# import os
import threading
import vlc                          # type: ignore
#
from config import Config
from datetime import datetime
from helpers import file_is_unreadable
from typing import Optional
from time import sleep

from log import log

lock = threading.Lock()


class Music:
    """
    Manage the playing of music tracks
    """

    def __init__(self) -> None:
        self.VLC = vlc.Instance()
        self.player = None
        self.max_volume = Config.VOLUME_VLC_DEFAULT

    def fade(self) -> None:
        """
        Fade the currently playing track.

        The actual management of fading runs in its own thread so as not
        to hold up the UI during the fade.
        """

        if not self.player:
            return

        if not self.player.get_position() > 0 and self.player.is_playing():
            return

        thread = threading.Thread(target=self._fade)
        thread.start()

    def _fade(self) -> None:
        """
        Implementation of fading the current track in a separate thread.
        """

        # Take a copy of current player to allow another track to be
        # started without interfering here
        with lock:
            p = self.player
            self.player = None

        # Sanity check
        if not p:
            return

        fade_time = Config.FADE_TIME / 1000
        steps = Config.FADE_STEPS
        sleep_time = fade_time / steps

        # We reduce volume by one mesure first, then by two measures,
        # then three, and so on.
        # The sum of the arithmetic sequence 1, 2, 3, ..n is
        # (n**2 + n) / 2
        total_measures_count = (steps**2 + steps) / 2

        measures_to_reduce_by = 0
        for i in range(1, steps + 1):
            measures_to_reduce_by += i
            volume_factor = 1 - (
                measures_to_reduce_by / total_measures_count)
            p.audio_set_volume(int(self.max_volume * volume_factor))
            sleep(sleep_time)

        with lock:
            p.stop()
            log.debug(f"Releasing player {p=}")
            p.release()

    def get_playtime(self) -> Optional[int]:
        """Return elapsed play time"""

        if not self.player:
            return None

        return self.player.get_time()

    def get_position(self) -> Optional[float]:
        """Return current position"""

        if not self.player:
            return None
        return self.player.get_position()

    def play(self, path: str,
             position: Optional[float] = None) -> Optional[int]:
        """
        Start playing the track at path.

        Log and return if path not found.
        """

        if file_is_unreadable(path):
            log.error(f"play({path}): path not readable")
            return None

        status = -1

        media = self.VLC.media_new_path(path)
        self.player = media.player_new_from_media()
        if self.player:
            self.player.audio_set_volume(self.max_volume)
            status = self.player.play()
            if position:
                self.player.set_position(position)

        return status

#
#     def set_position(self, ms):
#         """Set current play time in milliseconds from start"""
#
#         with lock:
#             return self.player.set_time(ms)

    def set_volume(self, volume, set_default=True):
        """Set maximum volume used for player"""

        if not self.player:
            return

        if set_default:
            self.max_volume = volume

        self.player.audio_set_volume(volume)

    def stop(self) -> float:
        """Immediately stop playing"""

        with lock:
            if not self.player:
                return 0.0

            position = self.player.get_position()
            self.player.stop()
            self.player.release()
            # Ensure we don't reference player after release
            self.player = None
            return position