/*
 * Copyright 2013 Canonical Ltd.
 * Copyright 2021 Robert Tari
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *      Lars Uebernickel <lars.uebernickel@canonical.com>
 *      Robert Tari <robert@tari.in>
 */

/**
 * MediaPlayerList is a list of media players that should appear in the sound menu.  Its main responsibility is
 * to listen for MPRIS players on the bus and attach them to the corresponding %Player objects.
 */
public class MediaPlayerListMpris : MediaPlayerList {

    public MediaPlayerListMpris () {
        this._players = new HashTable<string, MediaPlayerMpris> (str_hash, str_equal);

        BusWatcher.watch_namespace (BusType.SESSION, "org.mpris.MediaPlayer2", this.player_appeared, this.player_disappeared);
    }

    /* only valid while the list is not changed */
    public class Iterator : MediaPlayerList.Iterator {
        HashTableIter<string, MediaPlayerMpris> iter;

        public Iterator (MediaPlayerListMpris list) {
            this.iter = HashTableIter<string, MediaPlayerMpris> (list._players);
        }

        public override MediaPlayer? next_value () {
            MediaPlayerMpris? player;

            if (this.iter.next (null, out player))
                return player as MediaPlayer;
            else
                return null;
        }
    }

    public override MediaPlayerList.Iterator iterator () {
        return new Iterator (this) as MediaPlayerList.Iterator;
    }

    /**
     * Adds the player associated with @desktop_id.  Does nothing if such a player already exists.
     */
    MediaPlayerMpris? insert (string desktop_id) {
        debug("Inserting player: %s", desktop_id);

        var id = desktop_id.has_suffix (".desktop") ? desktop_id : desktop_id + ".desktop";
        MediaPlayerMpris? player = this._players.lookup (id);

        if (player == null) {
            var appinfo = new DesktopAppInfo (id);
            if (appinfo == null) {
                warning ("unable to find application '%s'", id);
                return null;
            }

            player = new MediaPlayerMpris (appinfo);
            this._players.insert (player.id, player);
            this.player_added (player);
        }

        return player;
    }

    /**
     * Removes the player associated with @desktop_id, unless it is currently running.
     */
    void remove (string desktop_id) {
        MediaPlayer? player = this._players.lookup (desktop_id);

        if (player != null && !player.is_running) {
            this._players.remove (desktop_id);
            this.player_removed (player);
        }
    }

    /**
     * Synchronizes the player list with @desktop_ids.  After this call, this list will only contain the players
     * in @desktop_ids.  Players that were running but are not in @desktop_ids will remain in the list.
     */
    public override void sync (string[] desktop_ids) {

        /* hash desktop_ids for faster lookup */
        var hash = new GenericSet<string> (str_hash, str_equal);
        foreach (var id in desktop_ids)
            hash.add (id);

        /* remove players that are not desktop_ids */
        foreach (var id in this._players.get_keys ()) {
            if (!hash.contains (id))
                this.remove (id);
        }

        /* insert all players (insert() takes care of not adding a player twice */
        foreach (var id in desktop_ids)
            this.insert (id);
    }

    HashTable<string, MediaPlayerMpris> _players;

    void player_appeared (DBusConnection connection, string name, string owner) {
        try {
            MprisRoot mpris2_root = Bus.get_proxy_sync (BusType.SESSION, name, MPRIS_MEDIA_PLAYER_PATH);

            var player = this.insert (mpris2_root.DesktopEntry);
            if (player != null)
                player.attach (mpris2_root, name);
        }
        catch (Error e) {
            warning ("unable to create mpris proxy for '%s': %s", name, e.message);
        }
    }

    void player_disappeared (DBusConnection connection, string dbus_name) {
        MediaPlayerMpris? player = this._players.find ( (name, player) => {
            return player.dbus_name == dbus_name;
        });

        if (player != null)
            player.detach ();
    }
}
