/*
    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) 2023 metamuffin <metamuffin.org>
*/
use crate::{
    database::Database,
    routes::ui::{account::session::Session, error::MyResult, CacheControlFile},
};
use anyhow::{anyhow, Context};
use jellybase::{
    cache::async_cache_file, federation::Federation, permission::NodePermissionExt,
    AssetLocationExt,
};
pub use jellycommon::AssetRole;
use jellycommon::{AssetLocation, LocalTrack, SourceTrackKind, TrackSource};
use log::info;
use rocket::{get, http::ContentType, State};
use std::{path::PathBuf, str::FromStr};
use tokio::fs::File;

#[get("/n/<id>/asset?<role>&<width>")]
pub async fn r_item_assets(
    session: Session,
    db: &State<Database>,
    id: &str,
    role: AssetRole,
    width: Option<usize>,
) -> MyResult<(ContentType, CacheControlFile)> {
    let node = db
        .node
        .get(&id.to_string())?
        .only_if_permitted(&session.user.permissions)
        .ok_or(anyhow!("node does not exist"))?;
    let mut asset = match role {
        AssetRole::Backdrop => node.private.backdrop,
        AssetRole::Poster => node.private.poster,
    };
    if let None = asset {
        if let Some(parent) = &node.public.path.last() {
            let parent = db.node.get(parent)?.ok_or(anyhow!("node does not exist"))?;
            asset = match role {
                AssetRole::Backdrop => parent.private.backdrop,
                AssetRole::Poster => parent.private.poster,
            };
        }
    };
    let asset = asset.unwrap_or(AssetLocation::Assets(
        PathBuf::from_str("fallback.avif").unwrap(),
    ));
    Ok(asset_with_res(asset, width).await?)
}

// TODO this can create "federation recursion" because track selection cannot be relied on.
#[get("/n/<id>/thumbnail?<t>&<width>")]
pub async fn r_node_thumbnail(
    session: Session,
    db: &State<Database>,
    fed: &State<Federation>,
    id: &str,
    t: f64,
    width: Option<usize>,
) -> MyResult<(ContentType, CacheControlFile)> {
    let node = db
        .node
        .get(&id.to_string())?
        .only_if_permitted(&session.user.permissions)
        .ok_or(anyhow!("node does not exist"))?;

    let media = node.public.media.ok_or(anyhow!("no media"))?;
    let (thumb_track_index, thumb_track) = media
        .tracks
        .iter()
        .enumerate()
        .find(|(_i, t)| matches!(t.kind, SourceTrackKind::Video { .. }))
        .ok_or(anyhow!("no video track to create a thumbnail of"))?;
    let source = node.private.source.ok_or(anyhow!("no source"))?;
    let thumb_track_source = &source[thumb_track_index];

    if t < 0. || t > media.duration {
        Err(anyhow!("thumbnail instant not within media duration"))?
    }

    let step = 8.;
    let t = (t / step).floor() * step;

    let asset = match thumb_track_source {
        TrackSource::Local(LocalTrack { path, .. }) => {
            // the track selected might be different from thumb_track
            jellytranscoder::thumbnail::create_thumbnail(path, t).await?
        }
        TrackSource::Remote(_) => {
            let session = fed
                .get_session(
                    thumb_track
                        .federated
                        .last()
                        .ok_or(anyhow!("federation broken"))?,
                )
                .await?;

            async_cache_file(&["fed-thumb", id, &format!("{t}")], |out| {
                session.node_thumbnail(out, id, 2048, t)
            })
            .await?
        }
    };

    Ok(asset_with_res(asset, width).await?)
}

async fn asset_with_res(
    asset: AssetLocation,
    width: Option<usize>,
) -> MyResult<(ContentType, CacheControlFile)> {
    // fit the resolution into a finite set so the maximum cache is finite too.
    let width = 2usize.pow(width.unwrap_or(2048).clamp(128, 2048).ilog2());
    let path = jellytranscoder::image::transcode(asset, 50., 5, width)
        .await
        .context("transcoding asset")?;
    info!("loading asset from {path:?}");
    Ok((
        ContentType::AVIF,
        CacheControlFile::new(File::open(path.path()).await.context("opening file")?).await,
    ))
}