pub mod abstraction;
pub mod key_value;

use crate::{
    service::rooms::timeline::PduCount, services, utils, Config, Error, PduEvent, Result, Services,
    SERVICES,
};
use abstraction::{KeyValueDatabaseEngine, KvTree};
use directories::ProjectDirs;
use lru_cache::LruCache;

use ruma::{
    events::{
        push_rules::{PushRulesEvent, PushRulesEventContent},
        room::message::RoomMessageEventContent,
        GlobalAccountDataEvent, GlobalAccountDataEventType, StateEventType,
    },
    push::Ruleset,
    CanonicalJsonValue, EventId, OwnedDeviceId, OwnedEventId, OwnedRoomId, OwnedUserId, RoomId,
    UserId,
};
use serde::Deserialize;
use std::{
    collections::{BTreeMap, HashMap, HashSet},
    fs::{self, remove_dir_all},
    io::Write,
    mem::size_of,
    path::Path,
    sync::{Arc, Mutex, RwLock},
    time::Duration,
};
use tokio::time::interval;

use tracing::{debug, error, info, warn};

pub struct KeyValueDatabase {
    _db: Arc<dyn KeyValueDatabaseEngine>,

    //pub globals: globals::Globals,
    pub(super) global: Arc<dyn KvTree>,
    pub(super) server_signingkeys: Arc<dyn KvTree>,

    //pub users: users::Users,
    pub(super) userid_password: Arc<dyn KvTree>,
    pub(super) userid_displayname: Arc<dyn KvTree>,
    pub(super) userid_avatarurl: Arc<dyn KvTree>,
    pub(super) userid_blurhash: Arc<dyn KvTree>,
    pub(super) userdeviceid_token: Arc<dyn KvTree>,
    pub(super) userdeviceid_metadata: Arc<dyn KvTree>, // This is also used to check if a device exists
    pub(super) userid_devicelistversion: Arc<dyn KvTree>, // DevicelistVersion = u64
    pub(super) token_userdeviceid: Arc<dyn KvTree>,

    pub(super) onetimekeyid_onetimekeys: Arc<dyn KvTree>, // OneTimeKeyId = UserId + DeviceKeyId
    pub(super) userid_lastonetimekeyupdate: Arc<dyn KvTree>, // LastOneTimeKeyUpdate = Count
    pub(super) keychangeid_userid: Arc<dyn KvTree>,       // KeyChangeId = UserId/RoomId + Count
    pub(super) keyid_key: Arc<dyn KvTree>, // KeyId = UserId + KeyId (depends on key type)
    pub(super) userid_masterkeyid: Arc<dyn KvTree>,
    pub(super) userid_selfsigningkeyid: Arc<dyn KvTree>,
    pub(super) userid_usersigningkeyid: Arc<dyn KvTree>,

    pub(super) userfilterid_filter: Arc<dyn KvTree>, // UserFilterId = UserId + FilterId

    pub(super) todeviceid_events: Arc<dyn KvTree>, // ToDeviceId = UserId + DeviceId + Count

    //pub uiaa: uiaa::Uiaa,
    pub(super) userdevicesessionid_uiaainfo: Arc<dyn KvTree>, // User-interactive authentication
    pub(super) userdevicesessionid_uiaarequest:
        RwLock<BTreeMap<(OwnedUserId, OwnedDeviceId, String), CanonicalJsonValue>>,

    //pub edus: RoomEdus,
    pub(super) readreceiptid_readreceipt: Arc<dyn KvTree>, // ReadReceiptId = RoomId + Count + UserId
    pub(super) roomuserid_privateread: Arc<dyn KvTree>, // RoomUserId = Room + User, PrivateRead = Count
    pub(super) roomuserid_lastprivatereadupdate: Arc<dyn KvTree>, // LastPrivateReadUpdate = Count
    pub(super) presenceid_presence: Arc<dyn KvTree>,    // PresenceId = RoomId + Count + UserId
    pub(super) userid_lastpresenceupdate: Arc<dyn KvTree>, // LastPresenceUpdate = Count

    //pub rooms: rooms::Rooms,
    pub(super) pduid_pdu: Arc<dyn KvTree>, // PduId = ShortRoomId + Count
    pub(super) eventid_pduid: Arc<dyn KvTree>,
    pub(super) roomid_pduleaves: Arc<dyn KvTree>,
    pub(super) alias_roomid: Arc<dyn KvTree>,
    pub(super) aliasid_alias: Arc<dyn KvTree>, // AliasId = RoomId + Count
    pub(super) publicroomids: Arc<dyn KvTree>,

    pub(super) threadid_userids: Arc<dyn KvTree>, // ThreadId = RoomId + Count

    pub(super) tokenids: Arc<dyn KvTree>, // TokenId = ShortRoomId + Token + PduIdCount

    /// Participating servers in a room.
    pub(super) roomserverids: Arc<dyn KvTree>, // RoomServerId = RoomId + ServerName
    pub(super) serverroomids: Arc<dyn KvTree>, // ServerRoomId = ServerName + RoomId

    pub(super) userroomid_joined: Arc<dyn KvTree>,
    pub(super) roomuserid_joined: Arc<dyn KvTree>,
    pub(super) roomid_joinedcount: Arc<dyn KvTree>,
    pub(super) roomid_invitedcount: Arc<dyn KvTree>,
    pub(super) roomuseroncejoinedids: Arc<dyn KvTree>,
    pub(super) userroomid_invitestate: Arc<dyn KvTree>, // InviteState = Vec<Raw<Pdu>>
    pub(super) roomuserid_invitecount: Arc<dyn KvTree>, // InviteCount = Count
    pub(super) userroomid_leftstate: Arc<dyn KvTree>,
    pub(super) roomuserid_leftcount: Arc<dyn KvTree>,

    pub(super) disabledroomids: Arc<dyn KvTree>, // Rooms where incoming federation handling is disabled

    pub(super) lazyloadedids: Arc<dyn KvTree>, // LazyLoadedIds = UserId + DeviceId + RoomId + LazyLoadedUserId

    pub(super) userroomid_notificationcount: Arc<dyn KvTree>, // NotifyCount = u64
    pub(super) userroomid_highlightcount: Arc<dyn KvTree>,    // HightlightCount = u64
    pub(super) roomuserid_lastnotificationread: Arc<dyn KvTree>, // LastNotificationRead = u64

    /// Remember the current state hash of a room.
    pub(super) roomid_shortstatehash: Arc<dyn KvTree>,
    pub(super) roomsynctoken_shortstatehash: Arc<dyn KvTree>,
    /// Remember the state hash at events in the past.
    pub(super) shorteventid_shortstatehash: Arc<dyn KvTree>,
    /// StateKey = EventType + StateKey, ShortStateKey = Count
    pub(super) statekey_shortstatekey: Arc<dyn KvTree>,
    pub(super) shortstatekey_statekey: Arc<dyn KvTree>,

    pub(super) roomid_shortroomid: Arc<dyn KvTree>,

    pub(super) shorteventid_eventid: Arc<dyn KvTree>,
    pub(super) eventid_shorteventid: Arc<dyn KvTree>,

    pub(super) statehash_shortstatehash: Arc<dyn KvTree>,
    pub(super) shortstatehash_statediff: Arc<dyn KvTree>, // StateDiff = parent (or 0) + (shortstatekey+shorteventid++) + 0_u64 + (shortstatekey+shorteventid--)

    pub(super) shorteventid_authchain: Arc<dyn KvTree>,

    /// RoomId + EventId -> outlier PDU.
    /// Any pdu that has passed the steps 1-8 in the incoming event /federation/send/txn.
    pub(super) eventid_outlierpdu: Arc<dyn KvTree>,
    pub(super) softfailedeventids: Arc<dyn KvTree>,

    /// ShortEventId + ShortEventId -> ().
    pub(super) tofrom_relation: Arc<dyn KvTree>,
    /// RoomId + EventId -> Parent PDU EventId.
    pub(super) referencedevents: Arc<dyn KvTree>,

    //pub account_data: account_data::AccountData,
    pub(super) roomuserdataid_accountdata: Arc<dyn KvTree>, // RoomUserDataId = Room + User + Count + Type
    pub(super) roomusertype_roomuserdataid: Arc<dyn KvTree>, // RoomUserType = Room + User + Type

    //pub media: media::Media,
    pub(super) mediaid_file: Arc<dyn KvTree>, // MediaId = MXC + WidthHeight + ContentDisposition + ContentType
    //pub key_backups: key_backups::KeyBackups,
    pub(super) backupid_algorithm: Arc<dyn KvTree>, // BackupId = UserId + Version(Count)
    pub(super) backupid_etag: Arc<dyn KvTree>,      // BackupId = UserId + Version(Count)
    pub(super) backupkeyid_backup: Arc<dyn KvTree>, // BackupKeyId = UserId + Version + RoomId + SessionId

    //pub transaction_ids: transaction_ids::TransactionIds,
    pub(super) userdevicetxnid_response: Arc<dyn KvTree>, // Response can be empty (/sendToDevice) or the event id (/send)
    //pub sending: sending::Sending,
    pub(super) servername_educount: Arc<dyn KvTree>, // EduCount: Count of last EDU sync
    pub(super) servernameevent_data: Arc<dyn KvTree>, // ServernameEvent = (+ / $)SenderKey / ServerName / UserId + PduId / Id (for edus), Data = EDU content
    pub(super) servercurrentevent_data: Arc<dyn KvTree>, // ServerCurrentEvents = (+ / $)ServerName / UserId + PduId / Id (for edus), Data = EDU content

    //pub appservice: appservice::Appservice,
    pub(super) id_appserviceregistrations: Arc<dyn KvTree>,

    //pub pusher: pusher::PushData,
    pub(super) senderkey_pusher: Arc<dyn KvTree>,

    pub(super) pdu_cache: Mutex<LruCache<OwnedEventId, Arc<PduEvent>>>,
    pub(super) shorteventid_cache: Mutex<LruCache<u64, Arc<EventId>>>,
    pub(super) auth_chain_cache: Mutex<LruCache<Vec<u64>, Arc<HashSet<u64>>>>,
    pub(super) eventidshort_cache: Mutex<LruCache<OwnedEventId, u64>>,
    pub(super) statekeyshort_cache: Mutex<LruCache<(StateEventType, String), u64>>,
    pub(super) shortstatekey_cache: Mutex<LruCache<u64, (StateEventType, String)>>,
    pub(super) our_real_users_cache: RwLock<HashMap<OwnedRoomId, Arc<HashSet<OwnedUserId>>>>,
    pub(super) appservice_in_room_cache: RwLock<HashMap<OwnedRoomId, HashMap<String, bool>>>,
    pub(super) lasttimelinecount_cache: Mutex<HashMap<OwnedRoomId, PduCount>>,
}

impl KeyValueDatabase {
    /// Tries to remove the old database but ignores all errors.
    pub fn try_remove(server_name: &str) -> Result<()> {
        let mut path = ProjectDirs::from("xyz", "koesters", "conduit")
            .ok_or_else(|| Error::bad_config("The OS didn't return a valid home directory path."))?
            .data_dir()
            .to_path_buf();
        path.push(server_name);
        let _ = remove_dir_all(path);

        Ok(())
    }

    fn check_db_setup(config: &Config) -> Result<()> {
        let path = Path::new(&config.database_path);

        let sled_exists = path.join("db").exists();
        let sqlite_exists = path.join("conduit.db").exists();
        let rocksdb_exists = path.join("IDENTITY").exists();

        let mut count = 0;

        if sled_exists {
            count += 1;
        }

        if sqlite_exists {
            count += 1;
        }

        if rocksdb_exists {
            count += 1;
        }

        if count > 1 {
            warn!("Multiple databases at database_path detected");
            return Ok(());
        }

        if sled_exists && config.database_backend != "sled" {
            return Err(Error::bad_config(
                "Found sled at database_path, but is not specified in config.",
            ));
        }

        if sqlite_exists && config.database_backend != "sqlite" {
            return Err(Error::bad_config(
                "Found sqlite at database_path, but is not specified in config.",
            ));
        }

        if rocksdb_exists && config.database_backend != "rocksdb" {
            return Err(Error::bad_config(
                "Found rocksdb at database_path, but is not specified in config.",
            ));
        }

        Ok(())
    }

    /// Load an existing database or create a new one.
    pub async fn load_or_create(config: Config) -> Result<()> {
        Self::check_db_setup(&config)?;

        if !Path::new(&config.database_path).exists() {
            std::fs::create_dir_all(&config.database_path)
                .map_err(|_| Error::BadConfig("Database folder doesn't exists and couldn't be created (e.g. due to missing permissions). Please create the database folder yourself."))?;
        }

        let builder: Arc<dyn KeyValueDatabaseEngine> = match &*config.database_backend {
            "sqlite" => {
                #[cfg(not(feature = "sqlite"))]
                return Err(Error::BadConfig("Database backend not found."));
                #[cfg(feature = "sqlite")]
                Arc::new(Arc::<abstraction::sqlite::Engine>::open(&config)?)
            }
            "rocksdb" => {
                #[cfg(not(feature = "rocksdb"))]
                return Err(Error::BadConfig("Database backend not found."));
                #[cfg(feature = "rocksdb")]
                Arc::new(Arc::<abstraction::rocksdb::Engine>::open(&config)?)
            }
            "persy" => {
                #[cfg(not(feature = "persy"))]
                return Err(Error::BadConfig("Database backend not found."));
                #[cfg(feature = "persy")]
                Arc::new(Arc::<abstraction::persy::Engine>::open(&config)?)
            }
            _ => {
                return Err(Error::BadConfig("Database backend not found."));
            }
        };

        if config.registration_token == Some(String::new()) {
            return Err(Error::bad_config("Registration token is empty"));
        }

        if config.max_request_size < 1024 {
            error!(?config.max_request_size, "Max request size is less than 1KB. Please increase it.");
        }

        let db_raw = Box::new(Self {
            _db: builder.clone(),
            userid_password: builder.open_tree("userid_password")?,
            userid_displayname: builder.open_tree("userid_displayname")?,
            userid_avatarurl: builder.open_tree("userid_avatarurl")?,
            userid_blurhash: builder.open_tree("userid_blurhash")?,
            userdeviceid_token: builder.open_tree("userdeviceid_token")?,
            userdeviceid_metadata: builder.open_tree("userdeviceid_metadata")?,
            userid_devicelistversion: builder.open_tree("userid_devicelistversion")?,
            token_userdeviceid: builder.open_tree("token_userdeviceid")?,
            onetimekeyid_onetimekeys: builder.open_tree("onetimekeyid_onetimekeys")?,
            userid_lastonetimekeyupdate: builder.open_tree("userid_lastonetimekeyupdate")?,
            keychangeid_userid: builder.open_tree("keychangeid_userid")?,
            keyid_key: builder.open_tree("keyid_key")?,
            userid_masterkeyid: builder.open_tree("userid_masterkeyid")?,
            userid_selfsigningkeyid: builder.open_tree("userid_selfsigningkeyid")?,
            userid_usersigningkeyid: builder.open_tree("userid_usersigningkeyid")?,
            userfilterid_filter: builder.open_tree("userfilterid_filter")?,
            todeviceid_events: builder.open_tree("todeviceid_events")?,

            userdevicesessionid_uiaainfo: builder.open_tree("userdevicesessionid_uiaainfo")?,
            userdevicesessionid_uiaarequest: RwLock::new(BTreeMap::new()),
            readreceiptid_readreceipt: builder.open_tree("readreceiptid_readreceipt")?,
            roomuserid_privateread: builder.open_tree("roomuserid_privateread")?, // "Private" read receipt
            roomuserid_lastprivatereadupdate: builder
                .open_tree("roomuserid_lastprivatereadupdate")?,
            presenceid_presence: builder.open_tree("presenceid_presence")?,
            userid_lastpresenceupdate: builder.open_tree("userid_lastpresenceupdate")?,
            pduid_pdu: builder.open_tree("pduid_pdu")?,
            eventid_pduid: builder.open_tree("eventid_pduid")?,
            roomid_pduleaves: builder.open_tree("roomid_pduleaves")?,

            alias_roomid: builder.open_tree("alias_roomid")?,
            aliasid_alias: builder.open_tree("aliasid_alias")?,
            publicroomids: builder.open_tree("publicroomids")?,

            threadid_userids: builder.open_tree("threadid_userids")?,

            tokenids: builder.open_tree("tokenids")?,

            roomserverids: builder.open_tree("roomserverids")?,
            serverroomids: builder.open_tree("serverroomids")?,
            userroomid_joined: builder.open_tree("userroomid_joined")?,
            roomuserid_joined: builder.open_tree("roomuserid_joined")?,
            roomid_joinedcount: builder.open_tree("roomid_joinedcount")?,
            roomid_invitedcount: builder.open_tree("roomid_invitedcount")?,
            roomuseroncejoinedids: builder.open_tree("roomuseroncejoinedids")?,
            userroomid_invitestate: builder.open_tree("userroomid_invitestate")?,
            roomuserid_invitecount: builder.open_tree("roomuserid_invitecount")?,
            userroomid_leftstate: builder.open_tree("userroomid_leftstate")?,
            roomuserid_leftcount: builder.open_tree("roomuserid_leftcount")?,

            disabledroomids: builder.open_tree("disabledroomids")?,

            lazyloadedids: builder.open_tree("lazyloadedids")?,

            userroomid_notificationcount: builder.open_tree("userroomid_notificationcount")?,
            userroomid_highlightcount: builder.open_tree("userroomid_highlightcount")?,
            roomuserid_lastnotificationread: builder.open_tree("userroomid_highlightcount")?,

            statekey_shortstatekey: builder.open_tree("statekey_shortstatekey")?,
            shortstatekey_statekey: builder.open_tree("shortstatekey_statekey")?,

            shorteventid_authchain: builder.open_tree("shorteventid_authchain")?,

            roomid_shortroomid: builder.open_tree("roomid_shortroomid")?,

            shortstatehash_statediff: builder.open_tree("shortstatehash_statediff")?,
            eventid_shorteventid: builder.open_tree("eventid_shorteventid")?,
            shorteventid_eventid: builder.open_tree("shorteventid_eventid")?,
            shorteventid_shortstatehash: builder.open_tree("shorteventid_shortstatehash")?,
            roomid_shortstatehash: builder.open_tree("roomid_shortstatehash")?,
            roomsynctoken_shortstatehash: builder.open_tree("roomsynctoken_shortstatehash")?,
            statehash_shortstatehash: builder.open_tree("statehash_shortstatehash")?,

            eventid_outlierpdu: builder.open_tree("eventid_outlierpdu")?,
            softfailedeventids: builder.open_tree("softfailedeventids")?,

            tofrom_relation: builder.open_tree("tofrom_relation")?,
            referencedevents: builder.open_tree("referencedevents")?,
            roomuserdataid_accountdata: builder.open_tree("roomuserdataid_accountdata")?,
            roomusertype_roomuserdataid: builder.open_tree("roomusertype_roomuserdataid")?,
            mediaid_file: builder.open_tree("mediaid_file")?,
            backupid_algorithm: builder.open_tree("backupid_algorithm")?,
            backupid_etag: builder.open_tree("backupid_etag")?,
            backupkeyid_backup: builder.open_tree("backupkeyid_backup")?,
            userdevicetxnid_response: builder.open_tree("userdevicetxnid_response")?,
            servername_educount: builder.open_tree("servername_educount")?,
            servernameevent_data: builder.open_tree("servernameevent_data")?,
            servercurrentevent_data: builder.open_tree("servercurrentevent_data")?,
            id_appserviceregistrations: builder.open_tree("id_appserviceregistrations")?,
            senderkey_pusher: builder.open_tree("senderkey_pusher")?,
            global: builder.open_tree("global")?,
            server_signingkeys: builder.open_tree("server_signingkeys")?,

            pdu_cache: Mutex::new(LruCache::new(
                config
                    .pdu_cache_capacity
                    .try_into()
                    .expect("pdu cache capacity fits into usize"),
            )),
            auth_chain_cache: Mutex::new(LruCache::new(
                (100_000.0 * config.conduit_cache_capacity_modifier) as usize,
            )),
            shorteventid_cache: Mutex::new(LruCache::new(
                (100_000.0 * config.conduit_cache_capacity_modifier) as usize,
            )),
            eventidshort_cache: Mutex::new(LruCache::new(
                (100_000.0 * config.conduit_cache_capacity_modifier) as usize,
            )),
            shortstatekey_cache: Mutex::new(LruCache::new(
                (100_000.0 * config.conduit_cache_capacity_modifier) as usize,
            )),
            statekeyshort_cache: Mutex::new(LruCache::new(
                (100_000.0 * config.conduit_cache_capacity_modifier) as usize,
            )),
            our_real_users_cache: RwLock::new(HashMap::new()),
            appservice_in_room_cache: RwLock::new(HashMap::new()),
            lasttimelinecount_cache: Mutex::new(HashMap::new()),
        });

        let db = Box::leak(db_raw);

        let services_raw = Box::new(Services::build(db, config)?);

        // This is the first and only time we initialize the SERVICE static
        *SERVICES.write().unwrap() = Some(Box::leak(services_raw));

        // Matrix resource ownership is based on the server name; changing it
        // requires recreating the database from scratch.
        if services().users.count()? > 0 {
            let conduit_user =
                UserId::parse_with_server_name("conduit", services().globals.server_name())
                    .expect("@conduit:server_name is valid");

            if !services().users.exists(&conduit_user)? {
                error!(
                    "The {} server user does not exist, and the database is not new.",
                    conduit_user
                );
                return Err(Error::bad_database(
                    "Cannot reuse an existing database after changing the server name, please delete the old one first."
                ));
            }
        }

        // If the database has any data, perform data migrations before starting
        let latest_database_version = 13;

        if services().users.count()? > 0 {
            // MIGRATIONS
            if services().globals.database_version()? < 1 {
                for (roomserverid, _) in db.roomserverids.iter() {
                    let mut parts = roomserverid.split(|&b| b == 0xff);
                    let room_id = parts.next().expect("split always returns one element");
                    let servername = match parts.next() {
                        Some(s) => s,
                        None => {
                            error!("Migration: Invalid roomserverid in db.");
                            continue;
                        }
                    };
                    let mut serverroomid = servername.to_vec();
                    serverroomid.push(0xff);
                    serverroomid.extend_from_slice(room_id);

                    db.serverroomids.insert(&serverroomid, &[])?;
                }

                services().globals.bump_database_version(1)?;

                warn!("Migration: 0 -> 1 finished");
            }

            if services().globals.database_version()? < 2 {
                // We accidentally inserted hashed versions of "" into the db instead of just ""
                for (userid, password) in db.userid_password.iter() {
                    let password = utils::string_from_bytes(&password);

                    let empty_hashed_password = password.map_or(false, |password| {
                        argon2::verify_encoded(&password, b"").unwrap_or(false)
                    });

                    if empty_hashed_password {
                        db.userid_password.insert(&userid, b"")?;
                    }
                }

                services().globals.bump_database_version(2)?;

                warn!("Migration: 1 -> 2 finished");
            }

            if services().globals.database_version()? < 3 {
                // Move media to filesystem
                for (key, content) in db.mediaid_file.iter() {
                    if content.is_empty() {
                        continue;
                    }

                    let path = services().globals.get_media_file(&key);
                    let mut file = fs::File::create(path)?;
                    file.write_all(&content)?;
                    db.mediaid_file.insert(&key, &[])?;
                }

                services().globals.bump_database_version(3)?;

                warn!("Migration: 2 -> 3 finished");
            }

            if services().globals.database_version()? < 4 {
                // Add federated users to services() as deactivated
                for our_user in services().users.iter() {
                    let our_user = our_user?;
                    if services().users.is_deactivated(&our_user)? {
                        continue;
                    }
                    for room in services().rooms.state_cache.rooms_joined(&our_user) {
                        for user in services().rooms.state_cache.room_members(&room?) {
                            let user = user?;
                            if user.server_name() != services().globals.server_name() {
                                info!(?user, "Migration: creating user");
                                services().users.create(&user, None)?;
                            }
                        }
                    }
                }

                services().globals.bump_database_version(4)?;

                warn!("Migration: 3 -> 4 finished");
            }

            if services().globals.database_version()? < 5 {
                // Upgrade user data store
                for (roomuserdataid, _) in db.roomuserdataid_accountdata.iter() {
                    let mut parts = roomuserdataid.split(|&b| b == 0xff);
                    let room_id = parts.next().unwrap();
                    let user_id = parts.next().unwrap();
                    let event_type = roomuserdataid.rsplit(|&b| b == 0xff).next().unwrap();

                    let mut key = room_id.to_vec();
                    key.push(0xff);
                    key.extend_from_slice(user_id);
                    key.push(0xff);
                    key.extend_from_slice(event_type);

                    db.roomusertype_roomuserdataid
                        .insert(&key, &roomuserdataid)?;
                }

                services().globals.bump_database_version(5)?;

                warn!("Migration: 4 -> 5 finished");
            }

            if services().globals.database_version()? < 6 {
                // Set room member count
                for (roomid, _) in db.roomid_shortstatehash.iter() {
                    let string = utils::string_from_bytes(&roomid).unwrap();
                    let room_id = <&RoomId>::try_from(string.as_str()).unwrap();
                    services().rooms.state_cache.update_joined_count(room_id)?;
                }

                services().globals.bump_database_version(6)?;

                warn!("Migration: 5 -> 6 finished");
            }

            if services().globals.database_version()? < 7 {
                // Upgrade state store
                let mut last_roomstates: HashMap<OwnedRoomId, u64> = HashMap::new();
                let mut current_sstatehash: Option<u64> = None;
                let mut current_room = None;
                let mut current_state = HashSet::new();
                let mut counter = 0;

                let mut handle_state =
                    |current_sstatehash: u64,
                     current_room: &RoomId,
                     current_state: HashSet<_>,
                     last_roomstates: &mut HashMap<_, _>| {
                        counter += 1;
                        let last_roomsstatehash = last_roomstates.get(current_room);

                        let states_parents = last_roomsstatehash.map_or_else(
                            || Ok(Vec::new()),
                            |&last_roomsstatehash| {
                                services()
                                    .rooms
                                    .state_compressor
                                    .load_shortstatehash_info(last_roomsstatehash)
                            },
                        )?;

                        let (statediffnew, statediffremoved) =
                            if let Some(parent_stateinfo) = states_parents.last() {
                                let statediffnew = current_state
                                    .difference(&parent_stateinfo.1)
                                    .copied()
                                    .collect::<HashSet<_>>();

                                let statediffremoved = parent_stateinfo
                                    .1
                                    .difference(&current_state)
                                    .copied()
                                    .collect::<HashSet<_>>();

                                (statediffnew, statediffremoved)
                            } else {
                                (current_state, HashSet::new())
                            };

                        services().rooms.state_compressor.save_state_from_diff(
                            current_sstatehash,
                            Arc::new(statediffnew),
                            Arc::new(statediffremoved),
                            2, // every state change is 2 event changes on average
                            states_parents,
                        )?;

                        /*
                        let mut tmp = services().rooms.load_shortstatehash_info(&current_sstatehash)?;
                        let state = tmp.pop().unwrap();
                        println!(
                            "{}\t{}{:?}: {:?} + {:?} - {:?}",
                            current_room,
                            "  ".repeat(tmp.len()),
                            utils::u64_from_bytes(&current_sstatehash).unwrap(),
                            tmp.last().map(|b| utils::u64_from_bytes(&b.0).unwrap()),
                            state
                                .2
                                .iter()
                                .map(|b| utils::u64_from_bytes(&b[size_of::<u64>()..]).unwrap())
                                .collect::<Vec<_>>(),
                            state
                                .3
                                .iter()
                                .map(|b| utils::u64_from_bytes(&b[size_of::<u64>()..]).unwrap())
                                .collect::<Vec<_>>()
                        );
                        */

                        Ok::<_, Error>(())
                    };

                for (k, seventid) in db._db.open_tree("stateid_shorteventid")?.iter() {
                    let sstatehash = utils::u64_from_bytes(&k[0..size_of::<u64>()])
                        .expect("number of bytes is correct");
                    let sstatekey = k[size_of::<u64>()..].to_vec();
                    if Some(sstatehash) != current_sstatehash {
                        if let Some(current_sstatehash) = current_sstatehash {
                            handle_state(
                                current_sstatehash,
                                current_room.as_deref().unwrap(),
                                current_state,
                                &mut last_roomstates,
                            )?;
                            last_roomstates
                                .insert(current_room.clone().unwrap(), current_sstatehash);
                        }
                        current_state = HashSet::new();
                        current_sstatehash = Some(sstatehash);

                        let event_id = db.shorteventid_eventid.get(&seventid).unwrap().unwrap();
                        let string = utils::string_from_bytes(&event_id).unwrap();
                        let event_id = <&EventId>::try_from(string.as_str()).unwrap();
                        let pdu = services()
                            .rooms
                            .timeline
                            .get_pdu(event_id)
                            .unwrap()
                            .unwrap();

                        if Some(&pdu.room_id) != current_room.as_ref() {
                            current_room = Some(pdu.room_id.clone());
                        }
                    }

                    let mut val = sstatekey;
                    val.extend_from_slice(&seventid);
                    current_state.insert(val.try_into().expect("size is correct"));
                }

                if let Some(current_sstatehash) = current_sstatehash {
                    handle_state(
                        current_sstatehash,
                        current_room.as_deref().unwrap(),
                        current_state,
                        &mut last_roomstates,
                    )?;
                }

                services().globals.bump_database_version(7)?;

                warn!("Migration: 6 -> 7 finished");
            }

            if services().globals.database_version()? < 8 {
                // Generate short room ids for all rooms
                for (room_id, _) in db.roomid_shortstatehash.iter() {
                    let shortroomid = services().globals.next_count()?.to_be_bytes();
                    db.roomid_shortroomid.insert(&room_id, &shortroomid)?;
                    info!("Migration: 8");
                }
                // Update pduids db layout
                let mut batch = db.pduid_pdu.iter().filter_map(|(key, v)| {
                    if !key.starts_with(b"!") {
                        return None;
                    }
                    let mut parts = key.splitn(2, |&b| b == 0xff);
                    let room_id = parts.next().unwrap();
                    let count = parts.next().unwrap();

                    let short_room_id = db
                        .roomid_shortroomid
                        .get(room_id)
                        .unwrap()
                        .expect("shortroomid should exist");

                    let mut new_key = short_room_id;
                    new_key.extend_from_slice(count);

                    Some((new_key, v))
                });

                db.pduid_pdu.insert_batch(&mut batch)?;

                let mut batch2 = db.eventid_pduid.iter().filter_map(|(k, value)| {
                    if !value.starts_with(b"!") {
                        return None;
                    }
                    let mut parts = value.splitn(2, |&b| b == 0xff);
                    let room_id = parts.next().unwrap();
                    let count = parts.next().unwrap();

                    let short_room_id = db
                        .roomid_shortroomid
                        .get(room_id)
                        .unwrap()
                        .expect("shortroomid should exist");

                    let mut new_value = short_room_id;
                    new_value.extend_from_slice(count);

                    Some((k, new_value))
                });

                db.eventid_pduid.insert_batch(&mut batch2)?;

                services().globals.bump_database_version(8)?;

                warn!("Migration: 7 -> 8 finished");
            }

            if services().globals.database_version()? < 9 {
                // Update tokenids db layout
                let mut iter = db
                    .tokenids
                    .iter()
                    .filter_map(|(key, _)| {
                        if !key.starts_with(b"!") {
                            return None;
                        }
                        let mut parts = key.splitn(4, |&b| b == 0xff);
                        let room_id = parts.next().unwrap();
                        let word = parts.next().unwrap();
                        let _pdu_id_room = parts.next().unwrap();
                        let pdu_id_count = parts.next().unwrap();

                        let short_room_id = db
                            .roomid_shortroomid
                            .get(room_id)
                            .unwrap()
                            .expect("shortroomid should exist");
                        let mut new_key = short_room_id;
                        new_key.extend_from_slice(word);
                        new_key.push(0xff);
                        new_key.extend_from_slice(pdu_id_count);
                        Some((new_key, Vec::new()))
                    })
                    .peekable();

                while iter.peek().is_some() {
                    db.tokenids.insert_batch(&mut iter.by_ref().take(1000))?;
                    debug!("Inserted smaller batch");
                }

                info!("Deleting starts");

                let batch2: Vec<_> = db
                    .tokenids
                    .iter()
                    .filter_map(|(key, _)| {
                        if key.starts_with(b"!") {
                            Some(key)
                        } else {
                            None
                        }
                    })
                    .collect();

                for key in batch2 {
                    db.tokenids.remove(&key)?;
                }

                services().globals.bump_database_version(9)?;

                warn!("Migration: 8 -> 9 finished");
            }

            if services().globals.database_version()? < 10 {
                // Add other direction for shortstatekeys
                for (statekey, shortstatekey) in db.statekey_shortstatekey.iter() {
                    db.shortstatekey_statekey
                        .insert(&shortstatekey, &statekey)?;
                }

                // Force E2EE device list updates so we can send them over federation
                for user_id in services().users.iter().filter_map(|r| r.ok()) {
                    services().users.mark_device_key_update(&user_id)?;
                }

                services().globals.bump_database_version(10)?;

                warn!("Migration: 9 -> 10 finished");
            }

            if services().globals.database_version()? < 11 {
                db._db
                    .open_tree("userdevicesessionid_uiaarequest")?
                    .clear()?;
                services().globals.bump_database_version(11)?;

                warn!("Migration: 10 -> 11 finished");
            }

            if services().globals.database_version()? < 12 {
                for username in services().users.list_local_users()? {
                    let user = match UserId::parse_with_server_name(
                        username.clone(),
                        services().globals.server_name(),
                    ) {
                        Ok(u) => u,
                        Err(e) => {
                            warn!("Invalid username {username}: {e}");
                            continue;
                        }
                    };

                    let raw_rules_list = services()
                        .account_data
                        .get(
                            None,
                            &user,
                            GlobalAccountDataEventType::PushRules.to_string().into(),
                        )
                        .unwrap()
                        .expect("Username is invalid");

                    let mut account_data =
                        serde_json::from_str::<PushRulesEvent>(raw_rules_list.get()).unwrap();
                    let rules_list = &mut account_data.content.global;

                    //content rule
                    {
                        let content_rule_transformation =
                            [".m.rules.contains_user_name", ".m.rule.contains_user_name"];

                        let rule = rules_list.content.get(content_rule_transformation[0]);
                        if rule.is_some() {
                            let mut rule = rule.unwrap().clone();
                            rule.rule_id = content_rule_transformation[1].to_owned();
                            rules_list
                                .content
                                .shift_remove(content_rule_transformation[0]);
                            rules_list.content.insert(rule);
                        }
                    }

                    //underride rules
                    {
                        let underride_rule_transformation = [
                            [".m.rules.call", ".m.rule.call"],
                            [".m.rules.room_one_to_one", ".m.rule.room_one_to_one"],
                            [
                                ".m.rules.encrypted_room_one_to_one",
                                ".m.rule.encrypted_room_one_to_one",
                            ],
                            [".m.rules.message", ".m.rule.message"],
                            [".m.rules.encrypted", ".m.rule.encrypted"],
                        ];

                        for transformation in underride_rule_transformation {
                            let rule = rules_list.underride.get(transformation[0]);
                            if let Some(rule) = rule {
                                let mut rule = rule.clone();
                                rule.rule_id = transformation[1].to_owned();
                                rules_list.underride.shift_remove(transformation[0]);
                                rules_list.underride.insert(rule);
                            }
                        }
                    }

                    services().account_data.update(
                        None,
                        &user,
                        GlobalAccountDataEventType::PushRules.to_string().into(),
                        &serde_json::to_value(account_data).expect("to json value always works"),
                    )?;
                }

                services().globals.bump_database_version(12)?;

                warn!("Migration: 11 -> 12 finished");
            }

            // This migration can be reused as-is anytime the server-default rules are updated.
            if services().globals.database_version()? < 13 {
                for username in services().users.list_local_users()? {
                    let user = match UserId::parse_with_server_name(
                        username.clone(),
                        services().globals.server_name(),
                    ) {
                        Ok(u) => u,
                        Err(e) => {
                            warn!("Invalid username {username}: {e}");
                            continue;
                        }
                    };

                    let raw_rules_list = services()
                        .account_data
                        .get(
                            None,
                            &user,
                            GlobalAccountDataEventType::PushRules.to_string().into(),
                        )
                        .unwrap()
                        .expect("Username is invalid");

                    let mut account_data =
                        serde_json::from_str::<PushRulesEvent>(raw_rules_list.get()).unwrap();

                    let user_default_rules = ruma::push::Ruleset::server_default(&user);
                    account_data
                        .content
                        .global
                        .update_with_server_default(user_default_rules);

                    services().account_data.update(
                        None,
                        &user,
                        GlobalAccountDataEventType::PushRules.to_string().into(),
                        &serde_json::to_value(account_data).expect("to json value always works"),
                    )?;
                }

                services().globals.bump_database_version(13)?;

                warn!("Migration: 12 -> 13 finished");
            }

            assert_eq!(
                services().globals.database_version().unwrap(),
                latest_database_version
            );

            info!(
                "Loaded {} database with version {}",
                services().globals.config.database_backend,
                latest_database_version
            );
        } else {
            services()
                .globals
                .bump_database_version(latest_database_version)?;

            // Create the admin room and server user on first run
            services().admin.create_admin_room().await?;

            warn!(
                "Created new {} database with version {}",
                services().globals.config.database_backend,
                latest_database_version
            );
        }

        // This data is probably outdated
        db.presenceid_presence.clear()?;

        services().admin.start_handler();

        // Set emergency access for the conduit user
        match set_emergency_access() {
            Ok(pwd_set) => {
                if pwd_set {
                    warn!("The Conduit account emergency password is set! Please unset it as soon as you finish admin account recovery!");
                    services().admin.send_message(RoomMessageEventContent::text_plain("The Conduit account emergency password is set! Please unset it as soon as you finish admin account recovery!"));
                }
            }
            Err(e) => {
                error!(
                    "Could not set the configured emergency password for the conduit user: {}",
                    e
                )
            }
        };

        services().sending.start_handler();

        Self::start_cleanup_task().await;
        if services().globals.allow_check_for_updates() {
            Self::start_check_for_updates_task();
        }

        Ok(())
    }

    #[tracing::instrument(skip(self))]
    pub fn flush(&self) -> Result<()> {
        let start = std::time::Instant::now();

        let res = self._db.flush();

        debug!("flush: took {:?}", start.elapsed());

        res
    }

    #[tracing::instrument]
    pub fn start_check_for_updates_task() {
        tokio::spawn(async move {
            let timer_interval = Duration::from_secs(60 * 60);
            let mut i = interval(timer_interval);
            loop {
                i.tick().await;
                let _ = Self::try_handle_updates().await;
            }
        });
    }

    async fn try_handle_updates() -> Result<()> {
        let response = services()
            .globals
            .default_client()
            .get("https://conduit.rs/check-for-updates/stable")
            .send()
            .await?;

        #[derive(Deserialize)]
        struct CheckForUpdatesResponseEntry {
            id: u64,
            date: String,
            message: String,
        }
        #[derive(Deserialize)]
        struct CheckForUpdatesResponse {
            updates: Vec<CheckForUpdatesResponseEntry>,
        }

        let response = serde_json::from_str::<CheckForUpdatesResponse>(&response.text().await?)
            .map_err(|_| Error::BadServerResponse("Bad version check response"))?;

        let mut last_update_id = services().globals.last_check_for_updates_id()?;
        for update in response.updates {
            last_update_id = last_update_id.max(update.id);
            if update.id > services().globals.last_check_for_updates_id()? {
                println!("{}", update.message);
                services()
                    .admin
                    .send_message(RoomMessageEventContent::text_plain(format!(
                    "@room: The following is a message from the Conduit developers. It was sent on '{}':\n\n{}",
                    update.date, update.message
                )))
            }
        }
        services()
            .globals
            .update_check_for_updates_id(last_update_id)?;

        Ok(())
    }

    #[tracing::instrument]
    pub async fn start_cleanup_task() {
        #[cfg(unix)]
        use tokio::signal::unix::{signal, SignalKind};

        use std::time::{Duration, Instant};

        let timer_interval =
            Duration::from_secs(services().globals.config.cleanup_second_interval as u64);

        tokio::spawn(async move {
            let mut i = interval(timer_interval);
            #[cfg(unix)]
            let mut s = signal(SignalKind::hangup()).unwrap();

            loop {
                #[cfg(unix)]
                tokio::select! {
                    _ = i.tick() => {
                        debug!("cleanup: Timer ticked");
                    }
                    _ = s.recv() => {
                        debug!("cleanup: Received SIGHUP");
                    }
                };
                #[cfg(not(unix))]
                {
                    i.tick().await;
                    debug!("cleanup: Timer ticked")
                }

                let start = Instant::now();
                if let Err(e) = services().globals.cleanup() {
                    error!("cleanup: Errored: {}", e);
                } else {
                    debug!("cleanup: Finished in {:?}", start.elapsed());
                }
            }
        });
    }
}

/// Sets the emergency password and push rules for the @conduit account in case emergency password is set
fn set_emergency_access() -> Result<bool> {
    let conduit_user = UserId::parse_with_server_name("conduit", services().globals.server_name())
        .expect("@conduit:server_name is a valid UserId");

    services().users.set_password(
        &conduit_user,
        services().globals.emergency_password().as_deref(),
    )?;

    let (ruleset, res) = match services().globals.emergency_password() {
        Some(_) => (Ruleset::server_default(&conduit_user), Ok(true)),
        None => (Ruleset::new(), Ok(false)),
    };

    services().account_data.update(
        None,
        &conduit_user,
        GlobalAccountDataEventType::PushRules.to_string().into(),
        &serde_json::to_value(&GlobalAccountDataEvent {
            content: PushRulesEventContent { global: ruleset },
        })
        .expect("to json value always works"),
    )?;

    res
}