#!/usr/bin/env python

import sys

import pygst
pygst.require('0.10')
import gst
import gobject
gobject.threads_init()

# 1 create a pipeline
# 2 set it to playing
# 3 wait for pipeline to go to playing
# 4 get the pipeline clock and the base_time
# 5 create a NetTimeProvider using the clock and port
# 6 inform clients of port and base_time

class MasterPipeline:

    def __init__(self, uri, port):
        self.port = int(port)
        self.uri = uri
        
        # 1 create a pipeline
        self.pipeline = gst.element_factory_make("playbin")
        self.pipeline.set_property("uri", 'file://' + self.uri)

        # connect a method to the bus messages
        self.bus = self.pipeline.get_bus()
        self.bus.add_signal_watch()
        self.bus.connect('message', self._busMessageCb)

        # create a mainloop to do event-based programming
        self.mainloop = gobject.MainLoop()

    def run(self):
        # 2 set pipeline to playing
        if self.pipeline.set_state(gst.STATE_PLAYING) == gst.STATE_CHANGE_FAILURE:
            print "Couldn't set the pipeline to PLAYING"
        self.mainloop.run()

    def _busMessageCb(self, bus, message):
        if message.type == gst.MESSAGE_STATE_CHANGED:
            if message.src == self.pipeline:
                previous, current, pending = message.parse_state_changed()
                if previous == gst.STATE_PAUSED and current == gst.STATE_PLAYING and pending == gst.STATE_VOID_PENDING:
                    # The pipeline is now playing
                    # get the clock
                    clock = self.pipeline.get_clock()
                    # get the base_time
                    base_time = self.pipeline.get_base_time()
                    # Create the NetTimeProvider
                    provider = gst.NetTimeProvider(clock, None, self.port)
                    # inform clients of port and base_time
                    print ("Start slave as: python ./play-slave.py %s [IP] %d %d"
                           % (self.uri, self.port, base_time))
        elif message.type in [gst.MESSAGE_ERROR, gst.MESSAGE_EOS]:
            # if we have finished playing or there is an error, we exit the mainloop
            self.mainloop.quit()

if __name__ == '__main__':
    uri, port = sys.argv[1:]
    pipeline = MasterPipeline(uri, port)
    pipeline.run()