#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>

#include <uv.h>

static int connection_count = 0;

static uv_buf_t alloc_buffer(uv_handle_t *handle, size_t suggested_size) {
  return uv_buf_init(calloc(1, suggested_size), suggested_size);
}

static void on_write_complete(uv_write_t *req, int status) {
  /* we could check status here, but we don't care; just free, and be done */
  free(req->data);
  free(req);
}

static void on_input(uv_stream_t *conn, ssize_t nread, uv_buf_t buf) {
  if (nread == -1) {
    /* here we could check uv_last_error(conn->loop).code to see whether it's UV_EOF or not */
    /* but we don't care; just close, and be done */
    connection_count--;
    if (connection_count == 0) {
      uv_stop(conn->loop);
    }
    uv_close((uv_handle_t *) conn, NULL);
  } else {
    uv_write_t *req = calloc(1, sizeof(uv_write_t));
    /* we just echo what came in. */
    req->data = buf.base;
    buf.len = nread;
    uv_write(req, conn, &buf, 1, on_write_complete);
  }
}

static void on_connection(uv_stream_t *serversock, int status) {
  uv_tcp_t *conn;

  if (status == -1) {
    /* error? */
    return;
  }

  conn = calloc(1, sizeof(uv_tcp_t));
  uv_tcp_init(serversock->loop, conn);
  if (uv_accept(serversock, (uv_stream_t *) conn) == 0) {
    connection_count++;
    uv_read_start((uv_stream_t *) conn, alloc_buffer, on_input);
  } else {
    uv_close((uv_handle_t *) conn, NULL);
  }
}

static int const PORTNUMBER = 5999;

int main(int argc, char const *argv[]) {
  uv_loop_t *uv = uv_default_loop();
  uv_tcp_t serversock;
  struct sockaddr_in bind_addr;

  printf("uvserver; libuv version %s\n", uv_version_string());

  if (argc > 1) {
    return 0;
  }

  printf("Accepting connections on port %d.\n", PORTNUMBER);
  uv_tcp_init(uv, &serversock);
  bind_addr = uv_ip4_addr("0.0.0.0", PORTNUMBER);
  uv_tcp_bind(&serversock, bind_addr);
  uv_listen((uv_stream_t *) &serversock, 4, on_connection);

  uv_run(uv, UV_RUN_DEFAULT);

  uv_loop_delete(uv);
  return 0;
}