/*
    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) 2026 metamuffin <metamuffin.org>
*/
#![feature(duration_constants)]

pub mod plugins;
pub mod reporting;

use crate::{
    plugins::{ImportContext, ImportPlugin, infojson::is_info_json, init_plugins, misc::is_cover},
    reporting::IMPORT_PROGRESS,
};
use anyhow::{Context, Result, anyhow};
use jellycache::{HashKey, cache_memory, cache_store};
use jellycommon::{NodeID, Visibility};
use jellydb::Database;
use jellyremuxer::{
    demuxers::create_demuxer_autodetect,
    matroska::{self, AttachedFile, Segment},
};
use log::info;
use rayon::{
    ThreadPoolBuilder,
    iter::{IntoParallelIterator, ParallelBridge, ParallelIterator},
};
use serde::{Deserialize, Serialize};
use std::{
    collections::HashSet,
    fs::{File, read_to_string},
    mem::swap,
    path::{Path, PathBuf},
    sync::{Arc, LazyLock, Mutex},
    time::UNIX_EPOCH,
};
use tokio::{runtime::Handle, sync::Semaphore, task::spawn_blocking};

#[rustfmt::skip]
#[derive(Debug, Deserialize, Serialize, Default)]
pub struct Config {
    media_path: PathBuf,
    api: ApiSecrets,
    num_threads: usize
}

#[derive(Serialize, Deserialize, Debug, Default)]
pub struct ApiSecrets {
    pub acoustid: Option<String>,
    pub tmdb: Option<String>,
    pub tvdb: Option<String>,
    pub imdb: Option<String>,
    pub omdb: Option<String>,
    pub fanart_tv: Option<String>,
    pub trakt: Option<String>,
}

pub static CONF_PRELOAD: Mutex<Option<Config>> = Mutex::new(None);
static CONF: LazyLock<Config> = LazyLock::new(|| {
    CONF_PRELOAD
        .lock()
        .unwrap()
        .take()
        .expect("import config not preloaded. logic error")
});

pub const USER_AGENT: &str = concat!(
    "jellything/",
    env!("CARGO_PKG_VERSION"),
    " +https://codeberg.org/metamuffin/jellything"
);

static IMPORT_SEM: LazyLock<Semaphore> = LazyLock::new(|| Semaphore::new(1));

pub fn is_importing() -> bool {
    IMPORT_SEM.available_permits() == 0
}

pub async fn import_wrap(db: Database, incremental: bool) -> Result<()> {
    let _sem = IMPORT_SEM.try_acquire().context("already importing")?;

    let rt = Handle::current();
    let tp = ThreadPoolBuilder::new()
        .thread_name(|n| format!("import #{n}"))
        .num_threads(CONF.num_threads)
        .build()?;

    let jh = spawn_blocking(move || {
        tp.install(|| {
            reporting::start_import();
            reporting::catch(import(&db, &rt, incremental));
            reporting::end_import();
        })
    });

    let _ = jh.await;

    Ok(())
}

fn import(db: &Database, rt: &Handle, incremental: bool) -> Result<()> {
    let plugins = init_plugins(&CONF.api);
    let files = Mutex::new(Vec::new());
    import_traverse(
        &CONF.media_path,
        db,
        incremental,
        NodeID::MIN,
        InheritedFlags::default(),
        &files,
    )?;
    let files = files.into_inner().unwrap();

    let mut nodes = Mutex::new(HashSet::new());

    files.into_par_iter().for_each(|(path, parent, iflags)| {
        reporting::set_task(format!("unknown: {path:?}"));
        import_file(db, &rt, &nodes, &plugins, &path, parent, iflags);
        IMPORT_PROGRESS
            .blocking_write()
            .as_mut()
            .unwrap()
            .finished_items += 1;
        reporting::set_task("idle".to_owned());
    });

    IMPORT_PROGRESS
        .blocking_write()
        .as_mut()
        .unwrap()
        .finished_items = 0;

    while !nodes.get_mut().unwrap().is_empty() {
        info!("process iter (size={})", nodes.get_mut().unwrap().len());
        let mut cur_nodes = HashSet::new();
        swap(nodes.get_mut().unwrap(), &mut cur_nodes);
        cur_nodes.into_par_iter().for_each(|node| {
            reporting::set_task(format!("unknown: {node}"));
            process_node(db, &rt, &plugins, &nodes, node);
            IMPORT_PROGRESS
                .blocking_write()
                .as_mut()
                .unwrap()
                .finished_items += 1;
            reporting::set_task("idle".to_owned());
        });
    }

    Ok(())
}

#[derive(Debug, Clone, Copy)]
pub struct InheritedFlags {
    visibility: Visibility,
    use_acoustid: bool,
}
impl Default for InheritedFlags {
    fn default() -> Self {
        Self {
            visibility: Visibility::Visible,
            use_acoustid: false,
        }
    }
}

fn import_traverse(
    path: &Path,
    db: &Database,
    incremental: bool,
    parent: NodeID,
    mut iflags: InheritedFlags,
    out: &Mutex<Vec<(PathBuf, NodeID, InheritedFlags)>>,
) -> Result<()> {
    if path.is_dir() {
        reporting::set_task(format!("indexing {path:?}"));

        let slug = get_node_slug(path).unwrap();
        let node = NodeID::from_slug(&slug);

        // Some flags need to applied immediatly because they are inherited
        if let Ok(content) = read_to_string(path.join("flags")) {
            for flag in content.lines() {
                match flag.trim() {
                    "hidden" => iflags.visibility = iflags.visibility.min(Visibility::Hidden),
                    "reduced" => iflags.visibility = iflags.visibility.min(Visibility::Reduced),
                    "use_acoustid" => iflags.use_acoustid = true,
                    _ => (),
                }
            }
        }

        db.update_node_init(node, |n| {
            if parent != NodeID::MIN {
                n.parents.insert(parent);
            }
            n.slug = slug;
            n.visibility = iflags.visibility;
        })?;

        path.read_dir()?.par_bridge().try_for_each(|e| {
            let path = e?.path();
            reporting::catch(
                import_traverse(&path, db, incremental, node, iflags, out)
                    .context(anyhow!("index {:?}", path.file_name().unwrap())),
            );
            anyhow::Ok(())
        })?;
        return Ok(());
    }

    if path.is_file() {
        let meta = path.metadata()?;
        let mtime = meta.modified()?.duration_since(UNIX_EPOCH)?.as_secs();

        if incremental {
            if let Some(last_mtime) = db.get_import_file_mtime(path)? {
                if last_mtime >= mtime {
                    return Ok(());
                }
            }
        }

        IMPORT_PROGRESS
            .blocking_write()
            .as_mut()
            .unwrap()
            .total_items += 1;
        out.lock().unwrap().push((path.to_owned(), parent, iflags));
    }
    Ok(())
}

fn import_file(
    db: &Database,
    rt: &Handle,
    nodes: &Mutex<HashSet<NodeID>>,
    plugins: &[Box<dyn ImportPlugin>],
    path: &Path,
    parent: NodeID,
    iflags: InheritedFlags,
) {
    let mut all_ok = true;
    let ct = ImportContext {
        db,
        rt,
        iflags,
        nodes,
    };
    let filename = path.file_name().unwrap().to_string_lossy();
    if filename == "flags" {
        let Some(content) =
            reporting::catch(read_to_string(path).context(anyhow!("read flags at {path:?}")))
        else {
            return;
        };
        nodes.lock().unwrap().insert(parent);
        for line in content.lines() {
            for p in plugins {
                let inf = p.info();
                if inf.handle_instruction {
                    reporting::set_task(format!("{}(inst): {path:?}", inf.name));
                    all_ok &= reporting::catch(
                        p.instruction(&ct, parent, line)
                            .context(anyhow!("{}(inst) {path:?}", inf.name)),
                    )
                    .is_some();
                }
            }
        }
    }

    if filename.ends_with("mkv") || filename.ends_with("mka") || filename.ends_with("mks") {
        let slug = get_node_slug(path).unwrap();
        let node = NodeID::from_slug(&slug);

        nodes.lock().unwrap().insert(node);
        all_ok &= reporting::catch(db.update_node_init(node, |node| {
            node.slug = slug;
            if parent != NodeID::MIN {
                node.parents.insert(parent);
            }
            node.visibility = iflags.visibility;
        }))
        .is_some();

        let flags = filename
            .split(".")
            .collect::<Vec<_>>()
            .into_iter()
            .skip(1)
            .rev()
            .skip(1)
            .rev();

        for line in flags {
            for p in plugins {
                let inf = p.info();
                if inf.handle_instruction {
                    reporting::set_task(format!("{}(inst): {path:?}", inf.name));
                    all_ok &= reporting::catch(
                        p.instruction(&ct, node, line)
                            .context(anyhow!("{}(inst) {path:?}", inf.name)),
                    )
                    .is_some();
                }
            }
        }

        reporting::set_task(format!("demuxer meta: {path:?}"));
        let Some(seg) =
            reporting::catch(read_media_metadata(path).context(anyhow!("media {path:?}")))
        else {
            return;
        };
        for p in plugins {
            let inf = p.info();
            if inf.handle_media {
                reporting::set_task(format!("{}(media): {path:?}", inf.name));
                all_ok &= reporting::catch(
                    p.media(&ct, node, path, &seg)
                        .context(anyhow!("{}(media) {path:?}", inf.name)),
                )
                .is_some();
            }
        }
    } else {
        for p in plugins {
            let inf = p.info();
            if inf.handle_file {
                reporting::set_task(format!("{}(file): {path:?}", inf.name));
                all_ok &= reporting::catch(
                    p.file(&ct, parent, path)
                        .context(anyhow!("{}(file) {path:?}", inf.name)),
                )
                .is_some();
            }
        }
    }

    if all_ok {
        reporting::catch(update_mtime(db, path).context("updating mtime"));
    }
}

fn process_node(
    db: &Database,
    rt: &Handle,
    plugins: &[Box<dyn ImportPlugin>],
    nodes: &Mutex<HashSet<NodeID>>,
    node: NodeID,
) {
    let Some(data) = reporting::catch(
        db.get_node(node)
            .and_then(|e| e.ok_or(anyhow!("node missing"))),
    ) else {
        return;
    };
    let slug = &data.slug;
    for p in plugins {
        let inf = p.info();
        if inf.handle_process {
            reporting::set_task(format!("{}(proc): {slug}", inf.name));
            let Some(data) = reporting::catch(
                db.get_node(node)
                    .and_then(|e| e.ok_or(anyhow!("node missing"))),
            ) else {
                return;
            };
            reporting::catch(
                p.process(
                    &ImportContext {
                        db,
                        rt,
                        iflags: InheritedFlags::default(),
                        nodes,
                    },
                    node,
                    &data,
                )
                .context(anyhow!("{}(proc) {slug}", inf.name)),
            );
        }
    }
}

fn update_mtime(db: &Database, path: &Path) -> Result<()> {
    let meta = path.metadata()?;
    let mtime = meta.modified()?.duration_since(UNIX_EPOCH)?.as_secs();
    db.set_import_file_mtime(path, mtime)?;
    Ok(())
}

fn get_node_slug(path: &Path) -> Option<String> {
    if path == CONF.media_path {
        return Some("library".to_string());
    }
    let filename = path.file_name()?.to_string_lossy();
    let filestem = filename.split_once(".").unwrap_or((&filename, "")).0;
    if path.parent()? == &CONF.media_path {
        Some(format!("{filestem}"))
    } else {
        let parent_filename = path.parent()?.file_name()?.to_string_lossy();
        let parent_filestem = parent_filename
            .split_once(".")
            .unwrap_or((&parent_filename, ""))
            .0;
        Some(format!("{parent_filestem}-{filestem}"))
    }
}

pub fn read_media_metadata(path: &Path) -> Result<Arc<matroska::Segment>> {
    cache_memory(
        &format!("media/metadata/{}.json", HashKey(path)),
        move || {
            let media = File::open(path)?;
            let mut media = create_demuxer_autodetect(Box::new(media))?
                .ok_or(anyhow!("media format unknown"))?;

            let info = media.info()?;
            let tracks = media.tracks()?;
            let tags = media.tags()?;
            let mut attachments = media.attachments()?;
            let chapters = media.chapters()?;

            // Replace data of useful attachments with cache key; delete data of all others
            if let Some(attachments) = &mut attachments {
                for att in &mut attachments.files {
                    if let Some(fname) = is_useful_attachment(&att) {
                        let key = cache_store(
                            format!("media/attachment/{}-{fname}", HashKey(path)),
                            || Ok(att.data.clone()),
                        )?;
                        att.data = key.as_bytes().to_vec();
                    } else {
                        att.data.clear();
                    }
                }
            }

            Ok(Segment {
                info,
                tracks,
                tags: tags.into_iter().collect(),
                attachments,
                chapters,
                ..Default::default()
            })
        },
    )
    .context("reading media metadata")
}

pub fn is_useful_attachment(a: &AttachedFile) -> Option<&'static str> {
    match a {
        _ if is_info_json(&a) => Some("info.json"),
        _ if is_cover(&a) => Some("cover.image"),
        _ => None,
    }
}

// for tok in filename_toks {
//     apply_node_flag(db, rthandle, apis, node, tok)?;
// }

// fn apply_musicbrainz_recording(
//     db: &Database,
//     rthandle: &Handle,
//     apis: &Apis,
//     node: NodeID,
//     mbid: String,
// ) -> Result<()> {
//     let rec = apis.musicbrainz.lookup_recording(mbid, rthandle)?;

//     db.update_node_init(node, |node| {
//         node.title = Some(rec.title.clone());
//         node.identifiers
//             .insert(IdentifierType::MusicbrainzRecording, rec.id.to_string());
//         if let Some(a) = rec.artist_credit.first() {
//             node.subtitle = Some(a.artist.name.clone());
//             node.identifiers
//                 .insert(IdentifierType::MusicbrainzArtist, a.artist.id.to_string());
//         }

//         // // TODO proper dedup
//         // node.people.clear();

//         for rel in &rec.relations {
//             use musicbrainz::reltypes::*;
//             let a = match rel.type_id.as_str() {
//                 INSTRUMENT => Some(("", CreditCategory::Instrument)),
//                 VOCAL => Some(("", CreditCategory::Vocal)),
//                 PRODUCER => Some(("", CreditCategory::Producer)),
//                 MIX => Some(("mix ", CreditCategory::Engineer)),
//                 PHONOGRAPHIC_COPYRIGHT => {
//                     Some(("phonographic copyright ", CreditCategory::Engineer))
//                 }
//                 PROGRAMMING => Some(("programming ", CreditCategory::Engineer)),
//                 _ => None,
//             };

//             if let Some((note, group)) = a {
//                 let artist = rel.artist.as_ref().unwrap();

//                 let artist = apis
//                     .musicbrainz
//                     .lookup_artist(artist.id.clone(), rthandle)?;

//                 let mut image_1 = None;
//                 let mut image_2 = None;

//                 for rel in &artist.relations {
//                     match rel.type_id.as_str() {
//                         WIKIDATA => {
//                             let url = rel.url.as_ref().unwrap().resource.clone();
//                             if let Some(id) = url.strip_prefix("https://www.wikidata.org/wiki/") {
//                                 if let Some(filename) =
//                                     apis.wikidata.query_image_path(id.to_owned(), rthandle)?
//                                 {
//                                     image_1 = Some(
//                                         apis.wikimedia_commons
//                                             .image_by_filename(filename, rthandle)?,
//                                     );
//                                 }
//                             }
//                         }
//                         VGMDB => {
//                             let url = rel.url.as_ref().unwrap().resource.clone();
//                             if let Some(id) = url.strip_prefix("https://vgmdb.net/artist/") {
//                                 let id = id.parse::<u64>().context("parse vgmdb id")?;
//                                 if let Some(path) = apis.vgmdb.get_artist_image(id, rthandle)? {
//                                     image_2 = Some(path);
//                                 }
//                             }
//                         }
//                         _ => (),
//                     }
//                 }
//                 let mut jobs = vec![];
//                 if !note.is_empty() {
//                     jobs.push(note.to_string());
//                 }
//                 jobs.extend(rel.attributes.clone());

//                 let _headshot = match image_1.or(image_2) {
//                     Some(x) => x,
//                     None => Asset(cache_store(
//                         format!("fallback/{}.image", HashKey(&artist.sort_name)),
//                         || generate_fallback(&artist.sort_name),
//                     )?),
//                 };

//                 node.credits.entry(group).or_default().push(Appearance {
//                     jobs,
//                     characters: vec![],
//                     node: NodeID([0; 32]), // TODO
//                 });
//             }
//         }

//         for isrc in &rec.isrcs {
//             node.identifiers
//                 .insert(IdentifierType::Isrc, isrc.to_string());
//         }
//         Ok(())
//     })?;
//     Ok(())
// }

// fn make_kebab(i: &str) -> String {
//     let mut o = String::with_capacity(i.len());
//     for c in i.chars() {
//         o.extend(match c {
//             'A'..='Z' | 'a'..='z' | '0'..='9' | '_' | '-' => Some(c),
//             ' ' => Some('-'),
//             _ => None,
//         });
//     }
//     o
// }