/***********************************************
        File Name: peer.h
        Author: Abby Cin
        Mail: abbytsing@gmail.com
        Created Time: 10/24/20 2:42 PM
***********************************************/

#ifndef _CONET_PEER_H_
#define _CONET_PEER_H_

class peer
{
public:
  peer(context& ctx, int fd) : ctx_{ctx}, fd_{fd} {}
  peer(peer&& r) noexcept : ctx_{r.ctx_}, fd_{r.fd_} { r.fd_ = -1; }
  ~peer() { this->close(); }

  auto read_some(char* data, int n)
  {
    struct awaiter
    {
      context& ctx_;
      int fd_;
      char* data_;
      int n_;
      awaiter(context& ctx, int f, char* data, int n) : ctx_{ctx}, fd_{f}, data_{data}, n_{n} {}

      bool await_ready() { return false; }

      bool await_suspend(handle_t co)
      {
        ctx_.push(fd_, co);
        return true; // same to `void await_suspend()`, immediately back to caller
      }

      int await_resume() { return ::read(fd_, data_, n_); }
    };
    return awaiter{ctx_, fd_, data, n};
  }

  // no guarantee that all data will be sent
  auto write_some(char* data, int n)
  {
    struct awaiter
    {
      peer* p_;
      int fd_;
      char* data_;
      int n_;
      int res_{0};
      awaiter(peer* p, int f, char* data, int n) : p_{p}, fd_{f}, data_{data}, n_{n} {}

      bool await_ready() { return false; }

      void await_suspend(handle_t) { res_ = ::write(fd_, data_, n_); }

      int await_resume() { return res_; }
    };
    return awaiter{this, fd_, data, n};
  }

  void close()
  {
    if(fd_ > 0)
    {
      ctx_.pop(fd_);
      ::close(fd_);
      fd_ = -1;
    }
  }

private:
  context& ctx_;
  int fd_;
};

#endif //_CONET_PEER_H_