import asyncio
import logging
from typing import Callable, Awaitable, Iterable

from yt_dlp import YoutubeDL
from yt_dlp.postprocessor import FFmpegExtractAudioPP

import config
import response
import id3pp


class _CreateYDL:

    @staticmethod
    def youtube() -> YoutubeDL:
        ydl = YoutubeDL({'format': 'ba'})
        ydl.add_post_processor(id3pp.InfoYouTubePP(), when='before_dl')
        ydl.add_post_processor(FFmpegExtractAudioPP(preferredcodec='mp3'), when='post_process')
        return ydl

    @staticmethod
    def yt_proxied() -> YoutubeDL:
        ydl = _CreateYDL.youtube()
        ydl.params['proxy'] = config.get().yt_proxy
        return ydl

    @staticmethod
    def yandex() -> YoutubeDL:
        return YoutubeDL()


create_ydl_fn = {
    'youtube': _CreateYDL.youtube,
    'yt_proxied': _CreateYDL.yt_proxied,
    'yandex': _CreateYDL.yandex,
}

ydl_fn_keys = create_ydl_fn.keys()

# need process=True for track title in extract_info output
NP_YDLS = {'yandex'}


class YdlLogger:

    def __init__(
            self,
            log_cb: Callable[[response.YdlLogLevel, str], Awaitable],
            loop: asyncio.AbstractEventLoop) -> None:
        self.log_cb = log_cb
        self.loop = loop
        self.mdlp_logger = logging.getLogger('musicdlp')

    def debug(self, msg: str) -> None:
        asyncio.run_coroutine_threadsafe(self.log_cb('debug', msg), self.loop)

    def info(self, _: str) -> None:  # afaik not used in yt-dlp
        pass

    def warning(self, msg: str) -> None:
        asyncio.run_coroutine_threadsafe(self.log_cb('warning', msg), self.loop)

    def error(self, msg: str) -> None:
        self.mdlp_logger.error(msg)
        asyncio.run_coroutine_threadsafe(self.log_cb('error', msg), self.loop)


class Downloader:

    def __init__(self, logger: YdlLogger | None = None) -> None:

        self.ydls: dict[str, YoutubeDL | None] = {
            'youtube': None,
            'yt_proxied': None,
            'yandex': None,
        }

        self.cur_ydl: YoutubeDL | None = None
        self.cur_site = ''

        self.id3pp_obj = id3pp.ID3TagsPP()

        self.logger = logger

    def choose_ydl(self, site: str) -> None:

        ydl = self.ydls[site]
        cfg = config.get()

        if ydl is None:
            ydl = create_ydl_fn[site]()

            if self.logger is not None:
                ydl.params['logger'] = self.logger

            ydl.params['outtmpl']['default'] = cfg.tmpl
            ydl.add_post_processor(self.id3pp_obj, when='post_process')

            cookies = cfg.cookies_dir / (site + '.txt')
            if cookies.exists():
                ydl.params['cookiefile'] = str(cookies)

        self.cur_ydl = ydl
        self.cur_site = site

    def get_cur_ydl(self) -> YoutubeDL:

        ydl = self.cur_ydl
        if ydl is None:
            raise RuntimeError('ydl object not initialized')
        return ydl

    async def get_playlist_items(self, url: str) -> list[str]:

        return await asyncio.get_event_loop().run_in_executor(
            None,
            Downloader._target_get_playlist_items,
            self.get_cur_ydl(),
            url,
            self.cur_site in NP_YDLS,
        )

    @staticmethod
    def _target_get_playlist_items(ydl: YoutubeDL, url: str, process: bool) -> list[str]:

        info = ydl.extract_info(url, download=False, process=process)
        if info is None:
            raise RuntimeError('ydl.extract_info returned None')
        return [
            entry['track'] if 'track' in entry else entry['title']
            for entry in info['entries']
        ]

    async def download(
            self,
            url: str,
            playlist_items: Iterable[int] | None = None) -> int:

        return await asyncio.get_event_loop().run_in_executor(
            None,
            Downloader._target_download,
            self.get_cur_ydl(),
            url,
            playlist_items,
        )

    @staticmethod
    def _target_download(
            ydl: YoutubeDL,
            url: str,
            playlist_items: Iterable[int] | None = None) -> int:

        if playlist_items:
            ydl.params['playlist_items'] = ','.join(str(i) for i in playlist_items)

        ret = ydl.download(url)
        del ydl.params['playlist_items']

        return ret

    def cleanup(self) -> None:

        for ydl in self.ydls.values():
            if ydl is not None:
                ydl.close()