led2/lightsync/frontend/app.js

// LightSync frontend — Phase 02-03 browser-audio architecture
// Browser <audio> element plays audio; server does beat detection via librosa
// 10Hz position ticks sent to server; server sends beat notifications back

const WS_URL = `${location.protocol === 'https:' ? 'wss' : 'ws'}://${location.host}/ws`;

async function apiPost(path, data) {
    const res = await fetch(path, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(data),
    });
    if (!res.ok) throw new Error(`POST ${path}: HTTP ${res.status}`);
    return res.json();
}

async function apiDelete(path) {
    const res = await fetch(path, { method: "DELETE" });
    if (!res.ok && res.status !== 204) throw new Error(`DELETE ${path}: HTTP ${res.status}`);
}

// --- Beat markers state ---
let beatTimestamps = [];   // sorted list of beat times in seconds
let audioDuration = 0;
let currentFilePath = "";  // absolute server path for beat/waveform fetches

// --- WebSocket client ---
class LightSyncClient {
    constructor() {
        this.ws = null;
        this.reconnectDelay = 2000;
        this._reconnectTimer = null;
    }

    connect() {
        if (this._reconnectTimer) {
            clearTimeout(this._reconnectTimer);
            this._reconnectTimer = null;
        }

        this.ws = new WebSocket(WS_URL);

        this.ws.onopen = () => {
            document.getElementById("status-dot").className = "status-dot connected";
            document.getElementById("status-text").textContent = "CONNECTED";
        };

        this.ws.onclose = () => {
            document.getElementById("status-dot").className = "status-dot";
            document.getElementById("status-text").textContent = "OFFLINE";
            this._reconnectTimer = setTimeout(() => this.connect(), this.reconnectDelay);
        };

        this.ws.onerror = () => {
            document.getElementById("status-dot").className = "status-dot error";
        };

        this.ws.onmessage = (event) => {
            const msg = JSON.parse(event.data);
            this.handleMessage(msg);
        };
    }

    handleMessage(msg) {
        if (msg.type === 'beat') {
            flashBeatIndicator();
        } else {
            console.debug('[ws]', msg);
        }
    }

    send(msg) {
        if (this.ws?.readyState === WebSocket.OPEN) {
            this.ws.send(JSON.stringify(msg));
        }
    }
}

// --- Beat indicator flash ---
function flashBeatIndicator() {
    const dot = document.getElementById('beat-indicator');
    if (!dot) return;
    dot.classList.add('beat-flash');
    // Remove class after animation completes (200ms)
    setTimeout(() => dot.classList.remove('beat-flash'), 200);
}

// --- Waveform + beat marker rendering ---
let waveformPeaks = [];

function drawWaveform(canvas, peaks, beats, duration) {
    const ctx = canvas.getContext('2d');
    const dpr = window.devicePixelRatio || 1;
    const rect = canvas.getBoundingClientRect();
    canvas.width = rect.width * dpr;
    canvas.height = rect.height * dpr;
    ctx.scale(dpr, dpr);

    const w = rect.width;
    const h = rect.height;
    const mid = h / 2;

    ctx.clearRect(0, 0, w, h);

    // Draw waveform bars using --accent color
    if (peaks.length > 0) {
        const barWidth = w / peaks.length;
        ctx.fillStyle = getComputedStyle(document.documentElement).getPropertyValue('--accent').trim() || '#0ff';
        for (let i = 0; i < peaks.length; i++) {
            const amp = peaks[i] * mid * 0.9;
            const x = i * barWidth;
            ctx.fillRect(x, mid - amp, Math.max(barWidth - 0.5, 0.5), amp * 2);
        }
    }

    // Draw beat markers as thin vertical lines
    if (beats.length > 0 && duration > 0) {
        ctx.strokeStyle = 'rgba(255, 200, 0, 0.6)';
        ctx.lineWidth = 1;
        for (const t of beats) {
            const x = (t / duration) * w;
            ctx.beginPath();
            ctx.moveTo(x, 0);
            ctx.lineTo(x, h);
            ctx.stroke();
        }
    }
}

async function loadWaveformAndBeats(filePath) {
    try {
        const encodedPath = encodeURIComponent(filePath);
        const [waveRes, beatRes] = await Promise.allSettled([
            fetch(`/api/audio/waveform?path=${encodedPath}&peaks=2000`),
            fetch(`/api/audio/beats?path=${encodedPath}`),
        ]);

        if (waveRes.status === 'fulfilled' && waveRes.value.ok) {
            const data = await waveRes.value.json();
            waveformPeaks = data.peaks;
        }

        if (beatRes.status === 'fulfilled' && beatRes.value.ok) {
            const data = await beatRes.value.json();
            beatTimestamps = data.beats || [];
            audioDuration = document.getElementById('player')?.duration || audioDuration;
        }

        redrawCanvas();
    } catch (err) {
        console.error('[waveform/beats]', err);
    }
}

function redrawCanvas() {
    const canvas = document.getElementById('waveform-canvas');
    if (canvas) {
        const audio = document.getElementById('player');
        const dur = (audio && isFinite(audio.duration)) ? audio.duration : audioDuration;
        drawWaveform(canvas, waveformPeaks, beatTimestamps, dur);
    }
}

// --- 10Hz position tick loop ---
let _tickInterval = null;

function startTickLoop() {
    if (_tickInterval) return;
    _tickInterval = setInterval(() => {
        const audio = document.getElementById('player');
        if (audio && !audio.paused && !audio.ended) {
            client.send({ type: 'tick', position: audio.currentTime });
        }
    }, 100);
}

function stopTickLoop() {
    if (_tickInterval) {
        clearInterval(_tickInterval);
        _tickInterval = null;
    }
}

// --- Audio element event wiring ---
function wireAudioElement() {
    const audio = document.getElementById('player');
    if (!audio) return;

    // Also send ticks on native timeupdate (~4Hz) as a fallback bridge
    audio.addEventListener('timeupdate', () => {
        if (!audio.paused) {
            client.send({ type: 'tick', position: audio.currentTime });
            updateCursor(audio.currentTime, audio.duration);
        }
    });

    audio.addEventListener('play', () => {
        client.send({ type: 'play', position: audio.currentTime });
        startTickLoop();
        document.getElementById('show-name').textContent = currentFilePath
            ? currentFilePath.split('/').pop()
            : '— playing —';
    });

    audio.addEventListener('pause', () => {
        client.send({ type: 'pause', position: audio.currentTime });
        stopTickLoop();
    });

    audio.addEventListener('ended', () => {
        stopTickLoop();
        client.send({ type: 'pause', position: audio.currentTime });
    });

    audio.addEventListener('seeked', () => {
        client.send({ type: 'seek', position: audio.currentTime });
        updateCursor(audio.currentTime, audio.duration);
    });

    audio.addEventListener('loadedmetadata', () => {
        audioDuration = audio.duration;
        redrawCanvas();
    });
}

function updateCursor(position, duration) {
    const cursor = document.getElementById('playback-cursor');
    const container = document.querySelector('.waveform-container');
    if (cursor && container && duration > 0) {
        const pct = (position / duration) * 100;
        cursor.style.left = pct + '%';
    }
}

// --- File selector ---
async function refreshFileList(selectValue) {
    const sel = document.getElementById('audio-select');
    if (!sel) return;
    try {
        const res = await fetch('/api/audio/files');
        if (!res.ok) return;
        const { files } = await res.json();
        const prev = selectValue ?? sel.value;
        sel.innerHTML = '<option value="">&#8212; select file &#8212;</option>';
        files.forEach(name => {
            const opt = document.createElement('option');
            opt.value = `/app/shows/${name}`;
            opt.textContent = name;
            if (opt.value === prev) opt.selected = true;
            sel.appendChild(opt);
        });
    } catch (e) {
        console.error('[audio] file list error:', e);
    }
}

// --- Upload handler ---
document.getElementById('audio-upload')?.addEventListener('change', async (e) => {
    const file = e.target.files?.[0];
    if (!file) return;
    const form = new FormData();
    form.append('file', file);
    try {
        const res = await fetch('/api/audio/upload', { method: 'POST', body: form });
        if (!res.ok) {
            const err = await res.json();
            console.error('[audio] upload failed:', err.detail);
            return;
        }
        const { path, beats } = await res.json();
        // Cache beat timestamps returned from upload response
        if (beats && beats.beats) {
            beatTimestamps = beats.beats;
        }
        // Options use /app/shows/filename as value — pass abs path to pre-select
        await refreshFileList(path);
        loadSelectedFile(path);
    } catch (err) {
        console.error('[audio] upload error:', err);
    }
    e.target.value = '';
});

// --- Load button handler ---
document.getElementById('btn-load')?.addEventListener('click', () => {
    const sel = document.getElementById('audio-select');
    const path = sel?.value;
    if (!path) return;
    // Convert /shows/filename to /app/shows/filename for absolute path
    const absPath = path.startsWith('/app/') ? path : `/app${path}`;
    loadSelectedFile(absPath);
});

function loadSelectedFile(absPath) {
    const audio = document.getElementById('player');
    if (!audio) return;

    // Derive the URL path from the absolute server path
    // /app/shows/song.mp3 -> /shows/song.mp3
    const urlPath = absPath.replace(/^\/app/, '');
    audio.src = urlPath;
    audio.load();

    currentFilePath = absPath;
    document.getElementById('show-name').textContent = absPath.split('/').pop();

    // Tell WebSocket which file is loaded for beat lookup
    client.send({ type: 'load', path: absPath });

    // Fetch waveform + beat markers
    loadWaveformAndBeats(absPath);
}

// --- Device management ---
async function loadDevices() {
    try {
        const res = await fetch("/api/devices");
        if (!res.ok) throw new Error(`HTTP ${res.status}`);
        const devices = await res.json();
        const list = document.getElementById("device-list");
        if (devices.length === 0) {
            list.innerHTML = '<span class="text-dim">no devices registered</span>';
            return;
        }
        list.innerHTML = devices.map(d =>
            `<div class="device-row">
                <div class="device-row-info">
                    <span class="text-accent">${escapeHtml(d.name)}</span>
                    <span class="text-dim">${escapeHtml(d.strip_type)} / ${d.led_count} LEDs / ${escapeHtml(d.ip)}:${d.port}</span>
                </div>
                <button class="device-remove" onclick="removeDevice('${d.id}')" title="Remove device">&times;</button>
            </div>`
        ).join("");
    } catch (err) {
        const list = document.getElementById("device-list");
        list.innerHTML = `<span class="text-dim">error loading devices</span>`;
        console.error("[devices]", err);
    }
}

async function removeDevice(id) {
    try {
        await apiDelete(`/api/devices/${id}`);
        await loadDevices();
    } catch (err) {
        console.error("[devices] remove failed:", err);
    }
}
window.removeDevice = removeDevice;

function escapeHtml(str) {
    const div = document.createElement("div");
    div.appendChild(document.createTextNode(String(str)));
    return div.innerHTML;
}

// --- Waveform click-to-seek ---
document.querySelector('.waveform-container')?.addEventListener('click', (e) => {
    const audio = document.getElementById('player');
    if (!audio || !isFinite(audio.duration) || audio.duration <= 0) return;
    const rect = e.currentTarget.getBoundingClientRect();
    const pct = (e.clientX - rect.left) / rect.width;
    audio.currentTime = pct * audio.duration;
});

// --- Resize redraws ---
window.addEventListener('resize', redrawCanvas);

// --- Init ---
const client = new LightSyncClient();
client.connect();
wireAudioElement();
loadDevices();
refreshFileList();

document.getElementById("add-device-form").addEventListener("submit", async (e) => {
    e.preventDefault();
    const form = e.target;
    const data = {
        name: form.elements["name"].value.trim(),
        strip_type: form.strip_type.value,
        led_count: parseInt(form.led_count.value, 10),
        ip: form.ip.value.trim(),
        port: parseInt(form.port.value, 10),
    };
    try {
        await apiPost("/api/devices", data);
        form.reset();
        form.port.value = "21324";
        await loadDevices();
    } catch (err) {
        console.error("[devices] add failed:", err);
    }
});