#include "socket/iocp.h"

#include "utils/thread_pool.h"

namespace Network {

IOCP::IOCP() {
  gen_ = std::mt19937(rd_());
  jitterDist_ = std::uniform_int_distribution<int>(-10, 10);
}

IOCP::~IOCP() { destruct(); }

void IOCP::destruct() {
#ifdef __linux__

#endif
}

void IOCP::registerSocket(IOCPPASSINDATA* data) {
#ifdef _WIN32
  HANDLE returnData = ::CreateIoCompletionPort(
      (HANDLE)data->socket->sock, completionPort_, data->socket->sock, 0);
  if (returnData == 0) completionPort_ = returnData;

  data->event = IOCPEVENT::READ;
  DWORD recvbytes = 0, flags = 0;
  ::WSARecv(data->socket->sock, &data->wsabuf, 1, &recvbytes, &flags,
            &data->overlapped, NULL);

#endif
}

int IOCP::recv(IOCPPASSINDATA* data) {
  SOCKET sock = data->socket->sock;
  std::lock_guard lock(*GetRecvQueueMutex_(sock));
  auto queue = GetRecvQueue_(sock);

  std::uint32_t left_data = data->wsabuf.len;
  std::uint32_t copied = 0;

  while (!queue->empty() && left_data != 0) {
    auto front = queue->front();
    queue->pop_front();

    std::uint32_t offset = front.second;
    std::uint32_t available = front.first.size() - offset;
    std::uint32_t to_copy = (left_data < available) ? left_data : available;

    ::memcpy(data->wsabuf.buf + copied, front.first.data() + offset, to_copy);
    copied += to_copy;
    left_data -= to_copy;
    offset += to_copy;

    if (offset < front.first.size()) {
      front.second = offset;
      queue->push_front(front);
      break;
    }
  }

  return copied;
}

int IOCP::send(SOCKET sock, std::vector<IOCPPASSINDATA*>* data) {
  auto lk = GetSendQueueMutex_(sock);
  auto queue = GetSendQueue_(sock);
  std::lock_guard lock(*lk);
  for (auto& it : *data) {
    it->event = IOCPEVENT::WRITE;
    queue->push_back(it);
  }

  IOCPThread_->enqueueJob(
      [this, sock](utils::ThreadPool* th, std::uint8_t __) {
        packet_sender_(sock);
      },
      0);
  return 0;
}

std::shared_ptr<std::list<IOCPPASSINDATA*>> IOCP::GetSendQueue_(SOCKET sock) {
  std::lock_guard lock(socket_mod_mutex_);
  if (send_queue_.find(sock) == send_queue_.end()) {
    send_queue_[sock] = std::make_shared<std::list<IOCPPASSINDATA*>>(
        std::list<IOCPPASSINDATA*>());
  }
  return send_queue_[sock];
}

std::shared_ptr<std::list<std::pair<std::vector<char>, std::uint32_t>>>
IOCP::GetRecvQueue_(SOCKET sock) {
  std::lock_guard lock(socket_mod_mutex_);
  if (recv_queue_.find(sock) == recv_queue_.end()) {
    recv_queue_[sock] = std::make_shared<
        std::list<std::pair<std::vector<char>, std::uint32_t>>>(
        std::list<std::pair<std::vector<char>, std::uint32_t>>());
  }
  return recv_queue_[sock];
}

std::shared_ptr<std::mutex> IOCP::GetSendQueueMutex_(SOCKET sock) {
  std::lock_guard lock(socket_mod_mutex_);
  if (send_queue_mutex_.find(sock) == send_queue_mutex_.end()) {
    send_queue_mutex_[sock] = std::make_shared<std::mutex>();
  }
  return send_queue_mutex_[sock];
}

std::shared_ptr<std::mutex> IOCP::GetRecvQueueMutex_(SOCKET sock) {
  std::lock_guard lock(socket_mod_mutex_);
  if (recv_queue_mutex_.find(sock) == recv_queue_mutex_.end()) {
    recv_queue_mutex_[sock] = std::make_shared<std::mutex>();
  }
  return recv_queue_mutex_[sock];
}

void IOCP::packet_sender_(SOCKET sock) {
  auto queue = GetSendQueue_(sock);
  std::unique_lock lock(*GetSendQueueMutex_(sock));

  std::vector<char> buf(16384);
  WSABUF wsabuf;
  DWORD sendbytes = 0;

  while (!queue->empty()) {
    auto front = queue->front();
    queue->pop_front();
    front->event = IOCPEVENT::WRITE;

    int data_len = 0;

    if (proto_ == SessionProtocol::TLS || proto_ == SessionProtocol::QUIC) {
      int ret = ::SSL_write(front->ssl, front->wsabuf.buf, front->wsabuf.len);
      if (ret <= 0) {
        int err = ::SSL_get_error(front->ssl, ret);
        if (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE) {
          queue->push_front(front);
          break;
        }
        std::unique_lock lk(socket_mod_mutex_);
        send_queue_.erase(sock);
        break;
      }

      while ((data_len = ::BIO_read(front->wbio, buf.data(), buf.size())) > 0) {
        wsabuf.buf = buf.data();
        wsabuf.len = data_len;

        ::WSASend(sock, &wsabuf, 1, &sendbytes, 0, nullptr, nullptr);
      }

    } else {
      data_len = front->wsabuf.len;
      wsabuf.buf = front->wsabuf.buf;
      wsabuf.len = data_len;
      ::WSASend(sock, &wsabuf, 1, &sendbytes, 0, nullptr, nullptr);
    }
  }
}

}  // namespace Network