/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <errno.h>

#ifndef _WIN32
# include <fcntl.h>
# include <sys/socket.h>
# include <unistd.h>
#endif

#include "uv.h"
#include "task.h"


#define NUM_CLIENTS 5
#define TRANSFER_BYTES (1 << 16)

#undef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b));


typedef enum {
  UNIDIRECTIONAL,
  DUPLEX
} test_mode_t;

typedef struct connection_context_s {
  uv_poll_t poll_handle;
  uv_timer_t timer_handle;
  uv_os_sock_t sock;
  size_t read, sent;
  int is_server_connection;
  int open_handles;
  int got_fin, sent_fin;
  unsigned int events, delayed_events;
} connection_context_t;

typedef struct server_context_s {
  uv_poll_t poll_handle;
  uv_os_sock_t sock;
  int connections;
} server_context_t;


static void delay_timer_cb(uv_timer_t* timer, int status);


static test_mode_t test_mode = DUPLEX;

static int closed_connections = 0;

static int valid_writable_wakeups = 0;
static int spurious_writable_wakeups = 0;


static int got_eagain(void) {
#ifdef _WIN32
  return WSAGetLastError() == WSAEWOULDBLOCK;
#else
  return errno == EAGAIN
      || errno == EINPROGRESS
#ifdef EWOULDBLOCK
      || errno == EWOULDBLOCK;
#endif
      ;
#endif
}


static void set_nonblocking(uv_os_sock_t sock) {
  int r;
#ifdef _WIN32
  unsigned long on = 1;
  r = ioctlsocket(sock, FIONBIO, &on);
  ASSERT(r == 0);
#else
  int flags = fcntl(sock, F_GETFL, 0);
  ASSERT(flags >= 0);
  r = fcntl(sock, F_SETFL, flags | O_NONBLOCK);
  ASSERT(r >= 0);
#endif
}


static uv_os_sock_t create_nonblocking_bound_socket(
    struct sockaddr_in bind_addr) {
  uv_os_sock_t sock;
  int r;

  sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
#ifdef _WIN32
  ASSERT(sock != INVALID_SOCKET);
#else
  ASSERT(sock >= 0);
#endif

  set_nonblocking(sock);

#ifndef _WIN32
  {
    /* Allow reuse of the port. */
    int yes = 1;
    r = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof yes);
    ASSERT(r == 0);
  }
#endif

  r = bind(sock, (const struct sockaddr*) &bind_addr, sizeof bind_addr);
  ASSERT(r == 0);

  return sock;
}


static void close_socket(uv_os_sock_t sock) {
  int r;
#ifdef _WIN32
  r = closesocket(sock);
#else
  r = close(sock);
#endif
  ASSERT(r == 0);
}


static connection_context_t* create_connection_context(
    uv_os_sock_t sock, int is_server_connection) {
  int r;
  connection_context_t* context;

  context = (connection_context_t*) malloc(sizeof *context);
  ASSERT(context != NULL);

  context->sock = sock;
  context->is_server_connection = is_server_connection;
  context->read = 0;
  context->sent = 0;
  context->open_handles = 0;
  context->events = 0;
  context->delayed_events = 0;
  context->got_fin = 0;
  context->sent_fin = 0;

  r = uv_poll_init_socket(uv_default_loop(), &context->poll_handle, sock);
  context->open_handles++;
  context->poll_handle.data = context;
  ASSERT(r == 0);

  r = uv_timer_init(uv_default_loop(), &context->timer_handle);
  context->open_handles++;
  context->timer_handle.data = context;
  ASSERT(r == 0);

  return context;
}


static void connection_close_cb(uv_handle_t* handle) {
  connection_context_t* context = (connection_context_t*) handle->data;

  if (--context->open_handles == 0) {
    if (test_mode == DUPLEX || context->is_server_connection) {
      ASSERT(context->read == TRANSFER_BYTES);
    } else {
      ASSERT(context->read == 0);
    }

    if (test_mode == DUPLEX || !context->is_server_connection) {
      ASSERT(context->sent == TRANSFER_BYTES);
    } else {
      ASSERT(context->sent == 0);
    }

    closed_connections++;

    free(context);
  }
}


static void destroy_connection_context(connection_context_t* context) {
  uv_close((uv_handle_t*) &context->poll_handle, connection_close_cb);
  uv_close((uv_handle_t*) &context->timer_handle, connection_close_cb);
}


static void connection_poll_cb(uv_poll_t* handle, int status, int events) {
  connection_context_t* context = (connection_context_t*) handle->data;
  unsigned int new_events;
  int r;

  ASSERT(status == 0);
  ASSERT(events & context->events);
  ASSERT(!(events & ~context->events));

  new_events = context->events;

  if (events & UV_READABLE) {
    int action = rand() % 7;

    switch (action) {
      case 0:
      case 1: {
        /* Read a couple of bytes. */
        static char buffer[74];
        r = recv(context->sock, buffer, sizeof buffer, 0);
        ASSERT(r >= 0);

        if (r > 0) {
          context->read += r;
        } else {
          /* Got FIN. */
          context->got_fin = 1;
          new_events &= ~UV_READABLE;
        }

        break;
      }

      case 2:
      case 3: {
        /* Read until EAGAIN. */
        static char buffer[931];
        r = recv(context->sock, buffer, sizeof buffer, 0);
        ASSERT(r >= 0);

        while (r > 0) {
          context->read += r;
          r = recv(context->sock, buffer, sizeof buffer, 0);
        }

        if (r == 0) {
          /* Got FIN. */
          context->got_fin = 1;
          new_events &= ~UV_READABLE;
        } else {
          ASSERT(got_eagain());
        }

        break;
      }

      case 4:
        /* Ignore. */
        break;

      case 5:
        /* Stop reading for a while. Restart in timer callback. */
        new_events &= ~UV_READABLE;
        if (!uv_is_active((uv_handle_t*) &context->timer_handle)) {
          context->delayed_events = UV_READABLE;
          uv_timer_start(&context->timer_handle, delay_timer_cb, 10, 0);
        } else {
          context->delayed_events |= UV_READABLE;
        }
        break;

      case 6:
        /* Fudge with the event mask. */
        uv_poll_start(&context->poll_handle, UV_WRITABLE, connection_poll_cb);
        uv_poll_start(&context->poll_handle, UV_READABLE, connection_poll_cb);
        context->events = UV_READABLE;
        break;

      default:
        ASSERT(0);
    }
  }

  if (events & UV_WRITABLE) {
    if (context->sent < TRANSFER_BYTES &&
        !(test_mode == UNIDIRECTIONAL && context->is_server_connection)) {
      /* We have to send more bytes. */
      int action = rand() % 7;

      switch (action) {
        case 0:
        case 1: {
          /* Send a couple of bytes. */
          static char buffer[103];

          int send_bytes = MIN(TRANSFER_BYTES - context->sent, sizeof buffer);
          ASSERT(send_bytes > 0);

          r = send(context->sock, buffer, send_bytes, 0);

          if (r < 0) {
            ASSERT(got_eagain());
            spurious_writable_wakeups++;
            break;
          }

          ASSERT(r > 0);
          context->sent += r;
          valid_writable_wakeups++;
          break;
        }

        case 2:
        case 3: {
          /* Send until EAGAIN. */
          static char buffer[1234];

          int send_bytes = MIN(TRANSFER_BYTES - context->sent, sizeof buffer);
          ASSERT(send_bytes > 0);

          r = send(context->sock, buffer, send_bytes, 0);

          if (r < 0) {
            ASSERT(got_eagain());
            spurious_writable_wakeups++;
            break;
          }

          ASSERT(r > 0);
          valid_writable_wakeups++;
          context->sent += r;

          while (context->sent < TRANSFER_BYTES) {
            send_bytes = MIN(TRANSFER_BYTES - context->sent, sizeof buffer);
            ASSERT(send_bytes > 0);

            r = send(context->sock, buffer, send_bytes, 0);

            if (r <= 0) break;
            context->sent += r;
          }
          ASSERT(r > 0 || got_eagain());
          break;
        }

        case 4:
          /* Ignore. */
         break;

        case 5:
          /* Stop sending for a while. Restart in timer callback. */
          new_events &= ~UV_WRITABLE;
          if (!uv_is_active((uv_handle_t*) &context->timer_handle)) {
            context->delayed_events = UV_WRITABLE;
            uv_timer_start(&context->timer_handle, delay_timer_cb, 100, 0);
          } else {
            context->delayed_events |= UV_WRITABLE;
          }
          break;

        case 6:
          /* Fudge with the event mask. */
          uv_poll_start(&context->poll_handle,
                        UV_READABLE,
                        connection_poll_cb);
          uv_poll_start(&context->poll_handle,
                        UV_WRITABLE,
                        connection_poll_cb);
          context->events = UV_WRITABLE;
          break;

        default:
          ASSERT(0);
      }

    } else {
      /* Nothing more to write. Send FIN. */
      int r;
#ifdef _WIN32
      r = shutdown(context->sock, SD_SEND);
#else
      r = shutdown(context->sock, SHUT_WR);
#endif
      ASSERT(r == 0);
      context->sent_fin = 1;
      new_events &= ~UV_WRITABLE;
    }
  }

  if (context->got_fin && context->sent_fin) {
    /* Sent and received FIN. Close and destroy context. */
    close_socket(context->sock);
    destroy_connection_context(context);
    context->events = 0;

  } else if (new_events != context->events) {
    /* Poll mask changed. Call uv_poll_start again. */
    context->events = new_events;
    uv_poll_start(handle, new_events, connection_poll_cb);
  }

  /* Assert that uv_is_active works correctly for poll handles. */
  if (context->events != 0) {
    ASSERT(uv_is_active((uv_handle_t*) handle));
  } else {
    ASSERT(!uv_is_active((uv_handle_t*) handle));
  }
}


static void delay_timer_cb(uv_timer_t* timer, int status) {
  connection_context_t* context = (connection_context_t*) timer->data;
  int r;

  /* Timer should auto stop. */
  ASSERT(!uv_is_active((uv_handle_t*) timer));

  /* Add the requested events to the poll mask. */
  ASSERT(context->delayed_events != 0);
  context->events |= context->delayed_events;
  context->delayed_events = 0;

  r = uv_poll_start(&context->poll_handle,
                    context->events,
                    connection_poll_cb);
  ASSERT(r == 0);
}


static server_context_t* create_server_context(
    uv_os_sock_t sock) {
  int r;
  server_context_t* context;

  context = (server_context_t*) malloc(sizeof *context);
  ASSERT(context != NULL);

  context->sock = sock;
  context->connections = 0;

  r = uv_poll_init_socket(uv_default_loop(), &context->poll_handle, sock);
  context->poll_handle.data = context;
  ASSERT(r == 0);

  return context;
}


static void server_close_cb(uv_handle_t* handle) {
  server_context_t* context = (server_context_t*) handle->data;
  free(context);
}


static void destroy_server_context(server_context_t* context) {
  uv_close((uv_handle_t*) &context->poll_handle, server_close_cb);
}


static void server_poll_cb(uv_poll_t* handle, int status, int events) {
  server_context_t* server_context = (server_context_t*)
                                          handle->data;
  connection_context_t* connection_context;
  struct sockaddr_in addr;
  socklen_t addr_len;
  uv_os_sock_t sock;
  int r;

  addr_len = sizeof addr;
  sock = accept(server_context->sock, (struct sockaddr*) &addr, &addr_len);
#ifdef _WIN32
  ASSERT(sock != INVALID_SOCKET);
#else
  ASSERT(sock >= 0);
#endif

  set_nonblocking(sock);

  connection_context = create_connection_context(sock, 1);
  connection_context->events = UV_READABLE | UV_WRITABLE;
  r = uv_poll_start(&connection_context->poll_handle,
                    UV_READABLE | UV_WRITABLE,
                    connection_poll_cb);
  ASSERT(r == 0);

  if (++server_context->connections == NUM_CLIENTS) {
    close_socket(server_context->sock);
    destroy_server_context(server_context);
  }
}


static void start_server(void) {
  uv_os_sock_t sock;
  server_context_t* context;
  int r;

  sock = create_nonblocking_bound_socket(uv_ip4_addr("127.0.0.1", TEST_PORT));
  context = create_server_context(sock);

  r = listen(sock, 100);
  ASSERT(r == 0);

  r = uv_poll_start(&context->poll_handle, UV_READABLE, server_poll_cb);
  ASSERT(r == 0);
}


static void start_client(void) {
  uv_os_sock_t sock;
  connection_context_t* context;
  struct sockaddr_in server_addr = uv_ip4_addr("127.0.0.1", TEST_PORT);
  int r;

  sock = create_nonblocking_bound_socket(uv_ip4_addr("0.0.0.0", 0));
  context = create_connection_context(sock, 0);

  context->events = UV_READABLE | UV_WRITABLE;
  r = uv_poll_start(&context->poll_handle,
                    UV_READABLE | UV_WRITABLE,
                    connection_poll_cb);
  ASSERT(r == 0);

  r = connect(sock, (struct sockaddr*) &server_addr, sizeof server_addr);
  ASSERT(r == 0 || got_eagain());
}


static void start_poll_test(void) {
  int i, r;

#ifdef _WIN32
  {
    struct WSAData wsa_data;
    int r = WSAStartup(MAKEWORD(2, 2), &wsa_data);
    ASSERT(r == 0);
  }
#endif

  start_server();

  for (i = 0; i < NUM_CLIENTS; i++)
    start_client();

  r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
  ASSERT(r == 0);

  /* Assert that at most five percent of the writable wakeups was spurious. */
  ASSERT(spurious_writable_wakeups == 0 ||
         (valid_writable_wakeups + spurious_writable_wakeups) /
         spurious_writable_wakeups > 20);

  ASSERT(closed_connections == NUM_CLIENTS * 2);

  MAKE_VALGRIND_HAPPY();
}


TEST_IMPL(poll_duplex) {
  test_mode = DUPLEX;
  start_poll_test();
  return 0;
}


TEST_IMPL(poll_unidirectional) {
  test_mode = UNIDIRECTIONAL;
  start_poll_test();
  return 0;
}