#include "TCP_Client.h"
#include "Core/Statistics/Frequency_Limit.h"
#include "Socket_p.h"

#include <chrono>
#include <string>

#ifdef _WIN32
  #include <winsock2.h>
  #include <ws2tcpip.h>
#else
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/select.h>
  #include <errno.h>
#endif

namespace Psc::socket {

static bool fd_writable_now(int fd) {
#ifdef _WIN32
  fd_set wfds;
  FD_ZERO(&wfds);
  FD_SET((SOCKET)fd, &wfds);
  timeval tv{};
  tv.tv_sec = 0; tv.tv_usec = 0;
  int r = select(0, nullptr, &wfds, nullptr, &tv);
  return r > 0 && FD_ISSET((SOCKET)fd, &wfds);
#else
  fd_set wfds;
  FD_ZERO(&wfds);
  FD_SET(fd, &wfds);
  timeval tv{};
  tv.tv_sec = 0; tv.tv_usec = 0;
  int r = select(fd + 1, nullptr, &wfds, nullptr, &tv);
  return r > 0 && FD_ISSET(fd, &wfds);
#endif
}


void TCP_Client::create() {
  send_buffer.init(max_buffer_size);

  auto rsf = socket::create_socket_fd(Socket_Type::TCP);
  if (!rsf) {
    last_err = rsf.error();
    socket_logger->c_debug("Tcp_Client::create", {}, LOG_POS + last_err.to_string());
    return;
  }

  socket_fd = rsf.value();
  set_state(Not_Set_Field);
  auto r = socket::set_reuse(socket_fd, true)
    .and_then([this]() { return socket::set_block(socket_fd, false); })
    .and_then([this]() { return socket::TCP::set_keep_alive(socket_fd, true); })
    .and_then([this]() { return socket::TCP::set_no_delay(socket_fd, true); })
    .and_then([this]() { return socket::set_reuse_addr(socket_fd, true); })

  ;

  if (!r) {
    last_err = r.error();
    socket_logger->error("Tcp_Client::create", {}, Psc::to_string(last_err) + " " + LOG_POS);
    (void)socket::close(socket_fd);
    socket_fd = -1;
    set_state(Not_Created);
    return;
  }

  // 这里最好检查 dest_address 是否已设置（你自己加一个标志位也行）


  set_state(Reconnecting);
  next_reconnect_tp = std::chrono::steady_clock::now();
  tick(); // 立即尝试一次
}


void TCP_Client::schedule_recreate(Enum_Err<NetError> e) {
  last_err = e;
  (void)socket::close(socket_fd);
  set_state(Not_Created);
  next_reconnect_tp = std::chrono::steady_clock::now() + std::chrono::milliseconds(reconnect_backoff_ms);
}

bool TCP_Client::start_connect() {
  if (socket_fd == -1) return false;

  auto r = socket::connect(socket_fd, dest_address);
  if (!r) {
    last_err = r.error();


    if (last_err.nerr == NetError::in_progress) {
      set_state(Connecting);
      return false; // 还没完成
    }

    if (last_err.nerr == NetError::already_connected) {
      set_state(Wait_Check);
      return true;
    }

    socket_logger->c_debug({}, {}, "连接失败:"+ VAR_STR_2(last_err, *this) + "\n");


    // 其它错误：进入退避重连
    schedule_recreate(last_err);
    return false;
  }

  return false;
}

bool TCP_Client::check_writeable() {
  return true;
}

void TCP_Client::tick() {
  if (socket_fd == -1) return;

  auto st = state.load();
  auto now = std::chrono::steady_clock::now();

  if (st == Not_Created) {
    create();
    return;
  }

  if (st == Reconnecting) {
    if (now >= next_reconnect_tp) {
      (void) start_connect();
    }
    return;
  }

  if (st == Connecting || st == Wait_Check) {
    set_state(Connected);
    return;
  }

  if (st == Connected) {
    flush_send_buffer();
    return;
  }
}

std::string TCP_Client::read() {
  if (socket_fd == -1) return "";



  // 如果还没连上，先推进连接状态
  tick();
  if (state.load(std::memory_order_relaxed) != Connected) return "";



  auto ret = socket::recv_all(socket_fd);
  if (!ret) {
    Enum_Err e = ret.error();

    // 下面这几个名字按你 NetError 实际枚举改：
    // - would_block: 非阻塞没数据，不算错
    // - in_progress/not_connected: 连接没完成
    if (e.nerr == NetError::would_block) return "";

    static Frequency_Limit drop_log_fl;
    if (drop_log_fl.test()) {
      socket_logger->c_debug("Tcp_Client::read recv失败", {},
        to_string() + " " + Ret_To_String(ret) + " " + LOG_POS);
    }

    // 断线类错误：进入退避重连（必要时你也可以 close+重建fd）
    schedule_recreate(e);
    return "";
  }

  auto r = ret.value();
  return r;
}

void TCP_Client::flush_send_buffer() {
  if (socket_fd == -1) return;
  if (state.load(std::memory_order_relaxed) != Connected) return;
  if (send_buffer.empty()) return;

  constexpr uint32_t patch_len = 1500;
  std::string buf;
  buf.resize(patch_len);

  while (true) {
    uint32_t n = send_buffer.peek_best_effort(buf.data(), patch_len);
    if (n == 0) break;
    auto r = socket::send(socket_fd, buf.data(), n);
    if (!r) {
      last_err = r.error();

      if (last_err.nerr == NetError::would_block) break;
      if (last_err.nerr == NetError::connection_aborted) {
        schedule_recreate(last_err);
      }
      else if (last_err.nerr == NetError::connection_reset) {
        schedule_recreate(last_err);
      } else {
        socket_logger->c_debug("Tcp_Client::send", {}, "触发重连 " + VAR_STR_2(last_err, *this));
        schedule_recreate(last_err);
      }
      return;
    }
    send_buffer.skip_best_effort((uint32_t)r.value());
  }
}

void TCP_Client::send(const std::string& data) {
  if (data.empty()) return;
  (void)send_buffer.write_best_effort((const uint8_t*)data.data(), (uint32_t)data.size());
  if (state != Connected) return;
  tick();
  flush_send_buffer();
}

std::string TCP_Client::to_string() {
  return VAR_STR_4(socket_fd, address, dest_address, state);
}
void TCP_Client::close() {
  if (socket_fd != -1) {
    auto r = socket::close(socket_fd);
    (void)r;
    socket_fd = -1;
    set_state(Not_Created);
  }
}

void TCP_Client::set_state(State s) {
  auto old_state = state.load();
  std::ostringstream oss;
  oss << to_string() << "状态变化:" << Psc::to_string(s) << "===>" << Psc::to_string(old_state) << std::endl;
  socket_logger->debug({}, {}, oss.str());
  if (on_state_change) on_state_change(state, s);
  state = s;
}

TCP_Client::~TCP_Client() {
  TCP_Client::close();
}

} // namespace Psc::socket