#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

#include "win.h"
#include "error.h"
#include "epoll.h"

static const char PING[] = "PING";
static const int NUM_PINGERS = 1000;
static const DWORD RUN_TIME = 40000;

int main(int argc, char* argv[]) {
  epoll_t epoll_hnd;
  int r;
  u_long one = 1;
  struct addrinfo hints;
  struct addrinfo* addrinfo;
  struct sockaddr_in addr;
  DWORD ticks_start, ticks_last;
  long long pings = 0, pings_sent = 0;
  int i;
  SOCKET srv;
  struct epoll_event ev;

  epoll_hnd = epoll_create();
  assert(epoll_hnd && epoll_hnd != INVALID_HANDLE_VALUE);

  memset(&hints, 0, sizeof hints);
  hints.ai_family = AF_INET;
  hints.ai_protocol = IPPROTO_UDP;

  r = getaddrinfo("localhost", NULL, &hints, &addrinfo);
  assert(r == 0);
  assert(addrinfo->ai_addrlen <= sizeof addr);

  memset(&addr, 0, sizeof addr);
  memcpy(&addr, addrinfo->ai_addr, addrinfo->ai_addrlen);
  addr.sin_port = htons(9123);

  freeaddrinfo(addrinfo);

  printf("resolved\n");

  srv = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  r = ioctlsocket(srv, FIONBIO, &one);
  assert(r == 0);

  r = bind(srv, (struct sockaddr*) &addr, sizeof addr);
  assert(r == 0);

  ev.events = EPOLLIN | EPOLLERR;
  ev.data.sock = srv;
  r = epoll_ctl(epoll_hnd, EPOLL_CTL_ADD, srv, &ev);
  assert(r == 0);

  for (i = 0; i < NUM_PINGERS; i++) {
    SOCKET sock;
    struct epoll_event ev;

    sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    r = ioctlsocket(sock, FIONBIO, &one);
    assert(r == 0);

    int one = 1;
    r = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
    assert(r == 0);

    r = connect(sock, (struct sockaddr*) &addr, sizeof addr);
    /* Unlike unix, windows sets the error to EWOULDBLOCK when the connection
     * is being established in the background.
     */
    assert(r == 0 || WSAGetLastError() == WSAEWOULDBLOCK);

    ev.events = EPOLLOUT | EPOLLERR | EPOLLONESHOT;
    ev.data.sock = sock;
    r = epoll_ctl(epoll_hnd, EPOLL_CTL_ADD, sock, &ev);
    assert(r == 0);
  }

  ticks_start = GetTickCount();
  ticks_last = ticks_start;

  for (;;) {
    int i, count;
    struct epoll_event events[16];
    DWORD ticks;

    ticks = GetTickCount();

    if (ticks >= ticks_last + 1000) {
      printf("%lld pings (%0.0f per sec), %lld sent (%0.0f per sec)\n",
             pings,
             (double) pings / (ticks - ticks_start) * 1000.0,
             pings_sent,
             (double) pings_sent / (ticks - ticks_start) * 1000.0);
      ticks_last = ticks;

      if (ticks - ticks_start > RUN_TIME)
        break;
    }

    count = epoll_wait(epoll_hnd, events, 15, 1000);
    assert(count >= 0);

    for (i = 0; i < count; i++) {
      int revents = events[i].events;

      if (revents & EPOLLERR) {
        SOCKET sock = events[i].data.sock;
        int r;
        int err = -1;
        int err_len = sizeof err;

        r = getsockopt(sock, SOL_SOCKET, SO_ERROR, (char*) &err, &err_len);
        assert(r == 0);
        fprintf(stderr, "Socket error: %d\n", err);

        r = epoll_ctl(epoll_hnd, EPOLL_CTL_DEL, sock, NULL);
        assert(r == 0);
        continue;
      }

      if (revents & EPOLLIN) {
        SOCKET sock = events[i].data.sock;
        char buf[1024];
        WSABUF wsa_buf;
        DWORD flags, bytes;
        int r;

        wsa_buf.buf = buf;
        wsa_buf.len = sizeof buf;

        flags = 0;
        for (;;) {
          r = WSARecv(sock, &wsa_buf, 1, &bytes, &flags, NULL, NULL);
          if (r == SOCKET_ERROR && WSAGetLastError() == WSAEWOULDBLOCK)
            break;
          assert(r >= 0);
          assert(bytes == sizeof PING);
          pings++;
        }

        continue;
      }

      if (revents & EPOLLOUT) {
        SOCKET sock = events[i].data.sock;
        WSABUF wsa_buf;
        DWORD bytes;
        int r;

        wsa_buf.buf = (char*) PING;
        wsa_buf.len = sizeof PING;
        r = WSASend(sock, &wsa_buf, 1, &bytes, 0, NULL, NULL);
        we_set_win_error(0);
        if (r < 0) perror("send");
        assert(r >= 0);
        assert(bytes == sizeof PING);

        pings_sent++;

        uint32_t rev = rand() & 0xff | EPOLLOUT | EPOLLONESHOT;
        struct epoll_event e;
        e.data.sock = sock;
        e.events = rev;
        if (epoll_ctl(epoll_hnd, EPOLL_CTL_ADD, sock, &e) < 0)
          abort();

        continue;
      }

      assert(0);
    }
  }

  r = epoll_close(epoll_hnd);
  assert(r == 0);

  closesocket(srv);

  return 0;
}