("authStaticKeyPub").str()));
  Bytes shFrame = fromhex(d.get("serverHelloFrameHex").str());
  size_t pos = 0;
  auto sh = WaFraming::unframe(shFrame, pos);
  WaNoise noise(ephPub);
  auto res = noise.client_handshake(ephPriv, ephPub, stPriv, stPub, *sh, Bytes{1, 2, 3, 4});
  check(res.has_value(), "handshake completed (server static+payload decrypted)");
  if (res) {
    check(tohex(WaFraming::frame(res->client_hello, true)) == d.get("clientHelloFrameHex").str(),
          "clientHello frame byte-exact");
    check(res->server_static.size() == 32, "server static key is 32 bytes");
    check(parse_cert_chain(res->server_payload).has_value(), "server payload parses as cert chain");
    check(noise.in_transport(), "transport keys derived");
  }
}

// ---- Signal session ----
static void test_signal() {
  std::printf("[signal]\n");
  Value d = Value::loads(slurp(path("session_ab.json")));
  auto& al = d.get("alice");
  auto& bo = d.get("bob");
  auto& eph = d.get("ephemeralsGenerated");
  WaSession::InitiatorParams p;
  p.local_identity = kpair(al.get("identityKeyPair"));
  p.local_base = kpair(al.get("baseKey"));
  p.remote_identity = sk33(fromhex(bo.get("identityKeyPair").get("pub").str()));
  p.remote_signed_pre = sk33(fromhex(bo.get("signedPreKey").get("keyPair").get("pub").str()));
  p.remote_pre_key = sk33(fromhex(bo.get("preKey").get("keyPair").get("pub").str()));
  p.has_pre_key = true;
  WaSession s = WaSession::initiate(p, kpair(eph.at(1)));
  s.set_pending(al.get("registrationId").as_int(), signal_pub(p.local_base.pub),
                bo.get("signedPreKey").get("id").as_int(), true, bo.get("preKey").get("id").as_int());
  WaCrypto::KeyPair nextR = kpair(eph.at(3));
  s.set_ratchet_generator([&]() { return nextR; });
  const Value& ex = d.get("exchanges");
  auto pt = [&](int i) {
    std::string t = ex.at(i).get("plaintext").str();
    return Bytes(t.begin(), t.end());
  };
  auto want = [&](int i) { return ex.at(i).get("ciphertextHex").str(); };
  auto o1 = s.encrypt(pt(0));
  check(o1.type == "pkmsg" && tohex(o1.serialized) == want(0), "exchange #1 pkmsg byte-exact");
  auto p2 = s.decrypt(fromhex(want(1)));
  check(p2 && std::string(p2->begin(), p2->end()) == ex.at(1).get("plaintext").str(), "exchange #2 decrypt");
  auto o3 = s.encrypt(pt(2));
  check(o3.type == "msg" && tohex(o3.serialized) == want(2), "exchange #3 msg byte-exact");
  auto o4 = s.encrypt(pt(3));
  check(o4.type == "msg" && tohex(o4.serialized) == want(3), "exchange #4 msg byte-exact");
  // session survives a serialize/deserialize round trip
  Bytes blob = s.serialize();
  check(WaSession::deserialize(blob).has_value(), "session serialize/deserialize");
}

// ---- hostile / malformed input (regression guard, incident WA-2026-10-27) ----
// Every parser of bytes off the wire must reject malformed input by throwing a
// std::exception (caught upstream), never by an unchecked huge allocation that
// aborts the process. A length field that overflows the bounds check used to
// reach vector::assign and throw std::length_error, which aborted the client.
// These cases must keep throwing a *handled* exception, never std::length_error
// and never crash. See docs/whatsapp.md section 13.
static void test_hostile() {
  std::printf("[hostile input]\n");
  bool ok = true;

  // 1. binary node whose content length claims 0xFFFFFFFF in a tiny buffer.
  //    flag(0) | LIST_8 size 2 | tag BINARY_8 "x" | content BINARY_32 0xFFFFFFFF
  Bytes huge_len = {0x00, 0xf8, 0x02, 0xfc, 0x01, 'x', 0xfe, 0xff, 0xff, 0xff, 0xff};
  try {
    WaBinary::decode(WaBinary::unpack(huge_len));
    ok = false;  // must not succeed
  } catch (const std::length_error&) {
    ok = false;  // the exact regression: an unchecked allocation
  } catch (const std::exception&) {
    // correct: a handled WireError / bounds error
  }
  check(ok, "binary decode rejects a 4GB length field without length_error");

  // 2. protobuf field 1, wire 2, length varint ~4 billion, no payload.
  Bytes huge_pb = {0x0a, 0xff, 0xff, 0xff, 0xff, 0x0f};
  ok = true;
  try {
    ProtoReader r(huge_pb);
    ProtoReader::Field f;
    while (r.next(f)) {
    }
    ok = false;
  } catch (const std::length_error&) {
    ok = false;
  } catch (const std::exception&) {
  }
  check(ok, "proto reader rejects an oversized length without length_error");

  // 2b. an overlong varint (continuation bytes past 64 bits) must throw, not
  //     shift-overflow. This is undefined behavior the sanitizer net caught.
  Bytes overlong = {0x08};                             // field 1, wire 0
  for (int i = 0; i < 12; ++i) overlong.push_back(0x80);  // 12 continuation bytes
  overlong.push_back(0x01);
  ok = true;
  try {
    ProtoReader r(overlong);
    ProtoReader::Field f;
    while (r.next(f)) {
    }
    ok = false;
  } catch (const std::exception&) {
  }
  check(ok, "proto reader rejects an overlong varint (no shift-overflow UB)");

  // 3. negative/short-buffer node tags and truncations throw cleanly.
  ok = true;
  for (const Bytes& bad : std::vector<Bytes>{{}, {0x00}, {0x00, 0xf8}, {0x00, 0xfe, 0x7f, 0xff, 0xff, 0xff},
                                             {0x00, 0xf8, 0x04, 0xfc, 0xff}}) {
    try {
      WaBinary::decode(WaBinary::unpack(bad));
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
  }
  check(ok, "truncated/short frames throw cleanly, never length_error");

  // 4. fuzz: random byte strings must each return or throw a std::exception,
  //    never a length_error and never a crash (surviving the loop is the proof).
  ok = true;
  for (int i = 0; i < 2000; ++i) {
    Bytes r = WaCrypto::random_bytes(1 + (i % 64));
    try {
      WaBinary::decode(WaBinary::unpack(r));
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    try {
      ProtoReader pr(r);
      ProtoReader::Field f;
      while (pr.next(f)) {
      }
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
  }
  check(ok, "2000 random inputs: no length_error, no crash");

  // 5. M1: frame reassembly with hostile cursor/length values yields "no
  //    frame yet", never a crash and never a wraparound slice.
  ok = true;
  try {
    Bytes buf = {0x00, 0x00, 0x05, 'h', 'e', 'l', 'l', 'o'};
    size_t pos = 99;  // cursor past the end: caller bug, still handled
    if (WaFraming::unframe(buf, pos).has_value()) ok = false;
    pos = 6;  // 2 bytes left, fewer than the 3-byte length prefix
    if (WaFraming::unframe(buf, pos).has_value() || pos != 6) ok = false;
    Bytes huge = {0xff, 0xff, 0xff};  // length 16M-1 claimed, 0 bytes present
    pos = 0;
    if (WaFraming::unframe(huge, pos).has_value() || pos != 0) ok = false;
    Bytes empty;
    pos = 0;
    if (WaFraming::unframe(empty, pos).has_value()) ok = false;
    pos = 0;  // exact frame still parses after the hostile attempts
    auto fr = WaFraming::unframe(buf, pos);
    if (!fr || fr->size() != 5 || pos != 8) ok = false;
  } catch (const std::exception&) {
    ok = false;  // unframe never throws; incomplete input is a routine negative
  }
  check(ok, "hostile frame cursors/lengths yield no frame, never crash");
}

// ---- device serialize round-trip (regression for incident WA-2026-10-27) ----
// A paired device serializes its optional jid/lid. The bug was a two-temporaries
// iterator range over `(jid ? *jid : "")` that only misfired once jid was set,
// so this test must cover the PAIRED case, not just a fresh device. Under the
// sanitizer net it also proves there is no lifetime UB in the path.
static void test_device() {
  std::printf("[device]\n");
  WaDevice d = WaDevice::generate();
  d.jid = "15551230000:7@s.whatsapp.net";  // synthetic, not a real account
  d.lid = "100000000000000:7@lid";
  d.push_name = "test";
  d.account = WaCrypto::random_bytes(186);
  Bytes blob = d.serialize();  // used to abort here with length_error
  auto back = WaDevice::deserialize(blob);
  bool ok = back && back->jid == d.jid && back->lid == d.lid && back->push_name == d.push_name &&
            back->account == d.account && back->registration_id == d.registration_id &&
            back->jid_device() == 7 && back->jid_user() == 15551230000ULL;
  check(ok, "paired device serialize/deserialize round-trip (jid+lid set)");
  // also the unpaired case (optionals empty), the other temporary branch
  WaDevice u = WaDevice::generate();
  auto ub = WaDevice::deserialize(u.serialize());
  check(ub && !ub->paired(), "unpaired device serialize/deserialize round-trip");
}

// Regression (docs/whatsapp.md section 14): a server-only JID decoded to "@s.whatsapp.net", and the
// pairing reply copied it as `to`, so the server refused pair-device-sign and login ended in 401.
static void test_server_jid() {
  WaNode n("iq");
  n.attrs["to"] = "s.whatsapp.net";
  n.attrs["from"] = "31630045827@s.whatsapp.net";
  Bytes wire{0};  // 1-byte flags header (0 = uncompressed), as WaClient::send_node frames it
  Bytes body = WaBinary::encode(n);
  wire.insert(wire.end(), body.begin(), body.end());
  WaNode back = WaBinary::decode(WaBinary::unpack(wire));
  check(back.attr("to") == "s.whatsapp.net", "server-only JID round-trips as s.whatsapp.net");
  check(back.attr("from") == "31630045827@s.whatsapp.net", "user JID round-trips unchanged");
}

// WaMedia against wa-go's golden vectors (Baileys-generated, MIT): every IV, derived key,
// ciphertext+MAC and both hashes must match byte for byte.
static void test_media() {
  Value d = Value::loads(slurp(path("media_vectors.json")));
  Bytes media_key = fromhex(d.get("mediaKeyHex").str());
  int ok = 0, total = 0;
  for (const auto& c : d.get("cases").items()) {
    const Value& pt = d.get("plaintexts").get(c.get("plaintext").str());
    Bytes plain = fromhex(pt.get("plaintextHex").str());
    std::string info = c.get("info").str();
    WaMedia::Keys k = WaMedia::expand(media_key, info);
    WaMedia::Encrypted e = WaMedia::encrypt(plain, info, media_key);
    bool keys_ok = tohex(k.iv) == c.get("iv").str() && tohex(k.cipher_key) == c.get("cipherKey").str() &&
                   tohex(k.mac_key) == c.get("macKey").str() && tohex(k.ref_key) == c.get("refKey").str();
    bool blob_ok = tohex(e.data_to_upload) == c.get("ciphertextHex").str();
    bool hash_ok = tohex(e.file_sha256) == c.get("fileSha256").str() && tohex(e.file_enc_sha256) == c.get("fileEncSha256").str();
    bool len_ok = e.file_length == plain.size();
    ++total;
    if (keys_ok && blob_ok && hash_ok && len_ok) ++ok;
    else std::printf("    mismatch: %s %s keys=%d blob=%d hash=%d len=%d\n", c.get("plaintext").str().c_str(), info.c_str(), keys_ok, blob_ok, hash_ok, len_ok);
  }
  check(total > 0 && ok == total, "media encrypt matches wa-go golden vectors (" + std::to_string(ok) + "/" + std::to_string(total) + ")");
  check(WaMedia::token(WaCrypto::sha256(Bytes{'a'})).size() == 44, "upload token is base64url with padding (44 chars for 32 bytes)");
}


// ---- app-state sync (docs/whatsapp.md section 14) ----
// Oracle: tests/whatsapp_data/appstate_vectors.json, generated by appstate_oracle.go with whatsmeow's own
// lthash, hkdfutil and protobuf packages. Nothing here is produced by the code under test.

static std::string make_temp_home() {
  std::string tmpl = "/tmp/wa_test_XXXXXX";
  char* d = ::mkdtemp(tmpl.data());
  return d ? std::string(d) : std::string();
}

static void test_lthash_and_keys() {
  std::printf("[appstate: keys and LTHash]\n");
  Value v = Value::loads(slurp(path("appstate_vectors.json")));
  Bytes key_data = fromhex(v.get("key_data").str());
  WaAppStateKeys k = WaAppStateKeys::expand(key_data);
  std::string want = v.get("expanded_keys").str();
  std::string got = tohex(k.index) + tohex(k.value_encryption) + tohex(k.value_mac) + tohex(k.snapshot_mac) + tohex(k.patch_mac);
  check(got == want, "expanded app-state keys match whatsmeow expandAppStateKeys (160 bytes)");

  // LTHash: add then remove is the identity; the order of items does not matter.
  Bytes a(32, 1), b(32, 2), c(32, 3);
  Bytes st = WaLtHash::zero();
  WaLtHash::subtract_then_add(st, {}, {a, b});
  WaLtHash::subtract_then_add(st, {a}, {c});
  Bytes st2 = WaLtHash::zero();
  WaLtHash::subtract_then_add(st2, {}, {c});
  WaLtHash::subtract_then_add(st2, {}, {b});
  check(st == st2, "LTHash: add a,b; remove a, add c equals add c; remove b (order-free, add/remove cancel)");
  Bytes st3 = WaLtHash::zero();
  WaLtHash::subtract_then_add(st3, {}, {a});
  WaLtHash::subtract_then_add(st3, {a}, {});
  check(st3 == WaLtHash::zero(), "LTHash: add then remove returns the zero state");
}

// Fake collection server: serves one snapshot and the given patches, and answers the external blob download.
struct FakeCollection {
  Bytes snapshot;
  std::vector<Bytes> patches;
  int iq_calls = 0;
  WaNode operator()(WaNode iq) {
    (void)iq;
    WaNode col("collection");
    col.attrs["name"] = WaAppStateSync::kContactsCollection;
    WaNode::Children kids;
    if (iq_calls == 0) {
      WaNode snap("snapshot");
      snap.content = Bytes{0x0a, 0x00};  // stands in for an ExternalBlobReference; the download hook returns the body
      kids.push_back(snap);
    }
    WaNode patches_node("patches");
    WaNode::Children pk;
    for (const auto& p : patches) {
      WaNode pn("patch");
      pn.content = p;
      pk.push_back(pn);
    }
    patches_node.content = pk;
    kids.push_back(patches_node);
    col.content = kids;
    ++iq_calls;
    WaNode sync("sync");
    sync.content = WaNode::Children{col};
    WaNode reply("iq");
    reply.content = WaNode::Children{sync};
    return reply;
  }
};

static WaAppStateSync::DownloadFn snapshot_download(const Bytes& snapshot) {
  return [snapshot](const WaExternalBlobRef&, std::string&) -> std::optional<Bytes> { return snapshot; };
}

static void test_appstate_sync() {
  std::printf("[appstate: snapshot and patch sync]\n");
  Value v = Value::loads(slurp(path("appstate_vectors.json")));
  Bytes key_id = fromhex(v.get("key_id").str());
  Bytes key_data = fromhex(v.get("key_data").str());
  Bytes snapshot = fromhex(v.get("snapshot").str());
  Bytes patch = fromhex(v.get("patch").str());
  Bytes tampered = fromhex(v.get("patch_tampered").str());
  std::string name = WaAppStateSync::kContactsCollection;
  std::vector<std::string> logs;
  auto log = [&](const std::string& s) { logs.push_back(s); };

  // 1. good chain: snapshot then one patch
  {
    std::string home = make_temp_home();
    WaStore store(home, "sync");
    store.put_app_key(key_id, key_data, 1767225600123);
    FakeCollection col;
    col.patches = {patch};
    WaAppStateSync sync(store, log);
    auto rep = sync.sync(name, col, snapshot_download(snapshot));
    check(rep.error.empty() && rep.rejected == 0, "good snapshot+patch chain verifies (snapshot MAC, patch MAC, value and index MACs)");
    check(rep.patches_applied == 1 && rep.mutations_applied == 10, "applied 1 patch with 10 mutations (4 snapshot + 6 patch)");
    check(rep.contacts_saved == 6 && rep.contacts_removed == 1 && rep.contacts_unnamed == 1,
          "contacts: 6 saved (3 snapshot, 3 patch), 1 removed, 1 unnamed skipped");
    auto contacts = store.contacts();
    std::map<std::string, std::string> got(contacts.begin(), contacts.end());
    std::map<std::string, std::string> want = {
        {"31611111111@s.whatsapp.net", "Nigel Dokter (work)"},
        {"31622222222@s.whatsapp.net", "Ann"},
        {"31644444444@s.whatsapp.net", "Joop Visser"},
    };
    check(got == want, "wa_contact holds exactly the named contacts after snapshot + patch (C removed, unnamed F and the pushName setting not stored)");
    auto ver = store.app_state_version(name);
    check(ver && ver->version == 2 && tohex(ver->hash) == v.get("patch_hash_hex").str(),
          "stored version 2 and LTHash state equal whatsmeow's state after the patch");
    // a second sync from the stored version is a no-op on the server side
    FakeCollection none;
    none.iq_calls = 1;  // the server sends no snapshot once the client is at version 2
    auto rep2 = sync.sync(name, none, snapshot_download(snapshot));
    check(rep2.error.empty() && rep2.patches_applied == 0 && rep2.version == 2, "a re-sync from version 2 with no new patches changes nothing");
    std::filesystem::remove_all(home);
  }

  // 2. tampered patch: MAC mismatch, the patch is not stored, the snapshot before it is
  {
    std::string home = make_temp_home();
    WaStore store(home, "tamper");
    store.put_app_key(key_id, key_data, 1767225600123);
    FakeCollection col;
    col.patches = {tampered};
    WaAppStateSync sync(store, log);
    auto rep = sync.sync(name, col, snapshot_download(snapshot));
    check(rep.rejected == 1 && rep.patches_applied == 0, "tampered patch is rejected (value MAC) and not applied");
    auto ver = store.app_state_version(name);
    check(ver && ver->version == 1, "after a rejected patch the stored version stays at the last verified state (1)");
    std::filesystem::remove_all(home);
  }

  // 3. missing key: nothing is stored, the key id is reported for a key request
  {
    std::string home = make_temp_home();
    WaStore store(home, "nokey");
    FakeCollection col;
    WaAppStateSync sync(store, log);
    auto rep = sync.sync(name, col, snapshot_download(snapshot));
    check(rep.missing_key_ids.size() == 1 && rep.missing_key_ids[0] == key_id && rep.contacts_saved == 0,
          "missing app-state key: key id reported, no data stored");
    check(!store.app_state_version(name).has_value(), "missing key leaves the collection version unset");
    std::filesystem::remove_all(home);
  }

  // 4. key share message parses to the oracle key; key request encodes a parseable Message
  {
    Bytes ks = fromhex(v.get("key_share_message").str());
    WaProtocolMessage pm = parse_protocol_message(ks);
    check(pm.type == 6 && pm.key_share.size() == 1 && pm.key_share[0].key_id == key_id && pm.key_share[0].key_data == key_data &&
              pm.key_share[0].timestamp == 1767225600123,
          "APP_STATE_SYNC_KEY_SHARE parses: key id, 32-byte key data, timestamp (whatsmeow proto)");
    Bytes kr = encode_app_state_key_request({key_id});
    WaProtocolMessage req = parse_protocol_message(kr);
    check(req.type == 7 && req.key_share.empty() && tohex(kr) == v.get("key_request_message").str(),
          "APP_STATE_SYNC_KEY_REQUEST encodes byte-exact to whatsmeow's Message");
  }
}

static void test_receiver() {
  std::printf("[appstate: key share receipt]\n");
  // Alice (the phone) starts a session with our device with X3DH and sends the key share as pkmsg.
  WaDevice bob = WaDevice::generate();
  WaCrypto::KeyPair alice_id = WaCrypto::generate_x25519();
  WaCrypto::KeyPair alice_base = WaCrypto::generate_x25519();
  WaCrypto::KeyPair one_time = WaCrypto::generate_x25519();
  std::string home = make_temp_home();
  WaStore store(home, "recv");
  store.put_prekey(77, Bytes(one_time.priv.begin(), one_time.priv.end()));

  WaSession::InitiatorParams p;
  p.local_identity = alice_id;
  p.local_base = alice_base;
  p.remote_identity = signal_pub(bob.identity_key.pub);
  p.remote_signed_pre = signal_pub(bob.signed_pre_key.pair.pub);
  p.remote_pre_key = signal_pub(one_time.pub);
  p.has_pre_key = true;
  WaSession s = WaSession::initiate(p, WaCrypto::generate_x25519());
  s.set_pending(1234, signal_pub(alice_base.pub), bob.signed_pre_key.key_id, true, 77);
  Bytes plain = fromhex(Value::loads(slurp(path("appstate_vectors.json"))).get("key_share_message").str());
  CiphertextMessage ct = s.encrypt(WaCrypto::pkcs7_pad(plain));
  WaNode enc("enc");
  enc.attrs["v"] = "2";
  enc.attrs["type"] = ct.type;
  enc.content = ct.serialized;

  WaReceiver rx(store);
  auto res = rx.decrypt(enc, "15550001111@s.whatsapp.net", bob);
  check(ct.type == "pkmsg" && res.ok && res.message == plain, "pkmsg from the phone decrypts to the key-share Message (X3DH responder + unpad)");
  check(store.load_session("15550001111.0").has_value(), "the new session is stored under the phone's signal address");
  Bytes bad = ct.serialized;
  bad.back() ^= 0x01;
  WaNode enc_bad("enc");
  enc_bad.attrs["type"] = ct.type;
  enc_bad.content = bad;
  auto corrupt = rx.decrypt(enc_bad, "15550001111@s.whatsapp.net", bob);
  check(!corrupt.ok, "a corrupted pkmsg is refused with a reason, not decrypted");
  std::filesystem::remove_all(home);
}

// The phone only pushes history and app-state keys to a companion that declares historySyncConfig
// (DeviceProps field 5), so registration must carry it.
static void test_device_props() {
  WaDeviceProps dp;
  Bytes with = dp.encode();
  dp.history_sync_config = false;
  Bytes without = dp.encode();
  check(with.size() > without.size() + 20, "DeviceProps carries historySyncConfig by default");
  ProtoReader r(with);
  ProtoReader::Field f;
  bool found = false;
  while (r.next(f)) found = found || (f.field == 5 && f.wire == 2);
  check(found, "DeviceProps field 5 (historySyncConfig) is length-delimited");
}

// Contact search: the user's phone has "Nigel Dokter"; the user types "Nigel", "Niggel", "dokter" or the number.
static void test_contact_search() {
  std::string home = "build/probe/wa_contact_test_home";
  std::filesystem::remove_all(home);
  WaStore store(home, "t");
  store.put_contact("31612345001@s.whatsapp.net", "Nigel Dokter");
  store.put_contact("31612345002@s.whatsapp.net", "Nina Smit");
  store.put_contact("31612345003@s.whatsapp.net", "Peter de Vries");
  auto top = [&](const std::string& q) {
    auto h = store.search_contacts(q, 3, 0.3);
    return h.empty() ? std::string("(none)") : h[0].name;
  };
  check(top("Nigel") == "Nigel Dokter", "contact search: first name");
  check(top("Niggel") == "Nigel Dokter", "contact search: typo (Niggel -> Nigel Dokter)");
  check(top("nigel dokter") == "Nigel Dokter", "contact search: full name, any case");
  check(top("dokter") == "Nigel Dokter", "contact search: surname only");
  check(top("12345003") == "Peter de Vries", "contact search: number fragment");
  check(store.search_contacts("zzzzqq", 3, 0.3).empty(), "contact search: nonsense matches nothing");
  store.remove_contact("31612345001@s.whatsapp.net");
  check(top("Nigel") != "Nigel Dokter", "contact search: removed contact is gone from the index");
  WaStore reopened(home, "t");
  check(reopened.search_contacts("Nina", 3, 0.3).size() >= 1, "contact search: index survives reopening the database");
  // unlink must survive the process: clear_device without a commit was rolled back at exit ("Already linked")
  {
    WaDevice d = WaDevice::generate();
    d.jid = "31612345002:5@s.whatsapp.net";
    store.save_device(d);
    check(store.has_device(), "a paired device is stored");
    store.clear_device();
    WaStore again(home, "t");
    check(!again.has_device(), "clear_device persists across reopening the database");
    check(again.search_contacts("Nina", 3, 0.3).size() >= 1, "clear_device keeps the contacts");
  }
  // send log: the floor under the rate caps
  check(store.sends_since(60) == 0, "send log starts empty");
  store.record_send("31612345002@s.whatsapp.net");
  store.record_send("31612345002@s.whatsapp.net");
  check(store.sends_since(60) == 2 && store.sends_since(86400) == 2, "send log counts sends in the window");
  std::filesystem::remove_all(home);
}

// Key-request bookkeeping (whatsmeow PR 1268): a request that never left the device must not block the
// retry for 24 h, so the mark can be cleared again.
static void test_key_request_rollback() {
  std::printf("[appstate: key request rollback]\n");
  std::string home = make_temp_home();
  WaStore store(home, "keyreq");
  Bytes id{0x01, 0x02, 0x03};
  check(!store.app_key_request_time(id).has_value(), "no request mark for a fresh key id");
  store.put_app_key_request_time(id, 1700000000);
  auto got = store.app_key_request_time(id);
  check(got && *got == 1700000000, "request mark is stored");
  store.clear_app_key_request_time(id);
  check(!store.app_key_request_time(id).has_value(), "clearing the mark frees the key id for an immediate retry");
  store.clear_app_key_request_time(id);  // clearing twice is a no-op, not an error
  check(!store.app_key_request_time(id).has_value(), "clearing an unmarked key id is harmless");
  std::filesystem::remove_all(home);
}

// Peer message helpers: own-sender classification (PN or LID, whatsmeow IsFromMe), the peer node shape
// (device-identity only on a prekey message), server_sync parsing and retry-receipt detection.
static void test_peer_helpers() {
  std::printf("[appstate: peer message helpers]\n");
  check(WaClient::is_own_sender("31630045827@s.whatsapp.net", "31630045827", "173735822786802"),
        "own PN sender is accepted");
  check(WaClient::is_own_sender("173735822786802@lid", "31630045827", "173735822786802"),
        "own LID sender is accepted (the phone answers from its LID)");
  check(WaClient::is_own_sender("31630045827:0@s.whatsapp.net", "31630045827", ""),
        "own sender with an explicit device 0 is accepted");
  check(!WaClient::is_own_sender("31611111111@s.whatsapp.net", "31630045827", "173735822786802"),
        "another user is not an own sender");
  check(!WaClient::is_own_sender("173735822786802@lid", "31630045827", ""),
        "an unknown LID is not accepted without a stored LID");

  WaNode enc("enc");
  enc.attrs["v"] = "2";
  enc.attrs["type"] = "pkmsg";
  enc.content = Bytes{1, 2, 3};
  Bytes account{9, 9, 9};
  WaNode pre = WaClient::build_peer_message_node("3EB0AA", "31630045827@s.whatsapp.net", enc, true, account);
  check(pre.tag == "message" && pre.attr("category") == "peer" && pre.attr("push_priority") == "high" &&
            pre.attr("to") == "31630045827@s.whatsapp.net" && pre.child("meta") != nullptr &&
            pre.child("enc") != nullptr && pre.child("device-identity") != nullptr,
        "peer node: meta + enc + device-identity on a prekey message");
  WaNode msg = WaClient::build_peer_message_node("3EB0AB", "31630045827@s.whatsapp.net", enc, false, account);
  check(msg.child("device-identity") == nullptr && msg.child("enc") != nullptr,
        "peer node: no device-identity on an existing-session message");

  WaNode notif("notification");
  notif.attrs["type"] = "server_sync";
  WaNode c1("collection");
  c1.attrs["name"] = "critical_unblock_low";
  WaNode c2("collection");
  c2.attrs["name"] = "regular_high";
  notif.content = WaNode::Children{c1, c2};
  auto cols = WaClient::server_sync_collections(notif);
  check(cols.size() == 2 && cols[0] == "critical_unblock_low" && cols[1] == "regular_high",
        "server_sync notification yields its collection names");

  WaNode retry("receipt");
  retry.attrs["type"] = "retry";
  WaNode read("receipt");
  read.attrs["type"] = "read";
  WaNode ack("ack");
  check(WaClient::is_retry_receipt(retry) && !WaClient::is_retry_receipt(read) && !WaClient::is_retry_receipt(ack),
        "only a retry receipt reads as one");
}

// Empty key shares (openclaw/wacli PR 443): the phone answers with keys that carry no key data. The share
// still parses, so the client can tell "answered empty" from "never answered".
static void test_empty_key_share() {
  std::printf("[appstate: empty key share]\n");
  ProtoWriter key;
  {
    ProtoWriter keyid;
    keyid.bytes(1, Bytes{0x7c, 0x57});
    key.message(1, keyid.data());
    ProtoWriter data;  // AppStateSyncKeyData without keyData: the phone has none
    data.varint(3, 1767225600);
    key.message(2, data.data());
  }
  ProtoWriter share;
  share.message(1, key.data());
  ProtoWriter pm;
  pm.varint(2, 6);  // APP_STATE_SYNC_KEY_SHARE
  pm.message(7, share.data());
  ProtoWriter m;
  m.message(12, pm.data());
  WaProtocolMessage out = parse_protocol_message(m.take());
  check(out.type == 6 && out.key_share.size() == 1 && out.key_share[0].key_data.empty(),
        "an empty key share parses with empty key data (answered, but nothing to store)");
}

// Push-name learning: every incoming message carries the sender's self-reported name in `notify`
// (whatsmeow message.go). A sender we have no name for is learned; saved, imported and aliased names win.
static void test_push_name_learning() {
  std::printf("[contacts: push-name learning]\n");
  const std::string me = "31630045827", my_lid = "173735822786802";
  auto msg = [](const std::string& from, const std::string& notify) {
    WaNode m("message");
    m.attrs["from"] = from;
    if (!notify.empty()) m.attrs["notify"] = notify;
    return m;
  };
  auto cand = [&](const WaNode& m) { return WaClient::push_name_candidate(m, me, my_lid); };
  {
    auto c = cand(msg("31611111111@s.whatsapp.net", "Nigel Dokter"));
    check(c && c->first == "31611111111@s.whatsapp.net" && c->second == "Nigel Dokter",
          "1:1 message learns the sender's push name");
  }
  {
    WaNode m = msg("179000000000001@lid", "Anne");
    m.attrs["sender_pn"] = "31622222222@s.whatsapp.net";
    auto c = cand(m);
    check(c && c->first == "31622222222@s.whatsapp.net" && c->second == "Anne",
          "a LID sender with a PN alternate is learned under the sendable PN");
  }
  {
    auto c = cand(msg("179000000000001@lid", "Anne"));
    check(c && c->first == "179000000000001@lid", "a LID sender without alternate is learned under its LID");
  }
  {
    WaNode m = msg("120363000000000@g.us", "Joop");
    m.attrs["participant"] = "31633333333@s.whatsapp.net";
    auto c = cand(m);
    check(c && c->first == "31633333333@s.whatsapp.net" && c->second == "Joop",
          "a group message learns the participant, not the group");
  }
  {
    WaNode m = msg("120363000000000@g.us", "Joop");
    m.attrs["participant"] = "179000000000002@lid";
    m.attrs["participant_pn"] = "31633333333@s.whatsapp.net";
    auto c = cand(m);
    check(c && c->first == "31633333333@s.whatsapp.net", "a group LID participant prefers its PN alternate");
  }
  check(!cand(msg("31630045827@s.whatsapp.net", "Me")), "our own messages teach nothing");
  check(!cand(msg("31611111111@s.whatsapp.net", "-")), "a '-' push name is not learned");
  check(!cand(msg("31611111111@s.whatsapp.net", "")), "a missing push name is not learned");
  check(!cand(msg("1234567890@newsletter", "Channel")), "a newsletter sender is not learned");
  {
    auto c = cand(msg("31611111111@s.whatsapp.net", std::string(300, 'x')));
    check(c && c->second.size() == 128, "an over-long push name is truncated, not refused");
  }

  std::string home = make_temp_home();
  WaStore store(home, "push");
  check(store.put_contact_if_absent("31611111111@s.whatsapp.net", "Nigel Dokter"),
        "first sighting of a sender is stored");
  check(!store.put_contact_if_absent("31611111111@s.whatsapp.net", "Nigel Changed"),
        "a second sighting does not overwrite");
  check(store.contacts().size() == 1 && store.contacts()[0].second == "Nigel Dokter",
        "the first learned name sticks");
  auto hits = store.search_contacts("Niggel", 3, 0.3);
  check(!hits.empty() && hits[0].name == "Nigel Dokter", "a learned name is searchable with typos");
  store.put_contact("31611111111@s.whatsapp.net", "Nigel Dokter (work)");  // app-state-grade name wins
  check(store.contacts()[0].second == "Nigel Dokter (work)", "a saved name overwrites a learned push name");
  check(!store.put_contact_if_absent("31611111111@s.whatsapp.net", "Nigel Again"),
        "a push name never overwrites a saved name");
  std::filesystem::remove_all(home);
}

// VCF fallback (problem.md): a .vcf exported on the phone feeds the same contact search the app-state sync feeds.
static void test_vcf_import() {
  std::printf("[contacts: vcf import]\n");
  const char* vcf =
      "BEGIN:VCARD\r\nVERSION:3.0\r\nFN:Nigel Dokter\r\nTEL;TYPE=CELL:+31 6 1234 5001\r\nEND:VCARD\r\n"
      "BEGIN:VCARD\r\nVERSION:3.0\r\nN:Smit;Nina;;;\r\nTEL:+31612345002\r\nTEL:0031612345003\r\nEND:VCARD\r\n"
      "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:Long \r\n Name\r\nTEL;TYPE=HOME:+31-6-1234-5004\r\nEND:VCARD\r\n"
      "BEGIN:VCARD\r\nVERSION:3.0\r\nFN:No Number\r\nEND:VCARD\r\n"
      "BEGIN:VCARD\r\nVERSION:3.0\r\nFN:Local Only\r\nTEL:0612345\r\nEND:VCARD\r\n";
  int skipped = 0;
  auto contacts = WaVcf::parse(vcf, skipped);
  check(contacts.size() == 4, "four usable numbers parse from five cards (one numberless, one local)");
  check(skipped == 2, "two cards skipped: no number, and a national number without country code");
  bool nigel = false, nina = false, unfolded = false;
  for (const auto& c : contacts) {
    if (c.name == "Nigel Dokter" && c.number == "31612345001") nigel = true;
    if (c.name == "Nina Smit" && (c.number == "31612345002" || c.number == "31612345003")) nina = true;
    if (c.name == "Long Name") unfolded = true;
  }
  check(nigel, "FN plus an international TEL with spaces");
  check(nina, "N fallback name plus two TELs (00 form normalized)");
  check(unfolded, "a folded FN line is unfolded");

  std::string home = make_temp_home();
  WaStore store(home, "vcf");
  WaVcf::Report rep = WaVcf::import_text(store, vcf);
  check(rep.imported == 4 && rep.skipped == 2 && rep.capped == 0, "import stores 4 numbers, skips 2, caps none");
  auto hits = store.search_contacts("Niggel", 3, 0.3);
  check(!hits.empty() && hits[0].name == "Nigel Dokter", "an imported contact is found by the typo-tolerant search");
  WaVcf::Report empty = WaVcf::import_text(store, "not a vcard at all");
  check(empty.imported == 0, "garbage imports nothing and throws nothing");
  std::filesystem::remove_all(home);
}

// M2 store: replays the op sequence of tests/whatsapp_data/store_oracle.go
// (which runs pinned whatsmeow itself) against WaStore/WaLidMap/WaJid and
// compares every observable outcome to tests/whatsapp_data/store_vectors.json.
// Signal addresses use the detz form ("user.device") where the oracle uses
// whatsmeow's ("user:device"); the vectors record outcomes, never addresses.
// JID strings are compared byte-for-byte.
static void test_store_m2() {
  std::printf("[store: M2 oracle differential]\\n");
  Value v = Value::loads(slurp(path("store_vectors.json")));
  auto kb = [&](const std::string& k) { return v.get(k).as_bool(); };
  auto ki = [&](const std::string& k) { return v.get(k).as_int(); };
  auto ks = [&](const std::string& k) { return v.get(k).str(); };
  auto key = [](uint8_t fill) { return Bytes(32, fill); };

  check(ki("muted_forever_unix") == WaConsts::kWaMutedForever, "kWaMutedForever equals whatsmeow MutedForever.Unix()");

  // JID normalization (pure WaJid checks against the oracle's types.JID).
  bool jids_ok = true;
  for (const auto& m : v.get("jid_non_ad").members()) {
    if (WaJid::parse(m.first).non_ad().str() != m.second.str()) jids_ok = false;
  }
  check(jids_ok, "ToNonAD strings match whatsmeow ParseJID+ToNonAD byte-for-byte");
  bool sig_ok = true;
  for (const auto& m : v.members()) {
    if (m.first.rfind("signal_user:", 0) == 0 && WaJid::parse(m.first.substr(12)).signal_user() != m.second.str())
      sig_ok = false;
  }
  check(sig_ok, "signal users match whatsmeow SignalAddressUser byte-for-byte");
  bool parse_ok = true;
  for (const auto& m : v.get("jid_parse_fails").members()) {
    bool threw = false;
    try {
      WaJid::parse(m.first);
    } catch (const std::invalid_argument&) {
      threw = true;
    }
    if (threw != m.second.as_bool()) parse_ok = false;
  }
  check(parse_ok, "WaJid::parse fails exactly where whatsmeow ParseJID fails");

  std::string home = make_temp_home();
  WaStore store(home, "m2");
  // Miss-safe readers: a lookup that should hit but misses yields "<miss>"
  // (a loud FAIL), never an operator* on a disengaged optional.
  auto sess_hex = [&](const std::string& a) {
    auto o = store.load_session(a);
    return o ? tohex(*o) : std::string("<miss>");
  };
  auto sec_hex = [&](const std::string& c, const std::string& s, const std::string& id) {
    auto o = store.message_secret(c, s, id);
    return o ? tohex(o->secret) : std::string("<miss>");
  };
  auto tok_hex = [&](const std::string& u) {
    auto o = store.privacy_token(u);
    return o ? tohex(o->token) : std::string("<miss>");
  };

  // Identities with trust tracking. Detz addresses use '.', upstream ':'.
  check(store.is_trusted_identity("15551234567.0", key(1)) == kb("trust_unknown"), "unknown identity is trusted (TOFU)");
  store.put_identity("15551234567.0", key(1));
  check(store.is_trusted_identity("15551234567.0", key(1)) == kb("trust_same"), "stored identity is trusted for its key");
  check(store.is_trusted_identity("15551234567.0", key(2)) == kb("trust_other"), "stored identity is not trusted for another key");
  store.put_identity("15551234567.0", key(2));
  check(!store.is_trusted_identity("15551234567.0", key(1)), "overwritten identity distrusts the old key");
  check(store.is_trusted_identity("15551234567.0", key(2)), "overwritten identity trusts the new key");
  store.put_identity("15551234567.5", key(3));
  store.delete_identity("15551234567.0");
  check(store.is_trusted_identity("15551234567.0", key(2)) == kb("trust_after_delete"), "deleted identity is unknown again");
  check(store.is_trusted_identity("15551234567.5", key(3)) == kb("trust_sibling_after_delete"),
        "deleting one device keeps the sibling");
  store.delete_all_identities("15551234567");
  check(store.is_trusted_identity("15551234567.5", key(3)) == kb("trust_sibling_after_delete_all"),
        "delete-all clears every device of the phone");
  // Upstream DeleteIdentity uses the LIKE query by accident, so deleting
  // "9%9:0" also wiped "999:0" (oracle trust_pct_sibling_after_pct_delete is
  // true, i.e. unknown). detz deletes exactly: the sibling row survives.
  check(kb("trust_pct_sibling_after_pct_delete"), "oracle records the upstream LIKE over-delete");
  store.put_identity("9%9.0", key(4));
  store.put_identity("999.0", key(5));
  store.delete_identity("9%9.0");
  check(store.is_trusted_identity("9%9.0", key(4)), "the deleted wildcard address is unknown again");
  check(store.is_trusted_identity("999.0", key(5)) && !store.is_trusted_identity("999.0", key(1)),
        "delete_identity is exact: a LIKE-special address deletes one row, not the pattern");

  // Sessions.
  check(store.has_session("15550001111.0") == kb("has_session_missing"), "no session for an unknown address");
  store.save_session("15550001111.0", Bytes{'s', 'e', 's', 's', '-', 'a', 'a', 'a'});
  store.save_session("15550001111.2", Bytes{'s', 'e', 's', 's', '-', 'b', 'b', 'b'});
  check(store.has_session("15550001111.0") == kb("has_session_present"), "a stored session is found");
  check(sess_hex("15550001111.0") == ks("get_session"), "session bytes round-trip");
  check(!store.load_session("15550009999.0").has_value() == kb("get_session_missing_null"), "missing session is empty");
  auto many = store.get_many_sessions({"15550001111.0", "15550009999.0", "15550001111.2"});
  auto many_it = many.find("15550001111.0");
  check(many_it != many.end() && many_it->second && tohex(*many_it->second) == ks("get_many_present"),
        "get-many returns the stored blob");
  check(!many["15550009999.0"].has_value() == kb("get_many_missing_null"), "get-many reports the miss as empty");
  check((many.size() == 3) == kb("get_many_all_keys"), "get-many holds every requested address");
  check(store.get_many_sessions({}).empty() == kb("get_many_empty_null"), "get-many of nothing is empty");
  store.put_many_sessions({{"15550002222.0", Bytes{'s', 'e', 's', 's', '-', 'c', 'c', 'c'}}});
  check(sess_hex("15550002222.0") == ks("get_many_put"), "put-many stores");
  store.delete_session("15550001111.2");
  check(store.has_session("15550001111.2") == kb("has_session_after_delete"), "delete removes one session");
  store.delete_all_sessions("15550001111");
  check(store.has_session("15550001111.0") == kb("has_session_after_delete_all"), "delete-all clears the phone");
  check(store.has_session("15550002222.0") == kb("has_other_after_delete_all"), "delete-all keeps other phones");

  // PN -> LID migration across sessions, identities and sender keys. Sender
  // keys have no M2 API (M4 owns them); the row is planted with raw SQL and
  // read back the same way, so the migrate arm is still proven.
  store.save_session("15550003333.0", Bytes{'s', 'e', 's', 's', '-', 'm', 'i', 'g'});
  store.put_identity("15550003333.0", key(6));
  {
    detz::store::SqlDb raw(WaStore::db_path(home, "m2"));
    raw.execute("INSERT INTO wa_sender_key (chat_id, sender_id, key) VALUES ('group@g.us', '15550003333.0', '73656e6465722d6d6967')");
    raw.commit();
  }
  auto sender_key = [&](const std::string& chat, const std::string& sender) -> std::optional<std::string> {
    detz::store::SqlDb raw(WaStore::db_path(home, "m2"));
    auto cur = raw.execute("SELECT key FROM wa_sender_key WHERE chat_id=? AND sender_id=?",
                           {detz::store::Cell(chat), detz::store::Cell(sender)});
    const auto* row = cur.first();
    std::optional<std::string> out;
    if (row != nullptr) out = (*row)[0].text();
    return out;
  };
  store.migrate_pn_to_lid("15550003333@s.whatsapp.net", "100000000000001@lid");
  check(ks("mig_lid_addr") == "100000000000001_1:0", "oracle pins the upstream agent-suffixed LID address");
  check(sess_hex("100000000000001.0") == ks("mig_session_moved"), "migrate moves the session to the plain-user LID");
  check(!store.load_session("15550003333.0").has_value() == kb("mig_session_gone"), "migrate deletes the PN session");
  check(store.is_trusted_identity("100000000000001.0", key(6)) == kb("mig_identity_moved"), "migrate moves the identity");
  check(store.is_trusted_identity("15550003333.0", key(6)) == kb("mig_identity_gone"), "migrate deletes the PN identity");
  check(sender_key("group@g.us", "100000000000001.0").value_or("") == ks("mig_sender_moved"),
        "migrate moves the sender key to the LID");
  check(!sender_key("group@g.us", "15550003333.0").has_value() == kb("mig_sender_gone"), "migrate deletes the PN sender key");
  store.migrate_pn_to_lid("15550003333@s.whatsapp.net", "100000000000001@lid");
  check(sess_hex("100000000000001.0") == ks("mig_repeat_still_moved"), "a repeated migrate is a no-op");

  // LID map.
  WaLidMap& lids = store.lid_map();
  check(!lids.lid_for_pn("15551112222@s.whatsapp.net").has_value() == kb("lid_miss_empty"), "unmapped PN misses without error");
  lids.put_mapping("100000000000002@lid", "15551112222@s.whatsapp.net");
  check(lids.lid_for_pn("15551112222@s.whatsapp.net").value_or("") == ks("lid_hit"), "mapped PN hits its LID");
  check(lids.lid_for_pn("15551112222:3@s.whatsapp.net").value_or("") == ks("lid_hit_device"),
        "the device survives the PN->LID lookup");
  check(lids.pn_for_lid("100000000000002@lid").value_or("") == ks("pn_hit"), "the reverse lookup hits the PN");
  bool lid_rej = false, pn_rej = false, swap_rej = false;
  try {
    lids.lid_for_pn("100000000000002@lid");
  } catch (const std::invalid_argument&) {
    lid_rej = true;
  }
  try {
    lids.pn_for_lid("15551112222@s.whatsapp.net");
  } catch (const std::invalid_argument&) {
    pn_rej = true;
  }
  try {
    lids.put_mapping("15551112222@s.whatsapp.net", "100000000000002@lid");
  } catch (const std::invalid_argument&) {
    swap_rej = true;
  }
  check(lid_rej == kb("lid_for_pn_rejects_lid"), "LID-for-PN rejects a LID input");
  check(pn_rej == kb("pn_for_lid_rejects_pn"), "PN-for-LID rejects a PN input");
  check(swap_rej == kb("put_mapping_rejects_swapped"), "put-mapping rejects swapped servers");
  lids.put_many_mappings({{"100000000000003@lid", "15551113333@s.whatsapp.net"},
                          {"100000000000003@lid", "15551113333@s.whatsapp.net"},
                          {"15551112222@s.whatsapp.net", "100000000000002@lid"}});
  auto ml = lids.many_lids_for_pns({"15551112222@s.whatsapp.net", "15551113333@s.whatsapp.net",
                                    "19998887777@s.whatsapp.net", "100000000000002@lid"});
  check(ml["15551112222@s.whatsapp.net"] == ks("many_lids_hit"), "batch lookup hits the cached PN");
  check(ml["15551113333@s.whatsapp.net"] == ks("many_lids_new"), "batch lookup hits the new mapping");
  check((ml.count("19998887777@s.whatsapp.net") == 0) == kb("many_lids_missing_absent"), "batch lookup omits the miss");
  check((int)ml.size() == ki("many_lids_size"), "batch lookup holds exactly the two mapped PNs");
  lids.put_mapping("100000000000004@lid", "15551112222@s.whatsapp.net");
  check(lids.lid_for_pn("15551112222@s.whatsapp.net").value_or("") == ks("lid_remapped"), "remapping moves the PN");
  check(!lids.pn_for_lid("100000000000002@lid").has_value() == kb("lid_remap_old_gone"),
        "remapping drops the stale reverse mapping");
  check(lids.alt_jid("15551112222@s.whatsapp.net").value_or("") == ks("alt_pn"), "alt-JID maps a PN to its LID");
  check(lids.alt_jid("100000000000004@lid").value_or("") == ks("alt_lid"), "alt-JID maps a LID to its PN");
  check(!lids.alt_jid("120363000000@g.us").has_value() == kb("alt_group_empty"), "alt-JID of a group is empty");
  lids.fill_cache();

  // Contacts: push, business, saved, batch and redacted names.
  auto [pc, pp] = store.put_push_name("15552223333@s.whatsapp.net", "Pushee");
  check(pc == kb("push_first_changed") && pp == ks("push_first_prev"), "first push name is stored");
  auto [pc2, pp2] = store.put_push_name("15552223333@s.whatsapp.net", "Pushee");
  (void)pp2;
  check(pc2 == kb("push_same_changed"), "an unchanged push name skips the write");
  auto [pc3, pp3] = store.put_push_name("15552223333@s.whatsapp.net", "Pushed");
  check(pc3 == kb("push_change_changed") && pp3 == ks("push_change_prev"), "a changed push name reports the previous one");
  auto [bc, bp] = store.put_business_name("15552223333@s.whatsapp.net", "Biz Co");
  (void)bp;
  check(bc == kb("biz_first_changed"), "first business name is stored");
  store.put_contact_name("15552223333@s.whatsapp.net", "First", "First Last");
  WaContactInfo ci = store.get_contact("15552223333@s.whatsapp.net");
  check(ci.found == kb("contact_found") && ci.first_name == ks("contact_first") && ci.full_name == ks("contact_full") &&
            ci.push_name == ks("contact_push") && ci.business_name == ks("contact_biz"),
        "the contact row holds saved, push and business names");
  check(store.get_contact("15550004444@s.whatsapp.net").found == kb("contact_missing_found"), "an unknown contact is not found");
  store.put_all_contact_names({{"15550005555@s.whatsapp.net", "A", "A A"},
                               {"15550005555@s.whatsapp.net", "B", "B B"},
                               {"15550006666@s.whatsapp.net", "C", "C C"}});
  check(store.get_contact("15550005555@s.whatsapp.net").first_name == ks("contact_dedup_first"),
        "batch contact names deduplicate, first rows win");
  store.put_many_redacted_phones({{"100000000000005@lid", "+1········80"}});
  check(store.get_contact("100000000000005@lid").redacted_phone == ks("contact_redacted"), "redacted phones are stored");
  auto all = store.all_contacts();
  check(all["15552223333@s.whatsapp.net"].push_name == "Pushed", "all-contacts holds the push name");
  check((all.size() >= 4) == kb("contact_all_count_ge"), "all-contacts holds every row");

  // Chat settings.
  WaChatSettings cs0 = store.chat_settings("15553334444@s.whatsapp.net");
  // Not-muted is represented differently (detz 0, whatsmeow zero time.Time)
  // but means the same on both sides; the stored row (0) is identical.
  check(cs0.found == kb("chat_missing_found") && cs0.muted_until == 0 && kb("chat_missing_muted_zero"),
        "an unknown chat has no settings");
  store.put_muted_until("15553334444@s.whatsapp.net", 1700000000);
  store.put_pinned("15553334444@s.whatsapp.net", true);
  store.put_archived("15553334444@s.whatsapp.net", true);
  WaChatSettings cs1 = store.chat_settings("15553334444@s.whatsapp.net");
  check(cs1.muted_until == ki("chat_muted") && cs1.pinned == kb("chat_pinned") && cs1.archived == kb("chat_archived") &&
            cs1.found == kb("chat_found"),
        "mute, pin and archive are stored");
  store.put_muted_until("15553334444@s.whatsapp.net", WaConsts::kWaMutedForever);
  check(store.chat_settings("15553334444@s.whatsapp.net").muted_until == WaConsts::kWaMutedForever,
        "muted-forever round-trips through the -1 row");
  check(kb("chat_forever"), "oracle confirms whatsmeow reads the -1 row back as MutedForever");
  store.put_muted_until("15553334444@s.whatsapp.net", 0);
  check(store.chat_settings("15553334444@s.whatsapp.net").muted_until == 0 && kb("chat_unmuted_zero"), "zero clears the mute");
  store.put_pinned("15553334444@s.whatsapp.net", false);
  WaChatSettings cs2 = store.chat_settings("15553334444@s.whatsapp.net");
  check(!cs2.pinned && cs2.archived, "unpinning keeps the archive flag");
  check(kb("chat_unpinned"), "oracle confirms whatsmeow keeps the archive flag too");
  store.put_wasa_root_secret_id("120363000001@g.us", "wasa-id-1");
  check(store.wasa_root_secret_id("120363000001@g.us").value_or("") == ks("wasa_hit"), "the WASA root secret id is stored");
  check(!store.wasa_root_secret_id("15553334444@s.whatsapp.net").has_value() == kb("wasa_missing_empty"),
        "a chat without a WASA id misses");

  // Message secrets, including the alternate LID/PN lookup.
  lids.put_mapping("100000000000006@lid", "15554445555@s.whatsapp.net");
  Bytes sec(32, 0x42);
  store.put_message_secret("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID1", sec);
  auto got_sec = store.message_secret("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID1");
  check(got_sec && tohex(got_sec->secret) == ks("secret_hit"), "the message secret is stored");
  check(got_sec && got_sec->sender == ks("secret_sender"), "the lookup reports the stored sender");
  store.put_message_secret("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID1", Bytes(32, 0x43));
  check(sec_hex("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID1") == ks("secret_dup_keeps_first"),
        "a duplicate secret keeps the first row");
  auto alt_sec = store.message_secret("100000000000006@lid", "100000000000006@lid", "MSGID1");
  check(alt_sec && tohex(alt_sec->secret) == ks("secret_alt_hit"), "the LID form finds the PN secret");
  check(alt_sec && alt_sec->sender == ks("secret_alt_sender"), "the alternate lookup reports the PN sender");
  check(!store.message_secret("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "NOPE").has_value() ==
            kb("secret_miss_null"),
        "an unknown secret id misses");
  store.put_message_secrets({{"15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID2", Bytes{'s', '2'}},
                             {"15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID3", Bytes{}},
                             {"", "15554445555@s.whatsapp.net", "MSGID4", Bytes{'s', '4'}}});
  check(sec_hex("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID2") == ks("secret_batch_hit"),
        "batch secrets store the valid rows");
  check(!store.message_secret("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID3").has_value() ==
            kb("secret_batch_skipped"),
        "batch secrets skip the empty rows");

  // Privacy tokens: newer wins, sender timestamps coalesce, expiry deletes.
  store.put_privacy_tokens({{"15554445555@s.whatsapp.net", Bytes{'t', 'o', 'k', '-', '1'}, 1700000000, std::nullopt}});
  auto tok = store.privacy_token("15554445555@s.whatsapp.net");
  check(tok && tohex(tok->token) == ks("token_hit") && tok->timestamp == ki("token_ts") &&
            !tok->sender_timestamp.has_value() == kb("token_sender_ts_zero"),
        "the privacy token is stored without a sender timestamp");
  store.put_privacy_tokens({{"15554445555@s.whatsapp.net", Bytes{'t', 'o', 'k', '-', 'o', 'l', 'd'}, 1600000000, std::nullopt}});
  check(tok_hex("15554445555@s.whatsapp.net") == ks("token_older_ignored"), "an older token leaves the row alone");
  store.put_privacy_tokens({{"15554445555@s.whatsapp.net", Bytes{'t', 'o', 'k', '-', '2'}, 1700000001, 1700000002}});
  tok = store.privacy_token("15554445555@s.whatsapp.net");
  check(tok && tohex(tok->token) == ks("token_newer_wins") && tok->sender_timestamp.value_or(0) == ki("token_sender_ts"),
        "a newer token wins and carries its sender timestamp");
  store.put_privacy_tokens({{"15554445555@s.whatsapp.net", Bytes{'t', 'o', 'k', '-', '3'}, 1700000003, std::nullopt}});
  auto tok3 = store.privacy_token("15554445555@s.whatsapp.net");
  check(tok3 && tok3->sender_timestamp.value_or(0) == ki("token_sender_ts_kept"),
        "an update without a sender timestamp keeps the stored one");
  auto tok_alt = store.privacy_token("100000000000006@lid");
  check(tok_alt && tohex(tok_alt->token) == ks("token_alt_hit"), "the LID form finds the PN token");
  check(tok_alt && tok_alt->user == ks("token_alt_user"), "the alternate token reports the PN user");
  store.put_privacy_tokens({{"15550007777@s.whatsapp.net", Bytes{'t', 'o', 'k', '-', 'x'}, 1500000000, std::nullopt},
                            {"15550008888@s.whatsapp.net", Bytes{'t', 'o', 'k', '-', 'y'}, 1800000000, std::nullopt}});
  check(store.delete_expired_privacy_tokens(1600000000) == ki("token_expired_deleted"), "expiry deletes one token");
  check(!store.privacy_token("15550007777@s.whatsapp.net").has_value() == kb("token_expired_gone"),
        "the expired token is gone, the fresh one survives");
  bool empty_tokens_threw = false;
  try {
    store.put_privacy_tokens({});
  } catch (const std::invalid_argument&) {
    empty_tokens_threw = true;
  }
  check(empty_tokens_threw == kb("put_tokens_empty_err"), "empty token input fails loudly on both sides");

  // Unlink integration: device-scoped rows go, contacts and the LID map stay.
  store.clear_device();
  check(!store.has_session("100000000000001.0"), "clear_device drops the sessions");
  check(store.is_trusted_identity("100000000000001.0", key(6)), "clear_device drops the identities");
  check(!store.message_secret("15554445555@s.whatsapp.net", "15554445555@s.whatsapp.net", "MSGID1").has_value(),
        "clear_device drops the message secrets");
  check(!store.privacy_token("15554445555@s.whatsapp.net").has_value(), "clear_device drops the privacy tokens");
  check(!store.chat_settings("15553334444@s.whatsapp.net").found, "clear_device drops the chat settings");
  check(store.get_contact("15552223333@s.whatsapp.net").found, "clear_device keeps the contacts");
  check(lids.lid_for_pn("15551112222@s.whatsapp.net").has_value(), "clear_device keeps the LID map");
  std::filesystem::remove_all(home);
}

// M2 hostile input: corrupt database rows, overlong keys, malformed JIDs and a
// fuzz loop over the string-taking store surface. Every case must throw a
// handled exception (never std::length_error) or succeed; surviving is proof.
static void test_store_hostile() {
  std::printf("[store: hostile input]\\n");
  std::string home = make_temp_home();
  WaStore store(home, "hostile");

  auto throws_handled = [](auto fn) {
    try {
      fn();
    } catch (const std::length_error&) {
      return false;
    } catch (const std::exception&) {
      return true;
    }
    return false;
  };
  check(throws_handled([&] { store.put_identity("1.0", Bytes(31, 1)); }), "a 31-byte identity key is rejected");
  check(throws_handled([&] { store.put_identity("1.0", Bytes(33, 1)); }), "a 33-byte identity key is rejected");
  check(throws_handled([&] { store.put_identity("1.0", Bytes()); }), "an empty identity key is rejected");
  std::string huge_addr(2000, '5');
  check(throws_handled([&] { store.save_session(huge_addr, Bytes{1}); }), "an overlong session address is rejected");
  check(throws_handled([&] { store.put_identity(huge_addr, Bytes(32, 1)); }), "an overlong identity address is rejected");
  check(throws_handled([&] { store.lid_map().lid_for_pn("a.b.c@s.whatsapp.net"); }), "a malformed PN JID is rejected");
  std::string huge_jid(2000, '1');
  huge_jid += "@s.whatsapp.net";
  check(throws_handled([&] { store.lid_map().lid_for_pn(huge_jid); }), "an overlong JID is rejected");
  check(throws_handled([&] { store.put_privacy_tokens({}); }), "empty token input throws");
  check(throws_handled([&] { store.message_secret("u:x@y", "s@s.whatsapp.net", "id"); }), "a malformed secret chat is rejected");

  // Corrupt rows planted with raw SQL: a short identity key and a session blob
  // past the cap must throw a handled error, never allocate blindly.
  store.put_identity("15550001111.0", Bytes(32, 7));
  store.save_session("15550001111.0", Bytes{9});
  {
    detz::store::SqlDb raw(WaStore::db_path(home, "hostile"));
    raw.execute("UPDATE wa_identity SET key='ab' WHERE addr='15550001111.0'");
    raw.execute("UPDATE wa_session SET blob='" + std::string(3 * 1024 * 1024, 'a') + "' WHERE addr='15550001111.0'");
    raw.commit();
  }
  check(throws_handled([&] { store.is_trusted_identity("15550001111.0", Bytes(32, 7)); }),
        "a corrupt identity length throws, never length_error");
  check(throws_handled([&] { store.load_session("15550001111.0"); }), "an oversized session blob throws before allocating");

  // Wide inputs: a 2000-address get-many and a 650-row batch (chunked 300/300/50).
  std::vector<std::string> addrs;
  for (int i = 0; i < 2000; ++i) addrs.push_back("1999000" + std::to_string(i) + ".0");
  check(store.get_many_sessions(addrs).size() == 2000, "get-many serves 2000 addresses");
  std::vector<WaContactEntry> bulk;
  for (int i = 0; i < 650; ++i)
    bulk.push_back({"1999888" + std::to_string(1000 + i) + "@s.whatsapp.net", "N" + std::to_string(i), "N" + std::to_string(i)});
  store.put_all_contact_names(bulk);
  check(store.get_contact("19998881000@s.whatsapp.net").first_name == "N0" &&
            store.get_contact("19998881649@s.whatsapp.net").first_name == "N649",
        "a 650-row batch survives chunking");

  // Fuzz: hostile strings through every string-taking entry point.
  bool ok = true;
  uint64_t st = 0x12345678;
  auto rnd = [&]() {
    st = st * 6364136223846793005ull + 1442695040888963407ull;
    return st >> 33;
  };
  const char* alpha = "@.:%_0123456789abLIDs.whatsapp.net";
  for (int i = 0; i < 3000 && ok; ++i) {
    size_t n = 1 + rnd() % 60;
    std::string s;
    for (size_t k = 0; k < n; ++k) s.push_back(alpha[rnd() % 33]);
    if (rnd() % 16 == 0) s.append(1200, '9');  // sometimes overlong
    try {
      store.lid_map().lid_for_pn(s);
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    try {
      store.lid_map().pn_for_lid(s);
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    try {
      store.lid_map().alt_jid(s);
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    try {
      store.put_contact_name(s, "f", "g");
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    try {
      store.get_contact(s);
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    try {
      store.chat_settings(s);
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    // WaJid strings round-trip: parse(str()) is str() again.
    try {
      WaJid j = WaJid::parse(s);
      if (WaJid::parse(j.str()).str() != j.str()) ok = false;
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
  }
  check(ok, "3000 hostile strings: handled or accepted, never length_error, JIDs round-trip");
  std::filesystem::remove_all(home);
}

// ---- M1: token dictionary freshness (whatsmeow token_oracle.go) ----
static void test_tokens() {
  std::printf("[tokens]\n");
  Value d = Value::loads(slurp(path("token_vectors.json")));
  check(d.get("dict_version").as_int(0) == kDictVersion, "dict version is whatsmeow DictVersion (3)");
  const Value& single = d.get("single");
  bool sok = single.is_array() && single.size() == kSingleByteTokens.size();
  for (size_t i = 0; sok && i < kSingleByteTokens.size(); ++i)
    sok = single.at(i).str() == std::string(kSingleByteTokens[i]);
  check(sok, "236 single-byte tokens match whatsmeow verbatim");
  const Value& dbl = d.get("double");
  bool dok = dbl.is_array() && dbl.size() == kDoubleByteTokens.size();
  for (size_t x = 0; dok && x < kDoubleByteTokens.size(); ++x) {
    dok = dbl.at(x).is_array() && dbl.at(x).size() == kDoubleByteTokens[x].size();
    for (size_t i = 0; dok && i < kDoubleByteTokens[x].size(); ++i)
      dok = dbl.at(x).at(i).str() == std::string(kDoubleByteTokens[x][i]);
  }
  check(dok, "4x256 double-byte tokens match whatsmeow verbatim");
  const Value& c = d.get("consts");
  bool cok = c.get("ListEmpty").as_int(-1) == WaBinary::LIST_EMPTY &&
             c.get("Dictionary0").as_int(-1) == WaBinary::DICTIONARY_0 &&
             c.get("Dictionary1").as_int(-1) == WaBinary::DICTIONARY_1 &&
             c.get("Dictionary2").as_int(-1) == WaBinary::DICTIONARY_2 &&
             c.get("Dictionary3").as_int(-1) == WaBinary::DICTIONARY_3 &&
             c.get("InteropJID").as_int(-1) == WaBinary::INTEROP_JID &&
             c.get("FBJID").as_int(-1) == WaBinary::FB_JID && c.get("ADJID").as_int(-1) == WaBinary::AD_JID &&
             c.get("List8").as_int(-1) == WaBinary::LIST_8 && c.get("List16").as_int(-1) == WaBinary::LIST_16 &&
             c.get("JIDPair").as_int(-1) == WaBinary::JID_PAIR && c.get("Hex8").as_int(-1) == WaBinary::HEX_8 &&
             c.get("Binary8").as_int(-1) == WaBinary::BINARY_8 &&
             c.get("Binary20").as_int(-1) == WaBinary::BINARY_20 &&
             c.get("Binary32").as_int(-1) == WaBinary::BINARY_32 &&
             c.get("Nibble8").as_int(-1) == WaBinary::NIBBLE_8 &&
             c.get("PackedMax").as_int(-1) == WaBinary::PACKED_MAX &&
             c.get("SingleByteMax").as_int(-1) == WaBinary::SINGLE_BYTE_MAX;
  check(cok, "wire tag consts equal token.* (18 values)");
  // Probes: bare-tag nodes are deterministic, so our encoder must match
  // whatsmeow's marshal byte-for-byte; every probe also decodes back.
  int ok = 0, n = 0;
  for (const auto& p : d.get("probes").items()) {
    ++n;
    const std::string s = p.get("string").str();
    WaNode back = WaBinary::decode(WaBinary::unpack(fromhex(p.get("wire_hex").str())));
    if (back.tag != s) continue;
    Bytes raw;
    raw.push_back(0);
    Bytes enc = WaBinary::encode(WaNode(s));
    raw.insert(raw.end(), enc.begin(), enc.end());
    if (tohex(raw) == p.get("wire_hex").str()) ++ok;
  }
  check(ok == n && n > 10, "token probe nodes encode byte-exact (" + std::to_string(ok) + "/" +
                               std::to_string(n) + ", single + all 4 dicts + literal)");
}

// ---- M1: iq request/response (whatsmeow iq_oracle.go) ----
static void test_iq() {
  std::printf("[iq]\n");
  Value d = Value::loads(slurp(path("iq_vectors.json")));
  // Decode direction: whatsmeow wrote the bytes, we read them.
  int ok = 0, n = 0;
  for (const auto& v : d.get("decode").items()) {
    ++n;
    WaNode node = WaBinary::decode(WaBinary::unpack(fromhex(v.get("wire_hex").str())));
    bool good = node.tag == v.get("tag").str();
    for (const auto& m : v.get("attrs").members()) good = good && node.attr(m.first) == m.second.str();
    good = good && node.attrs.size() == v.get("attrs").size();
    const Value& kids = v.get("children");
    for (size_t i = 0; good && i < kids.size(); ++i) good = node.child(kids.at(i).str()) != nullptr;
    WaIqError err = WaIq::parse_error(node);
    good = good && err.code() == (int)v.get("code").as_int(0) && err.text() == v.get("text").str() &&
           err.has_error_node() == v.get("has_error").as_bool();
    if (good) ++ok;
  }
  check(ok == n && n == 9, "iq nodes decode + classify like whatsmeow (" + std::to_string(ok) + "/" +
                               std::to_string(n) + ": ping, count, 404, 500, bare, result, 3 disconnects)");
  // Encode direction: deterministic nodes must match whatsmeow's marshal bytes.
  int eok = 0, en = 0;
  for (const auto& v : d.get("encode").items()) {
    ++en;
    WaNode node(v.get("tag").str());
    for (const auto& m : v.get("attrs").members()) node.attrs[m.first] = m.second.str();
    Bytes raw;
    raw.push_back(0);
    Bytes enc = WaBinary::encode(node);
    raw.insert(raw.end(), enc.begin(), enc.end());
    const std::string got = tohex(raw);
    if (v.has("wire_hex")) {
      if (got == v.get("wire_hex").str()) ++eok;
    } else {
      for (const auto& w : v.get("wire_set").items())
        if (got == w.str()) {
          ++eok;
          break;
        }
    }
  }
  check(eok == en && en == 4, "iq nodes encode within whatsmeow's bytes (" + std::to_string(eok) + "/" +
                                  std::to_string(en) + ": exact x2, order-set x2)");
  // JID-valued attrs have two valid wire forms: whatsmeow writes its typed
  // JID as JID_PAIR, we write the same string as its single-byte token; the
  // decode checks above prove both read back to "s.whatsapp.net".
  WaNode to_form("iq");
  to_form.attrs["to"] = "s.whatsapp.net";
  Bytes to_raw = WaBinary::encode(to_form);
  check(to_raw.size() == 5 && to_raw[3] == 0x11 && to_raw[4] == 0x03,
        "our server-JID attr encodes as the 1-byte token (compact valid form)");
  // WaIq::build assembles the ping exactly as whatsmeow sendIQAsyncAndGetData does.
  WaIqQuery q;
  q.ns = "w:p";
  q.type = "get";
  q.to = WaConsts::kServerJid;
  q.id = "42.7-9";
  WaNode ping = WaIq::build(q);
  check(ping.tag == "iq" && ping.attr("id") == "42.7-9" && ping.attr("xmlns") == "w:p" &&
            ping.attr("type") == "get" && ping.attr("to") == "s.whatsapp.net" &&
            !ping.has_attr("smax_id") && !ping.has_attr("target"),
        "WaIq::build shapes the keepalive ping (id/xmlns/type/to, no smax/target)");
  WaIqQuery qs = q;
  qs.smax_id = "99";
  qs.target = "31611111111@s.whatsapp.net";
  WaNode with_extra = WaIq::build(qs);
  check(with_extra.attr("smax_id") == "99" && with_extra.attr("target") == "31611111111@s.whatsapp.net",
        "WaIq::build carries smax_id + target when set");
  // Request ids mirror whatsmeow "<byte0>.<byte1>-<counter>".
  check(WaIq::generate_id("42.7-", 9) == "42.7-9", "request id is prefix + counter");
  std::string pfx = WaIq::new_prefix();
  check(pfx.size() >= 5 && pfx.back() == '-' && pfx.find('.') != std::string::npos,
        "request prefix has the <n>.<m>- shape");
  check(WaIq::new_prefix().size() >= 5, "a second prefix draws cleanly");
  // Disconnect predicates on the oracle's disconnect nodes.
  const Value& dec = d.get("decode");
  auto by_name = [&](const std::string& name) {
    for (const auto& v : dec.items())
      if (v.get("name").str() == name) return WaBinary::decode(WaBinary::unpack(fromhex(v.get("wire_hex").str())));
    return WaNode("missing");
  };
  WaNode e401 = by_name("stream_error_401"), conf = by_name("stream_error_conflict"),
         e515 = by_name("stream_error_515"), pong = by_name("iq_result_ping");
  check(WaIq::is_disconnect_node(e401) && WaIq::is_disconnect_node(conf) && WaIq::is_disconnect_node(e515) &&
            !WaIq::is_disconnect_node(pong),
        "disconnect nodes recognized (stream:error yes, iq result no)");
  check(WaIq::is_auth_error_disconnect(e401) && WaIq::is_auth_error_disconnect(conf) &&
            !WaIq::is_auth_error_disconnect(e515) && !WaIq::is_auth_error_disconnect(pong),
        "auth disconnects (401, replaced) separated from the 515 restart");
  WaNode xml_end("xmlstreamend");
  check(WaIq::is_disconnect_node(xml_end) && !WaIq::is_auth_error_disconnect(xml_end),
        "xmlstreamend disconnects without being an auth error");
  // Error taxonomy mirrors whatsmeow errors.go.
  WaIqError e404 = WaIq::parse_error(by_name("iq_error_404"));
  check(e404.is(WaIqError::not_found()) && !e404.is(WaIqError::internal_server_error()),
        "parsed 404 is ErrIQNotFound, not ErrIQInternalServerError");
  check(WaIqError::timed_out().message() == "info query timed out", "timeout message matches ErrIQTimedOut");
  check(WaIqError::not_found().message() == "info query returned status 404: item-not-found",
        "status message matches IQError.Error");
  check(WaDisconnectedError::for_iq().message() == "websocket disconnected before info query returned response",
        "disconnect message matches DisconnectedError.Error");
  check(WaDisconnectedError::for_iq().is(WaDisconnectedError("info query")) &&
            !WaDisconnectedError::for_iq().is(WaDisconnectedError("message send")),
        "disconnect equivalence is by action");
  WaIqError bare = WaIq::parse_error(by_name("iq_error_bare"));
  check(bare.code() == 0 && !bare.has_error_node(), "a result without <error> parses to code 0");
  // Hostile shapes: never throw, never overflow, code reads 0.
  WaNode evil("iq");
  evil.content = WaNode::Children{WaNode("error")};
  WaNode* child = const_cast<WaNode*>(evil.child("error"));
  child->attrs["code"] = "not-a-number";
  check(WaIq::parse_error(evil).code() == 0, "a non-numeric error code reads 0");
  child->attrs["code"] = "99999999999999999999999";
  check(WaIq::parse_error(evil).code() == 0, "an overflowing error code reads 0, no UB");
  child->attrs.erase("code");
  child->attrs["text"] = std::string(70000, 'x');
  check(WaIq::parse_error(evil).code() == 0, "a missing code with a huge text reads 0");
  // Socket guards fail loudly without any network.
  bool threw = false;
  try {
    WaSocket s;
    s.send_frame(Bytes{1, 2, 3});
  } catch (const WaSocketError&) {
    threw = true;
  }
  check(threw, "sending on an unconnected socket throws WaSocketError");
  WaSocketStatusError with_status("connect: refused", 403);
  check(with_status.status() == 403 && std::string(with_status.what()).find("403") != std::string::npos,
        "the status-carrying socket error keeps its code (ErrWithStatusCode role)");
}

// ---- M1: keepalive schedule (deterministic clock) ----
static void test_keepalive() {
  std::printf("[keepalive]\n");
  check(WaConsts::kWaKeepAliveResponseDeadline == 10 && WaConsts::kWaKeepAliveIntervalMin == 20 &&
            WaConsts::kWaKeepAliveIntervalMax == 30 && WaConsts::kWaKeepAliveMaxFailTime == 180,
        "keepalive caps equal whatsmeow (10s deadline, 20-30s jitter, 3min horizon)");
  WaKeepAlive ka([]() { return 25000; });
  ka.start(100000);
  check(!ka.due(100000) && !ka.due(124999) && ka.due(125000), "first ping due after the interval");
  check(ka.error_count() == 0, "no errors at start");
  ka.record_pong(125000);
  check(ka.error_count() == 0 && ka.last_success_ms() == 125000 && !ka.due(149999) && ka.due(150000),
        "a pong clears errors and advances the schedule");
  check(!ka.record_timeout(150000) && ka.error_count() == 1, "one unanswered ping counts, no reconnect yet");
  check(!ka.record_timeout(175000) && ka.error_count() == 2, "errors accumulate across pings");
  ka.record_pong(200000);
  check(ka.error_count() == 0 && ka.last_success_ms() == 200000, "a later pong recovers the streak");
  // Failures spanning more than 3 minutes force a reconnect (whatsmeow KeepAliveMaxFailTime).
  WaKeepAlive dying([]() { return 25000; });
  dying.start(0);
  bool forced = false;
  for (int64_t t = 25000; t <= 400000 && !forced; t += 25000) forced = dying.record_timeout(t);
  check(forced && dying.error_count() == 8, "8 unanswered pings (200s of failure) force a reconnect");
  WaKeepAlive edge([]() { return 25000; });
  edge.start(0);
  bool early = true;
  for (int i = 0; i < 7; ++i) early = early && !edge.record_timeout(25000 + i * 25000);
  check(early && edge.record_timeout(200000), "the horizon trips past 180s, not before");
  // The default jitter always stays inside 20-30s.
  bool in_range = true;
  for (int i = 0; i < 200; ++i) {
    WaKeepAlive probe;
    probe.start(0);
    int64_t wait = probe.next_due_ms();
    in_range = in_range && wait >= 20000 && wait <= 30000;
  }
  check(in_range, "default jitter stays inside 20-30s over 200 draws");
  check(WaConsts::kWaIqDefaultTimeout == 75, "default iq wait is whatsmeow defaultRequestTimeout (75s)");
}

// ---- M1: Noise parity + server certificate (whatsmeow cert_oracle.go) ----
static void test_server_cert() {
  std::printf("[server-cert]\n");
  Value d = Value::loads(slurp(path("cert_vectors.json")));
  Value n = Value::loads(slurp(path("noise.json")));
  // Re-run the handshake over the wa-go trace: our decrypted bytes must equal
  // whatsmeow's own NoiseHandshake output from the oracle.
  auto ephPriv = a32(fromhex(n.get("ephemeralKeyPriv").str()));
  auto ephPub = a32(fromhex(n.get("ephemeralKeyPub").str()));
  auto stPriv = a32(fromhex(n.get("authStaticKeyPriv").str()));
  auto stPub = a32(fromhex(n.get("authStaticKeyPub").str()));
  Bytes shFrame = fromhex(n.get("serverHelloFrameHex").str());
  size_t pos = 0;
  auto sh = WaFraming::unframe(shFrame, pos);
  WaNoise noise(ephPub);
  auto res = noise.client_handshake(ephPriv, ephPub, stPriv, stPub, *sh, Bytes{1, 2, 3, 4});
  check(res.has_value(), "handshake completes (mix_shared_secret refactor)");
  check(res && tohex(res->server_static) == d.get("server_static_hex").str(),
        "server static equals whatsmeow NoiseHandshake output");
  check(res && tohex(res->server_payload) == d.get("server_payload_hex").str(),
        "server payload equals whatsmeow NoiseHandshake output (241 bytes)");
  // Details fields match whatsmeow's waCert parse field by field.
  auto chain = parse_cert_chain(fromhex(d.get("server_payload_hex").str()));
  auto im = parse_cert_details(chain->intermediate_details);
  auto leaf = parse_cert_details(chain->leaf_details);
  const Value& oi = d.get("intermediate");
  const Value& ol = d.get("leaf");
  check(im && im->serial == (uint32_t)oi.get("serial").as_int(0) &&
            im->issuer_serial == (uint32_t)oi.get("issuer_serial").as_int(0) &&
            tohex(im->key) == oi.get("key_hex").str() &&
            im->not_before == (uint64_t)oi.get("not_before").as_int(0) &&
            im->not_after == (uint64_t)oi.get("not_after").as_int(0),
        "intermediate details match whatsmeow (serial 3, issuer 0, key, window)");
  check(leaf && leaf->serial == (uint32_t)ol.get("serial").as_int(0) &&
            leaf->issuer_serial == (uint32_t)ol.get("issuer_serial").as_int(0) &&
            tohex(leaf->key) == ol.get("key_hex").str() &&
            leaf->not_before == (uint64_t)ol.get("not_before").as_int(0) &&
            leaf->not_after == (uint64_t)ol.get("not_after").as_int(0),
        "leaf details match whatsmeow (serial 354, issuer 3, key, window)");
  Bytes pubkey(WaConsts::kWaCertPubKey.begin(), WaConsts::kWaCertPubKey.end());
  check(tohex(pubkey) == d.get("wacert_pubkey_hex").str(), "pinned key equals whatsmeow WACertPubKey");
  check(WaConsts::kWaCertIssuerSerial == 0, "pinned issuer serial equals whatsmeow WACertIssuerSerial");
  // The captured leaf is expired today, so travel inside its window: every
  // check must pass there (the oracle confirms the signatures are genuine).
  Bytes payload = fromhex(d.get("server_payload_hex").str());
  Bytes server_static = fromhex(d.get("server_static_hex").str());
  int64_t mid = (int64_t)(((uint64_t)ol.get("not_before").as_int(0) + (uint64_t)ol.get("not_after").as_int(0)) / 2);
  bool accepted = false;
  try {
    WaServerCert::verify(payload, server_static, mid);
    accepted = true;
  } catch (const std::exception&) {
  }
  check(accepted, "a genuine chain verifies inside its validity window");
  bool expired = false;
  try {
    WaServerCert::verify(payload, server_static);
  } catch (const WaCertError& e) {
    expired = std::string(e.what()).find("expired") != std::string::npos;
  }
  check(expired, "the same chain is refused as expired today");
  // Tamper with every verified property: each must fail closed with a reason.
  auto tampers = [&](const std::string& name, const Bytes& bad_payload, const Bytes& bad_static) {
    bool threw = false;
    try {
      WaServerCert::verify(bad_payload, bad_static, mid);
    } catch (const WaCertError&) {
      threw = true;
    } catch (const std::length_error&) {
      threw = false;
    }
    check(threw, "tampered chain refused: " + name);
  };
  Bytes bad_sig = payload;
  bad_sig[bad_sig.size() - 1] ^= 0x01;
  tampers("flipped signature byte", bad_sig, server_static);
  Bytes bad_static = server_static;
  bad_static[0] ^= 0x01;
  tampers("wrong server static", payload, bad_static);
  tampers("truncated chain", Bytes(payload.begin(), payload.begin() + payload.size() / 2), server_static);
  tampers("empty chain", Bytes{}, server_static);
  tampers("empty static", payload, Bytes{});
  tampers("garbage chain", Bytes(241, 0xab), server_static);
  // Hostile protobuf inside the chain: oversized lengths and overlong varints
  // must throw a handled error, never length_error, never UB.
  bool hostile_ok = true;
  for (const Bytes& evil : {Bytes{0x0a, 0xff, 0xff, 0xff, 0xff, 0x0f}, Bytes{0x12, 0x80, 0x80, 0x80, 0x80,
                                                                                0x80, 0x80, 0x80, 0x80, 0x80, 0x7f},
                            Bytes{0x0a}, Bytes{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f}}) {
    try {
      WaServerCert::verify(evil, server_static, mid);
    } catch (const std::length_error&) {
      hostile_ok = false;
    } catch (const std::exception&) {
    }
  }
  check(hostile_ok, "hostile chain bytes rejected without length_error");
  // A swapped leaf/intermediate must not verify (regression: the fields were swapped).
  WaCertChainParsed swapped;
  swapped.leaf_details = chain->intermediate_details;
  swapped.leaf_signature = chain->intermediate_signature;
  swapped.intermediate_details = chain->leaf_details;
  swapped.intermediate_signature = chain->leaf_signature;
  // Re-encode the swap through the writer to feed verify() bytes.
  ProtoWriter wl, wi, wc;
  wl.message(1, swapped.leaf_details);
  wl.bytes(2, swapped.leaf_signature);
  wi.message(1, swapped.intermediate_details);
  wi.bytes(2, swapped.intermediate_signature);
  wc.message(1, wl.take());
  wc.message(2, wi.take());
  bool swap_threw = false;
  try {
    WaServerCert::verify(wc.take(), server_static, mid);
  } catch (const WaCertError&) {
    swap_threw = true;
  }
  check(swap_threw, "a leaf/intermediate swap is refused");
}

// ---- pairing oracle differentials (M3): every byte against pairing_vectors.json ----
static void test_pairing_oracle() {
  std::printf("[pairing: Go oracle differentials]\n");
  Value v = Value::loads(slurp(path("pairing_vectors.json")));

  for (int n : {1, 2, 3, 4, 5, 6, 10}) {
    std::string key = "b32_" + std::to_string(n);
    check(WaPairing::linking_base32_encode(fromhex(v.get(key + "_hex").str())) == v.get(key).str(),
          "linking base32 of " + std::to_string(n) + " bytes matches Go (pad included)");
  }
  std::string hello_code = v.get("hello_code").str();
  check(WaPairing::format_linking_code(hello_code) == hello_code.substr(0, 4) + "-" + hello_code.substr(4),
        "linking code formats XXXX-XXXX");

  check(WaPairing::normalize_phone("+31 (6) 12-34-56-78") == "31612345678", "phone strips to digits");
  try {
    WaPairing::normalize_phone("12345");
    check(false, "short phone throws");
  } catch (const std::exception& e) {
    check(std::string(e.what()).find("phone number too short") != std::string::npos, "short phone says too short");
  }
  try {
    WaPairing::normalize_phone("06123456789");
    check(false, "leading-zero phone throws");
  } catch (const std::exception& e) {
    check(std::string(e.what()).find("must not start with 0") != std::string::npos,
          "leading-zero phone demands international");
  }

  const std::pair<WaPairClientType, char> chars[] = {
      {WaPairClientType::kUnknown, '0'},           {WaPairClientType::kChrome, '1'},
      {WaPairClientType::kEdge, '2'},              {WaPairClientType::kFirefox, '3'},
      {WaPairClientType::kIE, '4'},                {WaPairClientType::kOpera, '5'},
      {WaPairClientType::kSafari, '6'},            {WaPairClientType::kElectron, '7'},
      {WaPairClientType::kUwp, '8'},               {WaPairClientType::kOtherWebClient, '9'},
      {WaPairClientType::kMacOs, 'c'},             {WaPairClientType::kAndroid, 'e'},
  };
  bool chars_ok = true;
  for (const auto& [t, c] : chars) chars_ok = chars_ok && wa_pair_client_char(t) == c;
  check(chars_ok, "12 client-type wire characters match pair-code.go");
  check(wa_default_qr_client_type(1, 0) == WaPairClientType::kChrome, "default client: device CHROME");
  check(wa_default_qr_client_type(2, 0) == WaPairClientType::kFirefox, "default client: device FIREFOX");
  check(wa_default_qr_client_type(6, 0) == WaPairClientType::kEdge, "default client: device EDGE");
  check(wa_default_qr_client_type(16, 0) == WaPairClientType::kAndroid, "default client: device ANDROID_PHONE");
  check(wa_default_qr_client_type(0, 14) == WaPairClientType::kOtherWebClient, "default client: WEB agent");
  check(wa_default_qr_client_type(0, 24) == WaPairClientType::kMacOs, "default client: MACOS agent");
  check(wa_default_qr_client_type(0, 0) == WaPairClientType::kUnknown, "default client: unknown stays unknown");

  Bytes noise_pub = fromhex(v.get("qr_noise_hex").str());
  Bytes ident_pub = fromhex(v.get("qr_ident_hex").str());
  Bytes adv = fromhex(v.get("qr_adv_hex").str());
  check(WaPairing::make_qr_data(fromhex(v.get("qr_ref_hex").str()), noise_pub, ident_pub, adv, '1') ==
            v.get("qr").str(),
        "QR string matches makeQRData byte for byte");

  check(WaPairing::linking_base32_encode(fromhex(v.get("hello_code_raw_hex").str())) == hello_code,
        "hello linking code matches Go");
  check(tohex(WaPairing::wrap_companion_ephemeral(fromhex(v.get("hello_salt_hex").str()),
                                                 fromhex(v.get("hello_iv_hex").str()), hello_code,
                                                 fromhex(v.get("hello_eph_pub_hex").str()))) ==
            v.get("hello_ephemeral_hex").str(),
        "hello ephemeral wrap (PBKDF2+CTR) matches Go (80 bytes)");

  WaPairing::CodePairingResult fin = WaPairing::finish_code_pairing(
      v.get("finish_code").str(), fromhex(v.get("finish_wrapped_primary_hex").str()),
      fromhex(v.get("finish_primary_ident_pub_hex").str()), a32(fromhex(v.get("finish_own_eph_priv_hex").str())),
      a32(fromhex(v.get("finish_own_ident_priv_hex").str())), fromhex(v.get("finish_adv_random_hex").str()),
      fromhex(v.get("finish_bundle_salt_hex").str()), fromhex(v.get("finish_bundle_nonce_hex").str()));
  check(tohex(fin.wrapped_key_bundle) == v.get("finish_wrapped_bundle_hex").str(),
        "code-pairing key bundle matches Go");
  check(tohex(fin.adv_secret) == v.get("finish_adv_secret_hex").str(), "code-pairing ADV secret matches Go");

  std::string ref = v.get("pass_ref").str();
  WaPasskey::Prologue pro = WaPasskey::build_prologue(fromhex(v.get("pass_eph_pub_hex").str()), 0, ref,
                                                      fromhex(v.get("pass_companion_nonce_hex").str()));
  check(tohex(pro.ident) == v.get("proto_ident_hex").str(), "CompanionEphemeralIdentity bytes match Go");
  check(tohex(pro.commitment) == v.get("proto_commitment_hex").str(), "prologue commitment matches Go");
  check(tohex(pro.prologue) == v.get("proto_prologue_hex").str(), "ProloguePayload bytes match Go");
  check(tohex(WaPasskey::derive_handoff_key(adv)) == v.get("pass_handoff_hex").str(), "handoff key matches Go");
  check(tohex(WaPasskey::derive_encryption_key(fromhex(v.get("pass_shared_hex").str()), 0, ref)) ==
            v.get("pass_enc_key_hex").str(),
        "passkey encryption key matches Go");
  check(WaPasskey::derive_confirmation_code(fromhex(v.get("pass_primary_nonce_hex").str()),
                                            fromhex(v.get("pass_companion_nonce_hex").str()),
                                            fromhex(v.get("pass_primary_pub_hex").str())) ==
            v.get("pass_confirm_code").str(),
        "passkey confirmation code matches Go");
  check(tohex(WaPasskey::seal_pairing_request(fromhex(v.get("pass_enc_key_hex").str()),
                                              fromhex(v.get("pass_req_iv_hex").str()), noise_pub, ident_pub, adv)) ==
            v.get("proto_encrypted_req_hex").str(),
        "sealed PairingRequest matches Go");

  WaPairingRequest req;
  req.companion_public_key = noise_pub;
  req.companion_identity_key = ident_pub;
  req.adv_secret = adv;
  check(tohex(req.encode()) == v.get("proto_pairing_request_hex").str(), "PairingRequest bytes match Go");
  WaCompanionCommitment cc;
  cc.hash = fromhex(v.get("proto_commitment_hex").str());
  check(tohex(cc.encode()) == v.get("proto_commitment_msg_hex").str(), "CompanionCommitment bytes match Go");
  WaPrimaryEphemeralIdentity prim = parse_primary_ephemeral_identity(fromhex(v.get("proto_primary_ident_hex").str()));
  check(tohex(prim.public_key) == v.get("pass_primary_pub_hex").str(), "PrimaryEphemeralIdentity pub parses");
  check(tohex(prim.nonce) == v.get("pass_primary_nonce_hex").str(), "PrimaryEphemeralIdentity nonce parses");
  WaClientPairingProps props = parse_client_pairing_props(fromhex(v.get("proto_props_hex").str()));
  check(props.has_chat_db_lid_migrated && props.chat_db_lid_migrated, "props: lid-migrated true present");
  check(props.has_syncd_pure_lid_session && !props.syncd_pure_lid_session, "props: pure-lid false present");
  check(props.has_snapshot_recovery && props.snapshot_recovery, "props: snapshot-recovery true present");
  check(!props.has_hs_thumbnail_sync, "props: thumbnail-sync absent stays absent");
  check(tohex(props.subscription_sync_payload) == "09080706", "props: subscription payload parses");

  // WebAuthn: Go's exact JSON out of our marshaler, Go's exact bytes out of our parser.
  Value resp_json = Value::loads(v.get("webauthn_resp_json").str());
  Value resp_data = resp_json.get("response");
  WaWebAuthnResponse resp;
  resp.id = resp_json.get("id").str();
  resp.raw_id = WaPasskey::base64url_decode(resp_json.get("rawId").str());
  resp.type = resp_json.get("type").str();
  resp.client_data_json = WaPasskey::base64url_decode(resp_data.get("clientDataJSON").str());
  resp.authenticator_data = WaPasskey::base64url_decode(resp_data.get("authenticatorData").str());
  resp.signature = WaPasskey::base64url_decode(resp_data.get("signature").str());
  check(WaPasskey::marshal_response(resp) == v.get("webauthn_resp_json").str(),
        "WebAuthnResponse marshal matches Go byte for byte (null userHandle)");
  resp.user_handle = WaPasskey::base64url_decode(
      Value::loads(v.get("webauthn_resp_uh_json").str()).get("response").get("userHandle").str());
  check(WaPasskey::marshal_response(resp) == v.get("webauthn_resp_uh_json").str(),
        "WebAuthnResponse marshal matches Go with userHandle");
  WaWebAuthnResponse nasty{"a\"b\\c<d>e&f", "public-key", {1}, {2}, {3}, {4}, std::nullopt};
  check(WaPasskey::marshal_response(nasty) == v.get("webauthn_resp_nasty_json").str(),
        "WebAuthnResponse escapes like Go's encoding/json");
  std::string pub_json = v.get("webauthn_pub_json").str();
  WaWebAuthnPublicKey pub = WaPasskey::parse_public_key(Bytes(pub_json.begin(), pub_json.end()));
  check(tohex(pub.challenge) == v.get("webauthn_ch_hex").str(), "WebAuthnPublicKey challenge bytes match Go");
  check(pub.timeout == 60000 && pub.rp_id == "whatsapp.com", "WebAuthnPublicKey timeout/rpId parse");
  check(pub.allow.size() == 1 && pub.allow[0].type == "public-key", "WebAuthnPublicKey allowCredentials parse");
  check(WaPasskey::base64url_encode(pub.allow[0].id) ==
            Value::loads(pub_json).get("allowCredentials").at(0).get("id").str(),
        "WebAuthnPublicKey credential id round-trips through base64url");
  check(pub.allow[0].transports.size() == 2 && pub.user_verification == "preferred",
        "WebAuthnPublicKey transports/userVerification parse");
  check(!pub.extensions_json.empty(), "WebAuthnPublicKey extensions carried opaquely");
}

// ---- pairing node shapes and error texts (M3): structural, against pair*.go ----
static WaNode bytes_child(const std::string& tag, const Bytes& b) {
  WaNode n(tag);
  n.content = b;
  return n;
}

static void test_pairing_nodes() {
  std::printf("[pairing: node shapes and errors]\n");
  Bytes eph80(80, 7), noise32(32, 1), ident32(32, 2);
  WaNode hello = WaPairing::build_hello_iq("1.1", "31612345678@s.whatsapp.net", true, eph80, noise32, '1', "Chrome (Linux)");
  check(hello.tag == "iq" && hello.attr("xmlns") == "md" && hello.attr("type") == "set", "hello iq envelope");
  const WaNode* reg = hello.child("link_code_companion_reg");
  check(reg != nullptr && reg->attr("stage") == "companion_hello", "hello stage + tag");
  check(reg->attr("should_show_push_notification") == "true", "hello push flag renders true");
  check(reg->child("link_code_pairing_wrapped_companion_ephemeral_pub") != nullptr, "hello carries wrapped key");
  check(reg->child("companion_server_auth_key_pub")->bytes()->size() == 32, "hello carries noise pub");
  check(reg->child("companion_platform_id")->text() == "1", "hello carries client type");
  check(reg->child("link_code_pairing_nonce")->bytes()->size() == 1, "hello carries the zero nonce");

  WaNode reply("iq");
  reply.content = WaNode::Children{bytes_child("link_code_companion_reg", {})};
  WaNode::Children reg_kids{bytes_child("link_code_pairing_ref", Bytes{'r', 'e', 'f'})};
  const_cast<WaNode*>(reply.child("link_code_companion_reg"))->content = reg_kids;
  check(WaPairing::parse_pairing_ref(reply) == "ref", "pairing ref parses");
  try {
    WaPairing::parse_pairing_ref(WaNode("iq"));
    check(false, "missing reg throws");
  } catch (const WaElementMissingError& e) {
    check(std::string(e.what()) ==
              "missing <link_code_companion_reg> element in code link registration response",
          "ElementMissingError text matches Go");
  }

  WaNode fin = WaPairing::build_finish_iq("2.2", "316@s.whatsapp.net", Bytes(100, 9), ident32, "ref");
  check(fin.child("link_code_companion_reg")->attr("stage") == "companion_finish", "finish stage");
  check(fin.child("link_code_companion_reg")->child("companion_identity_public")->bytes()->size() == 32,
        "finish carries identity");

  WaNode note("notification");
  WaNode::Children note_kids{bytes_child("link_code_pairing_ref", Bytes{'r'}),
                             bytes_child("link_code_pairing_wrapped_primary_ephemeral_pub", Bytes(80, 3)),
                             bytes_child("primary_identity_pub", Bytes(32, 4))};
  WaNode reg_node("link_code_companion_reg");
  reg_node.content = note_kids;
  note.content = WaNode::Children{reg_node};
  WaPairing::CodeNotification cn = WaPairing::parse_code_notification(note);
  check(cn.pairing_ref == "r" && cn.wrapped_primary.size() == 80 && cn.primary_identity_pub.size() == 32,
        "code notification parses");
  try {
    WaPairing::parse_code_notification(WaNode("notification"));
    check(false, "bare notification throws");
  } catch (const WaElementMissingError&) {
    check(true, "bare notification throws ElementMissingError");
  }

  WaNode perr = WaPairing::build_pair_error("9.9", 401, "hmac-mismatch");
  check(perr.attr("type") == "error" && perr.child("error")->attr("code") == "401", "pair-error node shape");
  check(perr.child("error")->attr("text") == "hmac-mismatch", "pair-error text");
  WaNode lout = WaPairing::build_logout_iq("3.3", "316:7@s.whatsapp.net");
  const WaNode* rcd = lout.child("remove-companion-device");
  check(lout.attr("xmlns") == "md" && rcd != nullptr && rcd->attr("reason") == "user_initiated",
        "logout iq shape (Client.Logout)");

  check(WaPasskey::build_ref_iq("4.4").child("ref") != nullptr, "companion ref iq");
  check(WaPasskey::build_options_iq("5.5").child("passkey_request_options") != nullptr, "passkey options iq");
  WaNode ref_reply("iq");
  ref_reply.content = WaNode::Children{bytes_child("ref", Bytes{'a', 'b'})};
  check(WaPasskey::parse_ref(ref_reply) == "ab", "companion ref parses");
  WaNode pro = WaPasskey::build_prologue_iq("6.6", Bytes{1}, "{\"a\":1}", Bytes{2}, Bytes(32, 5));
  const WaNode* pp = pro.child("passkey_prologue");
  check(pp != nullptr && pp->children()->size() == 4, "prologue iq carries the handoff proof");
  WaNode pro2 = WaPasskey::build_prologue_iq("6.6", Bytes{1}, "{\"a\":1}", Bytes{2}, Bytes{});
  check(pro2.child("passkey_prologue")->children()->size() == 3, "prologue iq omits a missing proof");
  check(WaPasskey::build_nonce_iq("7.7", Bytes(32, 6)).child("companion_nonce")->bytes()->size() == 32,
        "companion nonce iq");
  check(WaPasskey::build_encrypted_request_iq("8.8", Bytes{9}).child("encrypted_pairing_request") != nullptr,
        "encrypted pairing request iq");

  check(wa_pair_err_message(WaPairErr::kInvalidDeviceIdentityHmac) ==
            "invalid device identity HMAC in pair success message",
        "pair HMAC error text matches Go");
  check(wa_pair_err_message(WaPairErr::kRejectedLocally) == "local PrePairCallback rejected pairing",
        "pair reject error text matches Go");
  WaPairProtoError pe("failed to parse x", "boom");
  check(std::string(pe.what()) == "failed to parse x: boom" && pe.unwrap() == "boom", "PairProtoError Error+Unwrap");
  WaPairDatabaseError de("failed to save x", "db gone");
  check(std::string(de.what()) == "failed to save x: db gone" && de.unwrap() == "db gone",
        "PairDatabaseError Error+Unwrap");

  WaPasskeyHandoffKey hk(Bytes(32, 1), 1000);
  check(hk.valid(1000) && hk.valid(1299) && !hk.valid(1300), "handoff key lives 5 minutes");
  check(!hk.valid(999), "handoff key rejects a backwards clock");
  check(!WaPasskeyHandoffKey(Bytes{}, 1000).valid(1000), "empty handoff key never valid");
}

// ---- QR channel behavior (M3): fake clock, no threads ----
static void test_qr_channel() {
  std::printf("[pairing: QR channel]\n");
  std::vector<WaQrChannel::Item> got;
  WaQrChannel ch([&](const WaQrChannel::Item& i) { got.push_back(i); });
  ch.poll(1000);
  check(got.empty(), "silent before the first QR event");
  ch.feed_qr({"c1", "c2", "c3", "c4", "c5", "c6"});
  ch.poll(1000);
  check(got.size() == 1 && got[0].code == "c1" && got[0].timeout_seconds == 60, "first of six lives 60s");
  ch.poll(1059);
  check(got.size() == 1, "no early re-emit");
  ch.rotate_adv("c1", "c1x");
  ch.poll(1059);
  check(got.size() == 2 && got[1].code == "c1x" && got[1].timeout_seconds == 60,
        "ADV rotation re-emits the rewritten code at once (fresh 60s on a full batch)");
  ch.poll(1118);
  check(got.size() == 2, "rotated code lives its fresh timeout");
  ch.poll(1119);
  check(got.size() == 3 && got[2].code == "c2" && got[2].timeout_seconds == 20, "second code follows after 20s");
  check(!ch.closed(), "open while codes remain");
  ch.feed_pair_success();
  check(ch.closed() && got.back().event == "success", "pair success closes with success");
  ch.feed_qr({"late"});
  ch.poll(9999);
  check(got.back().event == "success", "feeds after close are dropped");

  std::vector<WaQrChannel::Item> got2;
  WaQrChannel ch2([&](const WaQrChannel::Item& i) { got2.push_back(i); });
  ch2.feed_qr({"only"});
  ch2.poll(0);
  check(got2.size() == 1 && got2[0].timeout_seconds == 20, "a lone code lives 20s");
  ch2.poll(20);
  check(ch2.closed() && got2.back().event == "timeout", "exhaustion closes with timeout");

  std::vector<WaQrChannel::Item> got3;
  WaQrChannel ch3([&](const WaQrChannel::Item& i) { got3.push_back(i); });
  ch3.feed_scanned_without_multidevice();
  check(!ch3.closed() && got3.back().event == "err-scanned-without-multidevice", "multidevice hint is not terminal");
  ch3.feed_client_outdated();
  check(ch3.closed() && got3.back().event == "err-client-outdated", "outdated closes the channel");

  std::vector<WaQrChannel::Item> got4;
  bool confirmed = false;
  WaQrChannel ch4([&](const WaQrChannel::Item& i) { got4.push_back(i); });
  ch4.set_auto_confirm([&]() { confirmed = true; });
  WaPairPasskeyConfirmation skip{"AAAA-AAAA", true};
  ch4.feed_passkey_confirmation(skip);
  check(confirmed && got4.empty(), "skip-handoff confirmation auto-confirms without an item");
  WaPairPasskeyConfirmation show{"BBBB-BBBB", false};
  ch4.feed_passkey_confirmation(show);
  check(!ch4.closed() && got4.size() == 1 && got4[0].event == WaQrChannel::kEventPasskeyResponse &&
            got4[0].passkey_confirmation->code == "BBBB-BBBB",
        "shown confirmation emits for the user");
  ch4.feed_disconnected();
  check(ch4.closed() && got4.back().event == "timeout", "disconnect mid-pairing is the timeout item");
  check(WaQrChannel::err_unexpected_event().event == "err-unexpected-state", "unexpected-event item text");
}

// ---- pairing hostile input (M3): every new parser, same bar as test_hostile ----
static void test_pairing_hostile() {
  std::printf("[pairing: hostile input]\n");
  bool ok = true;
  auto hostile = [&](auto&& f) {
    try {
      f();
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
  };

  // pairing protos: oversized lengths, truncations, wrong field sizes.
  hostile([]() { parse_client_pairing_props(Bytes{0x2a, 0xff, 0xff, 0xff, 0xff, 0x0f}); });
  hostile([]() { parse_client_pairing_props(Bytes{0x0a}); });
  hostile([]() { parse_client_pairing_props(Bytes{}); });
  hostile([]() { parse_primary_ephemeral_identity(Bytes{}); });
  hostile([]() { parse_primary_ephemeral_identity(Bytes{0x0a, 0x20}); });
  hostile([]() {
    Bytes bad{0x0a, 0x1f};
    bad.insert(bad.end(), 31, 0x01);
    bad.push_back(0x12);
    bad.push_back(0x20);
    bad.insert(bad.end(), 32, 0x02);
    parse_primary_ephemeral_identity(bad);  // 31-byte pub must throw, not slice
  });
  hostile([]() { parse_companion_commitment(Bytes{0x0a, 0xff, 0xff, 0xff, 0xff, 0x0f}); });
  check(ok, "pairing protos reject hostile bytes without length_error");

  // passkey JSON: truncation, over-cap blobs, bad base64url, wrong types.
  ok = true;
  hostile([]() { WaPasskey::parse_public_key(Bytes{0x7b, 0x22}); });
  hostile([]() { WaPasskey::parse_public_key(Bytes(70000, 0x7b)); });
  hostile([]() {
    std::string j = "{\"challenge\":\"!!!not-base64!!!\",\"timeout\":1}";
    WaPasskey::parse_public_key(Bytes(j.begin(), j.end()));
  });
  hostile([]() {
    std::string j = "{\"challenge\":[1,2],\"timeout\":1}";
    WaPasskey::parse_public_key(Bytes(j.begin(), j.end()));
  });
  hostile([]() {
    std::string j = "{\"challenge\":\"AQ\",\"timeout\":\"soon\"}";
    WaPasskey::parse_public_key(Bytes(j.begin(), j.end()));
  });
  hostile([]() {
    std::string j = "{\"challenge\":\"AQ\",\"allowCredentials\":{}}";
    WaPasskey::parse_public_key(Bytes(j.begin(), j.end()));
  });
  hostile([]() {
    std::string j = "[1,2,3]";
    WaPasskey::parse_public_key(Bytes(j.begin(), j.end()));
  });
  hostile([]() { WaPasskey::base64url_decode("a"); });
  hostile([]() { WaPasskey::base64url_decode("a==="); });
  hostile([]() { WaPasskey::base64url_decode("!!!!"); });
  check(ok, "passkey JSON/base64url reject hostile bytes without length_error");

  // pairing crypto inputs: short/long secrets and keys throw with a reason.
  ok = true;
  hostile([]() { WaPairing::finish_code_pairing("ABCDEFGH", Bytes(79, 1), Bytes(32, 2), a32(Bytes(32, 3)),
                                               a32(Bytes(32, 4)), Bytes(32, 5), Bytes(32, 6), Bytes(12, 7)); });
  hostile([]() { WaPairing::finish_code_pairing("ABCDEFGH", Bytes(80, 1), Bytes(31, 2), a32(Bytes(32, 3)),
                                               a32(Bytes(32, 4)), Bytes(32, 5), Bytes(32, 6), Bytes(12, 7)); });
  hostile([]() { WaPairing::wrap_companion_ephemeral(Bytes(31, 1), Bytes(16, 2), "ABCDEFGH", Bytes(32, 3)); });
  hostile([]() { WaPairing::format_linking_code("ABCDEFG"); });
  hostile([]() { WaPasskey::derive_handoff_key(Bytes(31, 1)); });
  hostile([]() { WaPasskey::derive_encryption_key(Bytes(31, 1), 0, "ref"); });
  hostile([]() { WaPasskey::seal_pairing_request(Bytes(32, 1), Bytes(11, 2), Bytes(32, 3), Bytes(32, 4), Bytes(32, 5)); });
  hostile([]() { WaPairing::parse_code_notification(WaNode("notification")); });
  hostile([]() { WaPasskey::parse_continuation_node(WaNode("notification")); });
  hostile([]() { WaPasskey::parse_options_node(WaNode("notification")); });
  hostile([]() { WaPairing::parse_pairing_ref(WaNode("iq")); });
  hostile([]() { WaPasskey::parse_ref(WaNode("iq")); });
  check(ok, "pairing crypto/node inputs reject bad sizes without length_error");

  // fuzz: mutated oracle bytes through every new parser; surviving is the proof.
  Value v = Value::loads(slurp(path("pairing_vectors.json")));
  std::vector<Bytes> seeds = {
      fromhex(v.get("proto_props_hex").str()),
      fromhex(v.get("proto_primary_ident_hex").str()),
      Bytes(v.get("webauthn_pub_json").str().begin(), v.get("webauthn_pub_json").str().end()),
      fromhex(v.get("finish_wrapped_primary_hex").str()),
  };
  uint64_t rng = 0x12345678;
  auto next = [&]() {
    rng ^= rng << 13;
    rng ^= rng >> 7;
    rng ^= rng << 17;
    return rng;
  };
  ok = true;
  for (int i = 0; i < 3000; ++i) {
    Bytes m = seeds[i % seeds.size()];
    if (!m.empty()) {
      switch (next() % 3) {
        case 0:
          m[next() % m.size()] ^= static_cast<uint8_t>(1 + next() % 255);
          break;
        case 1:
          m.resize(next() % (m.size() + 1));
          break;
        default:
          m.insert(m.begin() + (next() % (m.size() + 1)), static_cast<uint8_t>(next() % 256));
          break;
      }
    }
    hostile([&]() { parse_client_pairing_props(m); });
    hostile([&]() { parse_primary_ephemeral_identity(m); });
    hostile([&]() { parse_companion_commitment(m); });
    hostile([&]() { WaPasskey::parse_public_key(m); });
    hostile([&]() { WaPasskey::base64url_decode(std::string(m.begin(), m.end())); });
  }
  check(ok, "3000 mutated pairing inputs: no length_error, no crash");
}

// ---- M5 media (docs/whatsapp.md section 21) ----
// Oracle: tests/whatsapp_data/media_vectors_m5.json, generated by media_oracle.go with whatsmeow's
// own hkdfutil, cbcutil, GetMediaType, error sentinels, StickerPack struct and retryafter package.
// The mms-type table and URL shapes are read from the whatsmeow source (no exported accessor);
// the tests below pin them as exact strings so any drift fails loudly.

// The oracle's test-data pattern (its generator, not the code under test).
static Bytes m5_pattern(size_t n) {
  Bytes b;
  for (size_t i = 0; i < n; ++i) b.push_back(static_cast<uint8_t>((i * 31 + 7) % 251));
  return b;
}

static FILE* m5_tmp_with(const Bytes& b) {
  FILE* f = ::tmpfile();
  if (f == nullptr) return nullptr;
  if (!b.empty()) std::fwrite(b.data(), 1, b.size(), f);
  std::rewind(f);
  return f;
}

static Bytes m5_slurp_file(FILE* f) {
  std::rewind(f);
  Bytes out;
  char buf[4096];
  size_t n = 0;
  while ((n = std::fread(buf, 1, sizeof(buf), f)) > 0) out.insert(out.end(), buf, buf + n);
  return out;
}

static WaMediaConn m5_conn(const std::string& h1, const std::string& h2 = "") {
  WaMediaConn c;
  c.auth = "test-auth";
  c.ttl = 3600;
  c.auth_ttl = 3600;
  c.max_buckets = 5;
  c.fetched_at = 1700000000;
  c.hosts.push_back(WaMediaConnHost{h1});
  if (!h2.empty()) c.hosts.push_back(WaMediaConnHost{h2});
  return c;
}

// Scripted media HTTP client: scripted results (or throws) per call, full request log.
struct FakeMediaHttp : WaMedia::HttpClient {
  struct Req {
    std::string method, url;
    Bytes body;
    std::vector<std::pair<std::string, std::string>> headers;
  };
  std::vector<Req> requests;
  std::vector<std::function<WaMedia::HttpResult()>> gets, posts, post_files, dells;
  size_t gi{0}, pi{0}, fi{0}, di{0};
  WaMedia::HttpResult get(const std::string& url, size_t max_bytes) override {
    (void)max_bytes;
    requests.push_back({"GET", url, {}, {}});
    if (gi >= gets.size()) throw WaMediaError(WaMediaErrorCode::Network, "fake: no more GETs");
    return gets[gi++]();
  }
  WaMedia::HttpResult post(const std::string& url, const Bytes& body, size_t max_response) override {
    (void)max_response;
    requests.push_back({"POST", url, body, {}});
    if (pi >= posts.size()) throw WaMediaError(WaMediaErrorCode::Network, "fake: no more POSTs");
    return posts[pi++]();
  }
  WaMedia::HttpResult post_file(const std::string& url, WaMediaFile* body, uint64_t size,
                                size_t max_response) override {
    (void)max_response;
    Bytes content(static_cast<size_t>(size), 0);
    size_t n = std::fread(content.data(), 1, content.size(), body);
    content.resize(n);
    requests.push_back({"POST_FILE", url, content, {}});
    if (fi >= post_files.size()) throw WaMediaError(WaMediaErrorCode::Network, "fake: no more POST_FILEs");
    return post_files[fi++]();
  }
  WaMedia::HttpResult del(const std::string& url,
                          const std::vector<std::pair<std::string, std::string>>& headers) override {
    requests.push_back({"DELETE", url, {}, headers});
    if (di >= dells.size()) throw WaMediaError(WaMediaErrorCode::Network, "fake: no more DELETEs");
    return dells[di++]();
  }
};

static WaMedia::HttpResult m5_http(long status, const Bytes& body, const std::string& retry_after = "") {
  WaMedia::HttpResult r;
  r.status = status;
  r.body = body;
  r.retry_after = retry_after;
  return r;
}

static std::function<WaMedia::HttpResult()> m5_net_err(const std::string& what) {
  return [what]() -> WaMedia::HttpResult { throw WaMediaError(WaMediaErrorCode::Network, what); };
}

static void test_media_m5() {
  std::printf("[media M5]\n");
  WaMedia::reset_test_hooks();
  FILE* probe = ::tmpfile();
  check(probe != nullptr, "tmpfile works");
  if (probe != nullptr) std::fclose(probe);

  Value v = Value::loads(slurp(path("media_vectors_m5.json")));

  // App-info strings and the mms-type table.
  const std::pair<WaMediaType, const char*> types[8] = {
      {WaMediaType::Image, "Image"},         {WaMediaType::Video, "Video"},
      {WaMediaType::Audio, "Audio"},         {WaMediaType::Document, "Document"},
      {WaMediaType::History, "History"},     {WaMediaType::AppState, "AppState"},
      {WaMediaType::StickerPack, "StickerPack"}, {WaMediaType::LinkThumbnail, "LinkThumbnail"},
  };
  bool infos_ok = true;
  for (const auto& [t, name] : types) {
    if (WaMediaTypes::app_info(t) != v.get("app_infos").get(name).str()) infos_ok = false;
    if (WaMediaTypes::parse_app_info(v.get("app_infos").get(name).str()) != t) infos_ok = false;
  }
  check(infos_ok, "8 app-info strings match the MediaType constants, parse round-trips");
  check(WaMediaTypes::mms_type(WaMediaType::Image) == "image", "mms image");
  check(WaMediaTypes::mms_type(WaMediaType::Video) == "video", "mms video");
  check(WaMediaTypes::mms_type(WaMediaType::Audio) == "audio", "mms audio");
  check(WaMediaTypes::mms_type(WaMediaType::Document) == "document", "mms document");
  check(WaMediaTypes::mms_type(WaMediaType::History) == "md-msg-hist", "mms history");
  check(WaMediaTypes::mms_type(WaMediaType::AppState) == "md-app-state", "mms app-state");
  check(WaMediaTypes::mms_type(WaMediaType::StickerPack) == "sticker-pack", "mms sticker-pack");
  check(WaMediaTypes::mms_type(WaMediaType::LinkThumbnail) == "thumbnail-link", "mms link-thumbnail");

  // Per-type encrypt vectors plus a decrypt round-trip through decrypt_blob.
  Bytes media_key = fromhex(v.get("media_key_hex").str());
  int ok = 0, total = 0;
  for (const auto& c : v.get("encrypt").items()) {
    std::string info = v.get("app_infos").get(c.get("type").str()).str();
    Bytes plain = fromhex(c.get("plaintextHex").str());
    WaMedia::Keys k = WaMedia::expand(media_key, info);
    WaMedia::Encrypted e = WaMedia::encrypt(plain, info, media_key);
    bool keys_ok = tohex(k.iv) == c.get("iv").str() && tohex(k.cipher_key) == c.get("cipherKey").str() &&
                   tohex(k.mac_key) == c.get("macKey").str() && tohex(k.ref_key) == c.get("refKey").str();
    bool blob_ok = tohex(e.data_to_upload) == c.get("ciphertextHex").str();
    bool hash_ok = tohex(e.file_sha256) == c.get("fileSha256").str() &&
                   tohex(e.file_enc_sha256) == c.get("fileEncSha256").str();
    bool round_ok = false;
    try {
      Bytes file(e.data_to_upload.begin(), e.data_to_upload.end() - 10);
      Bytes mac(e.data_to_upload.end() - 10, e.data_to_upload.end());
      WaMediaType t = WaMediaTypes::parse_app_info(info);
      round_ok = WaMedia::decrypt_blob(file, mac, media_key, t, e.file_enc_sha256, e.file_sha256) == plain;
    } catch (const std::exception&) {
    }
    ++total;
    if (keys_ok && blob_ok && hash_ok && round_ok && e.file_length == plain.size()) ++ok;
  }
  check(total == 16 && ok == total, "per-type encrypt matches oracle (16/16) with decrypt round-trip");

  // Streaming sidecars.
  Bytes siv = fromhex(v.get("sidecar_iv").str()), smac = fromhex(v.get("sidecar_mac_key").str());
  int sok = 0;
  for (const auto& c : v.get("sidecars").items()) {
    Bytes blob = fromhex(c.get("blobHex").str());
    if (tohex(WaMedia::streaming_sidecar(siv, smac, blob)) == c.get("sidecarHex").str()) ++sok;
  }
  check(sok == 4, "video sidecars match oracle (100B, 64K, 64K+21, 150000B)");

  // cbc_encrypt_stream byte parity.
  int stok = 0;
  for (const auto& c : v.get("streams").items()) {
    Bytes pt = fromhex(c.get("plaintextHex").str());
    FILE* in = m5_tmp_with(pt);
    FILE* out = m5_tmp_with(Bytes{});
    bool good = false;
    if (in != nullptr && out != nullptr) {
      try {
        WaMedia::StreamEncryptOut se = WaMedia::cbc_encrypt_stream(
            in, out, Bytes(32, 0x11), Bytes(16, 0x22), Bytes(32, 0x33));
        good = tohex(se.file_sha256) == c.get("fileSha256").str() &&
               tohex(se.file_enc_sha256) == c.get("fileEncSha256").str() &&
               se.file_length == static_cast<uint64_t>(c.get("fileLength").as_int()) &&
               se.upload_size == static_cast<uint64_t>(c.get("uploadSize").as_int()) &&
               tohex(m5_slurp_file(out)) == c.get("ciphertextHex").str();
      } catch (const std::exception&) {
      }
    }
    if (in != nullptr) std::fclose(in);
    if (out != nullptr) std::fclose(out);
    if (good) ++stok;
  }
  check(stok == 5, "cbc_encrypt_stream matches cbcutil.EncryptStream (empty..100000B)");

  // cbc_decrypt_file byte parity plus the bad-size error text.
  int dok = 0;
  for (const auto& c : v.get("decrypt_files").items()) {
    Bytes ct = fromhex(c.get("ciphertextHex").str());
    FILE* f = m5_tmp_with(ct);
    bool good = false;
    if (f != nullptr) {
      try {
        WaMedia::cbc_decrypt_file(f, Bytes(32, 0x11), Bytes(16, 0x22));
        good = tohex(m5_slurp_file(f)) == c.get("plaintextHex").str();
      } catch (const std::exception&) {
      }
      std::fclose(f);
    }
    if (good) ++dok;
  }
  check(dok == 5, "cbc_decrypt_file matches cbcutil.DecryptFile (empty..40000B)");
  {
    FILE* f = m5_tmp_with(m5_pattern(20));
    std::string msg;
    try {
      WaMedia::cbc_decrypt_file(f, Bytes(32, 0x11), Bytes(16, 0x22));
    } catch (const WaMediaError& e) {
      msg = e.what();
    }
    if (f != nullptr) std::fclose(f);
    check(msg == "wa media: " + v.get("decrypt_file_bad_size_error").str(),
          "decrypt_file bad size mirrors upstream text");
  }

  // GetMediaType mapping.
  bool gok = true;
  for (const auto& m : v.get("get_media_type").members()) {
    try {
      if (WaMediaTypes::app_info(WaMediaTypes::for_message(m.first)) != m.second.str()) gok = false;
    } catch (const std::exception&) {
      gok = false;
    }
  }
  bool gthrow = false;
  try {
    WaMediaTypes::for_message("PollCreationMessage");
  } catch (const WaMediaError& e) {
    gthrow = e.code() == WaMediaErrorCode::UnknownMediaType;
  }
  bool tthrow = false;
  try {
    WaMediaTypes::for_thumbnail("ImageMessage");
  } catch (const WaMediaError&) {
    tthrow = true;
  }
  check(gok && gthrow && tthrow, "for_message matches GetMediaType (10 classes), unknown throws");
  check(WaMediaTypes::for_thumbnail("ExtendedTextMessage") == WaMediaType::LinkThumbnail,
        "for_thumbnail maps ExtendedTextMessage to LinkThumbnail");

  // Error taxonomy strings.
  const Value& errs = v.get("errors");
  auto msg_is = [&](WaMediaErrorCode code, const std::string& key) {
    try {
      throw WaMediaError(code);
    } catch (const WaMediaError& e) {
      return std::string(e.what()) == "wa media: " + errs.get(key).str();
    }
    return false;
  };
  check(msg_is(WaMediaErrorCode::NoUrl, "no_url"), "err no url present");
  check(msg_is(WaMediaErrorCode::TooShort, "too_short"), "err file too short");
  check(msg_is(WaMediaErrorCode::InvalidHmac, "invalid_hmac"), "err invalid media hmac");
  check(msg_is(WaMediaErrorCode::InvalidEncSha256, "invalid_enc_sha"), "err invalid media enc sha");
  check(msg_is(WaMediaErrorCode::InvalidSha256, "invalid_sha"), "err invalid media sha");
  check(msg_is(WaMediaErrorCode::InvalidUnencryptedSha256, "invalid_unenc_sha"), "err invalid unencrypted sha");
  check(msg_is(WaMediaErrorCode::UnknownMediaType, "unknown_media_type"), "err unknown media type");
  check(msg_is(WaMediaErrorCode::NothingDownloadable, "nothing_downloadable"), "err nothing downloadable");
  check(msg_is(WaMediaErrorCode::FileLengthMismatch, "file_length_mismatch"), "err file length mismatch");
  check(std::string(WaMediaError(403).what()) == "wa media: " + errs.get("http_403").str(), "err http 403");
  check(std::string(WaMediaError(404).what()) == "wa media: " + errs.get("http_404").str(), "err http 404");
  check(std::string(WaMediaError(410).what()) == "wa media: " + errs.get("http_410").str(), "err http 410");
  check(std::string(WaMediaError(500).what()) == "wa media: " + errs.get("http_500").str(), "err http 500");
  check(WaMediaError(404).http_status() == 404, "http error carries its status");
  check(WaDownloadHttpError{404}.is(404) == (errs.get("is_404_404").str() == "true"), "DownloadHTTPError Is 404/404");
  check(WaDownloadHttpError{404}.is(403) == (errs.get("is_404_403").str() == "true"), "DownloadHTTPError Is 404/403");
  check(WaDownloadHttpError{500}.is(404) == (errs.get("is_500_404").str() == "true"), "DownloadHTTPError Is 500/404");
  check(WaMediaError(500, "upload").what() == std::string("wa media: upload failed with status code 500"),
        "upload http error names the operation");
  check(WaMediaError(500, "media delete").what() ==
            std::string("wa media: media delete failed with status code 500"),
        "delete http error names the operation");

  // Failover and retry classification.
  check(WaMediaError(WaMediaErrorCode::InvalidSha256).terminal_for_host_failover(), "plain-sha is terminal");
  check(WaMediaError(403).terminal_for_host_failover(), "403 is terminal");
  check(WaMediaError(404).terminal_for_host_failover(), "404 is terminal");
  check(WaMediaError(410).terminal_for_host_failover(), "410 is terminal");
  check(!WaMediaError(500).terminal_for_host_failover(), "500 fails over");
  check(!WaMediaError(WaMediaErrorCode::InvalidHmac).terminal_for_host_failover(), "bad HMAC fails over");
  bool rok = true;
  for (const auto& m : v.get("retry_should").members()) {
    bool want = m.second.as_bool();
    if (WaMediaError(std::stoi(m.first)).retryable() != want) rok = false;
  }
  rok = rok && WaMediaError(WaMediaErrorCode::Network).retryable() &&
        !WaMediaError(WaMediaErrorCode::InvalidSha256).retryable();
  check(rok, "retryable() matches retryafter.Should (429/502/503/504 + network)");
  check(WaMedia::parse_retry_after("120", 5, 1700000000) == v.get("retry_parse_seconds").as_int(),
        "Retry-After seconds");
  check(WaMedia::parse_retry_after("", 5, 1700000000) == v.get("retry_parse_empty").as_int(), "Retry-After empty");
  check(WaMedia::parse_retry_after("garbage", 5, 1700000000) == v.get("retry_parse_garbage").as_int(),
        "Retry-After garbage");
  check(WaMedia::parse_retry_after("Wed, 21 Oct 2030 07:28:00 GMT", 5, 1918798020) == 60, "Retry-After date");
  check(WaMedia::parse_retry_after("Wed, 21 Oct 2020 07:28:00 GMT", 5, 1918798020) == 0, "Retry-After past date");

  // Sticker pack JSON (oracle-marshalled from the real struct).
  {
    WaStickerPack pack = WaStickerPack::parse_json(v.get("sticker_pack_json").str());
    bool pok = pack.id == "pack-9" && pack.name == "Cats" && pack.publisher == "detz" &&
               pack.description == "fine cats" && pack.file_size == "1234" && pack.image_data_hash == "aabbcc" &&
               pack.animated == 0 && pack.lottie == 1 && pack.preview_image_ids.size() == 2 &&
               pack.tray_image_id == "tray-1" && pack.tray_image_preview == "preview-b64" &&
               pack.stickers.size() == 2;
    const WaStickerPackItem& a = pack.stickers[0];
    pok = pok && a.media_key == m5_pattern(32) && a.enc_file_hash == m5_pattern(32) &&
          a.file_hash == Bytes(32, 9) && a.direct_path == "/v/t62.123/abc?auth=1" &&
          a.url == "https://example.invalid/s1.webp" && a.file_size == 4242 && a.mime_type == "image/webp" &&
          a.height == 512 && a.width == 512 && a.emojis.size() == 2 && a.emojis[0] == "=^.^=" &&
          a.accessibility_text == "a cat" && a.handle == "h1" && a.sticker_hash_without_meta == Bytes(32, 7) &&
          a.preview_webp_id == "w1";
    pok = pok && a.get_direct_path() == a.direct_path && a.get_media_key() == a.media_key &&
          a.get_file_sha256() == a.file_hash && a.get_file_enc_sha256() == a.enc_file_hash &&
          a.get_file_size_bytes() == 4242;
    const WaStickerPackItem& b = pack.stickers[1];
    pok = pok && b.media_key == Bytes(32, 1) && b.file_size == 100 && b.emojis.empty() && b.handle.empty();
    check(pok, "sticker pack JSON parses with every field and getter");
  }

  // MediaConn parse.
  {
    WaNode mc("media_conn");
    mc.attrs["auth"] = "auth-token";
    mc.attrs["ttl"] = "900";
    mc.attrs["auth_ttl"] = "1800";
    mc.attrs["max_buckets"] = "5";
    WaNode h1("host"), h2("host");
    h1.attrs["hostname"] = "mmg.whatsapp.net";
    h2.attrs["hostname"] = "mmg2.whatsapp.net";
    mc.content = WaNode::Children{h1, h2};
    WaMediaConn c = WaMediaConn::parse(mc, 1700000000);
    check(c.auth == "auth-token" && c.ttl == 900 && c.auth_ttl == 1800 && c.max_buckets == 5 &&
              c.hosts.size() == 2 && c.first_host() == "mmg.whatsapp.net",
          "media_conn parses auth/ttls/hosts");
    check(c.expiry() == 1700000900, "media_conn expiry is fetched_at + ttl");
    check(!c.expired(1700000900) && c.expired(1700000901), "media_conn expiry boundary");
    int bad = 0;
    WaNode wrong("iq");
    try {
      WaMediaConn::parse(wrong, 0);
    } catch (const WaMediaError&) {
      ++bad;
    }
    WaNode noauth("media_conn");
    noauth.attrs["ttl"] = "1";
    noauth.attrs["auth_ttl"] = "1";
    noauth.attrs["max_buckets"] = "1";
    try {
      WaMediaConn::parse(noauth, 0);
    } catch (const WaMediaError&) {
      ++bad;
    }
    WaNode badttl("media_conn");
    badttl.attrs["auth"] = "a";
    badttl.attrs["ttl"] = "soon";
    badttl.attrs["auth_ttl"] = "1";
    badttl.attrs["max_buckets"] = "1";
    try {
      WaMediaConn::parse(badttl, 0);
    } catch (const WaMediaError&) {
      ++bad;
    }
    check(bad == 3, "media_conn rejects wrong tag, missing auth, bad ttl");
    WaMediaConn empty;
    bool threw = false;
    try {
      empty.first_host();
    } catch (const WaMediaError&) {
      threw = true;
    }
    check(threw, "first_host throws on an empty set");
  }

  // URL shapes (exact strings; formulas read from the whatsmeow call sites).
  {
    Bytes h(32, 0xab);
    check(WaMedia::download_url("mmg.whatsapp.net", "/v/x?auth=1", h, "image") ==
              "https://mmg.whatsapp.net/v/x?auth=1&hash=" + WaMedia::token(h) + "&mms-type=image&__wa-mms=",
          "download URL shape");
    check(WaMedia::upload_url("mmg.whatsapp.net", "mms", "image", "tok==", "a&b") ==
              "https://mmg.whatsapp.net/mms/image/tok==?auth=a%26b&token=tok%3D%3D",
          "upload URL shape (sorted query, escaped values)");
    check(WaMedia::delete_url("mmg.whatsapp.net", "image", "tok==", "/v/x", "a b", "e+h") ==
              "https://mmg.whatsapp.net/mms/image/tok==?auth=a%20b&d_md=L3YveA&e_handle=e%2Bh&token=tok%3D%3D",
          "delete URL shape (d_md raw base64url, sorted query)");
  }

  // Upload-response JSON.
  {
    WaMedia::UploadResponse r = WaMedia::UploadResponse::parse_json(
        R"({"url":"https://u","direct_path":"/v/d","handle":"h","object_id":"o"})");
    check(r.url == "https://u" && r.direct_path == "/v/d" && r.handle == "h" && r.object_id == "o",
          "upload response parses url/path/handle/object");
    int bad = 0;
    try {
      WaMedia::UploadResponse::parse_json(R"({"direct_path":"/v/d"})");
    } catch (const WaMediaError&) {
      ++bad;
    }
    try {
      WaMedia::UploadResponse::parse_json("not json");
    } catch (const WaMediaError&) {
      ++bad;
    }
    check(bad == 2, "upload response rejects missing url and bad JSON");
  }

  // Download plumbing over a fake transport (crypto already pinned above).
  {
    Bytes key = fromhex(v.get("media_key_hex").str());
    Bytes plain(1000, 0x41);
    WaMedia::Encrypted enc = WaMedia::encrypt(plain, "WhatsApp Image Keys", key);
    WaMedia::Downloadable img{"/v/img?auth=1", key, enc.file_sha256, enc.file_enc_sha256};
    auto fake = std::make_shared<FakeMediaHttp>();
    WaMedia::set_http_client(fake);
    std::vector<int> sleeps;
    WaMedia::set_sleeper([&](int s) { sleeps.push_back(s); });

    fake->gets.push_back([&]() { return m5_http(200, enc.data_to_upload); });
    Bytes got = WaMedia::download(img, "ImageMessage", m5_conn("h1.example"), "", false, 1 << 20);
    check(got == plain, "download returns the decrypted plaintext");
    check(fake->requests.size() == 1 && fake->requests[0].url.find("https://h1.example/v/img?auth=1&hash=") == 0 &&
              fake->requests[0].url.find("&mms-type=image&__wa-mms=") != std::string::npos,
          "download URL carries host, path, hash and mms-type");

    // Host failover then success: 5 exhausted retries on host 1, then host 2.
    for (int i = 0; i < WaConsts::kWaMediaDownloadRetries; ++i) fake->gets.push_back(m5_net_err("conn reset"));
    fake->gets.push_back([&]() { return m5_http(200, enc.data_to_upload); });
    sleeps.clear();
    got = WaMedia::download(img, "ImageMessage", m5_conn("h1.example", "h2.example"), "", false, 1 << 20);
    check(got == plain && fake->requests.size() == 7 && fake->requests.back().url.find("https://h2.example/") == 0 &&
              sleeps.size() == 4,
          "exhausted retries fail over to the next host");
    bool no_url = false;
    try {
      WaMedia::Downloadable bad = img;
      bad.direct_path.clear();
      WaMedia::download(bad, "ImageMessage", m5_conn("h1.example"), "", false, 1 << 20);
    } catch (const WaMediaError& e) {
      no_url = e.code() == WaMediaErrorCode::NoUrl;
    }
    check(no_url, "empty direct path raises NoUrl");

    // Terminal errors do not fail over.
    size_t before = fake->requests.size();
    bool t404 = false;
    fake->gets.push_back([&]() { return m5_http(404, Bytes{}); });
    try {
      WaMedia::download(img, "ImageMessage", m5_conn("h1.example", "h2.example"), "", false, 1 << 20);
    } catch (const WaMediaError& e) {
      t404 = e.code() == WaMediaErrorCode::Http && e.http_status() == 404;
    }
    check(t404 && fake->requests.size() == before + 1, "404 throws bare without touching host 2");

    // Retry inside one host with backoff sleeps, then success.
    fake->gets.push_back([&]() { return m5_http(503, Bytes{}); });
    fake->gets.push_back([&]() { return m5_http(503, Bytes{}, "2"); });
    fake->gets.push_back([&]() { return m5_http(200, enc.data_to_upload); });
    sleeps.clear();
    got = WaMedia::download(img, "ImageMessage", m5_conn("h1.example"), "", false, 1 << 20);
    check(got == plain && sleeps.size() == 2 && sleeps[0] == 1 && sleeps[1] == 2,
          "503 retries twice honoring Retry-After (1s, 2s)");
    check(fake->requests.size() == before + 4, "retries stay on the same host");

    // The last host wraps its failure with the trail.
    fake->gets.push_back([&]() { return m5_http(500, Bytes{}); });
    fake->gets.push_back([&]() { return m5_http(500, Bytes{}); });
    std::string wrap;
    try {
      WaMedia::download(img, "ImageMessage", m5_conn("h1.example", "h2.example"), "", false, 1 << 20);
    } catch (const WaMediaError& e) {
      wrap = e.what();
    }
    check(wrap.find("failed to download media from last host") != std::string::npos &&
              wrap.find("h1.example") != std::string::npos && wrap.find("h2.example") != std::string::npos,
          "last-host failure quotes the per-host trail");

    // download_any order, thumbnails, FB transport, unencrypted media.
    WaMedia::AnyDownloadable any;
    any.video = img;
    any.image = img;
    fake->gets.push_back([&]() { return m5_http(200, enc.data_to_upload); });
    WaMedia::download_any(any, m5_conn("h1.example"), 1 << 20);
    check(fake->requests.back().url.find("mms-type=image") != std::string::npos,
          "download_any prefers image over video");
    WaMedia::AnyDownloadable none;
    bool nada = false;
    try {
      WaMedia::download_any(none, m5_conn("h1.example"), 1 << 20);
    } catch (const WaMediaError& e) {
      nada = e.code() == WaMediaErrorCode::NothingDownloadable;
    }
    check(nada, "download_any with no parts raises NothingDownloadable");
    WaMedia::Encrypted tenc = WaMedia::encrypt(plain, "WhatsApp Link Thumbnail Keys", key);
    WaMedia::DownloadableThumb thumb{"/v/t?auth=1", key, tenc.file_sha256, tenc.file_enc_sha256};
    fake->gets.push_back([&]() { return m5_http(200, tenc.data_to_upload); });
    Bytes tgot = WaMedia::download_thumbnail(thumb, "ExtendedTextMessage", m5_conn("h1.example"), 1 << 20);
    check(tgot == plain && fake->requests.back().url.find("mms-type=thumbnail-link") != std::string::npos,
          "thumbnails download as thumbnail-link");
    bool thumb_bad = false;
    try {
      WaMedia::download_thumbnail(thumb, "ImageMessage", m5_conn("h1.example"), 1 << 20);
    } catch (const WaMediaError& e) {
      thumb_bad = e.code() == WaMediaErrorCode::UnknownMediaType;
    }
    check(thumb_bad, "thumbnail with a non-thumbnail class raises UnknownMediaType");
    WaMedia::Encrypted vence = WaMedia::encrypt(plain, "WhatsApp Video Keys", key);
    WaMedia::FbTransport fb{"/v/f?auth=1", key, vence.file_sha256, vence.file_enc_sha256, 123};
    fake->gets.push_back([&]() { return m5_http(200, vence.data_to_upload); });
    got = WaMedia::download_fb(fb, WaMediaType::Video, m5_conn("h1.example"), 1 << 20);
    check(got == plain && fake->requests.back().url.find("mms-type=video") != std::string::npos,
          "FB transport downloads with the caller type");
    Bytes raw(200, 0x77);
    Bytes rawhash = WaCrypto::sha256(raw);
    WaMedia::Downloadable unenc{"/v/u?auth=1", Bytes{}, rawhash, Bytes{}};
    fake->gets.push_back([&]() { return m5_http(200, raw); });
    check(WaMedia::download(unenc, "DocumentMessage", m5_conn("h1.example"), "", false, 1 << 20) == raw,
          "unencrypted media verifies its hash");
    fake->gets.push_back([&]() { return m5_http(200, raw); });
    check(WaMedia::download_media_with_only_path(m5_conn("h1.example"), "/v/u?auth=1", 1 << 20) == raw,
          "only-path fetch skips every check");
    WaMedia::reset_test_hooks();
  }

  // To-file downloads.
  {
    Bytes key = fromhex(v.get("media_key_hex").str());
    Bytes plain = m5_pattern(5000);
    WaMedia::Encrypted enc = WaMedia::encrypt(plain, "WhatsApp Audio Keys", key);
    WaMedia::Downloadable aud{"/v/a?auth=1", key, enc.file_sha256, enc.file_enc_sha256};
    auto fake = std::make_shared<FakeMediaHttp>();
    WaMedia::set_http_client(fake);
    WaMedia::set_sleeper([](int) {});
    fake->gets.push_back([&]() { return m5_http(200, enc.data_to_upload); });
    FILE* out = m5_tmp_with(Bytes{});
    WaMedia::download_to_file(aud, "AudioMessage", m5_conn("h1.example"), out, 1 << 20);
    check(m5_slurp_file(out) == plain, "download_to_file writes the plaintext");
    std::fclose(out);
    Bytes raw(300, 0x55);
    fake->gets.push_back([&]() { return m5_http(200, raw); });
    out = m5_tmp_with(Bytes{});
    WaMedia::download_media_with_only_path_to_file(m5_conn("h1.example"), "/v/u?auth=1", out, 1 << 20);
    check(m5_slurp_file(out) == raw, "only-path to-file writes the raw body");
    std::fclose(out);
    WaMedia::FbTransport fb{"/v/f?auth=1", key, enc.file_sha256, enc.file_enc_sha256, 0};
    fake->gets.push_back([&]() { return m5_http(200, enc.data_to_upload); });
    out = m5_tmp_with(Bytes{});
    WaMedia::download_fb_to_file(fb, WaMediaType::Audio, m5_conn("h1.example"), out, 1 << 20);
    check(m5_slurp_file(out) == plain, "FB to-file writes the plaintext");
    std::fclose(out);
    WaMedia::reset_test_hooks();
  }

  // Uploads and deletes over a fake transport.
  {
    auto fake = std::make_shared<FakeMediaHttp>();
    WaMedia::set_http_client(fake);
    WaMedia::set_sleeper([](int) {});
    Bytes key = fromhex(v.get("media_key_hex").str());
    Bytes plain(500, 0x42);
    WaMedia::Encrypted enc = WaMedia::encrypt(plain, "WhatsApp Image Keys", key);
    fake->posts.push_back([&]() {
      std::string j = R"({"url":"https://u","direct_path":"/v/d","handle":"h"})";
      return m5_http(200, Bytes(j.begin(), j.end()));
    });
    WaMedia::UploadResponse r =
        WaMedia::upload_encrypted(m5_conn("up.example"), WaMediaType::Image, plain, key);
    check(r.url == "https://u" && r.direct_path == "/v/d" && r.handle == "h" && r.media_key == key &&
              r.file_enc_sha256 == enc.file_enc_sha256 && r.file_sha256 == enc.file_sha256 &&
              r.file_length == 500 && r.streaming_sidecar.empty(),
          "upload_encrypted posts the blob and fills the response");
    check(fake->requests.back().method == "POST" && fake->requests.back().body == enc.data_to_upload &&
              fake->requests.back().url.find("https://up.example/mms/image/") == 0,
          "upload POST carries the ciphertext to /mms/<mms>/<token>");
    // Video gains a sidecar; the reader arm streams the same bytes.
    fake->posts.push_back([&]() {
      std::string j = R"({"url":"https://u"})";
      return m5_http(200, Bytes(j.begin(), j.end()));
    });
    r = WaMedia::upload_encrypted(m5_conn("up.example"), WaMediaType::Video, plain, key);
    WaMedia::Keys k = WaMedia::expand(key, "WhatsApp Video Keys");
    WaMedia::Encrypted vence = WaMedia::encrypt(plain, "WhatsApp Video Keys", key);
    check(r.streaming_sidecar == WaMedia::streaming_sidecar(k.iv, k.mac_key, vence.data_to_upload) &&
              !r.streaming_sidecar.empty(),
          "video upload attaches the streaming sidecar");
    FILE* pin = m5_tmp_with(plain);
    fake->post_files.push_back([&]() {
      std::string j = R"({"url":"https://u","direct_path":"/v/r"})";
      return m5_http(200, Bytes(j.begin(), j.end()));
    });
    r = WaMedia::upload_reader(m5_conn("up.example"), WaMediaType::Document, pin);
    std::fclose(pin);
    WaMedia::Encrypted dence = WaMedia::encrypt(plain, "WhatsApp Document Keys", r.media_key);
    check(r.direct_path == "/v/r" && r.file_length == 500 && r.media_key.size() == 32 &&
              fake->requests.back().method == "POST_FILE" && fake->requests.back().body == dence.data_to_upload,
          "upload_reader streams ciphertext equal to the one-shot encrypt");
    // Newsletter uploads are unencrypted with the newsletter- prefix.
    fake->posts.push_back([&]() {
      std::string j = R"({"url":"https://n","direct_path":"/v/n"})";
      return m5_http(200, Bytes(j.begin(), j.end()));
    });
    r = WaMedia::upload_newsletter(m5_conn("up.example"), WaMediaType::Image, plain);
    check(r.url == "https://n" && r.file_sha256 == WaCrypto::sha256(plain) && r.media_key.empty() &&
              r.file_enc_sha256.empty() &&
              fake->requests.back().url.find("/newsletter/newsletter-image/") != std::string::npos &&
              fake->requests.back().body == plain,
          "newsletter upload posts plaintext to /newsletter/newsletter-<mms>/");
    FILE* nin = m5_tmp_with(plain);
    fake->post_files.push_back([&]() {
      std::string j = R"({"url":"https://n"})";
      return m5_http(200, Bytes(j.begin(), j.end()));
    });
    r = WaMedia::upload_newsletter_reader(m5_conn("up.example"), WaMediaType::Image, nin);
    std::fclose(nin);
    check(r.file_length == 500 && r.file_sha256 == WaCrypto::sha256(plain) &&
              fake->requests.back().method == "POST_FILE" && fake->requests.back().body == plain,
          "newsletter reader hashes then posts the same bytes");
    // Deletes: query stripped, companion header, empty path is silent, errors name the op.
    fake->dells.push_back([&]() { return m5_http(200, Bytes{}); });
    WaMedia::delete_media(m5_conn("up.example"), WaMediaType::Image, "/v/x?auth=1", enc.file_enc_sha256, "eh",
                          "nonce");
    const auto& dq = fake->requests.back();
    check(dq.method == "DELETE" && dq.url.find("https://up.example/mms/image/") == 0 &&
              dq.url.find("auth=") != std::string::npos && dq.url.find("d_md=") != std::string::npos &&
              dq.url.find("auth=1") == std::string::npos && dq.headers.size() == 1 &&
              dq.headers[0].first == "Companion_User_Secret",
          "delete strips the query, signs the companion header");
    size_t nreq = fake->requests.size();
    WaMedia::delete_media(m5_conn("up.example"), WaMediaType::Image, "", enc.file_enc_sha256, "", "");
    check(fake->requests.size() == nreq, "delete with an empty path sends nothing");
    fake->dells.push_back([&]() { return m5_http(500, Bytes{}); });
    bool derr = false;
    try {
      WaMedia::delete_media(m5_conn("up.example"), WaMediaType::Image, "/v/x", enc.file_enc_sha256, "", "");
    } catch (const WaMediaError& e) {
      derr = std::string(e.what()).find("media delete failed with status code 500") != std::string::npos;
    }
    check(derr, "delete failure names the operation");
    // Sticker pack fetch.
    fake->gets.push_back([&]() {
      std::string j = v.get("sticker_pack_json").str();
      return m5_http(200, Bytes(j.begin(), j.end()));
    });
    WaStickerPack pack = WaMedia::fetch_sticker_pack("pack-9");
    check(pack.id == "pack-9" && pack.stickers.size() == 2 &&
              fake->requests.back().url ==
                  "https://static.whatsapp.net/sticker?lottie=1&cat=sticker_pack_data&id=pack-9&lg=en",
          "fetch_sticker_pack GETs the pack endpoint and parses it");
    WaMedia::reset_test_hooks();
  }
}

static void test_media_hostile() {
  std::printf("[media hostile]\n");
  WaMedia::reset_test_hooks();
  uint64_t lcg = 0x12345;
  auto rnd = [&](size_t n) {
    Bytes b;
    for (size_t i = 0; i < n; ++i) {
      lcg = lcg * 6364136223846793005ULL + 1442695040888963407ULL;
      b.push_back(static_cast<uint8_t>(lcg >> 33));
    }
    return b;
  };
  // A valid encrypted blob to mutate.
  Bytes key(32, 0x0a);
  Bytes plain = m5_pattern(1000);
  WaMedia::Encrypted enc = WaMedia::encrypt(plain, "WhatsApp Image Keys", key);
  bool ok = true;
  for (int i = 0; i < 3000; ++i) {
    Bytes blob = enc.data_to_upload;
    Bytes ekey = key, ehash = enc.file_enc_sha256, phash = enc.file_sha256;
    switch (i % 6) {
      case 0:  // truncate anywhere, including the empty blob
        blob.resize(rnd(2)[0] % (blob.size() + 1));
        break;
      case 1:  // flip bytes
        for (int f = 0; f < 1 + (i % 5); ++f) blob[rnd(2)[0] % blob.size()] ^= static_cast<uint8_t>(1 + (i % 255));
        break;
      case 2:  // wrong key/hash lengths
        ekey.resize(rnd(1)[0] % 40);
        ehash.resize(rnd(1)[0] % 40);
        break;
      case 3:  // extend with junk
        {
          Bytes junk = rnd(rnd(1)[0] % 100);
          blob.insert(blob.end(), junk.begin(), junk.end());
        }
        break;
      case 4:  // swap the MAC
        for (size_t j = 0; j < 10; ++j) blob[blob.size() - 10 + j] = rnd(1)[0];
        break;
      case 5: {  // split at a hostile MAC boundary, then decrypt the pieces
        size_t cut = rnd(2)[0] % (blob.size() + 1);
        Bytes file(blob.begin(), blob.begin() + static_cast<ptrdiff_t>(cut));
        Bytes mac(blob.begin() + static_cast<ptrdiff_t>(cut), blob.end());
        try {
          WaMedia::decrypt_blob(file, mac, ekey, WaMediaType::Image, ehash, phash);
        } catch (const std::length_error&) {
          ok = false;
        } catch (const std::exception&) {
        }
        continue;
      }
    }
    try {
      Bytes file, mac;
      WaMedia::split_encrypted_blob(blob, ehash, file, mac);
      WaMedia::decrypt_blob(file, mac, ekey, WaMediaType::Image, ehash, phash);
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
    // The same blob through the file decryptor.
    try {
      FILE* f = m5_tmp_with(blob);
      if (f != nullptr) {
        try {
          WaMedia::cbc_decrypt_file(f, Bytes(32, 0x11), Bytes(16, 0x22));
        } catch (const std::exception&) {
        }
        std::fclose(f);
      }
    } catch (const std::length_error&) {
      ok = false;
    } catch (const std::exception&) {
    }
  }
  check(ok, "3000 mutated blobs: handled or accepted, never length_error");
  // Hostile JSON, nodes, retry values and sidecar inputs.
  bool jok = true;
  std::string good_json = Value::loads(slurp(path("media_vectors_m5.json"))).get("sticker_pack_json").str();
  for (int i = 0; i < 500; ++i) {
    std::string mut = good_json;
    if (!mut.empty()) {
      mut[rnd(2)[0] % mut.size()] = static_cast<char>(rnd(1)[0]);
      if (i % 3 == 0) mut.resize(rnd(2)[0] % (mut.size() + 1));
    }
    try {
      WaStickerPack::parse_json(mut);
    } catch (const std::length_error&) {
      jok = false;
    } catch (const std::exception&) {
    }
    try {
      WaMedia::UploadResponse::parse_json(mut);
    } catch (const std::length_error&) {
      jok = false;
    } catch (const std::exception&) {
    }
    WaNode mc("media_conn");
    mc.attrs["auth"] = std::string(rnd(1)[0] % 8, 'a');
    mc.attrs["ttl"] = std::to_string(static_cast<int>(rnd(2)[0]) - 100);
    mc.attrs["auth_ttl"] = i % 2 == 0 ? "x" : "";
    mc.attrs["max_buckets"] = "5";
    try {
      WaMediaConn::parse(mc, 0);
    } catch (const std::length_error&) {
      jok = false;
    } catch (const std::exception&) {
    }
    try {
      Bytes rb = rnd(rnd(1)[0] % 40);
      WaMedia::streaming_sidecar(rb, rnd(32), rnd(rnd(1)[0] % 200));
    } catch (const std::length_error&) {
      jok = false;
    } catch (const std::exception&) {
    }
    try {
      Bytes rb(rnd(1)[0] % 300, 0);
      for (auto& c : rb) c = static_cast<uint8_t>(rnd(1)[0] % 128);
      std::string rs(rb.begin(), rb.end());
      WaMedia::parse_retry_after(rs, 5, 1700000000);
    } catch (const std::exception&) {
      jok = false;  // the parser must never throw at all
    }
  }
  check(jok, "500 hostile JSON/nodes/sidecars/retry-values: no length_error, retry parse never throws");
  // Deterministic edges.
  int edges = 0;
  try {
    WaMedia::download_url(std::string(9000, 'h'), "/v", Bytes(32, 0), "image");
  } catch (const WaMediaError& e) {
    edges += e.code() == WaMediaErrorCode::BadArgument ? 1 : 0;
  }
  try {
    WaStickerPack::parse_json(std::string(WaConsts::kWaStickerJsonMax + 1, 'x'));
  } catch (const WaMediaError&) {
    ++edges;
  }
  try {
    Bytes f, m;
    WaMedia::split_encrypted_blob(Bytes(100, 0), Bytes(31, 0), f, m);
  } catch (const WaMediaError& e) {
    edges += e.code() == WaMediaErrorCode::BadArgument ? 1 : 0;
  }
  // Corrupt padding with a recomputed MAC and hash: MAC passes, unpad must fail loudly.
  try {
    Bytes file(enc.data_to_upload.begin(), enc.data_to_upload.end() - 10);
    file[file.size() - 1] ^= 0x01;
    WaMedia::Keys k = WaMedia::expand(key, "WhatsApp Image Keys");
    Bytes mac = WaCrypto::hmac_sha256(k.mac_key, WaCrypto::concat({k.iv, file}));
    mac.resize(10);
    Bytes blob = file;
    blob.insert(blob.end(), mac.begin(), mac.end());
    Bytes new_enc_hash = WaCrypto::sha256(blob);
    WaMedia::decrypt_blob(file, mac, key, WaMediaType::Image, new_enc_hash, enc.file_sha256);
  } catch (const WaMediaError& e) {
    edges += std::string(e.what()).find("bad padding") != std::string::npos ? 1 : 0;
  }
  check(edges == 4, "overlong URL, oversized sticker body, short hash, corrupt padding all loud");
}

int main(int argc, char** argv) {
  DIR = argc > 1 ? argv[1] : "tests/whatsapp_data";
  test_tokens();
  test_iq();
  test_keepalive();
  test_server_cert();
  test_contact_search();
  test_device_props();
  test_crypto();
  test_codec();
  test_media();
  test_server_jid();
  test_client_payload();
  test_noise();
  test_signal();
  test_device();
  test_hostile();
  test_lthash_and_keys();
  test_appstate_sync();
  test_receiver();
  test_key_request_rollback();
  test_peer_helpers();
  test_empty_key_share();
  test_vcf_import();
  test_push_name_learning();
  test_store_m2();
  test_store_hostile();
  test_pairing_oracle();
  test_pairing_nodes();
  test_qr_channel();
  test_pairing_hostile();
  test_media_m5();
  test_media_hostile();
  std::printf("%s\n", g_fail == 0 ? "whatsapp: ALL OK" : "whatsapp: FAILURES");
  return g_fail == 0 ? 0 : 1;
}