use crate::download::filter::DownloadFilter;
use crate::utils::context::Context;
use crate::utils::download::{DownloadBuilder, DownloadFormat, DownloadFormatMetadata};
use crate::utils::ffmpeg::{FFmpegPreset, SOFTSUB_CONTAINERS};
use crate::utils::filter::Filter;
use crate::utils::format::{Format, SingleFormat};
use crate::utils::locale::{resolve_locales, LanguageTagging};
use crate::utils::log::progress;
use crate::utils::os::{free_file, has_ffmpeg, is_special_file};
use crate::utils::parse::parse_url;
use crate::utils::video::stream_data_from_stream;
use crate::Execute;
use anyhow::bail;
use anyhow::Result;
use crunchyroll_rs::media::Resolution;
use crunchyroll_rs::Locale;
use log::{debug, warn};
use std::collections::HashMap;
use std::path::Path;

#[derive(Clone, Debug, clap::Parser)]
#[clap(about = "Download a video")]
#[command(arg_required_else_help(true))]
pub struct Download {
    #[arg(help = format!("Audio language. Can only be used if the provided url(s) point to a series. \
    Available languages are: {}", Locale::all().into_iter().map(|l| l.to_string()).collect::<Vec<String>>().join(", ")))]
    #[arg(long_help = format!("Audio language. Can only be used if the provided url(s) point to a series. \
    Available languages are:\n  {}\nIETF tagged language codes for the shown available locales can be used too", Locale::all().into_iter().map(|l| format!("{:<6} → {}", l.to_string(), l.to_human_readable())).collect::<Vec<String>>().join("\n  ")))]
    #[arg(short, long, default_value_t = crate::utils::locale::system_locale())]
    pub(crate) audio: Locale,
    #[arg(skip)]
    output_audio_locale: String,
    #[arg(help = format!("Subtitle language. Available languages are: {}", Locale::all().into_iter().map(|l| l.to_string()).collect::<Vec<String>>().join(", ")))]
    #[arg(long_help = format!("Subtitle language. If set, the subtitle will be burned into the video and cannot be disabled. \
    Available languages are: {}\nIETF tagged language codes for the shown available locales can be used too", Locale::all().into_iter().map(|l| l.to_string()).collect::<Vec<String>>().join(", ")))]
    #[arg(short, long)]
    pub(crate) subtitle: Option<Locale>,
    #[arg(skip)]
    output_subtitle_locale: String,

    #[arg(help = "Name of the output file")]
    #[arg(long_help = "Name of the output file. \
    If you use one of the following pattern they will get replaced:\n  \
      {title}                    → Title of the video\n  \
      {series_name}              → Name of the series\n  \
      {season_name}              → Name of the season\n  \
      {audio}                    → Audio language of the video\n  \
      {width}                    → Width of the video\n  \
      {height}                   → Height of the video\n  \
      {season_number}            → Number of the season\n  \
      {episode_number}           → Number of the episode\n  \
      {relative_episode_number}  → Number of the episode relative to its season\n  \
      {sequence_number}          → Like '{episode_number}' but without possible non-number characters\n  \
      {relative_sequence_number} → Like '{relative_episode_number}' but with support for episode 0's and .5's\n  \
      {release_year}             → Release year of the video\n  \
      {release_month}            → Release month of the video\n  \
      {release_day}              → Release day of the video\n  \
      {series_id}                → ID of the series\n  \
      {season_id}                → ID of the season\n  \
      {episode_id}               → ID of the episode")]
    #[arg(short, long, default_value = "{title}.mp4")]
    pub(crate) output: String,
    #[arg(help = "Name of the output file if the episode is a special")]
    #[arg(long_help = "Name of the output file if the episode is a special. \
    If not set, the '-o'/'--output' flag will be used as name template")]
    #[arg(long)]
    pub(crate) output_specials: Option<String>,

    #[arg(help = "Sanitize the output file for use with all operating systems. \
    This option only affects template options and not static characters.")]
    #[arg(long, default_value_t = false)]
    pub(crate) universal_output: bool,

    #[arg(help = "Video resolution")]
    #[arg(long_help = "The video resolution. \
    Can either be specified via the pixels (e.g. 1920x1080), the abbreviation for pixels (e.g. 1080p) or 'common-use' words (e.g. best). \
    Specifying the exact pixels is not recommended, use one of the other options instead. \
    Crunchyroll let you choose the quality with pixel abbreviation on their clients, so you might be already familiar with the available options. \
    The available common-use words are 'best' (choose the best resolution available) and 'worst' (worst resolution available)")]
    #[arg(short, long, default_value = "best")]
    #[arg(value_parser = crate::utils::clap::clap_parse_resolution)]
    pub(crate) resolution: Resolution,

    #[arg(
        long,
        help = "Specified which language tagging the audio and subtitle tracks and language specific format options should have. \
        Valid options are: 'default' (how Crunchyroll uses it internally), 'ietf' (according to the IETF standard)"
    )]
    #[arg(
        long_help = "Specified which language tagging the audio and subtitle tracks and language specific format options should have. \
        Valid options are: 'default' (how Crunchyroll uses it internally), 'ietf' (according to the IETF standard; you might run in issues as there are multiple locales which resolve to the same IETF language code, e.g. 'es-LA' and 'es-ES' are both resolving to 'es')"
    )]
    #[arg(value_parser = LanguageTagging::parse)]
    pub(crate) language_tagging: Option<LanguageTagging>,

    #[arg(help = format!("Presets for converting the video to a specific coding format. \
    Available presets: \n  {}", FFmpegPreset::available_matches_human_readable().join("\n  ")))]
    #[arg(long_help = format!("Presets for converting the video to a specific coding format. \
    If you need more specific ffmpeg customizations you can pass ffmpeg output arguments instead of a preset as value. \
    Available presets: \n  {}", FFmpegPreset::available_matches_human_readable().join("\n  ")))]
    #[arg(long)]
    #[arg(value_parser = FFmpegPreset::parse)]
    pub(crate) ffmpeg_preset: Option<FFmpegPreset>,
    #[arg(
        help = "The number of threads used by ffmpeg to generate the output file. Does not work with every codec/preset"
    )]
    #[arg(
        long_help = "The number of threads used by ffmpeg to generate the output file. \
    Does not work with every codec/preset and is skipped entirely when specifying custom ffmpeg output arguments instead of a preset for `--ffmpeg-preset`. \
    By default, ffmpeg chooses the thread count which works best for the output codec"
    )]
    #[arg(long)]
    pub(crate) ffmpeg_threads: Option<usize>,

    #[arg(help = "Skip files which are already existing by their name")]
    #[arg(long, default_value_t = false)]
    pub(crate) skip_existing: bool,
    #[arg(help = "Skip special episodes")]
    #[arg(long, default_value_t = false)]
    pub(crate) skip_specials: bool,

    #[arg(help = "Includes chapters (e.g. intro, credits, ...)")]
    #[arg(long_help = "Includes chapters (e.g. intro, credits, ...). \
    Because chapters are essentially only special timeframes in episodes like the intro, most of the video timeline isn't covered by a chapter.
    These \"gaps\" are filled with an 'Episode' chapter because many video players are ignore those gaps and just assume that a chapter ends when the next chapter start is reached, even if a specific end-time is set.
    Also chapters aren't always available, so in this case, just a big 'Episode' chapter from start to end will be created")]
    #[arg(long, default_value_t = false)]
    pub(crate) include_chapters: bool,

    #[arg(help = "Skip any interactive input")]
    #[arg(short, long, default_value_t = false)]
    pub(crate) yes: bool,

    #[arg(help = "Force subtitles to be always burnt-in")]
    #[arg(long, default_value_t = false)]
    pub(crate) force_hardsub: bool,

    #[arg(help = "The number of threads used to download")]
    #[arg(short, long, default_value_t = num_cpus::get())]
    pub(crate) threads: usize,

    #[arg(help = "Url(s) to Crunchyroll episodes or series")]
    #[arg(required = true)]
    pub(crate) urls: Vec<String>,
}

impl Execute for Download {
    fn pre_check(&mut self) -> Result<()> {
        if !has_ffmpeg() {
            bail!("FFmpeg is needed to run this command")
        } else if Path::new(&self.output)
            .extension()
            .unwrap_or_default()
            .is_empty()
            && !is_special_file(&self.output)
            && self.output != "-"
        {
            bail!("No file extension found. Please specify a file extension (via `-o`) for the output file")
        }

        if self.subtitle.is_some() {
            if let Some(ext) = Path::new(&self.output).extension() {
                if self.force_hardsub {
                    warn!("Hardsubs are forced. Adding subtitles may take a while")
                } else if !["mkv", "mov", "mp4"].contains(&ext.to_string_lossy().as_ref()) {
                    warn!("Detected a container which does not support softsubs. Adding subtitles may take a while")
                }
            }
        }

        if let Some(special_output) = &self.output_specials {
            if Path::new(special_output)
                .extension()
                .unwrap_or_default()
                .is_empty()
                && !is_special_file(special_output)
                && special_output != "-"
            {
                bail!("No file extension found. Please specify a file extension (via `--output-specials`) for the output file")
            }
            if let Some(ext) = Path::new(special_output).extension() {
                if self.force_hardsub {
                    warn!("Hardsubs are forced for special episodes. Adding subtitles may take a while")
                } else if !["mkv", "mov", "mp4"].contains(&ext.to_string_lossy().as_ref()) {
                    warn!("Detected a container which does not support softsubs. Adding subtitles for special episodes may take a while")
                }
            }
        }

        if let Some(language_tagging) = &self.language_tagging {
            self.audio = resolve_locales(&[self.audio.clone()]).remove(0);
            self.subtitle = self
                .subtitle
                .as_ref()
                .map(|s| resolve_locales(&[s.clone()]).remove(0));
            self.output_audio_locale = language_tagging.for_locale(&self.audio);
            self.output_subtitle_locale = self
                .subtitle
                .as_ref()
                .map(|s| language_tagging.for_locale(s))
                .unwrap_or_default()
        } else {
            self.output_audio_locale = self.audio.to_string();
            self.output_subtitle_locale = self
                .subtitle
                .as_ref()
                .map(|s| s.to_string())
                .unwrap_or_default();
        }

        Ok(())
    }

    async fn execute(self, ctx: Context) -> Result<()> {
        if !ctx.crunchy.premium().await {
            warn!("You may not be able to download all requested videos when logging in anonymously or using a non-premium account")
        }

        let mut parsed_urls = vec![];

        let output_supports_softsubs = SOFTSUB_CONTAINERS.contains(
            &Path::new(&self.output)
                .extension()
                .unwrap_or_default()
                .to_string_lossy()
                .as_ref(),
        );
        let special_output_supports_softsubs = if let Some(so) = &self.output_specials {
            SOFTSUB_CONTAINERS.contains(
                &Path::new(so)
                    .extension()
                    .unwrap_or_default()
                    .to_string_lossy()
                    .as_ref(),
            )
        } else {
            output_supports_softsubs
        };

        for (i, url) in self.urls.clone().into_iter().enumerate() {
            let progress_handler = progress!("Parsing url {}", i + 1);
            match parse_url(&ctx.crunchy, url.clone(), true).await {
                Ok((media_collection, url_filter)) => {
                    progress_handler.stop(format!("Parsed url {}", i + 1));
                    parsed_urls.push((media_collection, url_filter))
                }
                Err(e) => bail!("url {} could not be parsed: {}", url, e),
            };
        }

        for (i, (media_collection, url_filter)) in parsed_urls.into_iter().enumerate() {
            let progress_handler = progress!("Fetching series details");
            let single_format_collection = DownloadFilter::new(
                url_filter,
                self.clone(),
                !self.yes,
                self.skip_specials,
                ctx.crunchy.premium().await,
            )
            .visit(media_collection)
            .await?;

            if single_format_collection.is_empty() {
                progress_handler.stop(format!("Skipping url {} (no matching videos found)", i + 1));
                continue;
            }
            progress_handler.stop(format!("Loaded series information for url {}", i + 1));

            single_format_collection.full_visual_output();

            let download_builder =
                DownloadBuilder::new(ctx.client.clone(), ctx.rate_limiter.clone())
                    .default_subtitle(self.subtitle.clone())
                    .force_hardsub(self.force_hardsub)
                    .output_format(if is_special_file(&self.output) || self.output == "-" {
                        Some("mpegts".to_string())
                    } else {
                        None
                    })
                    .ffmpeg_preset(self.ffmpeg_preset.clone().unwrap_or_default())
                    .ffmpeg_threads(self.ffmpeg_threads)
                    .threads(self.threads)
                    .audio_locale_output_map(HashMap::from([(
                        self.audio.clone(),
                        self.output_audio_locale.clone(),
                    )]))
                    .subtitle_locale_output_map(
                        self.subtitle.as_ref().map_or(HashMap::new(), |s| {
                            HashMap::from([(s.clone(), self.output_subtitle_locale.clone())])
                        }),
                    );

            for mut single_formats in single_format_collection.into_iter() {
                // the vec contains always only one item
                let single_format = single_formats.remove(0);

                let (download_format, format) = get_format(
                    &self,
                    &single_format,
                    if self.force_hardsub {
                        true
                    } else if single_format.is_special() {
                        !special_output_supports_softsubs
                    } else {
                        !output_supports_softsubs
                    },
                )
                .await?;

                let mut downloader = download_builder.clone().build();
                downloader.add_format(download_format);

                let formatted_path = if format.is_special() {
                    format.format_path(
                        self.output_specials
                            .as_ref()
                            .map_or((&self.output).into(), |so| so.into()),
                        self.universal_output,
                        self.language_tagging.as_ref(),
                    )
                } else {
                    format.format_path(
                        (&self.output).into(),
                        self.universal_output,
                        self.language_tagging.as_ref(),
                    )
                };
                let (path, changed) = free_file(formatted_path.clone());

                if changed && self.skip_existing {
                    debug!(
                        "Skipping already existing file '{}'",
                        formatted_path.to_string_lossy()
                    );
                    continue;
                }

                format.visual_output(&path);

                downloader.download(&path).await?
            }
        }

        Ok(())
    }
}

async fn get_format(
    download: &Download,
    single_format: &SingleFormat,
    try_peer_hardsubs: bool,
) -> Result<(DownloadFormat, Format)> {
    let stream = single_format.stream().await?;
    let Some((video, audio, contains_hardsub)) = stream_data_from_stream(
        &stream,
        &download.resolution,
        if try_peer_hardsubs {
            download.subtitle.clone()
        } else {
            None
        },
    )
    .await?
    else {
        if single_format.is_episode() {
            bail!(
                "Resolution ({}) is not available for episode {} ({}) of {} season {}",
                download.resolution,
                single_format.episode_number,
                single_format.title,
                single_format.series_name,
                single_format.season_number,
            )
        } else {
            bail!(
                "Resolution ({}) is not available for {} ({})",
                download.resolution,
                single_format.source_type(),
                single_format.title
            )
        }
    };

    let subtitle = if contains_hardsub {
        None
    } else if let Some(subtitle_locale) = &download.subtitle {
        if download.audio == Locale::ja_JP {
            stream
                .subtitles
                .get(subtitle_locale)
                // use closed captions as fallback if no actual subtitles are found
                .or_else(|| stream.captions.get(subtitle_locale))
                .cloned()
        } else {
            stream
                .captions
                .get(subtitle_locale)
                .or_else(|| stream.subtitles.get(subtitle_locale))
                .cloned()
        }
    } else {
        None
    };

    let download_format = DownloadFormat {
        video: (video.clone(), single_format.audio.clone()),
        audios: vec![(audio, single_format.audio.clone())],
        subtitles: subtitle.clone().map_or(vec![], |s| {
            vec![(
                s,
                single_format.audio != Locale::ja_JP && stream.subtitles.len() == 1,
            )]
        }),
        metadata: DownloadFormatMetadata {
            skip_events: if download.include_chapters {
                single_format.skip_events().await?
            } else {
                None
            },
        },
    };
    let mut format = Format::from_single_formats(vec![(
        single_format.clone(),
        video,
        subtitle.map_or(vec![], |s| {
            vec![(
                s,
                single_format.audio != Locale::ja_JP && stream.subtitles.len() == 1,
            )]
        }),
    )]);
    if contains_hardsub {
        let (_, subs) = format.locales.get_mut(0).unwrap();
        subs.push(download.subtitle.clone().unwrap())
    }

    stream.invalidate().await?;

    Ok((download_format, format))
}