#include "NHttpClientLibCurl.h"
#include "nakama-cpp/log/NLogger.h"
#include <curl/curl.h>
#include <memory.h>
#include <nakama-cpp/NHttpTransportInterface.h>
#include <nakama-cpp/log/NLogger.h>
#include <string>

#if __ANDROID__
#include "AndroidCA.h"
#endif

static int debug_callback(CURL* handle, curl_infotype type, char* data, size_t size, void* userp) {
  const char* text;
  (void)handle; /* prevent compiler warning */
  (void)userp;

  switch (type) {
    case CURLINFO_TEXT:
      NLOG(Nakama::NLogLevel::Debug, "libcurl debug info <=> Text: %s", data);
    default: /* in case a new one is introduced */
      return 0;

    case CURLINFO_HEADER_OUT:
      text = "=> Send header";
      break;
    case CURLINFO_DATA_OUT:
      text = "=> Send data";
      break;
    case CURLINFO_SSL_DATA_OUT:
      text = "=> Send SSL data";
      break;
    case CURLINFO_HEADER_IN:
      text = "<= Recv header";
      break;
    case CURLINFO_DATA_IN:
      text = "<= Recv data";
      break;
    case CURLINFO_SSL_DATA_IN:
      text = "<= Recv SSL data";
      break;
  }

  NLOG(Nakama::NLogLevel::Debug, "libcurl debug info: %s", text);
  return 0;
}

static size_t write_callback(char* buffer, size_t size, size_t nmemb, void* user_ctx) {
  Nakama::NHttpClientLibCurlContext* curl_ctx = (Nakama::NHttpClientLibCurlContext*)user_ctx;

  if (buffer != NULL) {
    // char buffer from libcurl is not null terminated.
    curl_ctx->append_body(std::string(buffer, nmemb * size));
  }

  return nmemb * size;
}

namespace Nakama {

NHttpClientLibCurl::NHttpClientLibCurl(const NPlatformParameters& platformParameters)
    : _curl_multi(curl_multi_init(), curl_multi_cleanup) {}

void NHttpClientLibCurl::request(const NHttpRequest& req, const NHttpResponseCallback& callback) noexcept {
  std::unique_ptr<CURL, decltype(&curl_easy_cleanup)> curl_easy(curl_easy_init(), curl_easy_cleanup);

  std::string uri = _base_uri + req.path + (req.queryArgs.empty() ? "" : "?");
  for (auto p : req.queryArgs) {
    uri += p.first + "=" + p.second + "&";
  };

  curl_slist* headers_list = NULL;

  for (auto it = req.headers.begin(); it != req.headers.end(); it++) {
    headers_list = curl_slist_append(headers_list, (it->first + ": " + it->second).c_str());
    if (headers_list == NULL) {
      NLOG(Nakama::NLogLevel::Error, "error writing header: %s", it->first.c_str());
      return;
    }
  }

  const char* callMethod = nullptr;
  switch (req.method) {
    case NHttpReqMethod::POST:
      callMethod = "POST";
      // manually set content-length if there's no body.
      if (req.body.empty()) {
        headers_list = curl_slist_append(headers_list, "Content-Length: 0");
        if (headers_list == NULL) {
          NLOG(Nakama::NLogLevel::Error, "error writing header: Content-Length");
          return;
        }
      }
      break;
    case NHttpReqMethod::GET:
      callMethod = "GET";
      break;
    case NHttpReqMethod::PUT:
      callMethod = "PUT";
      break;
    case NHttpReqMethod::DEL:
      callMethod = "DELETE";
      break;
  }

  CURLcode curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_URL, uri.c_str());
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("setting url", curl_code, callback);
    return;
  }

  if (_timeout >= std::chrono::milliseconds(0)) {
    curl_code = curl_easy_setopt(
        curl_easy.get(), CURLOPT_TIMEOUT_MS, std::chrono::duration_cast<std::chrono::milliseconds>(_timeout).count());
    if (curl_code != CURLE_OK) {
      handle_curl_easy_set_opt_error("setting timeout", curl_code, callback);
      return;
    }
  }

  curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_HTTPHEADER, headers_list);
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("adding headers", curl_code, callback);
    return;
  }

  if (req.body != "") {
    curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_COPYPOSTFIELDS, req.body.c_str());
    if (curl_code != CURLE_OK) {
      handle_curl_easy_set_opt_error("copying post fields", curl_code, callback);
      return;
    }
  }

  curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_CUSTOMREQUEST, callMethod);
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("adding call method", curl_code, callback);
    return;
  }

#if __ANDROID__
  CACertificateData* data = Nakama::getCaCertificates();
  if (data == nullptr) {
    // Has System.loadLibrary("nakama-sdk") been called?
    NLOG(Nakama::NLogLevel::Error, "error obtaining CA Certificates.");
    return;
  } else {
    struct curl_blob blob;
    blob.data = reinterpret_cast<char*>(data->data);
    blob.len = data->len;
    blob.flags = CURL_BLOB_COPY;
    curl_easy_setopt(curl_easy.get(), CURLOPT_CAINFO_BLOB, &blob);
  }
#endif

  curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_WRITEFUNCTION, write_callback);
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("adding write function", curl_code, callback);
    return;
  }

  std::unique_ptr<NHttpClientLibCurlContext> curl_ctx(new NHttpClientLibCurlContext(callback, headers_list));
  curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_WRITEDATA, curl_ctx.get());
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("adding curl context", curl_code, callback);
    return;
  }

  /* ask libcurl to show us the verbose output */
#ifdef CURL_DEBUG
  curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_VERBOSE, 1L);
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("setting verbose output", curl_code, callback);
    return;
  }

  curl_code = curl_easy_setopt(curl_easy.get(), CURLOPT_DEBUGFUNCTION, debug_callback);
  if (curl_code != CURLE_OK) {
    handle_curl_easy_set_opt_error("adding debug function", curl_code, callback);
    return;
  }
#endif
  const std::lock_guard lock(_mutex);

  CURLMcode curl_multi_code = curl_multi_add_handle(_curl_multi.get(), curl_easy.get());

  if (curl_multi_code != CURLM_OK) {
    auto response = std::shared_ptr<NHttpResponse>(new NHttpResponse());
    response->errorMessage =
        "curl_multi_add_handle() error while adding handle, code: " + std::string(curl_multi_strerror(curl_multi_code));
    response->statusCode = -1;
    callback(response);
    return;
  };

  std::pair<std::unique_ptr<CURL, decltype(&curl_easy_cleanup)>, std::unique_ptr<NHttpClientLibCurlContext>> pair(
      std::move(curl_easy), std::move(curl_ctx));
  _contexts.emplace_back(std::move(pair));
}

void NHttpClientLibCurl::setBaseUri(const std::string& uri) { _base_uri = uri; }

void NHttpClientLibCurl::setTimeout(std::chrono::milliseconds timeout) { _timeout = timeout; }

void NHttpClientLibCurl::tick() {
  std::unique_lock lock(_mutex, std::try_to_lock);
  if (!lock.owns_lock()) {
    return; // return immediately, tick() is expected to get called again. no reason to make tick block.
  }

  int running_handles = 0;
  CURLMcode mc = curl_multi_perform(_curl_multi.get(), &running_handles);

  lock.unlock();
  if (mc) {
    // log but do not return -- still see if any pending messages
    NLOG(Nakama::NLogLevel::Error, "curl_multi_perform() failed, code %d.\n", (int)mc);
  }

  struct CURLMsg* m = nullptr;
  CURLcode result;

  do {
    int msgq = 0;
    lock.lock();
    m = curl_multi_info_read(_curl_multi.get(), &msgq);
    lock.unlock();

    if (m && (m->msg == CURLMSG_DONE)) {
      lock.lock();
      result = m->data.result; // cache here because when we remove the easy handle, m is invalidated.
      CURL* e = m->easy_handle;
      long response_code;
      CURLcode curl_code = curl_easy_getinfo(e, CURLINFO_RESPONSE_CODE, &response_code);

      std::unique_ptr<NHttpClientLibCurlContext> context = NULL;

      auto it = _contexts.begin();
      while (it != _contexts.end()) {
        if (it->first.get() == e) {
          break;
        }

        it++;
      }

      if (it == _contexts.end()) {
        NLOG(Nakama::NLogLevel::Error, "curl_multi_info_read() error: untracked easy handle.");
        continue;
      }

      context = std::move(it->second);

      mc = curl_multi_remove_handle(_curl_multi.get(), e);
      if (mc) {
        NLOG(Nakama::NLogLevel::Error, "curl_multi_remove_handle() failed, code %d.\n", (int)mc);
      }

      _contexts.remove(*it);

      lock.unlock();

      auto callback = context->get_callback();
      if (callback != NULL) {
        NLOG_DEBUG("invoking curl callback");

        auto response = std::shared_ptr<NHttpResponse>(new NHttpResponse());
        response->body = context->get_body();

        if (result != CURLE_OK) {
          NLOG(Nakama::NLogLevel::Error, "curl easy handle returned code: %d \n", (int)result);
          response->statusCode = InternalStatusCodes::CONNECTION_ERROR;
        } else {
          response->statusCode = static_cast<int>(response_code);

          if (curl_code != CURLE_OK) {
            NLOG(
                Nakama::NLogLevel::Error, "curl_easy_getinfo() failed when getting response code, code %d.\n",
                (int)curl_code);
          }
        }

        callback(response);
      }
    }
  } while (m);
}

void NHttpClientLibCurl::cancelAllRequests() {
  const std::lock_guard lock(_mutex);
  for (auto it = _contexts.begin(); it != _contexts.end(); it++) {
    NHttpResponsePtr responsePtr(new NHttpResponse());

    responsePtr->statusCode = InternalStatusCodes::CANCELLED_BY_USER;
    responsePtr->errorMessage = "cancelled by user";

    it->second->get_callback()(responsePtr);
    CURLMcode mc = curl_multi_remove_handle(_curl_multi.get(), it->first.get());
    if (mc != CURLM_OK) {
      NLOG(Nakama::NLogLevel::Error, "curl_multi_remove_handle() failed, code %d.\n", (int)mc);
    }
  }

  _contexts.clear();
}

void NHttpClientLibCurl::handle_curl_easy_set_opt_error(
    std::string action,
    CURLcode code,
    const NHttpResponseCallback& callback) {
  auto response = std::shared_ptr<NHttpResponse>(new NHttpResponse());
  response->errorMessage =
      "curl_easy_getinfo() error while : " + action + ", code: " + std::string(curl_easy_strerror(code));
  response->statusCode = -1;
  callback(response);
}

}; // namespace Nakama