#!/usr/bin/env python

# Get a test sample with:
# youtube-dl -t http://www.youtube.com/watch?v=yWa-YXiSk2Y

import sys

import gobject
gobject.threads_init()

import gst


class Player:
    def __init__(self, filename, rate):
        self._filename = filename
        self._rate = rate

        self._player = gst.element_factory_make("playbin2", "player")
        self._player.set_property("uri", filename)
        self._player.connect("about-to-finish", self.on_about_to_finish)

        bus = self._player.get_bus()
        bus.add_signal_watch()
        bus.connect('message::state-changed', self.on_state_changed)

    def run(self):
        self._player.set_state(gst.STATE_PLAYING)
        loop = gobject.MainLoop()
        loop.run()

    def on_about_to_finish(self, player):
        sys.stderr.write(".")
        player.set_property("uri", self._filename)

        # XXX Ater the first iteration of the loop the playback rate is reset to
        # normal. Do I need to re-set the rate here?

        # If I uncomment the following line, the player hangs:
        #self.set_rate(self._date)

        # And it hangs also if I set the seek_event manually using position=0:
        #seek_event = gst.event_new_seek(self._rate,
        #        gst.FORMAT_TIME,
        #        gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
        #        gst.SEEK_TYPE_SET, 0,
        #        gst.SEEK_TYPE_NONE, 0)
        #self._player.send_event(seek_event)

    def on_state_changed(self, bus, msg):
        if msg.src != self._player:
            return

        print 'on_state_changed'
        old_state, new_state, pending = msg.parse_state_changed()
        print "%s -> %s" % (old_state, new_state)
        if new_state == gst.STATE_PAUSED:
            self.set_rate(self._rate)

    def set_rate(self, rate):
        self._rate = rate
        try:
            position, format = self._player.query_position(gst.FORMAT_TIME)
        except:
            position = 0

        # Create the seek event
        if rate > 0:
            seek_event = gst.event_new_seek(rate,
                    gst.FORMAT_TIME,
                    gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
                    gst.SEEK_TYPE_SET, position,
                    gst.SEEK_TYPE_NONE, 0)
        else:
            seek_event = gst.event_new_seek(rate,
                    gst.FORMAT_TIME,
                    gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
                    gst.SEEK_TYPE_SET, 0,
                    gst.SEEK_TYPE_SET, position)

        if seek_event:
            self._player.send_event(seek_event)
            gst.info("rate set to %s" % rate)
        else:
            gst.warining("change rate failed")


def main(args):
    def usage():
        sys.stdout.write("usage: %s <URI-OF-MEDIA-FILE>\n" % args[0])

    if len(args) != 2:
        usage()
        sys.exit(1)

    if not gst.uri_is_valid(args[1]):
        sys.stderr.write("Error: Invalid URI: %s\n" % args[1])
        sys.exit(1)

    player = Player(args[1], 3.0)
    player.run()

if __name__ == '__main__':
    sys.exit(main(sys.argv))