/*
    This file is part of jellything (https://codeberg.org/metamuffin/jellything)
    which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
    Copyright (C) 2024 metamuffin <metamuffin.org>
*/
use anyhow::{anyhow, bail, Context, Result};
use jellybase::CONF;
use jellycommon::{stream::StreamSpec, LocalTrack, Node};
use jellyremuxer::extract::extract_track;
use jellytranscoder::subtitles::webvtt_from_ass_blocks;
use tokio::io::{AsyncWriteExt, DuplexStream};

pub async fn webvtt_stream(
    node: Node,
    local_tracks: Vec<LocalTrack>,
    spec: StreamSpec,
    mut b: DuplexStream,
) -> Result<()> {
    // TODO cache

    // TODO should use snippets too? big films take too long...

    let tracki = *spec.tracks.get(0).ok_or(anyhow!("no track selected"))?;
    let local_track = local_tracks.get(0).ok_or(anyhow!("no tracks"))?.clone();
    let track = &node.public.media.unwrap().tracks[tracki];

    match track.codec.as_str() {
        "S_TEXT/UTF8" => bail!("no subrip yet"),
        "S_VOBSUB" => bail!("no vobsub yet"),
        "S_TEXT/ASS" => {
            let codec_private = local_track
                .codec_private
                .clone()
                .ok_or(anyhow!("ASS is missing required codec private data"))?;

            let ass_blocks = tokio::task::spawn_blocking(move || {
                extract_track(CONF.library_path.clone(), local_track)
            })
            .await??;

            let webvtt = webvtt_from_ass_blocks(
                node.public.title.clone().unwrap_or_default(),
                codec_private,
                ass_blocks,
            )
            .context("transcoding subtitles")?;

            tokio::task::spawn(async move {
                let _ = b.write_all(webvtt.as_bytes()).await;
            });
        }

        _ => bail!("unknown sub codec"),
    };
    Ok(())
}