/*
 * app.js - Glue between the DOM and StreamPlayer.
 *
 * - Polls the MediaMTX API (/v3/paths/get/game) to determine if the stream
 *   is live, and updates the status bar accordingly.
 * - Starts/stops StreamPlayer based on that status.
 * - Wires up the "Click to unmute" button (browsers autoplay muted).
 * - Authentik forward auth is handled at the NPM layer, so by the time
 *   this JS runs the user is already authenticated. No auth logic here.
 */

(function () {
    // /status is served by the OBS Python HTTP server, which proxies the
    // MediaMTX API internally. This avoids hitting /v3/ through NPM where
    // the server-level auth_request directive blocks it.
    const API_URL = '/status';
    const POLL_INTERVAL_MS = 5000;

    const els = {
        video: document.getElementById('video'),
        overlay: document.getElementById('overlay'),
        overlayTitle: document.getElementById('overlay-title'),
        overlayMessage: document.getElementById('overlay-message'),
        overlayCard: document.querySelector('.overlay-card'),
        statusIndicator: document.getElementById('status-indicator'),
        viewerCount: document.getElementById('viewer-count'),
        latency: document.getElementById('latency'),
        transport: document.getElementById('transport'),
        unmuteBtn: document.getElementById('unmute-btn'),
    };

    const state = {
        pathReady: false,
        playerState: 'offline',
    };

    // ---- overlay helpers -------------------------------------------------

    function showOverlay(title, message, isError) {
        els.overlayTitle.textContent = title;
        els.overlayMessage.textContent = message;
        els.overlayCard.classList.toggle('error', !!isError);
        els.overlay.hidden = false;
    }

    function hideOverlay() {
        els.overlay.hidden = true;
    }

    // ---- status bar helpers ---------------------------------------------

    function setStatusIndicator(label, cls) {
        els.statusIndicator.textContent = label;
        els.statusIndicator.className = 'status ' + cls;
    }

    function setViewerCount(n) {
        els.viewerCount.textContent = String(n);
    }

    function setLatency(ms) {
        els.latency.textContent = ms == null ? '--' : `${ms} ms`;
    }

    function setTransport(label) {
        els.transport.textContent = label || '--';
    }

    // ---- MediaMTX API polling -------------------------------------------

    async function pollPathStatus() {
        try {
            const res = await fetch(API_URL, { credentials: 'include' });
            if (res.status === 404) {
                applyPathStatus(false, 0);
                return;
            }
            if (!res.ok) {
                // 401/403 means session expired - force reload so NPM can redirect to Authentik.
                if (res.status === 401 || res.status === 403) {
                    window.location.reload();
                }
                return;
            }
            const data = await res.json();
            applyPathStatus(Boolean(data.ready), (data.readers || []).length);
        } catch (_) {
            applyPathStatus(false, 0);
        }
    }

    function applyPathStatus(ready, viewers) {
        setViewerCount(viewers);

        if (ready && !state.pathReady) {
            state.pathReady = true;
            setStatusIndicator('LIVE', 'live');
            showOverlay('Connecting to stream…', 'Negotiating WebRTC', false);
            window.StreamPlayer.start(els.video);
        } else if (!ready && state.pathReady) {
            state.pathReady = false;
            setStatusIndicator('OFFLINE', 'offline');
            setTransport('--');
            setLatency(null);
            showOverlay('Stream offline', 'Waiting for the streamer to start…', false);
            window.StreamPlayer.stop();
        }
    }

    // ---- Unmute / play button -------------------------------------------
    //
    // Browsers block autoplay with audio until a user gesture occurs.
    // When the video fails to autoplay (or is muted by the browser), we
    // surface a "Click to play" button so the user can unblock it manually.

    els.unmuteBtn.addEventListener('click', async () => {
        try {
            els.video.muted = false;
            await els.video.play();
            els.unmuteBtn.hidden = true;
        } catch (err) {
            console.warn('Unmute/play failed:', err);
        }
    });

    function maybeShowUnmute() {
        // Show the button if the video is muted OR paused (autoplay blocked).
        const needsGesture = els.video.muted || els.video.paused;
        els.unmuteBtn.hidden = !needsGesture;
        if (needsGesture) {
            els.unmuteBtn.textContent = els.video.muted ? 'Click to unmute' : 'Click to play';
        }
    }

    // ---- StreamPlayer event wiring --------------------------------------

    window.StreamPlayer.on('statechange', (s) => {
        state.playerState = s;
        if (s === 'playing') {
            hideOverlay();
            maybeShowUnmute();
        } else if (s === 'connecting') {
            showOverlay('Connecting…', 'Negotiating transport', false);
        } else if (s === 'error') {
            showOverlay('Playback error', 'Retrying…', true);
        } else if (s === 'offline' && state.pathReady) {
            showOverlay('Reconnecting…', 'The stream dropped; trying again', false);
        }
    });

    window.StreamPlayer.on('transport', (label) => setTransport(label));
    window.StreamPlayer.on('latency', (ms) => setLatency(ms));
    window.StreamPlayer.on('error', (err) => {
        console.warn('Stream error:', err);
    });

    // ---- boot -----------------------------------------------------------

    setStatusIndicator('OFFLINE', 'offline');
    showOverlay('Stream offline', 'Waiting for the streamer to start…', false);

    pollPathStatus();
    setInterval(pollPathStatus, POLL_INTERVAL_MS);
})();