# Copyright 2022 (c) Anna Schumaker.
"""A custom GObject managing a GStreamer playbin."""
import pathlib
from gi.repository import GObject
from gi.repository import Gst
from . import replaygain
from .. import path


class Player(GObject.GObject):
    """Wraps a GStreamer Playbin with an interface for our application."""

    volume = GObject.Property(type=float, default=1.0)

    file = GObject.Property(type=GObject.TYPE_PYOBJECT)
    have_track = GObject.Property(type=bool, default=False)

    def __init__(self):
        """Initialize the audio Player."""
        super().__init__()
        self._replaygain = replaygain.Filter()

        self._playbin = Gst.ElementFactory.make("playbin")
        self._playbin.set_property("audio-filter", self._replaygain)
        self._playbin.set_property("video-sink",
                                   Gst.ElementFactory.make("fakesink"))
        self._playbin.set_state(Gst.State.READY)

        bus = self._playbin.get_bus()
        bus.add_signal_watch()
        bus.connect("message::eos", self.__msg_eos)
        bus.connect("message::stream-start", self.__msg_stream_start)

        self.bind_property("volume", self._playbin, "volume")

        self.connect("notify::file", self.__notify_file)

    def __msg_eos(self, bus: Gst.Bus, message: Gst.Message) -> None:
        self.emit("eos")

    def __msg_stream_start(self, bus: Gst.Bus, message: Gst.Message) -> None:
        self.emit("file-loaded",
                  path.from_uri(self._playbin.get_property("current-uri")))

    def __notify_file(self, player: GObject.GObject, param) -> None:
        if self.file:
            uri = self.file.as_uri()
            print(f"audio: loading {uri}")
            self._playbin.set_property("uri", uri)

    def get_replaygain(self) -> tuple[bool, str | None]:
        """Get the current ReplayGain mode."""
        mode = self._replaygain.mode
        return (False, None) if mode == "disabled" else (True, mode)

    def get_state(self) -> Gst.State:
        """Get the current state of the Player."""
        return self._playbin.get_state(Gst.CLOCK_TIME_NONE).state

    def set_replaygain(self, enabled: bool, mode: str) -> None:
        """Set the ReplayGain mode."""
        self._replaygain.mode = mode if enabled else "disabled"

    def set_state_sync(self, state: Gst.State) -> None:
        """Set the state of the playbin, and wait for it to change."""
        if self._playbin.set_state(state) == Gst.StateChangeReturn.ASYNC:
            self.get_state()

    def shutdown(self) -> None:
        """Shut down the player."""
        self._playbin.set_state(Gst.State.NULL)

    @GObject.Signal(arg_types=(GObject.TYPE_PYOBJECT,))
    def file_loaded(self, file: pathlib.Path) -> None:
        """Signal that a new URI has started."""
        print("audio: file loaded")
        self.have_track = True

    @GObject.Signal
    def eos(self) -> None:
        """Signal that the current track has ended."""
        print("audio: end of stream")
        self.set_state_sync(Gst.State.READY)
        self.have_track = False
        self.file = None