/*
 * This file is part of the Nice GLib ICE library.
 *
 * (C) 2008-2009 Collabora Ltd.
 *  Contact: Youness Alaoui
 * (C) 2008-2009 Nokia Corporation. All rights reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Nice GLib ICE library.
 *
 * The Initial Developers of the Original Code are Collabora Ltd and Nokia
 * Corporation. All Rights Reserved.
 *
 * Contributors:
 *   Youness Alaoui, Collabora Ltd.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
 * case the provisions of LGPL are applicable instead of those above. If you
 * wish to allow use of your version of this file only under the terms of the
 * LGPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replace
 * them with the notice and other provisions required by the LGPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the LGPL.
 */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif


#include <glib.h>

#include "socket.h"
#include "socket-priv.h"
#include "agent-priv.h"

#include <string.h>

#ifndef G_OS_WIN32
#include <unistd.h>
#endif

typedef struct _NiceSocketQueuedSend NiceSocketQueuedSend;

struct _NiceSocketQueuedSend {
  guint8 *buf;  /* owned */
  gsize length;
  NiceAddress to;
};

/**
 * nice_socket_recv_messages:
 * @sock: a #NiceSocket
 * @recv_messages: (array length=n_recv_messages) (out caller-allocates):
 * array of #NiceInputMessages to return received messages in
 * @n_recv_messages: number of elements in the @recv_messages array
 *
 * Receive up to @n_recv_messages message on the socket, in a non-reliable,
 * non-blocking fashion. The total size of the buffers in each #NiceInputMessage
 * must be big enough to contain an entire message (65536 bytes), or excess
 * bytes will be silently dropped.
 *
 * On success, the number of messages received into @recv_messages is returned,
 * which may be less than @n_recv_messages if the call would have blocked
 * part-way through. If the socket would have blocked to begin with, or if
 * @n_recv_messages is zero, zero is returned. On failure, a negative value is
 * returned, but no further error information is available. Calling this
 * function on a socket which has closed is an error, and a negative value is
 * returned.
 *
 * If a positive N is returned, the first N messages in @recv_messages are
 * valid. Each valid message is guaranteed to have a non-zero
 * #NiceInputMessage::length, and its buffers are guaranteed to be filled
 * sequentially up to that number of bytes  If #NiceInputMessage::from was
 * non-%NULL for a valid message, it may be set to the address of the sender of
 * that received message.
 *
 * If the return value is zero or negative, the from return address and length
 * in every #NiceInputMessage in @recv_messages are guaranteed to be unmodified.
 * The buffers may have been modified.
 *
 * The base addresses and sizes of the buffers in a #NiceInputMessage are never
 * modified. Neither is the base address of #NiceInputMessage::from, nor the
 * base address and length of the #NiceInputMessage::buffers array.
 *
 * Returns: number of valid messages returned in @recv_messages, or a negative
 * value on error
 *
 * Since: 0.1.5
 */
gint
nice_socket_recv_messages (NiceSocket *sock,
    NiceInputMessage *recv_messages, guint n_recv_messages)
{
  g_return_val_if_fail (sock != NULL, -1);
  g_return_val_if_fail (n_recv_messages == 0 || recv_messages != NULL, -1);

  return sock->recv_messages (sock, recv_messages, n_recv_messages);
}

/**
 * nice_socket_send_messages:
 * @sock: a #NiceSocket
 * @messages: (array length=n_messages) (in caller-allocates):
 * array of #NiceOutputMessages containing the messages to send
 * @n_messages: number of elements in the @messages array
 *
 * Send up to @n_messages on the socket, in a non-reliable, non-blocking
 * fashion. The total size of the buffers in each #NiceOutputMessage
 * must be at most the maximum UDP payload size (65535 bytes), or excess
 * bytes will be silently dropped.
 *
 * On success, the number of messages transmitted from @messages is returned,
 * which may be less than @n_messages if the call would have blocked
 * part-way through. If the socket would have blocked to begin with, or if
 * @n_messages is zero, zero is returned. On failure, a negative value is
 * returned, but no further error information is available. Calling this
 * function on a socket which has closed is an error, and a negative value is
 * returned.
 *
 * If a positive N is returned, the first N messages in @messages have been
 * sent in full, and the remaining messages have not been sent at all.
 *
 * If #NiceOutputMessage::to is specified for a message, that will be used as
 * the destination address for the message. Otherwise, if %NULL, the default
 * destination for @sock will be used.
 *
 * Every field of every #NiceOutputMessage is guaranteed to be unmodified when
 * this function returns.
 *
 * Returns: number of messages successfully sent from @messages, or a negative
 * value on error
 *
 * Since: 0.1.5
 */
gint
nice_socket_send_messages (NiceSocket *sock, const NiceAddress *to,
    const NiceOutputMessage *messages, guint n_messages)
{
  g_return_val_if_fail (sock != NULL, -1);
  g_return_val_if_fail (n_messages == 0 || messages != NULL, -1);

  return sock->send_messages (sock, to, messages, n_messages);
}

/**
 * nice_socket_send_messages_reliable:
 * @sock: a #NiceSocket
 * @messages: (array length=n_messages) (in caller-allocates):
 * array of #NiceOutputMessages containing the messages to send
 * @n_messages: number of elements in the @messages array
 *
 * Send @n_messages on the socket, in a reliable, non-blocking fashion.
 * The total size of the buffers in each #NiceOutputMessage
 * must be at most the maximum UDP payload size (65535 bytes), or excess
 * bytes will be silently dropped.
 *
 * On success, the number of messages transmitted from @messages is returned,
 * which will be equal to @n_messages. If the call would have blocked part-way
 * though, the remaining bytes will be queued for sending later.
 * On failure, a negative value is returned, but no further error information
 * is available. Calling this function on a socket which has closed is an error,
 * and a negative value is returned. Calling this function on a socket which
 * is not TCP or does not have a TCP base socket, will result in an error.
 *
 * If #NiceOutputMessage::to is specified for a message, that will be used as
 * the destination address for the message. Otherwise, if %NULL, the default
 * destination for @sock will be used.
 *
 * Every field of every #NiceOutputMessage is guaranteed to be unmodified when
 * this function returns.
 *
 * Returns: number of messages successfully sent from @messages, or a negative
 * value on error
 *
 * Since: 0.1.5
 */
gint
nice_socket_send_messages_reliable (NiceSocket *sock, const NiceAddress *to,
    const NiceOutputMessage *messages, guint n_messages)
{
  g_return_val_if_fail (sock != NULL, -1);
  g_return_val_if_fail (n_messages == 0 || messages != NULL, -1);

  return sock->send_messages_reliable (sock, to, messages, n_messages);
}

/* Convenience wrapper around nice_socket_recv_messages(). Returns the number of
 * bytes received on success (which will be @len), zero if sending would block, or
 * -1 on error. */
gssize
nice_socket_recv (NiceSocket *sock, NiceAddress *from, gsize len,
    gchar *buf)
{
  GInputVector local_buf = { buf, len };
  NiceInputMessage local_message = { &local_buf, 1, from, 0};
  gint ret;

  ret = sock->recv_messages (sock, &local_message, 1);
  if (ret == 1)
    return local_message.length;
  return ret;
}

/* Convenience wrapper around nice_socket_send_messages(). Returns the number of
 * bytes sent on success (which will be @len), zero if sending would block, or
 * -1 on error. */
gssize
nice_socket_send (NiceSocket *sock, const NiceAddress *to, gsize len,
    const gchar *buf)
{
  GOutputVector local_buf = { buf, len };
  NiceOutputMessage local_message = { &local_buf, 1};
  gint ret;

  ret = sock->send_messages (sock, to, &local_message, 1);
  if (ret == 1)
    return len;
  return ret;
}

gssize
nice_socket_send_reliable (NiceSocket *sock, const NiceAddress *to, gsize len,
    const gchar *buf)
{
  GOutputVector local_buf = { buf, len };
  NiceOutputMessage local_message = { &local_buf, 1};
  gint ret;

  ret = sock->send_messages_reliable (sock, to, &local_message, 1);
  if (ret == 1)
    return len;
  return ret;
}

gboolean
nice_socket_is_reliable (NiceSocket *sock)
{
  return sock->is_reliable (sock);
}

gboolean
nice_socket_can_send (NiceSocket *sock, NiceAddress *addr)
{
  if (sock->can_send)
    return sock->can_send (sock, addr);
  return TRUE;
}

void
nice_socket_set_writable_callback (NiceSocket *sock,
    NiceSocketWritableCb callback, gpointer user_data)
{
  if (sock->set_writable_callback)
    sock->set_writable_callback (sock, callback, user_data);
}

void
nice_socket_free (NiceSocket *sock)
{
  if (sock) {
    sock->close (sock);
    g_slice_free (NiceSocket,sock);
  }
}

static void
nice_socket_free_queued_send (NiceSocketQueuedSend *tbs)
{
  g_free (tbs->buf);
  g_slice_free (NiceSocketQueuedSend, tbs);
}

void
nice_socket_queue_send (GQueue *send_queue, const NiceAddress *to,
    const NiceOutputMessage *messages, guint n_messages)
{
  guint i;

  if (n_messages == 0)
    return;

  /* Compact the message’s buffers before queueing. */
  for (i = 0; i < n_messages; i++) {
    NiceSocketQueuedSend *tbs;
    const NiceOutputMessage *message = &messages[i];
    gsize message_len_remaining = output_message_get_size (message);
    guint j;
    gsize offset = 0;

    if (message_len_remaining == 0)
      continue;

    /* Compact the buffer. */
    tbs = g_slice_new0 (NiceSocketQueuedSend);
    tbs->buf = g_malloc (message_len_remaining);
    tbs->length = message_len_remaining;

    if (to)
      tbs->to = *to;
    else
      memset (&tbs->to, 0, sizeof(NiceAddress));
    g_queue_push_tail (send_queue, tbs);

    for (j = 0;
         (message->n_buffers >= 0 && j < (guint) message->n_buffers) ||
         (message->n_buffers < 0 && message->buffers[j].buffer != NULL);
         j++) {
      const GOutputVector *buffer = &message->buffers[j];
      gsize len;

      len = MIN (buffer->size, message_len_remaining);
      memcpy (tbs->buf + offset, buffer->buffer, len);
      message_len_remaining -= len;
      offset += len;
    }

    g_assert (offset == tbs->length);
  }
}

void nice_socket_queue_send_with_callback (GQueue *send_queue,
    const NiceOutputMessage *message, gsize message_offset, gsize message_len,
    gboolean head, GSocket *gsock, GSource **io_source, GMainContext *context,
    GSourceFunc cb, gpointer user_data)
{
  NiceSocketQueuedSend *tbs;
  guint j;
  gsize offset = 0;

  if (message_offset >= message_len)
    return;

  tbs = g_slice_new0 (NiceSocketQueuedSend);
  tbs->length = message_len - message_offset;
  tbs->buf = g_malloc (tbs->length);

  if (head)
    g_queue_push_head (send_queue, tbs);
  else
    g_queue_push_tail (send_queue, tbs);

  if (io_source && gsock && context && cb && *io_source == NULL) {
    *io_source = g_socket_create_source(gsock, G_IO_OUT, NULL);
    g_source_set_callback (*io_source, (GSourceFunc) cb, user_data, NULL);
    g_source_attach (*io_source, context);
  }

  /* Move the data into the buffer. */
  for (j = 0;
       (message->n_buffers >= 0 && j < (guint) message->n_buffers) ||
       (message->n_buffers < 0 && message->buffers[j].buffer != NULL);
       j++) {
    const GOutputVector *buffer = &message->buffers[j];
    gsize len;

    /* Skip this buffer if it’s within @message_offset. */
    if (buffer->size <= message_offset) {
      message_offset -= buffer->size;
      continue;
    }

    len = MIN (tbs->length - offset, buffer->size - message_offset);
    memcpy (tbs->buf + offset, (guint8 *) buffer->buffer + message_offset, len);
    offset += len;
    if (message_offset >= len)
      message_offset -= len;
    else
      message_offset = 0;
  }
}

void nice_socket_flush_send_queue (NiceSocket *base_socket, GQueue *send_queue)
{
  NiceSocketQueuedSend *tbs;

  while ((tbs = g_queue_pop_head (send_queue))) {
    NiceAddress *to = &tbs->to;

    if (!nice_address_is_valid (to))
      to = NULL;

    /* We only queue reliable data */
    nice_socket_send_reliable (base_socket, to,
        tbs->length, (const gchar *) tbs->buf);
    nice_socket_free_queued_send (tbs);
  }
}

gboolean nice_socket_flush_send_queue_to_socket (GSocket *gsock,
    GQueue *send_queue)
{
  NiceSocketQueuedSend *tbs;
  GError *gerr = NULL;


  while ((tbs = g_queue_pop_head (send_queue)) != NULL) {
    int ret;

    GOutputVector local_bufs = { tbs->buf, tbs->length };
    ret = g_socket_send_message (gsock, NULL, &local_bufs, 1, NULL, 0,
        G_SOCKET_MSG_NONE, NULL, &gerr);

    if (ret < 0) {
      if (g_error_matches (gerr, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
        GOutputVector local_buf = { tbs->buf, tbs->length };
        NiceOutputMessage local_message = {&local_buf, 1};

        nice_socket_queue_send_with_callback (send_queue, &local_message,
            0, local_buf.size, TRUE, NULL, NULL, NULL, NULL, NULL);
        nice_socket_free_queued_send (tbs);
        g_error_free (gerr);
        return FALSE;
      }
      g_clear_error (&gerr);
    } else if (ret < (int) tbs->length) {
      GOutputVector local_buf = { tbs->buf + ret, tbs->length - ret };
      NiceOutputMessage local_message = {&local_buf, 1};

      nice_socket_queue_send_with_callback (send_queue, &local_message,
          0, local_buf.size, TRUE, NULL, NULL, NULL, NULL, NULL);
      nice_socket_free_queued_send (tbs);
      return FALSE;
    }

    nice_socket_free_queued_send (tbs);
  }

  return TRUE;
}

void
nice_socket_free_send_queue (GQueue *send_queue)
{
  g_queue_foreach (send_queue, (GFunc) nice_socket_free_queued_send, NULL);
  g_queue_clear (send_queue);
}