import os
import pathlib
import random
import shutil
import tempfile
import time
from collections.abc import Callable
from concurrent import futures
from uuid import uuid4

import ffmpeg
import m3u8
import requests
from constants import CHUNK_SIZE, COVER_NAME
from requests.exceptions import HTTPError
from rich.progress import Progress, TaskID
from tidalapi import Album, Mix, Playlist, Session, Track, UserPlaylist, Video
from tidalapi.exceptions import TooManyRequests
from tidalapi.media import AudioExtensions, Codec, Quality, StreamManifest, VideoExtensions

from tidal_dl_ng.config import Settings
from tidal_dl_ng.constants import EXTENSION_LYRICS, REQUESTS_TIMEOUT_SEC, MediaType, QualityVideo
from tidal_dl_ng.helper.decryption import decrypt_file, decrypt_security_token
from tidal_dl_ng.helper.exceptions import MediaMissing
from tidal_dl_ng.helper.path import check_file_exists, format_path_media, path_file_sanitize, url_to_filename
from tidal_dl_ng.helper.tidal import (
    instantiate_media,
    items_results_all,
    name_builder_album_artist,
    name_builder_artist,
    name_builder_item,
    name_builder_title,
)
from tidal_dl_ng.metadata import Metadata
from tidal_dl_ng.model.downloader import DownloadSegmentResult
from tidal_dl_ng.model.gui_data import ProgressBars


# TODO: Set appropriate client string and use it for video download.
# https://github.com/globocom/m3u8#using-different-http-clients
class RequestsClient:
    def download(
        self, uri: str, timeout: int = REQUESTS_TIMEOUT_SEC, headers: dict | None = None, verify_ssl: bool = True
    ):
        if not headers:
            headers = {}

        o = requests.get(uri, timeout=timeout, headers=headers)

        return o.text, o.url


# TODO: Use pathlib.Path everywhere
class Download:
    settings: Settings
    session: Session
    skip_existing: bool = False
    fn_logger: Callable
    progress_gui: ProgressBars
    progress: Progress

    def __init__(
        self,
        session: Session,
        path_base: str,
        fn_logger: Callable,
        skip_existing: bool = False,
        progress_gui: ProgressBars = None,
        progress: Progress = None,
    ):
        self.settings = Settings()
        self.session = session
        self.skip_existing = skip_existing
        self.fn_logger = fn_logger
        self.progress_gui = progress_gui
        self.progress = progress
        self.path_base = path_base

        if not self.settings.data.path_binary_ffmpeg and (
            self.settings.data.video_convert_mp4 or self.settings.data.extract_flac
        ):
            self.settings.data.video_convert_mp4 = False
            self.settings.data.extract_flac = False

            self.fn_logger.error(
                "FFmpeg path is not set. Videos can be downloaded but will not be processed. FLAC cannot be "
                "extracted from MP4 containers. Make sure FFmpeg is installed. The path to the FFmpeg binary must "
                "be set in (`path_binary_ffmpeg`)."
            )

    def _download(
        self,
        media: Track | Video,
        path_file: pathlib.Path,
    ) -> (bool, pathlib.Path):
        media_name: str = name_builder_item(media)
        urls: [str]
        path_base: pathlib.Path = path_file.parent
        result_segments: bool = True
        dl_segment_results: [DownloadSegmentResult] = []

        # Get urls for media.
        if isinstance(media, Track):
            urls = media.get_stream().get_stream_manifest().urls
            stream_manifest: StreamManifest = media.get_stream().get_stream_manifest()
        elif isinstance(media, Video):
            m3u8_variant: m3u8.M3U8 = m3u8.load(media.get_url())
            # Find the desired video resolution or the next best one.
            m3u8_playlist, codecs = self._extract_video_stream(m3u8_variant, int(self.settings.data.quality_video))
            # Populate urls.
            urls = m3u8_playlist.files

        # Set the correct progress output channel.
        if self.progress_gui is None:
            progress_to_stdout: bool = True
        else:
            progress_to_stdout: bool = False
            # Send signal to GUI with media name
            self.progress_gui.item_name.emit(media_name[:30])

        # Compute total iterations for progress
        urls_count: int = len(urls)

        if urls_count > 1:
            progress_total: int = urls_count
            block_size: int | None = None
        elif urls_count == 1:
            # Get file size and compute progress steps
            r = requests.head(urls[0], timeout=REQUESTS_TIMEOUT_SEC)
            total_size_in_bytes: int = int(r.headers.get("content-length", 0))
            block_size: int | None = 1048576
            progress_total: float = total_size_in_bytes / block_size
        else:
            raise ValueError

        # Create progress Task
        p_task: TaskID = self.progress.add_task(
            f"[blue]Item '{media_name[:30]}'",
            total=progress_total,
            visible=progress_to_stdout,
        )

        # Download segments until progress is finished.
        while not self.progress.tasks[p_task].finished:
            with futures.ThreadPoolExecutor(
                max_workers=self.settings.data.downloads_simultaneous_per_track_max
            ) as executor:
                # Dispatch all download tasks to worker threads
                l_futures: [any] = [
                    executor.submit(self._download_segment, url, path_base, block_size, p_task, progress_to_stdout)
                    for url in urls
                ]
                # Report results as they become available
                for future in futures.as_completed(l_futures):
                    # Retrieve result
                    result_dl_segment: DownloadSegmentResult = future.result()

                    dl_segment_results.append(result_dl_segment)

                    # check for a link that was skipped
                    if not result_dl_segment.result and (result_dl_segment.url is not urls[-1]):
                        # Sometimes it happens, if a track is very short (< 8 seconds or so), that the last URL in `urls` is
                        # invalid (HTTP Error 500) and not necessary. File won't be corrupt.
                        # If this is NOT the case, but any other URL has resulted in an error,
                        # mark the whole thing as corrupt.
                        result_segments = False

        tmp_path_file_decrypted: pathlib.Path = path_file

        # Only if no error happened while downloading.
        if result_segments:
            # Bring list into right order, so segments can be easily merged.
            dl_segment_results.sort(key=lambda x: x.id_segment)
            reult_merge: bool = self._segments_merge(path_file, dl_segment_results)

            if reult_merge and isinstance(media, Track) and stream_manifest.is_encrypted:
                key, nonce = decrypt_security_token(stream_manifest.encryption_key)
                tmp_path_file_decrypted = path_file.with_suffix("_decrypted")
                decrypt_file(path_file, tmp_path_file_decrypted, key, nonce)

        return result_segments, tmp_path_file_decrypted

    def _segments_merge(self, path_file, dl_segment_results) -> bool:
        result: bool

        # Copy the content of all segments into one file.
        try:
            with path_file.open("wb") as f_target:
                for dl_segment_result in dl_segment_results:
                    if dl_segment_result.result:
                        with dl_segment_result.path_segment.open("rb") as f_segment:
                            # Read and write junks, which gives better HDD write performance
                            while segment := f_segment.read(CHUNK_SIZE):
                                f_target.write(segment)

                        # Delete segment from HDD
                        dl_segment_result.path_segment.unlink()

            result = True
        except:
            result = False

        return result

    def _download_segment(
        self, url: str, path_base: pathlib.Path, block_size: int | None, p_task: TaskID, progress_to_stdout: bool
    ) -> DownloadSegmentResult:
        result: bool = False
        path_segment: pathlib.Path = path_base / url_to_filename(url)
        # Calculate the segment ID based on the file name within the URL.
        id_segment: int = int(path_segment.stem)
        error: HTTPError | None = None

        try:
            # Create the request object with stream=True, so the content won't be loaded into memory at once.
            r = requests.get(url, stream=True, timeout=REQUESTS_TIMEOUT_SEC)

            r.raise_for_status()

            # Write the content to disk. If `chunk_size` is set to `None` the whole file will be written at once.
            with path_segment.open("wb") as f:
                for data in r.iter_content(chunk_size=block_size):
                    f.write(data)
                    # Advance progress bar.
                    self.progress.advance(p_task)

            result = True
        except HTTPError as e:
            error = e
            self.progress.advance(p_task)
            self.fn_logger.exception(e)

        # To send the progress to the GUI, we need to emit the percentage.
        if not progress_to_stdout:
            self.progress_gui.item.emit(self.progress.tasks[p_task].percentage)

        return DownloadSegmentResult(
            result=result, url=url, path_segment=path_segment, id_segment=id_segment, error=error
        )

    def item(
        self,
        file_template: str,
        media: Track | Video = None,
        media_id: str = None,
        media_type: MediaType = None,
        video_download: bool = True,
        download_delay: bool = False,
        quality_audio: Quality | None = None,
        quality_video: QualityVideo | None = None,
        is_parent_album: bool = False,
    ) -> (bool, str):
        try:
            if media_id and media_type:
                # If no media instance is provided, we need to create the media instance.
                media = instantiate_media(self.session, media_type, media_id)
            elif isinstance(media, Track):  # Check if media is available not deactivated / removed from TIDAL.
                if not media.available:
                    self.fn_logger.info(
                        f"This track is not available for listening anymore on TIDAL. Skipping: {name_builder_item(media)}"
                    )

                    return False, ""
                else:
                    # Re-create media instance with full album information
                    media = self.session.track(media.id, with_album=True)
            elif not media:
                raise MediaMissing
        except:
            return False, ""

        # If video download is not allowed end here
        if not video_download and isinstance(media, Video):
            self.fn_logger.info(
                f"Video downloads are deactivated (see settings). Skipping video: {name_builder_item(media)}"
            )

            return False, ""

        # Create file name and path
        file_extension_dummy: str = AudioExtensions.FLAC
        file_name_relative = format_path_media(file_template, media)
        path_media_dst: pathlib.Path = (
            (pathlib.Path(self.path_base).expanduser() / file_name_relative).resolve().absolute()
        )

        # Sanitize final path_file to fit into OS boundaries.
        path_media_dst = pathlib.Path(
            path_file_sanitize(str(path_media_dst.with_suffix(file_extension_dummy)), adapt=True)
        )

        # Compute if and how downloads need to be skipped.
        if self.skip_existing:
            skip_file: bool = check_file_exists(path_media_dst, extension_ignore=True)
        else:
            skip_file: bool = False

        if not skip_file:
            # Get extension.
            file_extension: str
            do_flac_extract = False
            # If a quality is explicitly set, change it and remember the previously set quality.
            quality_audio_old: Quality = self.adjust_quality_audio(quality_audio)
            quality_video_old: QualityVideo = self.adjust_quality_video(quality_video)

            if isinstance(media, Track):
                try:
                    media_stream = media.get_stream()
                except TooManyRequests:
                    self.fn_logger.exception(
                        f"Too many requests against TIDAL backend. Skipping '{name_builder_item(media)}'. "
                        f"Consider to activate delay between downloads."
                    )

                    return False, ""

                file_extension = media_stream.get_stream_manifest().file_extension
                # Use M4A extension for MP4 audio tracks, because it looks better and is completely interchangeable.
                file_extension = AudioExtensions.M4A if file_extension == AudioExtensions.MP4 else file_extension

                if self.settings.data.extract_flac and (
                    media_stream.get_stream_manifest().codecs.upper() == Codec.FLAC
                    and file_extension != AudioExtensions.FLAC
                ):
                    file_extension = AudioExtensions.FLAC
                    do_flac_extract = True
            elif isinstance(media, Video):
                file_extension = AudioExtensions.MP4 if self.settings.data.video_convert_mp4 else VideoExtensions.TS

            # TODO: correct extension

            # Create a temp directory and file.
            with tempfile.TemporaryDirectory(ignore_cleanup_errors=True) as tmp_path_dir:
                tmp_path_file: pathlib.Path = pathlib.Path(tmp_path_dir) / str(uuid4())

                # Create empty file
                tmp_path_file.touch()

                # Download media.
                result_download, tmp_path_file = self._download(media=media, path_file=tmp_path_file)

                if result_download:
                    # Convert video from TS to MP4
                    if isinstance(media, Video) and self.settings.data.video_convert_mp4:
                        # Convert `*.ts` file to `*.mp4` using ffmpeg
                        tmp_path_file = self._video_convert(tmp_path_file)

                    # Extract FLAC from MP4 container using ffmpeg
                    if isinstance(media, Track) and self.settings.data.extract_flac and do_flac_extract:
                        tmp_path_file = self._extract_flac(tmp_path_file)

                    tmp_path_lyrics: pathlib.Path | None = None
                    tmp_path_cover: pathlib.Path | None = None

                    # Write metadata to file.
                    if not isinstance(media, Video):
                        result_metadata, tmp_path_lyrics, tmp_path_cover = self.metadata_write(
                            media, tmp_path_file, is_parent_album
                        )

                    # Move lyrics file
                    if self.settings.data.lyrics_file and not isinstance(media, Video):
                        self._move_lyrics(tmp_path_lyrics, path_media_dst)

                    # Move cover file
                    if self.settings.data.cover_album_file:
                        self._move_cover(tmp_path_cover, path_media_dst)

                # Move final file to the configured destination directory.
                os.makedirs(path_media_dst.parent, exist_ok=True)
                shutil.move(tmp_path_file, path_media_dst)

            if quality_audio:
                # Set quality back to the global user value
                self.adjust_quality_audio(quality_audio_old)

            if quality_video:
                # Set quality back to the global user value
                self.adjust_quality_video(quality_video_old)
        else:
            self.fn_logger.debug(f"Download skipped, since file exists: '{path_media_dst}'")

        status_download: bool = not skip_file

        # Whether a file was downloaded or skipped and the download delay is enabled, wait until the next download.
        # Only use this, if you have a list of several Track items.
        if download_delay and not skip_file:
            time_sleep: float = round(random.SystemRandom().uniform(2, 5), 1)

            self.fn_logger.debug(f"Next download will start in {time_sleep} seconds.")
            time.sleep(time_sleep)

        return status_download, path_media_dst

    def adjust_quality_audio(self, quality) -> Quality:
        # Save original quality settings
        quality_old: Quality = self.session.audio_quality
        self.session.audio_quality = quality

        return quality_old

    def adjust_quality_video(self, quality) -> QualityVideo:
        quality_old: QualityVideo = self.settings.data.quality_video

        self.settings.data.quality_video = quality

        return quality_old

    def _move_file(self, path_file_source: pathlib.Path, path_file_destination: str | pathlib.Path) -> bool:
        result: bool

        # Check if the file was downloaded
        if path_file_source and os.path.isfile(path_file_source):
            # Move it.
            shutil.move(path_file_source, path_file_destination)

            result = True
        else:
            result = False

        return result

    def _move_lyrics(self, path_lyrics: pathlib.Path, file_media_dst: pathlib.Path) -> bool:
        # Build tmp lyrics filename
        path_file_lyrics: pathlib.Path = file_media_dst.with_suffix(EXTENSION_LYRICS)
        result: bool = self._move_file(path_lyrics, path_file_lyrics)

        return result

    def _move_cover(self, path_cover: pathlib.Path, file_media_dst: pathlib.Path) -> bool:
        # Build tmp lyrics filename
        path_file_cover: pathlib.Path = file_media_dst.parent / COVER_NAME
        result: bool = self._move_file(path_cover, path_file_cover)

        return result

    def lyrics_to_file(self, dir_destination: pathlib.Path, lyrics: str) -> str:
        return self.write_to_tmp_file(dir_destination, mode="x", content=lyrics)

    def cover_to_file(self, dir_destination: pathlib.Path, image: bytes) -> str:
        return self.write_to_tmp_file(dir_destination, mode="xb", content=image)

    def write_to_tmp_file(self, dir_destination: pathlib.Path, mode: str, content: str | bytes) -> str:
        result: str = dir_destination / str(uuid4())
        encoding: str | None = "utf-8" if isinstance(content, str) else None

        try:
            with open(result, mode=mode, encoding=encoding) as f:
                f.write(content)
        except:
            result = ""

        return result

    @staticmethod
    def cover_data(url: str = None, path_file: str = None) -> str | bytes:
        result: str | bytes = ""

        if url:
            try:
                result = requests.get(url, timeout=REQUESTS_TIMEOUT_SEC).content
            except Exception as e:
                # TODO: Implement propper logging.
                print(e)
        elif path_file:
            try:
                with open(path_file, "rb") as f:
                    result = f.read()
            except OSError as e:
                # TODO: Implement propper logging.
                print(e)

        return result

    def metadata_write(
        self, track: Track, path_media: pathlib.Path, is_parent_album: bool
    ) -> (bool, pathlib.Path | None, pathlib.Path | None):
        result: bool = False
        path_lyrics: pathlib.Path | None = None
        path_cover: pathlib.Path | None = None
        release_date: str = (
            track.album.available_release_date.strftime("%Y-%m-%d")
            if track.album.available_release_date
            else track.album.release_date.strftime("%Y-%m-%d") if track.album.release_date else ""
        )
        copy_right: str = track.copyright if hasattr(track, "copyright") and track.copyright else ""
        isrc: str = track.isrc if hasattr(track, "isrc") and track.isrc else ""
        lyrics: str = ""
        cover_data: bytes = None

        if self.settings.data.lyrics_embed or self.settings.data.lyrics_file:
            # Try to retrieve lyrics.
            try:
                lyrics_obj = track.lyrics()

                if lyrics_obj.subtitles:
                    lyrics = lyrics_obj.subtitles
                elif lyrics_obj.text:
                    lyrics = lyrics_obj.text
            except:
                lyrics = ""
                # TODO: Implement proper logging.
                print(f"Could not retrieve lyrics for `{name_builder_item(track)}`.")

        if lyrics and self.settings.data.lyrics_file:
            path_lyrics = self.lyrics_to_file(path_media.parent, lyrics)

        if self.settings.data.metadata_cover_embed or (self.settings.data.cover_album_file and is_parent_album):
            url_cover = track.album.image(int(self.settings.data.metadata_cover_dimension))
            cover_data = self.cover_data(url=url_cover)

        if cover_data and self.settings.data.cover_album_file and is_parent_album:
            path_cover = self.cover_to_file(path_media.parent, cover_data)

        # `None` values are not allowed.
        m: Metadata = Metadata(
            path_file=path_media,
            lyrics=lyrics,
            copy_right=copy_right,
            title=name_builder_title(track),
            artists=name_builder_artist(track),
            album=track.album.name if track.album else "",
            tracknumber=track.track_num,
            date=release_date,
            isrc=isrc,
            albumartist=name_builder_album_artist(track),
            totaltrack=track.album.num_tracks if track.album and track.album.num_tracks else 1,
            totaldisc=track.album.num_volumes if track.album and track.album.num_volumes else 1,
            discnumber=track.volume_num if track.volume_num else 1,
            cover_data=cover_data if self.settings.data.metadata_cover_embed else None,
        )

        m.save()

        result = True

        return result, path_lyrics, path_cover

    def items(
        self,
        file_template: str,
        media: Album | Playlist | UserPlaylist | Mix = None,
        media_id: str = None,
        media_type: MediaType = None,
        video_download: bool = False,
        download_delay: bool = True,
        quality_audio: Quality | None = None,
        quality_video: QualityVideo | None = None,
    ):
        # If no media instance is provided, we need to create the media instance.
        if media_id and media_type:
            media = instantiate_media(self.session, media_type, media_id)
        elif not media:
            raise MediaMissing

        # Create file name and path
        file_name_relative = format_path_media(file_template, media)

        # Get the name of the list and check, if videos should be included.
        videos_include: bool = True

        if isinstance(media, Mix):
            list_media_name = media.title[:30]
        elif video_download:
            list_media_name = name_builder_title(media)[:30]
        else:
            videos_include = False
            list_media_name = name_builder_title(media)[:30]

        # Get all items of the list.
        items = items_results_all(media, videos_include=videos_include)

        # Determine where to redirect the progress information.
        if self.progress_gui is None:
            progress_stdout: bool = True
        else:
            progress_stdout: bool = False
            self.progress_gui.list_name.emit(list_media_name[:30])

        # Create the list progress task.
        p_task1: TaskID = self.progress.add_task(
            f"[green]List '{list_media_name}'", total=len(items), visible=progress_stdout
        )

        is_album: bool = isinstance(media, Album)

        # Iterate through list items
        while not self.progress.finished:
            for item_media in items:
                # Download the item.
                status, result_path_file = self.item(
                    media=item_media,
                    file_template=file_name_relative,
                    quality_audio=quality_audio,
                    quality_video=quality_video,
                    download_delay=download_delay,
                    is_parent_album=is_album,
                )

                # Advance progress bar.
                self.progress.advance(p_task1)

                if not progress_stdout:
                    self.progress_gui.list_item.emit(self.progress.tasks[p_task1].percentage)

    def _video_convert(self, path_file: pathlib.Path) -> pathlib.Path:
        path_file_out: pathlib.Path = path_file.with_suffix(AudioExtensions.MP4)
        result, _ = (
            ffmpeg.input(path_file)
            .output(path_file_out, map=0, c="copy", loglevel="quiet")
            .run(cmd=self.settings.data.path_binary_ffmpeg)
        )

        return path_file_out

    def _extract_flac(self, path_media_src: pathlib.Path) -> pathlib.Path:
        path_media_out = path_media_src.with_suffix(AudioExtensions.FLAC)
        result, _ = (
            ffmpeg.input(path_media_src)
            .output(
                path_media_out, map=0, movflags="use_metadata_tags", acodec="copy", map_metadata="0:g", loglevel="quiet"
            )
            .run(cmd=self.settings.data.path_binary_ffmpeg)
        )

        return path_media_out

    def _extract_video_stream(self, m3u8_variant: m3u8.M3U8, quality: int) -> (m3u8.M3U8 | bool, str):
        m3u8_playlist: m3u8.M3U8 | bool = False
        resolution_best: int = 0
        mime_type: str = ""

        if m3u8_variant.is_variant:
            for playlist in m3u8_variant.playlists:
                if resolution_best < playlist.stream_info.resolution[1]:
                    resolution_best = playlist.stream_info.resolution[1]
                    m3u8_playlist = m3u8.load(playlist.uri)
                    mime_type = playlist.stream_info.codecs

                    if quality == playlist.stream_info.resolution[1]:
                        break

        return m3u8_playlist, mime_type