/*
 * Copyright © 2018 Benjamin Otte
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors: Benjamin Otte <otte@gnome.org>
 */

#include "config.h"

#include "gtkmediastream.h"

#include "gtkintl.h"

/**
 * SECTION:gtkmediastream
 * @Short_description: Display media in GTK
 * @Title: GtkMediaStream
 * @See_also: #GdkPaintable
 *
 * #GtkMediaStream is the integration point for media playback inside GTK.
 *
 * FIXME: Write more about how frameworks should implement this thing and how
 * GTK widgets exist (once they do) that consume it.
 */

typedef struct _GtkMediaStreamPrivate GtkMediaStreamPrivate;

struct _GtkMediaStreamPrivate
{
  gint64 timestamp;
  gint64 duration;
  GError *error;
  double volume;

  guint has_audio : 1;
  guint has_video : 1;
  guint playing : 1;
  guint ended : 1;
  guint seekable : 1;
  guint seeking : 1;
  guint loop : 1;
  guint prepared : 1;
  guint muted : 1;
};

enum {
  PROP_0,
  PROP_PREPARED,
  PROP_ERROR,
  PROP_HAS_AUDIO,
  PROP_HAS_VIDEO,
  PROP_PLAYING,
  PROP_ENDED,
  PROP_TIMESTAMP,
  PROP_DURATION,
  PROP_SEEKABLE,
  PROP_SEEKING,
  PROP_LOOP,
  PROP_MUTED,
  PROP_VOLUME,

  N_PROPS,
};

static GParamSpec *properties[N_PROPS] = { NULL, };

static void
gtk_media_stream_paintable_snapshot (GdkPaintable *paintable,
                                     GdkSnapshot  *snapshot,
                                     double        width,
                                     double        height)
{
}

static void
gtk_media_stream_paintable_init (GdkPaintableInterface *iface)
{
  /* We implement the behavior for "no video stream" here */
  iface->snapshot = gtk_media_stream_paintable_snapshot;
}

G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GtkMediaStream, gtk_media_stream, G_TYPE_OBJECT,
                                  G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
                                                         gtk_media_stream_paintable_init)
                                  G_ADD_PRIVATE (GtkMediaStream))

#define GTK_MEDIA_STREAM_WARN_NOT_IMPLEMENTED_METHOD(obj,method) \
  g_critical ("Media stream of type '%s' does not implement GtkMediaStream::" # method, G_OBJECT_TYPE_NAME (obj))

static gboolean
gtk_media_stream_default_play (GtkMediaStream *self)
{
  GTK_MEDIA_STREAM_WARN_NOT_IMPLEMENTED_METHOD (self, play);

  return FALSE;
}

static void
gtk_media_stream_default_pause (GtkMediaStream *self)
{
  GTK_MEDIA_STREAM_WARN_NOT_IMPLEMENTED_METHOD (self, pause);
}

static void
gtk_media_stream_default_seek (GtkMediaStream *self,
                               gint64          timestamp)
{
  gtk_media_stream_seek_failed (self);
}

static void
gtk_media_stream_default_update_audio (GtkMediaStream *self,
                                       gboolean        muted,
                                       double          volume)
{
}

static void
gtk_media_stream_default_realize (GtkMediaStream *self,
                                  GdkSurface      *surface)
{
}

static void
gtk_media_stream_default_unrealize (GtkMediaStream *self,
                                    GdkSurface      *surface)
{
}

static void
gtk_media_stream_set_property (GObject      *object,
                               guint         prop_id,
                               const GValue *value,
                               GParamSpec   *pspec)

{
  GtkMediaStream *self = GTK_MEDIA_STREAM (object);

  switch (prop_id)
    {
    case PROP_PLAYING:
      gtk_media_stream_set_playing (self, g_value_get_boolean (value));
      break;

    case PROP_LOOP:
      gtk_media_stream_set_loop (self, g_value_get_boolean (value));
      break;

    case PROP_MUTED:
      gtk_media_stream_set_muted (self, g_value_get_boolean (value));
      break;

    case PROP_VOLUME:
      gtk_media_stream_set_volume (self, g_value_get_double (value));
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
gtk_media_stream_get_property (GObject    *object,
                               guint       prop_id,
                               GValue     *value,
                               GParamSpec *pspec)
{
  GtkMediaStream *self = GTK_MEDIA_STREAM (object);
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  switch (prop_id)
    {
    case PROP_PREPARED:
      g_value_set_boolean (value, priv->prepared);
      break;

    case PROP_ERROR:
      g_value_set_boxed (value, priv->error);
      break;

    case PROP_HAS_AUDIO:
      g_value_set_boolean (value, priv->has_audio);
      break;

    case PROP_HAS_VIDEO:
      g_value_set_boolean (value, priv->has_video);
      break;

    case PROP_PLAYING:
      g_value_set_boolean (value, priv->playing);
      break;

    case PROP_ENDED:
      g_value_set_boolean (value, priv->ended);
      break;

    case PROP_TIMESTAMP:
      g_value_set_int64 (value, priv->timestamp);
      break;

    case PROP_DURATION:
      g_value_set_int64 (value, priv->duration);
      break;

    case PROP_SEEKABLE:
      g_value_set_boolean (value, priv->seekable);
      break;

    case PROP_SEEKING:
      g_value_set_boolean (value, priv->seeking);
      break;

    case PROP_LOOP:
      g_value_set_boolean (value, priv->loop);
      break;

    case PROP_MUTED:
      g_value_set_boolean (value, priv->muted);
      break;

    case PROP_VOLUME:
      g_value_set_double (value, priv->volume);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
gtk_media_stream_dispose (GObject *object)
{
  GtkMediaStream *self = GTK_MEDIA_STREAM (object);
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_clear_error (&priv->error);

  G_OBJECT_CLASS (gtk_media_stream_parent_class)->dispose (object);
}

static void
gtk_media_stream_finalize (GObject *object)
{
#if 0
  GtkMediaStream *self = GTK_MEDIA_STREAM (object);
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);
#endif

  G_OBJECT_CLASS (gtk_media_stream_parent_class)->finalize (object);
}

static void
gtk_media_stream_class_init (GtkMediaStreamClass *class)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (class);

  class->play = gtk_media_stream_default_play;
  class->pause = gtk_media_stream_default_pause;
  class->seek = gtk_media_stream_default_seek;
  class->update_audio = gtk_media_stream_default_update_audio;
  class->realize = gtk_media_stream_default_realize;
  class->unrealize = gtk_media_stream_default_unrealize;

  gobject_class->set_property = gtk_media_stream_set_property;
  gobject_class->get_property = gtk_media_stream_get_property;
  gobject_class->finalize = gtk_media_stream_finalize;
  gobject_class->dispose = gtk_media_stream_dispose;

  /**
   * GtkMediaStream:prepared:
   *
   * Whether the stream has finished initializing and existence of
   * audio and video is known.
   */
  properties[PROP_PREPARED] =
    g_param_spec_boolean ("prepared",
                          P_("Prepared"),
                          P_("Whether the stream has finished initializing"),
                          FALSE,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:error:
   *
   * %NULL for a properly working stream or the #GError that the stream is in.
   */
  properties[PROP_ERROR] =
    g_param_spec_boxed ("error",
                        P_("Error"),
                        P_("Error the stream is in"),
                        G_TYPE_ERROR,
                        G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:has-audio:
   *
   * Whether the stream contains audio
   */
  properties[PROP_HAS_AUDIO] =
    g_param_spec_boolean ("has-audio",
                          P_("Has audio"),
                          P_("Whether the stream contains audio"),
                          FALSE,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:has-video:
   *
   * Whether the stream contains video
   */
  properties[PROP_HAS_VIDEO] =
    g_param_spec_boolean ("has-video",
                          P_("Has video"),
                          P_("Whether the stream contains video"),
                          FALSE,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:playing:
   *
   * Whether the stream is currently playing.
   */
  properties[PROP_PLAYING] =
    g_param_spec_boolean ("playing",
                          P_("Playing"),
                          P_("Whether the stream is playing"),
                          FALSE,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:ended:
   *
   * Set when playback has finished.
   */
  properties[PROP_ENDED] =
    g_param_spec_boolean ("ended",
                          P_("Ended"),
                          P_("Set when playback has finished"),
                          FALSE,
                          G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:timestamp:
   *
   * The current presentation timestamp in microseconds.
   */
  properties[PROP_TIMESTAMP] =
    g_param_spec_int64 ("timestamp",
                        P_("Timestamp"),
                        P_("Timestamp in microseconds"),
                        0, G_MAXINT64, 0,
                        G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:duration:
   *
   * The stream's duration in microseconds or 0 if unknown.
   */
  properties[PROP_DURATION] =
    g_param_spec_int64 ("duration",
                        P_("Duration"),
                        P_("Timestamp in microseconds"),
                        0, G_MAXINT64, 0,
                        G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:seekable:
   *
   * Set unless the stream is known to not support seeking.
   */
  properties[PROP_SEEKABLE] =
    g_param_spec_boolean ("seekable",
                          P_("Seekable"),
                          P_("Set unless seeking is not supported"),
                          TRUE,
                          G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:seeking:
   *
   * Set while a seek is in progress.
   */
  properties[PROP_SEEKING] =
    g_param_spec_boolean ("seeking",
                          P_("Seeking"),
                          P_("Set while a seek is in progress"),
                          FALSE,
                          G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:loop:
   *
   * Try to restart the media from the beginning once it ended.
   */
  properties[PROP_LOOP] =
    g_param_spec_boolean ("loop",
                          P_("Loop"),
                          P_("Try to restart the media from the beginning once it ended."),
                          FALSE,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:muted:
   *
   * Whether the audio stream should be muted.
   */
  properties[PROP_MUTED] =
    g_param_spec_boolean ("muted",
                          P_("Muted"),
                          P_("Whether the audio stream should be muted."),
                          FALSE,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkMediaStream:volume:
   *
   * Volume of the audio stream.
   */
  properties[PROP_VOLUME] =
    g_param_spec_boolean ("volume",
                          P_("Volume"),
                          P_("Volume of the audio stream."),
                          1.0,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  g_object_class_install_properties (gobject_class, N_PROPS, properties);
}

static void
gtk_media_stream_init (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  priv->volume = 1.0;
}

gboolean
gtk_media_stream_is_prepared (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->prepared;
}

gboolean
gtk_media_stream_has_audio (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->has_audio;
}

gboolean
gtk_media_stream_has_video (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->has_video;
}

void
gtk_media_stream_play (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  if (priv->error)
    return;

  if (priv->playing)
    return;

  if (GTK_MEDIA_STREAM_GET_CLASS (self)->play (self))
    {
      g_object_freeze_notify (G_OBJECT (self));

      priv->playing = TRUE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PLAYING]);

      if (priv->ended)
        {
          priv->ended = FALSE;
          g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ENDED]);
        }

      g_object_thaw_notify (G_OBJECT (self));
    }
}

void
gtk_media_stream_pause (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  /* Don't check for error here because we call this function right
   * after setting the error to pause the stream */

  if (!priv->playing)
    return;

  GTK_MEDIA_STREAM_GET_CLASS (self)->pause (self);

  priv->playing = FALSE;
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PLAYING]);
}

gboolean
gtk_media_stream_get_playing (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->playing;
}

void
gtk_media_stream_set_playing (GtkMediaStream *self,
                              gboolean        playing)
{
  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  if (playing)
    gtk_media_stream_play (self);
  else
    gtk_media_stream_pause (self);
}

gboolean
gtk_media_stream_get_ended (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->ended;
}

gint64
gtk_media_stream_get_timestamp (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->timestamp;
}

/**
 * gtk_media_stream_get_duration:
 * @self: a #GtkmediaStream
 *
 * Gets the duration of the stream. If the duration is not known,
 * 0 will be returned.
 *
 * Returns: the duration of the stream or 0 if not known.
 **/
gint64
gtk_media_stream_get_duration (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->duration;
}

/**
 * gtk_media_stream_is_seekable:
 * @self: a #GtkMediaStream
 *
 * Checks if a stream may be seekable.
 *
 * This is meant to be a hint. Streams may not allow seeking even if
 * this function returns %TRUE. However, if this function returns
 * %FALSE, streams are guaranteed to not be seekable and user interfaces
 * may hide controls that allow seeking.
 *
 * It is allowed to call gtk_media_stream_seek() on a non-seekable
 * stream, though it will not do anything.
 *
 * Returns: %TRUE if the stream may support seeking
 **/
gboolean
gtk_media_stream_is_seekable (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->seekable;
}

/**
 * gtk_media_stream_is_seeking:
 * @self: a #GtkMediaStream
 *
 * Checks if there is currently a seek operation going on.
 *
 * Returns: %TRUE if a seek operation is ongoing.
 **/
gboolean
gtk_media_stream_is_seeking (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->seeking;
}

/**
 * gtk_media_stream_get_error:
 * @self: a #GtkMediaStream
 *
 * If the stream is in an error state, returns the #GError explaining that state.
 * Any type of error can be reported here depending on the implementation of the
 * media stream.
 *
 * A media stream in an error cannot be operated on, calls like
 * gtk_media_stream_play() or gtk_media_stream_seek() will not have any effect.
 *
 * #GtkMediaStream itself does not provide a way to unset an error, but
 * implementations may provide options. For example, a #GtkMediaFile will unset
 * errors when a new source is set with ie gtk_media_file_set_file().
 *
 * Returns: (nullable) (transfer none): %NULL if not in an error state or
 *    the #GError of the stream
 **/
const GError *
gtk_media_stream_get_error (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->error;
}

/**
 * gtk_media_stream_seek:
 * @self: a #GtkMediaStream
 * @timestamp: timestamp to seek to.
 *
 * Start a seek operation on @self to @timestamp. If @timestamp is out of range,
 * it will be clamped.
 *
 * Seek operations may not finish instantly. While a seek operation is
 * in process, the GtkMediaStream:seeking property will be set.
 *
 * When calling gtk_media_stream_seek() during an ongoing seek operation,
 * the new seek wil override any pending seek.
 **/
void
gtk_media_stream_seek (GtkMediaStream *self,
                       gint64          timestamp)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);
  gboolean was_seeking;

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (timestamp >= 0);

  if (priv->error)
    return;

  if (!priv->seekable)
    return;

  g_object_freeze_notify (G_OBJECT (self));

  was_seeking = priv->seeking;
  priv->seeking = TRUE;

  GTK_MEDIA_STREAM_GET_CLASS (self)->seek (self, timestamp);

  if (was_seeking != priv->seeking)
    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEEKING]);

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_get_loop:
 * @self: a #GtkMediaStream
 *
 * Returns whether the stream is set to loop. See
 * gtk_media_stream_set_loop() for details.
 *
 * Returns: %TRUE if the stream should loop
 **/
gboolean
gtk_media_stream_get_loop (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->loop;
}

/**
 * gtk_media_stream_set_loop:
 * @self: a #GtkMediaStream
 * @loop: %TRUE if the stream should loop
 *
 * Sets whether the stream should loop, ie restart playback from
 * the beginning instead of stopping at the end.
 *
 * Not all streams may support looping, in particular non-seekable
 * streams. Those streams will ignore the loop setting and just end.
 **/
void
gtk_media_stream_set_loop (GtkMediaStream *self,
                           gboolean        loop)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  if (priv->loop == loop)
    return;

  priv->loop = loop;
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOOP]);
}

/**
 * gtk_media_stream_get_muted:
 * @self: a #GtkMediaStream
 *
 * Returns whether the audio for the stream is muted.
 * See gtk_media_stream_set_muted() for details.
 *
 * Returns: %TRUE if the stream is muted
 **/
gboolean
gtk_media_stream_get_muted (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->muted;
}

/**
 * gtk_media_stream_set_muted:
 * @self: a #GtkMediaStream
 * @muted: %TRUE if the stream should be muted
 *
 * Sets whether the audio stream should be muted. Muting a stream will
 * cause no audio to be played, but it does not modify the volume.
 * This means that muting and then unmuting the stream will restore
 * the volume settings.
 *
 * If the stream has no audio, calling this function will still work
 * but it will not have an audible effect.
 **/
void
gtk_media_stream_set_muted (GtkMediaStream *self,
                            gboolean        muted)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  if (priv->muted == muted)
    return;

  priv->muted = muted;

  GTK_MEDIA_STREAM_GET_CLASS (self)->update_audio (self, priv->muted, priv->volume);

  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MUTED]);
}

/**
 * gtk_media_stream_get_volume:
 * @self: a #GtkMediaStream
 *
 * Returns the volume of the audio for the stream.
 * See gtk_media_stream_set_volume() for details.
 *
 * Returns: volume of the stream from 0.0 to 1.0
 **/
double
gtk_media_stream_get_volume (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_val_if_fail (GTK_IS_MEDIA_STREAM (self), FALSE);

  return priv->volume;
}

/**
 * gtk_media_stream_set_volume:
 * @self: a #GtkMediaStream
 * @volume: New volume of the stream from 0.0 to 1.0
 *
 * Sets the volume of the audio stream. This function call will work even if
 * the stream is muted.
 *
 * The given @volume should range from 0.0 for silence to 1.0 for as loud as
 * possible. Values outside of this range will be clamped to the nearest
 * value.
 *
 * If the stream has no audio or is muted, calling this function will still
 * work but it will not have an immediate audible effect. When the stream is
 * unmuted, the new volume setting will take effect.
 **/
void
gtk_media_stream_set_volume (GtkMediaStream *self,
                             double          volume)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  volume = CLAMP (volume, 0.0, 1.0);

  if (priv->volume == volume)
    return;

  priv->volume = volume;

  GTK_MEDIA_STREAM_GET_CLASS (self)->update_audio (self, priv->muted, priv->volume);

  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_VOLUME]);
}

/**
 * gtk_media_stream_realize:
 * @self: a #GtkMediaStream
 * @surface: a #GdkSurface
 *
 * Called by users to attach the media stream to a #GdkSurface they manage.
 * The stream can then access the resources of @surface for its rendering
 * purposes. In particular, media streams might want to create
 * #GdkGLContexts or sync to the #GdkFrameClock.
 *
 * Whoever calls this function is responsible for calling
 * gtk_media_stream_unrealize() before either the stream or @surface get
 * destroyed.
 *
 * Multiple calls to this function may happen from different users of the
 * video, even with the same @surface. Each of these calls must be followed
 * by its own call to gtk_media_stream_unrealize().
 *
 * It is not required to call this function to make a media stream work.
 **/
void
gtk_media_stream_realize (GtkMediaStream *self,
                          GdkSurface      *surface)
{
  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (GDK_IS_SURFACE (surface));

  g_object_ref (self);
  g_object_ref (surface);

  GTK_MEDIA_STREAM_GET_CLASS (self)->realize (self, surface);
}

/**
 * gtk_media_stream_unrealize:
 * @self: a #GtkMediaStream previously realized
 * @surface: the #GdkSurface the stream was realized with
 *
 * Undoes a previous call to gtk_media_stream_realize() and causes
 * the stream to release all resources it had allocated from @surface.
 **/
void
gtk_media_stream_unrealize (GtkMediaStream *self,
                            GdkSurface      *surface)
{
  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (GDK_IS_SURFACE (surface));

  GTK_MEDIA_STREAM_GET_CLASS (self)->unrealize (self, surface);

  g_object_unref (surface);
  g_object_unref (self);
}

/**
 * gtk_media_stream_prepared:
 * @self: a #GtkMediaStream
 * @has_audio: %TRUE if the stream should advertise audio support
 * @has_video: %TRUE if the stream should advertise video support
 * @seekable: %TRUE if the stream should advertise seekability
 * @duration: The duration of the stream or 0 if unknown
 *
 * Called by #GtkMediaStream implementations to advertise the stream
 * being ready to play and providing details about the stream.
 *
 * Note that the arguments are hints. If the stream implementation
 * cannot determine the correct values, it is better to err on the
 * side of caution and return %TRUE. User interfaces will use those
 * values to determine what controls to show.
 *
 * This function may not be called again until the stream has been
 * reset via gtk_media_stream_unprepared().
 **/
void
gtk_media_stream_prepared (GtkMediaStream *self,
                           gboolean        has_audio,
                           gboolean        has_video,
                           gboolean        seekable,
                           gint64          duration)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (!gtk_media_stream_is_prepared (self));

  g_object_freeze_notify (G_OBJECT (self));

  if (priv->has_audio != has_audio)
    {
      priv->has_audio = has_audio;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_HAS_AUDIO]);
    }
  if (priv->has_video != has_video)
    {
      priv->has_video = has_video;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_HAS_VIDEO]);
    }
  if (priv->seekable != seekable)
    {
      priv->seekable = seekable;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEEKABLE]);
    }
  if (priv->duration != duration)
    {
      priv->duration = duration;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DURATION]);
    }

  priv->prepared = TRUE;
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PREPARED]);

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_unprepared:
 * @self: a #GtkMediaStream
 *
 * Resets a given media stream implementation. gtk_media_stream_prepared()
 * can now be called again.
 *
 * This function will also reset any error state the stream was in.
 **/
void
gtk_media_stream_unprepared (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (gtk_media_stream_is_prepared (self));

  g_object_freeze_notify (G_OBJECT (self));

  gtk_media_stream_pause (self);

  if (priv->has_audio)
    {
      priv->has_audio = FALSE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_HAS_AUDIO]);
    }
  if (priv->has_video)
    {
      priv->has_video = FALSE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_HAS_VIDEO]);
    }
  if (priv->seekable)
    {
      priv->seekable = FALSE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEEKABLE]);
    }
  if (priv->seeking)
    {
      priv->seeking = FALSE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEEKING]);
    }
  if (priv->duration != 0)
    {
      priv->duration = 0;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DURATION]);
    }
  if (priv->timestamp != 0)
    {
      priv->timestamp = 0;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_TIMESTAMP]);
    }
  if (priv->error)
    {
      g_clear_error (&priv->error);
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ERROR]);
    }

  priv->prepared = FALSE;
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PREPARED]);

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_gerror:
 * @self: a #GtkMediaStream
 * @error: (transfer full): the #GError to set
 *
 * Sets @self into an error state. This will pause the stream
 * (you can check for an error via gtk_media_stream_get_error() in
 * your GtkMediaStream.pause() implementation), abort pending seeks
 * and mark the stream as prepared.
 *
 * To unset an error, the stream must be reset via a call to
 * gtk_media_stream_unprepared().
 **/
void
gtk_media_stream_gerror (GtkMediaStream *self,
                         GError         *error)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (gtk_media_stream_get_error (self) == NULL);
  g_return_if_fail (error != NULL);

  g_object_freeze_notify (G_OBJECT (self));

  priv->error = error;

  gtk_media_stream_pause (self);

  if (!priv->prepared)
    {
      priv->prepared = TRUE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PREPARED]);
    }
  
  if (priv->seeking)
    gtk_media_stream_seek_failed (self);
  
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ERROR]);

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_error:
 * @self: a #GtkMediaStream
 * @domain: error domain
 * @code: error code
 * @format: printf()-style format for error message
 * @...: parameters for message format
 *
 * Sets @self into an error state using a printf()-style format string.
 *
 * This is a utility function that calls gtk_media_stream_gerror(). See
 * that function for details.  
 **/
void
gtk_media_stream_error (GtkMediaStream *self,
                        GQuark          domain,
                        gint            code,
                        const gchar    *format,
                        ...)
{
  GError *error;
  va_list args;

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (domain != 0);
  g_return_if_fail (format != NULL);

  va_start (args, format);
  error = g_error_new_valist (domain, code, format, args);
  va_end (args);

  gtk_media_stream_gerror (self, error);
}

/**
 * gtk_media_stream_error_valist:
 * @self: a #GtkMediaStream
 * @domain: error domain
 * @code: error code
 * @format: printf()-style format for error message
 * @args: #va_list of parameters for the message format
 *
 * Sets @self into an error state using a printf()-style format string.
 *
 * This is a utility function that calls gtk_media_stream_gerror(). See
 * that function for details.  
 */
void
gtk_media_stream_error_valist (GtkMediaStream *self,
                               GQuark          domain,
                               gint            code,
                               const gchar    *format,
                               va_list         args)
{
  GError *error;

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (domain != 0);
  g_return_if_fail (format != NULL);

  error = g_error_new_valist (domain, code, format, args);

  gtk_media_stream_gerror (self, error);
}

/**
 * gtk_media_stream_update:
 * @self: a #GtkMediaStream
 * @timestamp: the new timestamp
 *
 * Media stream implementations should regularly call this function to
 * update the timestamp reported by the stream. It is up to
 * implementations to call this at the frequency they deem appropriate.
 **/
void
gtk_media_stream_update (GtkMediaStream *self,
                         gint64          timestamp)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));

  g_object_freeze_notify (G_OBJECT (self));

  /* Timestamp before duration is important here.
   * This way the duration notify will be emitted first which will
   * make GtkMediaControls update adjustment->upper so that the
   * timestamp notify will cause the timestamp to not be clamped.
   */
  if (priv->timestamp != timestamp)
    {
      priv->timestamp = timestamp;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_TIMESTAMP]);
    }
  if (priv->duration > 0 && timestamp > priv->duration)
    {
      priv->duration = priv->timestamp;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DURATION]);
    }

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_ended:
 * @self: a #GtkMediaStream
 *
 * Pauses the media stream and marks it as ended. This is a hint only, calls
 * to GtkMediaStream.play() may still happen.
 **/
void
gtk_media_stream_ended (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (!gtk_media_stream_get_ended (self));

  g_object_freeze_notify (G_OBJECT (self));

  gtk_media_stream_pause (self);

  priv->ended = TRUE;
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ENDED]);

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_seek_success:
 * @self: a #GtkMediaStream
 *
 * Ends a seek operation started via GtkMediaStream.seek() successfully.
 * This function will unset the GtkMediaStream:ended property if it was
 * set.
 *
 * See gtk_media_stream_seek_failed() for the other way of
 * ending a seek.
 **/
void
gtk_media_stream_seek_success (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (gtk_media_stream_is_seeking (self));

  g_object_freeze_notify (G_OBJECT (self));

  priv->seeking = FALSE;
  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEEKING]);

  if (priv->ended)
    {
      priv->ended = FALSE;
      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ENDED]);
    }

  g_object_thaw_notify (G_OBJECT (self));
}

/**
 * gtk_media_stream_seek_failed:
 * @self: a #GtkMediaStream
 *
 * Ends a seek operation started via GtkMediaStream.seek() as a failure.
 * This will not cause an error on the stream and will assume that
 * playback continues as if no seek had happened.
 *
 * See gtk_media_stream_seek_success() for the other way of
 * ending a seek.
 **/
void
gtk_media_stream_seek_failed (GtkMediaStream *self)
{
  GtkMediaStreamPrivate *priv = gtk_media_stream_get_instance_private (self);

  g_return_if_fail (GTK_IS_MEDIA_STREAM (self));
  g_return_if_fail (gtk_media_stream_is_seeking (self));

  priv->seeking = FALSE;

  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEEKING]);
}