/*
 * vim: set sts=2 sw=2 et :
 *
 * License: LGPL-2.1+
 * Copyright (c) 2014 Nirbheek Chauhan <nirbheek@centricular.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "lib.h"

static void stp_disconnect_cleanup_client (TranscodeClientCtx *ctx);

static gboolean
invoke_g_hash_table_remove (TranscodeServerCtx *ctx)
{
  g_hash_table_remove (ctx->parent_ctx_table, ctx->path);
  return G_SOURCE_REMOVE;
}

static gboolean
invoke_g_free_client_context (TranscodeClientCtx *ctx)
{
  g_free (ctx);
  return G_SOURCE_REMOVE;
}

gboolean
stp_on_gst_bus_message (GstBus             *bus,
                        GstMessage         *msg,
                        TranscodeServerCtx *ctx)
{
  GError *error = NULL;
  char *tmp = NULL;

  switch (GST_MESSAGE_TYPE (msg)) {
    case GST_MESSAGE_ERROR:
      gst_message_parse_error (msg, &error, &tmp);
      g_critical ("ERROR from element %s: %s",
                  GST_OBJECT_NAME (msg->src), error->message);
      g_critical ("Debug info: %s", tmp);
      g_error_free (error);
      g_free (tmp);
      /* Setting the server response will only work if the request
       * hasn't already finished, so we check that */
      if (!ctx->stream_finished)
        soup_message_set_status (ctx->msg, SOUP_STATUS_INTERNAL_SERVER_ERROR);
      /* Cleanup in the default main context,
       * because GHashTable is not thread-safe */
      g_main_context_invoke_full (NULL, G_PRIORITY_HIGH,
                                  (GSourceFunc)invoke_g_hash_table_remove,
                                  ctx, NULL);
      break;
    case GST_MESSAGE_EOS:
      g_debug ("End of file");
      /* Cleanup in the default main context,
       * because GHashTable is not thread-safe */
      g_main_context_invoke_full (NULL, G_PRIORITY_HIGH,
                                  (GSourceFunc)invoke_g_hash_table_remove,
                                  ctx, NULL);
      break;
    default:
      //stp_print_status ("%s\n", gst_message_type_get_name (msg->type));
      break;
  }

  return TRUE;
}

/* When the incoming stream reaches EOS, we call this
 * which initiates a shutdown for all clients and then
 * the server itself */
void
stp_cleanup_transcode_server_ctx (TranscodeServerCtx *ctx)
{
  g_debug (">>> Doing server cleanup");

  /* Disconnect and free the context for each client */
  g_list_foreach (ctx->clients, (GFunc)stp_disconnect_cleanup_client, NULL);
  g_list_free (ctx->clients);

  /* Cleanup gstreamer pipeline */
  gst_element_set_state (ctx->pipeline, GST_STATE_NULL);
  gst_object_unref (ctx->pipeline);

  g_free (ctx);
}

static GstPadProbeReturn
pad_blocked_cleanup_cb (GstPad             *srcpad,
                        GstPadProbeInfo    *info,
                        TranscodeClientCtx *ctx)
{
  GstElement *tee;
  GstElement *sinkbin = GST_ELEMENT (gst_element_get_parent (ctx->appsink));

  stp_print_status (".");
  /* Remove the probe */
  gst_pad_remove_probe (srcpad, GST_PAD_PROBE_INFO_ID (info));

  tee = gst_pad_get_parent_element (srcpad);
  gst_pad_unlink (srcpad, ctx->ghostsinkpad);
  gst_element_release_request_pad (tee, srcpad);
  gst_object_unref (srcpad);
  gst_object_unref (tee);

  gst_element_set_state (sinkbin, GST_STATE_NULL);
  gst_bin_remove (GST_BIN (ctx->server_ctx->pipeline), sinkbin);
  gst_object_unref (sinkbin);

  stp_print_status (" Client cleanup done!\n");
  return GST_PAD_PROBE_OK;
}

/* When a client leaves or is kicked, we set the response status
 * and then call cleanup here. This involves removing the appsink
 * branch for the client from the pipeline, and then freeing the
 * context. */
void
stp_cleanup_transcode_client_ctx (TranscodeClientCtx *ctx)
{
  GstPad *srcpad;
  TranscodeServerCtx *server_ctx = ctx->server_ctx;
  GstElement *sinkbin = GST_ELEMENT (gst_element_get_parent (ctx->appsink));

  stp_print_status (">>> Doing client cleanup.");

  g_source_remove (ctx->timeout_handler_id);
  ctx->timeout_handler_id = 0;

  server_ctx->clients = g_list_remove (server_ctx->clients, ctx);

  /* Block sinkpad and srcpad, then unlink and remove */
  srcpad = gst_pad_get_peer (ctx->ghostsinkpad);

  gst_pad_add_probe (srcpad, GST_PAD_PROBE_TYPE_BLOCK,
                     (GstPadProbeCallback) pad_blocked_cleanup_cb,
                     ctx, (GDestroyNotify)g_free);

  gst_object_unref (sinkbin);
  stp_print_status (".");
}

/* When shutting down a client due to a server shutdown,
 * we just need to remove the client timeout handler and
 * free the context. The rest is owned by the pipeline. */
static void
stp_disconnect_cleanup_client (TranscodeClientCtx *ctx)
{
  stp_print_status (">>> Disconnecting client on server shutdown\n");

  /* FIXME: This isn't actually setting the status for client 
   * connections, and clients are just left hanging */
  soup_message_set_status (ctx->msg, SOUP_STATUS_GONE);
  soup_message_body_complete (ctx->msg->response_body);

  g_source_remove (ctx->timeout_handler_id);
  ctx->timeout_handler_id = 0;
  /* Don't call the "finished" handler and do a double-free */
  g_signal_handler_disconnect (ctx->msg, ctx->finished_handler_id);

  /* There might still be functions which use the ctx waiting 
   * to be invoked on the next main context dispatch, so we 
   * free this at the end of all those dispatches. */
  g_main_context_invoke_full (NULL, G_PRIORITY_LOW,
                              (GSourceFunc)invoke_g_free_client_context,
                              ctx, NULL);
}

/* Returns a copy of the streamheader GstBuffer */
GstBuffer*
stp_get_streamheader_from_caps (GstCaps *caps)
{
  GstStructure *s;
  const GValue *array, *value;

  s = gst_caps_get_structure (caps, 0);
  array = gst_structure_get_value (s, "streamheader");
  g_return_val_if_fail (GST_VALUE_HOLDS_ARRAY (array), NULL);

  value = gst_value_array_get_value (array, 0);
  g_return_val_if_fail (G_VALUE_TYPE (value) == GST_TYPE_BUFFER, NULL);

  return gst_buffer_copy (g_value_peek_pointer (value));
}

/* Returns a GstBuffer which has consumed the passed-in data */
GstBuffer*
stp_get_gst_buffer (SoupBuffer *chunk)
{
  gsize len;
  const guint8 *d;
  SoupBuffer *copy;
  GstBuffer *buffer;
  GstMemory *memory;

  copy = soup_buffer_copy (chunk);
  soup_buffer_get_data (copy, &d, &len);
  buffer = gst_buffer_new ();
  memory = gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY,
                                  (guint8*)d, len, 0, len, copy,
                                  (GDestroyNotify)soup_buffer_free);
  gst_buffer_append_memory (buffer, memory);
  return buffer;
}