use std::{
    collections::{BTreeMap, HashMap},
    sync::{Arc, Mutex as StdMutex, OnceLock},
};

use lru_cache::LruCache;
use tokio::sync::{broadcast, Mutex, RwLock};

use crate::{observability::FilterReloadHandles, Config, Result};

pub(crate) mod account_data;
pub(crate) mod admin;
pub(crate) mod appservice;
pub(crate) mod globals;
pub(crate) mod key_backups;
pub(crate) mod media;
pub(crate) mod pdu;
pub(crate) mod pusher;
pub(crate) mod rooms;
pub(crate) mod sending;
pub(crate) mod transaction_ids;
pub(crate) mod uiaa;
pub(crate) mod users;

static SERVICES: OnceLock<&'static Services> = OnceLock::new();

/// Convenient access to the global [`Services`] instance
pub(crate) fn services() -> &'static Services {
    SERVICES.get().expect("`Services::install` should have been called first")
}

pub(crate) struct Services {
    pub(crate) appservice: appservice::Service,
    pub(crate) pusher: pusher::Service,
    pub(crate) rooms: rooms::Service,
    pub(crate) transaction_ids: transaction_ids::Service,
    pub(crate) uiaa: uiaa::Service,
    pub(crate) users: users::Service,
    pub(crate) account_data: account_data::Service,
    pub(crate) admin: Arc<admin::Service>,
    pub(crate) globals: globals::Service,
    pub(crate) key_backups: key_backups::Service,
    pub(crate) media: media::Service,
    pub(crate) sending: Arc<sending::Service>,
}

impl Services {
    #[allow(clippy::too_many_lines)]
    pub(crate) fn build<
        D: appservice::Data
            + pusher::Data
            + rooms::Data
            + transaction_ids::Data
            + uiaa::Data
            + users::Data
            + account_data::Data
            + globals::Data
            + key_backups::Data
            + media::Data
            + sending::Data
            + 'static,
    >(
        db: &'static D,
        config: Config,
        reload_handles: FilterReloadHandles,
    ) -> Result<Self> {
        Ok(Self {
            appservice: appservice::Service::build(db)?,
            pusher: pusher::Service {
                db,
            },
            rooms: rooms::Service {
                alias: rooms::alias::Service::new(db),
                auth_chain: rooms::auth_chain::Service::new(
                    db,
                    #[allow(
                        clippy::as_conversions,
                        clippy::cast_sign_loss,
                        clippy::cast_possible_truncation
                    )]
                    {
                        (100_000.0 * config.cache_capacity_modifier) as usize
                    },
                ),
                directory: db,
                edus: rooms::edus::Service {
                    read_receipt: db,
                    typing: rooms::edus::typing::Service {
                        typing: RwLock::new(BTreeMap::new()),
                        last_typing_update: RwLock::new(BTreeMap::new()),
                        typing_update_sender: broadcast::channel(100).0,
                    },
                },
                event_handler: rooms::event_handler::Service,
                lazy_loading: rooms::lazy_loading::Service {
                    db,
                    lazy_load_waiting: Mutex::new(HashMap::new()),
                },
                metadata: db,
                outlier: db,
                pdu_metadata: rooms::pdu_metadata::Service {
                    db,
                },
                search: db,
                short: rooms::short::Service::new(
                    db,
                    #[allow(
                        clippy::as_conversions,
                        clippy::cast_sign_loss,
                        clippy::cast_possible_truncation
                    )]
                    {
                        (100_000.0 * config.cache_capacity_modifier) as usize
                    },
                    #[allow(
                        clippy::as_conversions,
                        clippy::cast_sign_loss,
                        clippy::cast_possible_truncation
                    )]
                    {
                        (100_000.0 * config.cache_capacity_modifier) as usize
                    },
                ),
                state: rooms::state::Service {
                    db,
                },
                state_accessor: rooms::state_accessor::Service {
                    db,
                    #[allow(
                        clippy::as_conversions,
                        clippy::cast_sign_loss,
                        clippy::cast_possible_truncation
                    )]
                    server_visibility_cache: StdMutex::new(LruCache::new(
                        (100.0 * config.cache_capacity_modifier) as usize,
                    )),
                    #[allow(
                        clippy::as_conversions,
                        clippy::cast_sign_loss,
                        clippy::cast_possible_truncation
                    )]
                    user_visibility_cache: StdMutex::new(LruCache::new(
                        (100.0 * config.cache_capacity_modifier) as usize,
                    )),
                },
                state_cache: rooms::state_cache::Service {
                    db,
                },
                state_compressor: rooms::state_compressor::Service {
                    db,
                    #[allow(
                        clippy::as_conversions,
                        clippy::cast_sign_loss,
                        clippy::cast_possible_truncation
                    )]
                    stateinfo_cache: StdMutex::new(LruCache::new(
                        (100.0 * config.cache_capacity_modifier) as usize,
                    )),
                },
                timeline: rooms::timeline::Service::new(
                    db,
                    config.pdu_cache_capacity,
                ),
                threads: rooms::threads::Service {
                    db,
                },
                spaces: rooms::spaces::Service {
                    roomid_spacechunk_cache: Mutex::new(LruCache::new(200)),
                },
                user: db,
            },
            transaction_ids: db,
            uiaa: uiaa::Service::new(db),
            users: users::Service {
                db,
                connections: StdMutex::new(BTreeMap::new()),
            },
            account_data: db,
            admin: admin::Service::build(),
            key_backups: db,
            media: media::Service {
                db,
            },
            sending: sending::Service::build(db, &config),

            globals: globals::Service::load(db, config, reload_handles)?,
        })
    }

    /// Installs `self` to be globally accessed via [`services`]
    pub(crate) fn install(self) {
        assert!(
            SERVICES.set(Box::leak(Box::new(self))).is_ok(),
            "Services::install was called more than once"
        );
    }
}