"""
This is the generic archiver used by auto-archiver, which uses `yt-dlp` under the hood.

This module is responsible for downloading and processing media content from platforms
supported by `yt-dlp`, such as YouTube, Facebook, and others. It provides functionality
for retrieving videos, subtitles, comments, and other metadata, and it integrates with
the broader archiving framework.

### Features
- Supports downloading videos and playlists.
- Retrieves metadata like titles, descriptions, upload dates, and durations.
- Downloads subtitles and comments when enabled.
- Configurable options for handling live streams, proxies, and more.

### Dropins
- For websites supported by `yt-dlp` that also contain posts in addition to videos
 (e.g. Facebook, Twitter, Bluesky), dropins can be created to extract post data and create 
 metadata objects. Some dropins are included in this generic_archiver by default, but
custom dropins can be created to handle additional websites and passed to the archiver
via the command line using the `--dropins` option (TODO!).

"""


import datetime, os, yt_dlp, pysubs2
import importlib
from typing import Type
from yt_dlp.extractor.common import InfoExtractor

from loguru import logger

from auto_archiver.archivers.archiver import Archiver
from ...core import Metadata, Media, ArchivingContext

class GenericArchiver(Archiver):
    name = "youtubedl_archiver" #left as is for backwards compat
    _dropins = {}

    def __init__(self, config: dict) -> None:
        super().__init__(config)
        self.subtitles = bool(self.subtitles)
        self.comments = bool(self.comments)
        self.livestreams = bool(self.livestreams)
        self.live_from_start = bool(self.live_from_start)
        self.end_means_success = bool(self.end_means_success)
        self.allow_playlist = bool(self.allow_playlist)
        self.max_downloads = self.max_downloads


    def suitable_extractors(self, url: str) -> list[str]:
        """
        Returns a list of valid extractors for the given URL"""
        for info_extractor in yt_dlp.YoutubeDL()._ies.values():
            if info_extractor.suitable(url) and info_extractor.working():
                yield info_extractor
        
    def suitable(self, url: str) -> bool:
        """
        Checks for valid URLs out of all ytdlp extractors.
        Returns False for the GenericIE, which as labelled by yt-dlp: 'Generic downloader that works on some sites'
        """
        return any(self.suitable_extractors(url))
    
    def download_additional_media(self, video_data: dict, info_extractor: InfoExtractor, metadata: Metadata) -> Metadata:
        """
        Downloads additional media like images, comments, subtitles, etc.

        Creates a 'media' object and attaches it to the metadata object.
        """

        # Just get the main thumbnail. More thumbnails are available in
        # video_data['thumbnails'] should they be required
        thumbnail_url = video_data.get('thumbnail')
        if thumbnail_url:
            try:
                cover_image_path = self.download_from_url(thumbnail_url)
                media = Media(cover_image_path)
                metadata.add_media(media, id="cover")
            except Exception as e:
                logger.error(f"Error downloading cover image {thumbnail_url}: {e}")

        dropin = self.dropin_for_name(info_extractor.ie_key())
        if dropin:
            try:
                metadata = dropin.download_additional_media(video_data, info_extractor, metadata)
            except AttributeError:
                pass

        return metadata

    def keys_to_clean(self, info_extractor: InfoExtractor, video_data: dict) -> dict:
        """
        Clean up the ytdlp generic video data to make it more readable and remove unnecessary keys that ytdlp adds
        """

        base_keys = ['formats', 'thumbnail', 'display_id', 'epoch', 'requested_downloads',
                     'duration_string', 'thumbnails', 'http_headers', 'webpage_url_basename', 'webpage_url_domain',
                     'extractor', 'extractor_key', 'playlist', 'playlist_index', 'duration_string', 'protocol', 'requested_subtitles',
                     'format_id', 'acodec', 'vcodec', 'ext', 'epoch', '_has_drm', 'filesize', 'audio_ext', 'video_ext', 'vbr', 'abr',
                     'resolution', 'dynamic_range', 'aspect_ratio', 'cookies', 'format', 'quality', 'preference', 'artists',
                     'channel_id', 'subtitles', 'tbr', 'url', 'original_url', 'automatic_captions', 'playable_in_embed', 'live_status',
                     '_format_sort_fields', 'chapters', 'requested_formats', 'format_note',
                     'audio_channels', 'asr', 'fps', 'was_live', 'is_live', 'heatmap', 'age_limit', 'stretched_ratio']
        
        dropin = self.dropin_for_name(info_extractor.ie_key())
        if dropin:
            try:
                base_keys += dropin.keys_to_clean(video_data, info_extractor)
            except AttributeError:
                pass

        return base_keys
    
    def add_metadata(self, video_data: dict, info_extractor: InfoExtractor, url:str, result: Metadata) -> Metadata:
        """
        Creates a Metadata object from the given video_data
        """

        # first add the media
        result = self.download_additional_media(video_data, info_extractor, result)

        # keep both 'title' and 'fulltitle', but prefer 'title', falling back to 'fulltitle' if it doesn't exist
        result.set_title(video_data.pop('title', video_data.pop('fulltitle', "")))
        result.set_url(url)

        # extract comments if enabled
        if self.comments:
            result.set("comments", [{
                "text": c["text"],
                "author": c["author"], 
                "timestamp": datetime.datetime.fromtimestamp(c.get("timestamp"), tz = datetime.timezone.utc)
            } for c in video_data.get("comments", [])])

        # then add the common metadata
        if timestamp := video_data.pop("timestamp", None):
            timestamp = datetime.datetime.fromtimestamp(timestamp, tz = datetime.timezone.utc).isoformat()
            result.set_timestamp(timestamp)
        if upload_date := video_data.pop("upload_date", None):
            upload_date = datetime.datetime.strptime(upload_date, '%Y%m%d').replace(tzinfo=datetime.timezone.utc)
            result.set("upload_date", upload_date)
        
        # then clean away any keys we don't want
        for clean_key in self.keys_to_clean(info_extractor, video_data):
            video_data.pop(clean_key, None)
        
        # then add the rest of the video data
        for k, v in video_data.items():
            if v:
                result.set(k, v)

        return result

    def get_metadata_for_post(self, info_extractor: Type[InfoExtractor], url: str, ydl: yt_dlp.YoutubeDL) -> Metadata:
        """
        Calls into the ytdlp InfoExtract subclass to use the prive _extract_post method to get the post metadata.
        """

        ie_instance = info_extractor(downloader=ydl)
        dropin = self.dropin_for_name(info_extractor.ie_key())
        if not dropin:
            # TODO: add a proper link to 'how to create your own dropin'
            logger.debug(f"""Could not find valid dropin for {info_extractor.IE_NAME}.
                     Why not try creating your own, and make sure it has a valid function called 'create_metadata'. Learn more: https://auto-archiver.readthedocs.io/en/latest/user_guidelines.html#""")
            return False
        
        post_data = dropin.extract_post(url, ie_instance)
        return dropin.create_metadata(post_data, ie_instance, self, url)

    def get_metadata_for_video(self, data: dict, info_extractor: Type[InfoExtractor], url: str, ydl: yt_dlp.YoutubeDL) -> Metadata:

        # this time download
        ydl.params['getcomments'] = self.comments
        #TODO: for playlist or long lists of videos, how to download one at a time so they can be stored before the next one is downloaded?
        data = ydl.extract_info(url, ie_key=info_extractor.ie_key(), download=True)
        if "entries" in data:
            entries = data.get("entries", [])
            if not len(entries):
                logger.warning('YoutubeDLArchiver could not find any video')
                return False
        else: entries = [data]

        result = Metadata()

        for entry in entries:
            try:
                filename = ydl.prepare_filename(entry)
                if not os.path.exists(filename):
                    filename = filename.split('.')[0] + '.mkv'

                new_media = Media(filename)
                for x in ["duration", "original_url", "fulltitle", "description", "upload_date"]:
                    if x in entry: new_media.set(x, entry[x])

                # read text from subtitles if enabled
                if self.subtitles:
                    for lang, val in (data.get('requested_subtitles') or {}).items():
                        try:    
                            subs = pysubs2.load(val.get('filepath'), encoding="utf-8")
                            text = " ".join([line.text for line in subs])
                            new_media.set(f"subtitles_{lang}", text)
                        except Exception as e:
                            logger.error(f"Error loading subtitle file {val.get('filepath')}: {e}")
                result.add_media(new_media)
            except Exception as e:
                logger.error(f"Error processing entry {entry}: {e}")

        return self.add_metadata(data, info_extractor, url, result)
    
    def dropin_for_name(self, dropin_name: str, additional_paths = [], package=__package__) -> Type[InfoExtractor]:

        if dropin_name == "generic":
            # no need for a dropin for the generic extractor (?)
            return None

        dropin_class_name = dropin_name.title()
        def _load_dropin(dropin):
            dropin_class = getattr(dropin, dropin_class_name)()
            return self._dropins.setdefault(dropin_name, dropin_class)

        try:
            return self._dropins[dropin_name]
        except KeyError:
            pass

        # TODO: user should be able to pass --dropins="/some/folder,/other/folder" as a cmd line option
        # which would allow the user to override the default dropins/add their own
        paths = [] + additional_paths
        for path in paths:
            dropin_path = os.path.join(path, f"{dropin_name}.py")
            dropin_spec = importlib.util.spec_from_file_location(dropin_name, dropin_path)
            if not dropin_spec:
                continue
            try:
                dropin = importlib.util.module_from_spec(dropin_spec)
                dropin_spec.loader.exec_module(dropin)
                return _load_dropin(dropin)
            except (FileNotFoundError, ModuleNotFoundError):
                pass
        
        # fallback to loading the dropins within auto-archiver
        try:
            return _load_dropin(importlib.import_module(f".{dropin_name}", package=package))
        except ModuleNotFoundError:
            pass

        return None

    def download_for_extractor(self, info_extractor: InfoExtractor, url: str, ydl: yt_dlp.YoutubeDL) -> Metadata:
        """
        Tries to download the given url using the specified extractor
        
        It first tries to use ytdlp directly to download the video. If the post is not a video, it will then try to
        use the extractor's _extract_post method to get the post metadata if possible.
        """
        # when getting info without download, we also don't need the comments
        ydl.params['getcomments'] = False
        result = False

        dropin_submodule = self.dropin_for_name(info_extractor.ie_key())

        try:
            if dropin_submodule and dropin_submodule.skip_ytdlp_download(info_extractor, url):
                raise Exception(f"Skipping using ytdlp to download files for {info_extractor.ie_key()}")

            # don't download since it can be a live stream
            data = ydl.extract_info(url, ie_key=info_extractor.ie_key(), download=False)
            if data.get('is_live', False) and not self.livestreams:
                logger.warning("Livestream detected, skipping due to 'livestreams' configuration setting")
                return False
            # it's a valid video, that the youtubdedl can download out of the box
            result = self.get_metadata_for_video(data, info_extractor, url, ydl)

        except Exception as e:
            logger.debug(f'Issue using "{info_extractor.IE_NAME}" extractor to download video (error: {repr(e)}), attempting to use extractor to get post data instead')
            try:
                result = self.get_metadata_for_post(info_extractor, url, ydl)
            except (yt_dlp.utils.DownloadError, yt_dlp.utils.ExtractorError) as post_e:
                logger.error(f'Error downloading metadata for post: {post_e}')
                return False
            except Exception as generic_e:
                logger.debug(f'Attempt to extract using ytdlp extractor "{info_extractor.IE_NAME}" failed:  \n  {repr(generic_e)}', exc_info=True)
                return False
        
        if result:
            extractor_name = "yt-dlp"
            if info_extractor:
                extractor_name += f"_{info_extractor.ie_key()}"

            if self.end_means_success:
                result.success(extractor_name)
            else:
                result.status = extractor_name

        return result

    def download(self, item: Metadata) -> Metadata:
        url = item.get_url()

        if item.netloc in ['facebook.com', 'www.facebook.com'] and self.facebook_cookie:
            logger.debug('Using Facebook cookie')
            yt_dlp.utils.std_headers['cookie'] = self.facebook_cookie
        
        ydl_options = {'outtmpl': os.path.join(ArchivingContext.get_tmp_dir(), f'%(id)s.%(ext)s'), 'quiet': False, 'noplaylist': not self.allow_playlist , 'writesubtitles': self.subtitles, 'writeautomaticsub': self.subtitles, "live_from_start": self.live_from_start, "proxy": self.proxy, "max_downloads": self.max_downloads, "playlistend": self.max_downloads}

        if item.netloc in ['youtube.com', 'www.youtube.com']:
            if self.cookies_from_browser:
                logger.debug(f'Extracting cookies from browser {self.cookies_from_browser} for Youtube')
                ydl_options['cookiesfrombrowser'] = (self.cookies_from_browser,)
            elif self.cookie_file:
                logger.debug(f'Using cookies from file {self.cookie_file}')
                ydl_options['cookiefile'] = self.cookie_file

        ydl = yt_dlp.YoutubeDL(ydl_options) # allsubtitles and subtitleslangs not working as expected, so default lang is always "en"

        for info_extractor in self.suitable_extractors(url):
            result = self.download_for_extractor(info_extractor, url, ydl)
            if result:
                return result
       

        return False