#include "Http.hpp"

#include <cctype>

#include "Caps.hpp"

namespace molo::example::fw {

Method parse_method(std::string_view name) {
  if (name == "GET") return Method::Get;
  if (name == "POST") return Method::Post;
  if (name == "PUT") return Method::Put;
  if (name == "PATCH") return Method::Patch;
  if (name == "DELETE") return Method::Delete;
  if (name == "HEAD") return Method::Head;
  if (name == "OPTIONS") return Method::Options;
  if (name == "PROPFIND") return Method::Propfind;
  if (name == "PROPPATCH") return Method::Proppatch;
  if (name == "MKCOL") return Method::Mkcol;
  if (name == "COPY") return Method::Copy;
  if (name == "MOVE") return Method::Move;
  if (name == "LOCK") return Method::Lock;
  if (name == "UNLOCK") return Method::Unlock;
  return Method::Unknown;
}

std::string method_name(Method method) {
  switch (method) {
    case Method::Get: return "GET";
    case Method::Post: return "POST";
    case Method::Put: return "PUT";
    case Method::Patch: return "PATCH";
    case Method::Delete: return "DELETE";
    case Method::Head: return "HEAD";
    case Method::Options: return "OPTIONS";
    case Method::Propfind: return "PROPFIND";
    case Method::Proppatch: return "PROPPATCH";
    case Method::Mkcol: return "MKCOL";
    case Method::Copy: return "COPY";
    case Method::Move: return "MOVE";
    case Method::Lock: return "LOCK";
    case Method::Unlock: return "UNLOCK";
    case Method::Unknown: return "UNKNOWN";
  }
  return "UNKNOWN";
}

namespace {

bool name_eq(std::string_view a, std::string_view b) {
  if (a.size() != b.size()) return false;
  for (std::size_t i = 0; i < a.size(); ++i) {
    if (std::tolower((unsigned char)a[i]) != std::tolower((unsigned char)b[i]))
      return false;
  }
  return true;
}

}  // namespace

void Headers::set(std::string name, std::string value) {
  for (auto& e : entries_) {
    if (name_eq(e.first, name)) {
      e.second = value;
      return;
    }
  }
  entries_.emplace_back(std::move(name), std::move(value));
}

std::string Headers::get(std::string_view name) const {
  for (const auto& e : entries_) {
    if (name_eq(e.first, name)) return e.second;
  }
  return "";
}

bool Headers::has(std::string_view name) const {
  for (const auto& e : entries_) {
    if (name_eq(e.first, name)) return true;
  }
  return false;
}

const std::vector<std::pair<std::string, std::string>>& Headers::entries()
    const {
  return entries_;
}

std::string Request::query_or(std::string_view key,
                              std::string_view fallback) const {
  auto it = query.find(std::string(key));
  if (it == query.end()) return std::string(fallback);
  return it->second;
}

std::string Request::param_or(std::string_view key,
                              std::string_view fallback) const {
  auto it = path_params.find(std::string(key));
  if (it == path_params.end()) return std::string(fallback);
  return it->second;
}

std::string Request::cookie_or(std::string_view key,
                               std::string_view fallback) const {
  auto it = cookies.find(std::string(key));
  if (it == cookies.end()) return std::string(fallback);
  return it->second;
}

Response::Response(int status, std::string body, std::string content_type)
    : status(status), body(std::move(body)) {
  headers.set("Content-Type", std::move(content_type));
}

std::string Response::content_type() const {
  return headers.get("Content-Type");
}

TextResponse::TextResponse(std::string body, int status)
    : Response(status, std::move(body), "text/plain; charset=utf-8") {}

HtmlResponse::HtmlResponse(std::string body, int status)
    : Response(status, std::move(body), "text/html; charset=utf-8") {}

JsonResponse::JsonResponse(std::string body, int status)
    : Response(status, std::move(body), "application/json") {}

XmlResponse::XmlResponse(std::string body, int status)
    : Response(status, std::move(body), "application/xml") {}

RedirectResponse::RedirectResponse(std::string location, bool permanent)
    : Response(permanent ? 301 : 302, "", "text/plain; charset=utf-8") {
  headers.set("Location", std::move(location));
}

FileResponse::FileResponse(std::string body, std::string content_type,
                           std::string filename)
    : Response(200, std::move(body), std::move(content_type)) {
  headers.set("Content-Disposition",
              "attachment; filename=\"" + filename + "\"");
}

StreamingResponse::StreamingResponse(std::vector<std::string> chunks)
    : Response(200, "", "text/plain; charset=utf-8"), chunks(std::move(chunks)) {
  for (const auto& c : this->chunks) body += c;
  headers.set("Transfer-Encoding", "chunked");
  if (this->chunks.size() > caps::kMaxStreamChunks) {
    status = 500;
    body = "chunk cap exceeded";
  }
}

SseResponse::SseResponse(std::vector<std::string> events)
    : Response(200, "", "text/event-stream"), events(std::move(events)) {
  for (const auto& e : this->events) body += "data: " + e + "\n\n";
}

std::string url_decode(std::string_view in) {
  std::string out;
  out.reserve(in.size());
  for (std::size_t i = 0; i < in.size(); ++i) {
    if (in[i] == '%' && i + 2 < in.size() &&
        std::isxdigit((unsigned char)in[i + 1]) &&
        std::isxdigit((unsigned char)in[i + 2])) {
      int hi = std::isdigit((unsigned char)in[i + 1])
                   ? in[i + 1] - '0'
                   : std::tolower((unsigned char)in[i + 1]) - 'a' + 10;
      int lo = std::isdigit((unsigned char)in[i + 2])
                   ? in[i + 2] - '0'
                   : std::tolower((unsigned char)in[i + 2]) - 'a' + 10;
      out.push_back((char)(hi * 16 + lo));
      i += 2;
    } else if (in[i] == '+') {
      out.push_back(' ');
    } else {
      out.push_back(in[i]);
    }
  }
  return out;
}

std::map<std::string, std::string> parse_query(std::string_view qs) {
  std::map<std::string, std::string> out;
  std::size_t start = 0;
  std::size_t fields = 0;
  while (start <= qs.size() && fields < caps::kMaxFormFields) {
    std::size_t amp = qs.find('&', start);
    if (amp == std::string_view::npos) amp = qs.size();
    std::string_view pair = qs.substr(start, amp - start);
    std::size_t eq = pair.find('=');
    if (eq == std::string_view::npos) {
      if (!pair.empty()) out[url_decode(pair)] = "";
    } else {
      out[url_decode(pair.substr(0, eq))] = url_decode(pair.substr(eq + 1));
    }
    ++fields;
    start = amp + 1;
  }
  return out;
}

std::map<std::string, std::string> parse_cookies(std::string_view header) {
  std::map<std::string, std::string> out;
  std::size_t start = 0;
  while (start < header.size()) {
    std::size_t semi = header.find(';', start);
    if (semi == std::string_view::npos) semi = header.size();
    std::string_view pair = header.substr(start, semi - start);
    std::size_t eq = pair.find('=');
    if (eq != std::string_view::npos) {
      std::string k(pair.substr(0, eq));
      std::string v(pair.substr(eq + 1));
      while (!k.empty() && k.front() == ' ') k.erase(k.begin());
      while (!v.empty() && v.front() == ' ') v.erase(v.begin());
      if (!k.empty()) out[k] = v;
    }
    start = semi + 1;
  }
  return out;
}

std::map<std::string, std::string> parse_form(std::string_view body) {
  return parse_query(body);
}

std::string status_text(int status) {
  switch (status) {
    case 200: return "OK";
    case 201: return "Created";
    case 207: return "Multi-Status";
    case 301: return "Moved Permanently";
    case 302: return "Found";
    case 400: return "Bad Request";
    case 401: return "Unauthorized";
    case 403: return "Forbidden";
    case 404: return "Not Found";
    case 405: return "Method Not Allowed";
    case 406: return "Not Acceptable";
    case 409: return "Conflict";
    case 413: return "Content Too Large";
    case 422: return "Unprocessable Entity";
    case 429: return "Too Many Requests";
    case 500: return "Internal Server Error";
    case 501: return "Not Implemented";
    default: return "Unknown";
  }
}

std::string json_escape(std::string_view in) {
  std::string out;
  out.reserve(in.size() + 2);
  for (char c : in) {
    switch (c) {
      case '"': out += "\\\""; break;
      case '\\': out += "\\\\"; break;
      case '\n': out += "\\n"; break;
      case '\r': out += "\\r"; break;
      case '\t': out += "\\t"; break;
      default: out.push_back(c); break;
    }
  }
  return out;
}

}  // namespace molo::example::fw