// 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 <map>
#include <string>

#include "json.h"
#include "wa_binary.h"
#include "wa_crypto.h"
#include "wa_device.h"
#include "wa_noise.h"
#include "wa_proto.h"
#include "wa_signal.h"
#include "wa_appstate.h"
#include "wa_media.h"
#include "wa_receiver.h"
#include "wa_store.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");
}

// ---- 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");
  // 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);
}

int main(int argc, char** argv) {
  DIR = argc > 1 ? argv[1] : "tests/whatsapp_data";
  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();
  std::printf("%s\n", g_fail == 0 ? "whatsapp: ALL OK" : "whatsapp: FAILURES");
  return g_fail == 0 ? 0 : 1;
}