/*
    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::{
    account::session::Session,
    layout::LayoutPage,
    node::{DatabaseNodeUserDataExt, NodeCard},
};
use crate::{
    database::Database,
    routes::{
        api::AcceptJson,
        locale::AcceptLanguage,
        ui::{error::MyResult, layout::DynLayoutPage},
    },
};
use anyhow::Context;
use chrono::{Datelike, Utc};
use jellybase::{locale::tr, CONF};
use jellycommon::{api::ApiHomeResponse, user::WatchedState, NodeID, NodeKind, Rating, Visibility};
use rocket::{get, serde::json::Json, Either, State};

#[get("/home")]
pub fn r_home(
    sess: Session,
    db: &State<Database>,
    aj: AcceptJson,
    lang: AcceptLanguage,
) -> MyResult<Either<DynLayoutPage, Json<ApiHomeResponse>>> {
    let AcceptLanguage(lang) = lang;
    let mut items = db.list_nodes_with_udata(&sess.user.name)?;

    let mut toplevel = db
        .get_node_children(NodeID::from_slug("library"))
        .context("root node missing")?
        .into_iter()
        .map(|n| db.get_node_with_userdata(n, &sess))
        .collect::<anyhow::Result<Vec<_>>>()?;
    toplevel.sort_by_key(|(n, _)| n.index.unwrap_or(usize::MAX));

    let mut categories = Vec::<(String, Vec<_>)>::new();

    categories.push((
        tr(lang, "home.bin.continue_watching", &[]).to_string(),
        items
            .iter()
            .filter(|(_, u)| matches!(u.watched, WatchedState::Progress(_)))
            .cloned()
            .collect(),
    ));
    categories.push((
        tr(lang, "home.bin.watchlist", &[]).to_string(),
        items
            .iter()
            .filter(|(_, u)| matches!(u.watched, WatchedState::Pending))
            .cloned()
            .collect(),
    ));

    items.retain(|(n, _)| matches!(n.visibility, Visibility::Visible));

    items.sort_by_key(|(n, _)| n.release_date.map(|d| -d).unwrap_or(i64::MAX));

    categories.push((
        tr(lang, "home.bin.latest_video", &[]).to_string(),
        items
            .iter()
            .filter(|(n, _)| matches!(n.kind, NodeKind::Video))
            .take(16)
            .cloned()
            .collect(),
    ));
    categories.push((
        tr(lang, "home.bin.latest_music", &[]).to_string(),
        items
            .iter()
            .filter(|(n, _)| matches!(n.kind, NodeKind::Music))
            .take(16)
            .cloned()
            .collect(),
    ));
    categories.push((
        tr(lang, "home.bin.latest_short_form", &[]).to_string(),
        items
            .iter()
            .filter(|(n, _)| matches!(n.kind, NodeKind::ShortFormVideo))
            .take(16)
            .cloned()
            .collect(),
    ));

    items.sort_by_key(|(n, _)| {
        n.ratings
            .get(&Rating::Tmdb)
            .map(|x| (*x * -1000.) as i32)
            .unwrap_or(0)
    });

    categories.push((
        tr(lang, "home.bin.max_rating", &[]).to_string(),
        items
            .iter()
            .take(16)
            .filter(|(n, _)| n.ratings.contains_key(&Rating::Tmdb))
            .cloned()
            .collect(),
    ));

    items.retain(|(n, _)| {
        matches!(
            n.kind,
            NodeKind::Video | NodeKind::Movie | NodeKind::Episode | NodeKind::Music
        )
    });

    categories.push((
        tr(lang, "home.bin.daily_random", &[]).to_string(),
        (0..16)
            .flat_map(|i| Some(items[cheap_daily_random(i).checked_rem(items.len())?].clone()))
            .collect(),
    ));

    {
        let mut items = items.clone();
        items.retain(|(_, u)| matches!(u.watched, WatchedState::Watched));
        categories.push((
            tr(lang, "home.bin.watch_again", &[]).to_string(),
            (0..16)
                .flat_map(|i| Some(items[cheap_daily_random(i).checked_rem(items.len())?].clone()))
                .collect(),
        ));
    }

    items.retain(|(n, _)| matches!(n.kind, NodeKind::Music));
    categories.push((
        tr(lang, "home.bin.daily_random_music", &[]).to_string(),
        (0..16)
            .flat_map(|i| Some(items[cheap_daily_random(i).checked_rem(items.len())?].clone()))
            .collect(),
    ));

    Ok(if *aj {
        Either::Right(Json(ApiHomeResponse {
            toplevel,
            categories,
        }))
    } else {
        Either::Left(LayoutPage {
            title: tr(lang, "home", &[]).to_string(),
            content: markup::new! {
                h2 { "Explore " @CONF.brand }
                ul.children.hlist {@for (node, udata) in &toplevel {
                    li { @NodeCard { node, udata, lang: &lang } }
                }}
                @for (name, nodes) in &categories {
                    @if !nodes.is_empty() {
                        h2 { @name }
                        ul.children.hlist {@for (node, udata) in nodes {
                            li { @NodeCard { node, udata, lang: &lang } }
                        }}
                    }
                }
            },
            ..Default::default()
        })
    })
}

fn cheap_daily_random(i: usize) -> usize {
    xorshift(xorshift(Utc::now().num_days_from_ce() as u64) + i as u64) as usize
}

fn xorshift(mut x: u64) -> u64 {
    x ^= x << 13;
    x ^= x >> 7;
    x ^= x << 17;
    x
}