#!/usr/bin/env python3

import sys

from math import pi

import gi
gi.require_version('Gst', '1.0')
from gi.repository import Gst
Gst.init(None)

from gi.repository import GLib


PIPELINE_SRC = """
videotestsrc pattern=18 background-color=4294901760 ! intervideosink
"""

#PIPELINE_SRC = """
#v4l2src ! video/x-raw,width=320,height=240 ! intervideosink
#"""

PIPELINE_SINK = """
intervideosrc timeout=-1 ! videoconvert ! rotate name=rotate ! videoconvert ! autovideosink
"""


class Player:
    def __init__(self):
        self.loop = GLib.MainLoop()
        self.pipeline_src = Gst.parse_launch(PIPELINE_SRC)
        self.pipeline_sink = Gst.parse_launch(PIPELINE_SINK)

        self.rotate = self.pipeline_sink.get_by_name('rotate')
        self.paused = 0
        self.angle = 0

        bus = self.pipeline_src.get_bus()
        bus.add_signal_watch()
        bus.connect('message::eos', self.on_eos)
        bus.connect('message::error', self.on_error)
        bus.connect('message::state-changed', self .on_state_changed)

    def run(self):
        self.pipeline_src.set_state(Gst.State.PLAYING)
        self.pipeline_sink.set_state(Gst.State.PLAYING)
        self.loop.run()

    def quit(self):
        self.pipeline_sink.set_state(Gst.State.NULL)
        self.pipeline_src.set_state(Gst.State.NULL)
        self.loop.quit()

    def on_rotate(self):
        self.angle -= pi / 100
        self.angle %= 2 * pi
        self.rotate.set_property("angle", self.angle)

    def on_input(self):
        print(self.paused)
        if self.paused:
            self.pipeline_src.set_state(Gst.State.PLAYING)
        else:
            self.pipeline_src.set_state(Gst.State.PAUSED)

        self.paused ^= 1

    def on_eos(self, bus, msg):
        self.quit()

    def on_error(self, bus, msg):
        (err, debug) = msg.parse_error()
        print("Error: %s" % err)
        self.quit()

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

        old_state, new_state, pending = msg.parse_state_changed()
        print("%s from %s to %s" % (msg.src.get_name(), old_state, new_state))


def main():
    player = Player()

    def stdin_cb(source, condition):
        source.readline()
        player.on_input()
        return True

    def timeout_cb():
        player.on_rotate()
        return True

    GLib.io_add_watch(sys.stdin, GLib.IO_IN, stdin_cb)
    GLib.timeout_add(100, timeout_cb)

    print("\nPress Enter to freeze the video\n")
    player.run()


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