pragma Singleton

import QtQuick
import QtQml.Models
import Quickshell.Services.Mpris

QtObject {
    id: root

    readonly property var players: (Mpris.players.values ?? []).filter(p => p.trackTitle || p.playbackState === MprisPlaybackState.Playing || p.playbackState === MprisPlaybackState.Paused)
    property int playerIdx: 0
    readonly property MprisPlayer player: players[playerIdx] ?? players[0] ?? null
    readonly property bool playing: player?.playbackState === MprisPlaybackState.Playing

    property string _selectedIdentity: ""
    property var _lastPlayedTime: ({})

    onPlayerChanged: {
        if (player)
            _selectedIdentity = player.identity ?? "";
    }

    onPlayersChanged: {
        if (_selectedIdentity) {
            const idx = players.findIndex(p => (p.identity ?? "") === _selectedIdentity);
            if (idx >= 0) {
                playerIdx = idx;
            } else {
                _switchToBest();
            }
        } else {
            _switchToBest();
        }
    }

    // Watch all raw players for state changes via Instantiator -
    // delegates persist across state changes since the model only
    // changes on player add/remove, not property changes
    property Instantiator _stateWatchers: Instantiator {
        model: Mpris.players
        delegate: QtObject {
            required property MprisPlayer modelData
            property Connections _conn: Connections {
                target: modelData
                function onPlaybackStateChanged() {
                    root._onPlaybackStateChanged(modelData);
                }
            }
        }
    }

    function _onPlaybackStateChanged(p) {
        if (!p)
            return;

        const identity = p.identity ?? "";

        if (p.playbackState === MprisPlaybackState.Playing) {
            const times = Object.assign({}, _lastPlayedTime);
            times[identity] = Date.now();
            _lastPlayedTime = times;

            // Always switch to the newly playing player
            if (player !== p) {
                const idx = players.indexOf(p);
                if (idx >= 0) {
                    playerIdx = idx;
                    _selectedIdentity = identity;
                }
            }
        } else if (p.playbackState === MprisPlaybackState.Paused && p === player) {
            _switchToPlaying();
        }
    }

    function _switchToPlaying() {
        let best = -1;
        let bestTime = 0;
        for (let i = 0; i < players.length; i++) {
            if (players[i].playbackState === MprisPlaybackState.Playing) {
                const t = _lastPlayedTime[players[i].identity ?? ""] || 0;
                if (best < 0 || t > bestTime) {
                    best = i;
                    bestTime = t;
                }
            }
        }
        if (best >= 0) {
            playerIdx = best;
            _selectedIdentity = players[best].identity ?? "";
        }
    }

    function _switchToBest() {
        let best = -1;
        let bestTime = 0;
        let bestPlaying = -1;
        let bestPlayingTime = 0;

        for (let i = 0; i < players.length; i++) {
            const identity = players[i].identity ?? "";
            const t = _lastPlayedTime[identity] || 0;
            if (players[i].playbackState === MprisPlaybackState.Playing) {
                if (bestPlaying < 0 || t > bestPlayingTime) {
                    bestPlaying = i;
                    bestPlayingTime = t;
                }
            }
            if (best < 0 || t > bestTime) {
                best = i;
                bestTime = t;
            }
        }

        const chosen = bestPlaying >= 0 ? bestPlaying : (best >= 0 ? best : 0);
        playerIdx = chosen;
        if (players[chosen])
            _selectedIdentity = players[chosen].identity ?? "";
    }

    function switchPlayer(idx) {
        playerIdx = idx;
        if (players[idx])
            _selectedIdentity = players[idx].identity ?? "";
    }
}