/* GStreamer

 *

 * sprinkle.c: sample application to dynamically mix tones with adder

 *

 * Copyright (C) <2009> Wim Taymans <wim dot taymans at gmail dot 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.

 */

/*

 * Produces a sweeping sprinkle of tones by dynamically adding and removing

 * elements to adder.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <gst/gst.h>

static GstElement *pipeline, *adder;

static GMainLoop *loop;

typedef struct

{

  GstElement *element;

  GstPad *srcpad;

  GstPad *sinkpad;

  gdouble freq;

} SourceInfo;

/* dynamically add the source to the pipeline and link it to a new pad on

 * adder */

static SourceInfo *

add_source (gdouble freq)

{

  SourceInfo *info;

  info = g_new0 (SourceInfo, 1);

  info->freq = freq;

  /* make source with unique name */

  info->element = gst_element_factory_make ("audiotestsrc", NULL);

  g_object_set (info->element, "freq", freq, NULL);

  /* add to the bin */

  gst_bin_add (GST_BIN (pipeline), info->element);

  /* get pad from the element */

  info->srcpad = gst_element_get_static_pad (info->element, "src");

  /* get new pad from adder, adder will now wait for data on this pad */

  info->sinkpad = gst_element_get_request_pad (adder, "sink_%u");

  /* link pad to adder */

  gst_pad_link (info->srcpad, info->sinkpad);

  /* and play the element */

  gst_element_set_state (info->element, GST_STATE_PLAYING);

  g_print ("added freq %f\n", info->freq);

  return info;

}

/* remove the source from the pipeline after removing it from adder */

static void

remove_source (SourceInfo * info)

{

  g_print ("remove freq %f\n", info->freq);

  /* lock the state so that we can put it to NULL without the parent messing

   * with our state */

  gst_element_set_locked_state (info->element, TRUE);

  /* first stop the source. Remember that this might block when in the PAUSED

   * state. Alternatively one could send EOS to the source, install an event

   * probe and schedule a state change/unlink/release from the mainthread.

   * Note that changing the state of a source makes it emit an EOS, which can

   * make adder go EOS. */

  gst_element_set_state (info->element, GST_STATE_NULL);

  /* unlink from adder */

  gst_pad_unlink (info->srcpad, info->sinkpad);

  gst_object_unref (info->srcpad);

  /* remove from the bin */

  gst_bin_remove (GST_BIN (pipeline), info->element);

  /* give back the pad */

  gst_element_release_request_pad (adder, info->sinkpad);

  gst_object_unref (info->sinkpad);

  g_free (info);

}

/* we'll keep the state of the sources in this structure. We keep 3 sources

 * alive */

typedef struct

{

  guint count;

  SourceInfo *infos[3];

} SprinkleState;

static SprinkleState *

create_state (void)

{

  SprinkleState *state;

  state = g_new0 (SprinkleState, 1);

  return state;

}

static void

free_state (SprinkleState * state)

{

  SourceInfo *info;

  gint i;

  for (i = 0; i < 3; i++) {

    info = state->infos[i];

    if (info)

      remove_source (info);

  }

  g_free (state);

}

static gboolean

do_sprinkle (SprinkleState * state)

{

  SourceInfo *info;

  gint i;

  /* first remove the oldest info */

  info = state->infos[2];

  if (info)

    remove_source (info);

  /* move sources */

  for (i = 2; i > 0; i--) {

    state->infos[i] = state->infos[i - 1];

  }

  /* add new source, stop adding sources after 10 rounds. */

  if (state->count < 10) {

    state->infos[0] = add_source ((state->count * 100) + 200);

    state->count++;

  } else {

    state->infos[0] = NULL;

    /* if no more sources left, quit */

    if (!state->infos[2])

      g_main_loop_quit (loop);

  }

  return TRUE;

}

static void

message_received (GstBus * bus, GstMessage * message, GstPipeline * pipeline)

{

  const GstStructure *s;

  s = gst_message_get_structure (message);

  g_print ("message from \"%s\" (%s): ",

      GST_STR_NULL (GST_ELEMENT_NAME (GST_MESSAGE_SRC (message))),

      gst_message_type_get_name (GST_MESSAGE_TYPE (message)));

  if (s) {

    gchar *sstr;

    sstr = gst_structure_to_string (s);

    g_print ("%s\n", sstr);

    g_free (sstr);

  } else {

    g_print ("no message details\n");

  }

}

static void

eos_message_received (GstBus * bus, GstMessage * message,

    GstPipeline * pipeline)

{

  message_received (bus, message, pipeline);

  g_main_loop_quit (loop);

}

int

main (int argc, char *argv[])

{

  GstBus *bus;

  GstElement *filter, *convert, *sink;

  GstCaps *caps;

  gboolean linked;

  SprinkleState *state;

  gst_init (&argc, &argv);

  loop = g_main_loop_new (NULL, TRUE);

  pipeline = gst_pipeline_new ("pipeline");

  /* add the fixed part to the pipeline. Remember that we need a capsfilter

   * after adder so that multiple sources are not racing to negotiate

   * a format */

  adder = gst_element_factory_make ("adder", "adder");

  filter = gst_element_factory_make ("capsfilter", "filter");

  convert = gst_element_factory_make ("audioconvert", "convert");

  sink = gst_element_factory_make ("autoaudiosink", "sink");

  caps = gst_caps_new_simple ("audio/x-raw",

      "format", G_TYPE_STRING, "S16LE",

      "channels", G_TYPE_INT, 1, "rate", G_TYPE_INT, 44100, NULL);

  g_object_set (filter, "caps", caps, NULL);

  gst_caps_unref (caps);

  gst_bin_add_many (GST_BIN (pipeline), adder, filter, convert, sink, NULL);

  linked = gst_element_link_many (adder, filter, convert, sink, NULL);

  g_assert (linked);

  /* setup message handling */

  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));

  gst_bus_add_signal_watch_full (bus, G_PRIORITY_HIGH);

  g_signal_connect (bus, "message::error", (GCallback) message_received,

      pipeline);

  g_signal_connect (bus, "message::warning", (GCallback) message_received,

      pipeline);

  g_signal_connect (bus, "message::eos", (GCallback) eos_message_received,

      pipeline);

  /* we set the pipeline to PLAYING, the pipeline will not yet preroll because

   * there is no source providing data for it yet */

  gst_element_set_state (pipeline, GST_STATE_PLAYING);

  /* and add the function that modifies the pipeline every 100ms */

  state = create_state ();

  g_timeout_add (100, (GSourceFunc) do_sprinkle, state);

  /* go to main loop */

  g_main_loop_run (loop);

  gst_element_set_state (pipeline, GST_STATE_NULL);

  free_state (state);

  gst_object_unref (bus);

  gst_object_unref (pipeline);

  return 0;

}