/*
    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) 2025 metamuffin <metamuffin.org>
*/
use super::{error::MyResult, CacheControlFile};
use crate::logic::session::Session;
use anyhow::{anyhow, bail, Context};
use base64::Engine;
use jellybase::{assetfed::AssetInner, database::Database, federation::Federation, CONF};
use jellycache::async_cache_file;
use jellycommon::{LocalTrack, NodeID, PeopleGroup, SourceTrackKind, TrackSource};
use log::info;
use rocket::{get, http::ContentType, response::Redirect, State};
use std::{path::PathBuf, str::FromStr};

pub const AVIF_QUALITY: f32 = 50.;
pub const AVIF_SPEED: u8 = 5;

#[get("/asset/<token>?<width>")]
pub async fn r_asset(
    _session: Session,
    fed: &State<Federation>,
    token: &str,
    width: Option<usize>,
) -> MyResult<(ContentType, CacheControlFile)> {
    let width = width.unwrap_or(2048);
    let asset = AssetInner::deser(token)?;

    let path = if let AssetInner::Federated { host, asset } = asset {
        let session = fed.get_session(&host).await?;

        let asset = base64::engine::general_purpose::URL_SAFE.encode(asset);
        async_cache_file("fed-asset", &asset, |out| async {
            session.asset(out, &asset, width).await
        })
        .await?
    } else {
        let source = resolve_asset(asset).await.context("resolving asset")?;

        // fit the resolution into a finite set so the maximum cache is finite too.
        let width = 2usize.pow(width.clamp(128, 2048).ilog2());
        jellytranscoder::image::transcode(&source, AVIF_QUALITY, AVIF_SPEED, width)
            .await
            .context("transcoding asset")?
    };
    info!("loading asset from {path:?}");
    Ok((
        ContentType::AVIF,
        CacheControlFile::new_cachekey(&path.abs()).await?,
    ))
}

pub async fn resolve_asset(asset: AssetInner) -> anyhow::Result<PathBuf> {
    match asset {
        AssetInner::Cache(c) => Ok(c.abs()),
        AssetInner::Assets(c) => Ok(CONF.asset_path.join(c)),
        AssetInner::Media(c) => Ok(CONF.media_path.join(c)),
        _ => bail!("wrong asset type"),
    }
}

#[get("/n/<id>/poster?<width>")]
pub async fn r_item_poster(
    _session: Session,
    db: &State<Database>,
    id: NodeID,
    width: Option<usize>,
) -> MyResult<Redirect> {
    // TODO perm
    let node = db.get_node(id)?.ok_or(anyhow!("node does not exist"))?;

    let mut asset = node.poster.clone();
    if asset.is_none() {
        if let Some(parent) = node.parents.last().copied() {
            let parent = db.get_node(parent)?.ok_or(anyhow!("node does not exist"))?;
            asset = parent.poster.clone();
        }
    };
    let asset = asset.unwrap_or_else(|| {
        AssetInner::Assets(format!("fallback-{:?}.avif", node.kind).into()).ser()
    });
    Ok(Redirect::permanent(rocket::uri!(r_asset(asset.0, width))))
}

#[get("/n/<id>/backdrop?<width>")]
pub async fn r_item_backdrop(
    _session: Session,
    db: &State<Database>,
    id: NodeID,
    width: Option<usize>,
) -> MyResult<Redirect> {
    // TODO perm
    let node = db.get_node(id)?.ok_or(anyhow!("node does not exist"))?;

    let mut asset = node.backdrop.clone();
    if asset.is_none() {
        if let Some(parent) = node.parents.last().copied() {
            let parent = db.get_node(parent)?.ok_or(anyhow!("node does not exist"))?;
            asset = parent.backdrop.clone();
        }
    };
    let asset = asset.unwrap_or_else(|| {
        AssetInner::Assets(format!("fallback-{:?}.avif", node.kind).into()).ser()
    });
    Ok(Redirect::permanent(rocket::uri!(r_asset(asset.0, width))))
}

#[get("/n/<id>/person/<index>/asset?<group>&<width>")]
pub async fn r_person_asset(
    _session: Session,
    db: &State<Database>,
    id: NodeID,
    index: usize,
    group: String,
    width: Option<usize>,
) -> MyResult<Redirect> {
    // TODO perm

    let node = db.get_node(id)?.ok_or(anyhow!("node does not exist"))?;
    let app = node
        .people
        .get(&PeopleGroup::from_str(&group).map_err(|()| anyhow!("unknown people group"))?)
        .ok_or(anyhow!("group has no members"))?
        .get(index)
        .ok_or(anyhow!("person does not exist"))?;

    let asset = app
        .person
        .headshot
        .to_owned()
        .unwrap_or(AssetInner::Assets("fallback-Person.avif".into()).ser());
    Ok(Redirect::permanent(rocket::uri!(r_asset(asset.0, width))))
}

// TODO this can create "federation recursion" because track selection cannot be relied on.
//? TODO is this still relevant?

#[get("/n/<id>/thumbnail?<t>&<width>")]
pub async fn r_node_thumbnail(
    _session: Session,
    db: &State<Database>,
    fed: &State<Federation>,
    id: NodeID,
    t: f64,
    width: Option<usize>,
) -> MyResult<Redirect> {
    let node = db.get_node(id)?.ok_or(anyhow!("node does not exist"))?;

    let media = node.media.as_ref().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 = media
        .tracks
        .get(thumb_track_index)
        .ok_or(anyhow!("no source"))?;
    let thumb_track_source = source.source.clone();

    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(a) => {
            let AssetInner::LocalTrack(LocalTrack { path, .. }) = AssetInner::deser(&a.0)? else {
                return Err(anyhow!("track set to wrong asset type").into());
            };
            // the track selected might be different from thumb_track
            jellytranscoder::thumbnail::create_thumbnail(&CONF.media_path.join(path), t).await?
        }
        TrackSource::Remote(_) => {
            // TODO in the new system this is preferrably a property of node ext for regular fed
            let session = fed
                .get_session(
                    thumb_track
                        .federated
                        .last()
                        .ok_or(anyhow!("federation broken"))?,
                )
                .await?;

            async_cache_file("fed-thumb", (id, t as i64), |out| {
                session.node_thumbnail(out, id.into(), 2048, t)
            })
            .await?
        }
    };

    Ok(Redirect::temporary(rocket::uri!(r_asset(
        AssetInner::Cache(asset).ser().0,
        width
    ))))
}