/* GStreamer
 *
 * Copyright (C) 2007 Rene Stadler <mail@renestadler.de>
 * Copyright (C) 2007-2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
 *
 * 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.
 */

/**
 * SECTION:element-giosrc
 * @title: giosrc
 * @see_also: #GstFileSrc, #GstGnomeVFSSrc, #GstGioSink
 *
 * This plugin reads data from a local or remote location specified
 * by an URI. This location can be specified using any protocol supported by
 * the GIO library or it's VFS backends. Common protocols are 'file', 'http',
 * 'ftp', or 'smb'.
 *
 * If an URI or #GFile is not mounted giosrc will post a message of type
 * %GST_MESSAGE_ELEMENT with name "not-mounted" on the bus. The message
 * also contains the #GFile and the corresponding URI.
 * Applications can use the "not-mounted" message to mount the #GFile
 * by calling g_file_mount_enclosing_volume() and then restart the
 * pipeline after the mounting has succeeded. Note that right after the
 * "not-mounted" message a normal error message is posted on the bus which
 * should be ignored if "not-mounted" is handled by the application, for
 * example by calling gst_bus_set_flushing(bus, TRUE) after the "not-mounted"
 * message was received and gst_bus_set_flushing(bus, FALSE) after the
 * mounting was successful.
 *
 * ## Example launch lines
 * |[
 * gst-launch-1.0 -v giosrc location=file:///home/joe/foo.xyz ! fakesink
 * ]|
 *  The above pipeline will simply read a local file and do nothing with the
 * data read. Instead of giosrc, we could just as well have used the
 * filesrc element here.
 * |[
 * gst-launch-1.0 -v giosrc location=smb://othercomputer/foo.xyz ! filesink location=/home/joe/foo.xyz
 * ]|
 *  The above pipeline will copy a file from a remote host to the local file
 * system using the Samba protocol.
 * |[
 * gst-launch-1.0 -v giosrc location=smb://othercomputer/demo.mp3 ! decodebin ! audioconvert ! audioresample ! autoaudiosink
 * ]|
 *  The above pipeline will read and decode and play an mp3 file from a
 * SAMBA server.
 *
 */

/* FIXME: We would like to mount the enclosing volume of an URL
 *        if it isn't mounted yet but this is possible async-only.
 *        Unfortunately this requires a running main loop from the
 *        default context and we can't guarantuee this!
 *
 *        We would also like to do authentication while mounting.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "gstgiosrc.h"
#include <string.h>

GST_DEBUG_CATEGORY_STATIC (gst_gio_src_debug);
#define GST_CAT_DEFAULT gst_gio_src_debug

enum
{
  PROP_0,
  PROP_LOCATION,
  PROP_FILE,
  PROP_GROWING_FILE,
};

static gint waiting_data_signal = 0;
static gint done_waiting_data_signal = 0;

#define gst_gio_src_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstGioSrc, gst_gio_src,
    GST_TYPE_GIO_BASE_SRC, gst_gio_uri_handler_do_init (g_define_type_id));

static void gst_gio_src_finalize (GObject * object);

static void gst_gio_src_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_gio_src_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

static GInputStream *gst_gio_src_get_stream (GstGioBaseSrc * bsrc);

static gboolean gst_gio_src_query (GstBaseSrc * base_src, GstQuery * query);

static gboolean
gst_gio_src_check_deleted (GstGioSrc * src)
{
  GstGioBaseSrc *bsrc = GST_GIO_BASE_SRC (src);

  if (!g_file_query_exists (src->file, bsrc->cancel)) {
    gchar *uri = g_file_get_uri (src->file);

    GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, (NULL),
        ("The underlying file %s is not available anymore", uri));

    g_free (uri);

    return TRUE;
  }

  return FALSE;
}

static void
gst_gio_src_file_changed_cb (GstGioSrc * src)
{
  GST_DEBUG_OBJECT (src, "Underlying file changed.");
  GST_OBJECT_LOCK (src);
  src->changed = TRUE;
  if (src->monitoring_mainloop)
    g_main_loop_quit (src->monitoring_mainloop);
  GST_OBJECT_UNLOCK (src);

  gst_gio_src_check_deleted (src);
}

static void
gst_gio_src_waited_for_data (GstGioBaseSrc * bsrc)
{
  GstGioSrc *src = GST_GIO_SRC (bsrc);

  src->waiting_for_data = FALSE;
  g_signal_emit (bsrc, done_waiting_data_signal, 0, NULL);
}

static gboolean
gst_gio_src_wait_for_data (GstGioBaseSrc * bsrc)
{
  GMainContext *ctx;
  GstGioSrc *src = GST_GIO_SRC (bsrc);

  g_return_val_if_fail (!src->monitor, FALSE);

  if (gst_gio_src_check_deleted (src))
    return FALSE;

  GST_OBJECT_LOCK (src);
  if (!src->is_growing) {
    GST_OBJECT_UNLOCK (src);

    return FALSE;
  }

  src->monitor = g_file_monitor (src->file, G_FILE_MONITOR_NONE,
      bsrc->cancel, NULL);

  if (!src->monitor) {
    GST_OBJECT_UNLOCK (src);

    GST_WARNING_OBJECT (bsrc, "Could not create a monitor");
    return FALSE;
  }

  g_signal_connect_swapped (src->monitor, "changed",
      G_CALLBACK (gst_gio_src_file_changed_cb), src);
  GST_OBJECT_UNLOCK (src);

  if (!src->waiting_for_data) {
    g_signal_emit (src, waiting_data_signal, 0, NULL);
    src->waiting_for_data = TRUE;
  }

  ctx = g_main_context_new ();
  g_main_context_push_thread_default (ctx);
  GST_OBJECT_LOCK (src);
  src->changed = FALSE;
  src->monitoring_mainloop = g_main_loop_new (ctx, FALSE);
  GST_OBJECT_UNLOCK (src);

  g_main_loop_run (src->monitoring_mainloop);

  g_signal_handlers_disconnect_by_func (src->monitor,
      gst_gio_src_file_changed_cb, src);

  GST_OBJECT_LOCK (src);
  gst_clear_object (&src->monitor);
  g_main_loop_unref (src->monitoring_mainloop);
  src->monitoring_mainloop = NULL;
  GST_OBJECT_UNLOCK (src);

  g_main_context_pop_thread_default (ctx);
  g_main_context_unref (ctx);

  return src->changed;
}

static gboolean
gst_gio_src_unlock (GstBaseSrc * base_src)
{
  GstGioSrc *src = GST_GIO_SRC (base_src);

  GST_LOG_OBJECT (src, "triggering cancellation");

  GST_OBJECT_LOCK (src);
  while (src->monitoring_mainloop) {
    /* Ensure that we have already started the mainloop */
    if (!g_main_loop_is_running (src->monitoring_mainloop)) {
      GST_OBJECT_UNLOCK (src);

      /* Letting a chance for the waiting for data function to cleanup the
       * mainloop. */
      g_thread_yield ();

      GST_OBJECT_LOCK (src);
      continue;
    }
    g_main_loop_quit (src->monitoring_mainloop);
    break;
  }
  GST_OBJECT_UNLOCK (src);

  return GST_CALL_PARENT_WITH_DEFAULT (GST_BASE_SRC_CLASS, unlock, (base_src),
      TRUE);
}

static void
gst_gio_src_class_init (GstGioSrcClass * klass)
{
  GObjectClass *gobject_class = (GObjectClass *) klass;
  GstElementClass *gstelement_class = (GstElementClass *) klass;
  GstBaseSrcClass *gstbasesrc_class = (GstBaseSrcClass *) klass;
  GstGioBaseSrcClass *gstgiobasesrc_class = (GstGioBaseSrcClass *) klass;

  GST_DEBUG_CATEGORY_INIT (gst_gio_src_debug, "gio_src", 0, "GIO source");

  gobject_class->finalize = gst_gio_src_finalize;
  gobject_class->set_property = gst_gio_src_set_property;
  gobject_class->get_property = gst_gio_src_get_property;

  g_object_class_install_property (gobject_class, PROP_LOCATION,
      g_param_spec_string ("location", "Location", "URI location to read from",
          NULL, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**
   * GstGioSrc:file:
   *
   * #GFile to read from.
   */
  g_object_class_install_property (gobject_class, PROP_FILE,
      g_param_spec_object ("file", "File", "GFile to read from",
          G_TYPE_FILE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**
   * GstGioSrc:is-growing:
   *
   * Whether the file is currently growing. When activated EOS is never pushed
   * and the user needs to handle it himself. This modes allows to keep reading
   * the file while it is being written on file.
   *
   * You can reset the property to %FALSE at any time and the file will start
   * not being considered growing and EOS will be pushed when required.
   *
   * Since: 1.20
   */
  g_object_class_install_property (gobject_class, PROP_GROWING_FILE,
      g_param_spec_boolean ("is-growing", "File is growing",
          "Whether the file is growing, ignoring its end",
          FALSE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gst_element_class_set_static_metadata (gstelement_class, "GIO source",
      "Source/File",
      "Read from any GIO-supported location",
      "Ren\xc3\xa9 Stadler <mail@renestadler.de>, "
      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");

  gstbasesrc_class->query = GST_DEBUG_FUNCPTR (gst_gio_src_query);
  gstbasesrc_class->unlock = GST_DEBUG_FUNCPTR (gst_gio_src_unlock);

  gstgiobasesrc_class->get_stream = GST_DEBUG_FUNCPTR (gst_gio_src_get_stream);
  gstgiobasesrc_class->close_on_stop = TRUE;
  gstgiobasesrc_class->wait_for_data = gst_gio_src_wait_for_data;
  gstgiobasesrc_class->waited_for_data = gst_gio_src_waited_for_data;

  /**
   * GstGioSrc::waiting-data:
   *
   * Signal notifying that we are stalled waiting for data
   *
   * Since: 1.20
   */
  waiting_data_signal = g_signal_new ("waiting-data",
      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL,
      NULL, G_TYPE_NONE, 0);

  /**
   * GstGioSrc::done-waiting-data:
   *
   * Signal notifying that we are done waiting for data
   *
   * Since: 1.20
   */
  done_waiting_data_signal = g_signal_new ("done-waiting-data",
      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL,
      NULL, G_TYPE_NONE, 0);
}

static void
gst_gio_src_init (GstGioSrc * src)
{
}

static void
gst_gio_src_finalize (GObject * object)
{
  GstGioSrc *src = GST_GIO_SRC (object);

  if (src->file) {
    g_object_unref (src->file);
    src->file = NULL;
  }

  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
}

static void
gst_gio_src_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstGioSrc *src = GST_GIO_SRC (object);

  switch (prop_id) {
    case PROP_LOCATION:{
      const gchar *uri = NULL;

      if (GST_STATE (src) == GST_STATE_PLAYING ||
          GST_STATE (src) == GST_STATE_PAUSED) {
        GST_WARNING
            ("Setting a new location or GFile not supported in PLAYING or PAUSED state");
        break;
      }

      GST_OBJECT_LOCK (GST_OBJECT (src));
      if (src->file)
        g_object_unref (src->file);

      uri = g_value_get_string (value);

      if (uri) {
        src->file = g_file_new_for_uri (uri);

        if (!src->file) {
          GST_ERROR ("Could not create GFile for URI '%s'", uri);
        }
      } else {
        src->file = NULL;
      }
      GST_OBJECT_UNLOCK (GST_OBJECT (src));
      break;
    }
    case PROP_GROWING_FILE:
    {
      gboolean was_growing;

      GST_OBJECT_LOCK (src);
      was_growing = src->is_growing;
      src->is_growing = g_value_get_boolean (value);
      gst_base_src_set_dynamic_size (GST_BASE_SRC (src), src->is_growing);
      gst_base_src_set_automatic_eos (GST_BASE_SRC (src), !src->is_growing);

      while (was_growing && !src->is_growing && src->monitoring_mainloop) {
        /* Ensure that we have already started the mainloop */
        if (!g_main_loop_is_running (src->monitoring_mainloop)) {
          GST_OBJECT_UNLOCK (src);
          /* Letting a chance for the waiting for data function to cleanup the
           * mainloop. */
          GST_OBJECT_LOCK (src);
          continue;
        }
        g_main_loop_quit (src->monitoring_mainloop);
        break;
      }
      GST_OBJECT_UNLOCK (src);

      break;
    }
    case PROP_FILE:
      if (GST_STATE (src) == GST_STATE_PLAYING ||
          GST_STATE (src) == GST_STATE_PAUSED) {
        GST_WARNING
            ("Setting a new location or GFile not supported in PLAYING or PAUSED state");
        break;
      }

      GST_OBJECT_LOCK (GST_OBJECT (src));
      if (src->file)
        g_object_unref (src->file);

      src->file = g_value_dup_object (value);

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

static void
gst_gio_src_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstGioSrc *src = GST_GIO_SRC (object);

  switch (prop_id) {
    case PROP_LOCATION:{
      gchar *uri;

      GST_OBJECT_LOCK (GST_OBJECT (src));
      if (src->file) {
        uri = g_file_get_uri (src->file);
        g_value_set_string (value, uri);
        g_free (uri);
      } else {
        g_value_set_string (value, NULL);
      }
      GST_OBJECT_UNLOCK (GST_OBJECT (src));
      break;
    }
    case PROP_FILE:
      GST_OBJECT_LOCK (GST_OBJECT (src));
      g_value_set_object (value, src->file);
      GST_OBJECT_UNLOCK (GST_OBJECT (src));
      break;
    case PROP_GROWING_FILE:
    {
      g_value_set_boolean (value, src->is_growing);
      break;
    }
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static gboolean
gst_gio_src_query (GstBaseSrc * base_src, GstQuery * query)
{
  gboolean res;
  GstGioSrc *src = GST_GIO_SRC (base_src);

  switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_SCHEDULING:
    {
      gchar *scheme;
      GstSchedulingFlags flags;

      flags = 0;
      if (src->file == NULL)
        goto forward_parent;

      scheme = g_file_get_uri_scheme (src->file);
      if (scheme == NULL)
        goto forward_parent;

      if (strcmp (scheme, "file") == 0) {
        GST_LOG_OBJECT (src, "local URI, assuming random access is possible");
        flags |= GST_SCHEDULING_FLAG_SEEKABLE;
      } else if (strcmp (scheme, "http") == 0 || strcmp (scheme, "https") == 0) {
        GST_LOG_OBJECT (src, "blacklisted protocol '%s', "
            "no random access possible", scheme);
      } else {
        GST_LOG_OBJECT (src, "unhandled protocol '%s', asking parent", scheme);
        goto forward_parent;
      }
      g_free (scheme);

      gst_query_set_scheduling (query, flags, 1, -1, 0);
      gst_query_add_scheduling_mode (query, GST_PAD_MODE_PUSH);
      GST_OBJECT_LOCK (src);
      if (flags & GST_SCHEDULING_FLAG_SEEKABLE && !src->is_growing)
        gst_query_add_scheduling_mode (query, GST_PAD_MODE_PULL);
      GST_OBJECT_UNLOCK (src);

      res = TRUE;
      break;
    }
    default:
    forward_parent:
      res = GST_CALL_PARENT_WITH_DEFAULT (GST_BASE_SRC_CLASS,
          query, (base_src, query), FALSE);
      break;
  }

  return res;
}

static GInputStream *
gst_gio_src_get_stream (GstGioBaseSrc * bsrc)
{
  GstGioSrc *src = GST_GIO_SRC (bsrc);
  GError *err = NULL;
  GInputStream *stream;
  GCancellable *cancel = bsrc->cancel;
  gchar *uri = NULL;

  if (src->file == NULL) {
    GST_ELEMENT_ERROR (src, RESOURCE, OPEN_READ, (NULL),
        ("No location or GFile given"));
    return NULL;
  }

  uri = g_file_get_uri (src->file);
  if (!uri)
    uri = g_strdup ("(null)");

  stream = G_INPUT_STREAM (g_file_read (src->file, cancel, &err));

  if (stream == NULL && !gst_gio_error (src, "g_file_read", &err, NULL)) {
    if (GST_GIO_ERROR_MATCHES (err, NOT_FOUND)) {
      GST_ELEMENT_ERROR (src, RESOURCE, NOT_FOUND, (NULL),
          ("Could not open location %s for reading: %s", uri, err->message));
    } else if (GST_GIO_ERROR_MATCHES (err, NOT_MOUNTED)) {
      gst_element_post_message (GST_ELEMENT_CAST (src),
          gst_message_new_element (GST_OBJECT_CAST (src),
              gst_structure_new ("not-mounted", "file", G_TYPE_FILE, src->file,
                  "uri", G_TYPE_STRING, uri, NULL)));

      GST_ELEMENT_ERROR (src, RESOURCE, OPEN_READ, (NULL),
          ("Location %s not mounted: %s", uri, err->message));
    } else {
      GST_ELEMENT_ERROR (src, RESOURCE, OPEN_READ, (NULL),
          ("Could not open location %s for reading: %s", uri, err->message));
    }

    g_free (uri);
    g_clear_error (&err);
    return NULL;
  } else if (stream == NULL) {
    g_free (uri);
    return NULL;
  }

  GST_DEBUG_OBJECT (src, "opened location %s", uri);
  g_free (uri);

  return stream;
}