(function () {
  'use strict';

  // ── DOM refs ──────────────────────────────────────────────────────────────
  const body         = document.body;
  const wsDot        = document.getElementById('ws-dot');
  const statsPanel   = document.getElementById('stats-panel');
  const resizeHandle = document.getElementById('resize-handle');
  const stateLabelEl = document.getElementById('state-label');
  const progressFill  = document.getElementById('progress-fill');
  const progressLabel = document.getElementById('progress-label');
  const svModel     = document.getElementById('sv-model');
  const svState     = document.getElementById('sv-state');
  const svPrompt    = document.getElementById('sv-prompt');
  const svSpeed     = document.getElementById('sv-speed');
  const svTokens    = document.getElementById('sv-tokens');
  const svLoadStage   = document.getElementById('sv-load-stage');
  const svSleepTimer  = document.getElementById('sv-sleep-timer');
  const svReqs        = document.getElementById('sv-reqs');

  // ── State class management ────────────────────────────────────────────────
  const ALL_STATES = [
    'offline','starting','loading','warming_up','idle',
    'sleeping','waiting','processing_prompt','generating','unloading','error'
  ];

  const STATE_LABELS = {
    offline:  'LOG OFFLINE',   // llamagochi can't read the log file
    error:    'LOAD ERROR',
  };

  function stateLabel(stateName) {
    return STATE_LABELS[stateName] ?? stateName.replace(/_/g, ' ').toUpperCase();
  }

  function applyState(stateName) {
    ALL_STATES.forEach(s => body.classList.remove('state-' + s));
    body.classList.add('state-' + (ALL_STATES.includes(stateName) ? stateName : 'offline'));
  }

  // ── DOM update ────────────────────────────────────────────────────────────
  function fmt(val, unit) {
    return val != null ? val.toFixed(1) + ' ' + unit : '—';
  }

  function truncate(str, max) {
    return str.length > max ? '…' + str.slice(-(max - 1)) : str;
  }

  function update(msg) {
    const { state, model, loading, metrics, request_count, sleeping_since } = msg;

    applyState(state);

    stateLabelEl.textContent = stateLabel(state);
    svState.textContent      = stateLabel(state).toLowerCase();
    svModel.textContent    = model || '—';
    svReqs.textContent     = request_count ?? 0;

    // Progress bar: model loading or prompt processing
    if (loading) {
      const stageName  = (loading.current ?? '').replace(/_/g, ' ');
      const stageIdx   = (loading.stages ?? []).indexOf(loading.current);
      const totalStages = (loading.stages ?? []).length;
      const stagePct   = Math.round((loading.progress ?? 0) * 100);
      const overallPct = totalStages > 0
        ? Math.round(((stageIdx + (loading.progress ?? 0)) / totalStages) * 100)
        : stagePct;
      progressFill.style.width  = overallPct + '%';
      progressLabel.textContent = stageName
        + (totalStages > 1 ? '  ' + (stageIdx + 1) + '/' + totalStages : '')
        + '  ' + stagePct + '%';
      svLoadStage.textContent   = totalStages > 1
        ? stageName + ' (' + (stageIdx + 1) + '/' + totalStages + ')'
        : stageName;
    } else if (state === 'processing_prompt' && metrics && metrics.prompt_progress != null) {
      const pct = Math.round(metrics.prompt_progress * 100);
      progressFill.style.width  = pct + '%';
      progressLabel.textContent = 'PROMPT  ' + pct + '%';
      svLoadStage.textContent   = '—';
    } else {
      progressFill.style.width  = '0%';
      progressLabel.textContent = '';
      svLoadStage.textContent   = '—';
    }

    // Metrics
    if (metrics) {
      svPrompt.textContent  = fmt(metrics.prompt_speed, 't/s');
      svSpeed.textContent   = fmt(metrics.gen_speed, 't/s');
      svTokens.textContent  = metrics.n_decoded != null ? metrics.n_decoded + ' tok' : '—';
    } else {
      svPrompt.textContent = svSpeed.textContent = svTokens.textContent = '—';
    }

    // Sleep timer
    if (state === 'sleeping' && sleeping_since) {
      startSleepTimer(sleeping_since);
    } else {
      stopSleepTimer();
    }

    // Pulse dot on message
    wsDot.classList.remove('pulse');
    void wsDot.offsetWidth; // force reflow to restart animation
    wsDot.classList.add('pulse');
  }

  // ── Stats panel resize ───────────────────────────────────────────────────
  const SCREEN_W = 280;
  let dragStartX = 0, dragStartW = 0, dragging = false;

  function startDrag(x) {
    dragging   = true;
    dragStartX = x;
    dragStartW = statsPanel.offsetWidth;
    resizeHandle.classList.add('dragging');
    body.style.cursor     = 'ew-resize';
    body.style.userSelect = 'none';
  }
  function onDrag(x) {
    if (!dragging) return;
    const w = Math.min(Math.max(dragStartW + (x - dragStartX), SCREEN_W), SCREEN_W * 3);
    statsPanel.style.flex = '0 0 ' + w + 'px';
  }
  function endDrag() {
    if (!dragging) return;
    dragging = false;
    resizeHandle.classList.remove('dragging');
    body.style.cursor = body.style.userSelect = '';
  }

  resizeHandle.addEventListener('mousedown', e => { e.preventDefault(); startDrag(e.clientX); });
  document.addEventListener('mousemove',  e => onDrag(e.clientX));
  document.addEventListener('mouseup',    endDrag);

  resizeHandle.addEventListener('touchstart', e => { e.preventDefault(); startDrag(e.touches[0].clientX); }, { passive: false });
  document.addEventListener('touchmove',  e => { if (dragging) { e.preventDefault(); onDrag(e.touches[0].clientX); } }, { passive: false });
  document.addEventListener('touchend',   endDrag);

  // ── Sleep timer ───────────────────────────────────────────────────────────
  let sleepingSince = null;
  let sleepInterval = null;

  function formatDuration(sec) {
    const h = Math.floor(sec / 3600);
    const m = Math.floor((sec % 3600) / 60);
    const s = sec % 60;
    if (h > 0) return h + 'h ' + m + 'm';
    if (m > 0) return m + 'm ' + s + 's';
    return s + 's';
  }

  function tickSleepTimer() {
    if (!sleepingSince) return;
    const elapsed = Math.floor((Date.now() - new Date(sleepingSince).getTime()) / 1000);
    svSleepTimer.textContent = formatDuration(elapsed);
  }

  function startSleepTimer(since) {
    if (sleepingSince === since) return;
    sleepingSince = since;
    clearInterval(sleepInterval);
    tickSleepTimer();
    sleepInterval = setInterval(tickSleepTimer, 1000);
  }

  function stopSleepTimer() {
    sleepingSince = null;
    clearInterval(sleepInterval);
    sleepInterval = null;
    svSleepTimer.textContent = '—';
  }

  // ── HTTP polling fallback ─────────────────────────────────────────────────
  let pollTimer = null;
  const POLL_MS = 2000;

  async function pollOnce() {
    try {
      const r = await fetch('/state');
      if (!r.ok) throw new Error(r.status);
      update(await r.json());
      wsDot.className = 'polling';
    } catch {
      wsDot.className = '';  // red: llamagochi itself unreachable
    }
  }

  function startPolling() {
    if (pollTimer) return;
    pollOnce();
    pollTimer = setInterval(pollOnce, POLL_MS);
  }

  function stopPolling() {
    clearInterval(pollTimer);
    pollTimer = null;
  }

  // ── WebSocket with auto-reconnect ─────────────────────────────────────────
  let ws = null;
  let retryDelay = 1000;
  const MAX_DELAY = 30000;

  function connect() {
    const url = (location.protocol === 'https:' ? 'wss:' : 'ws:') + '//' + location.host + '/ws';
    ws = new WebSocket(url);

    ws.addEventListener('open', () => {
      stopPolling();
      wsDot.className = 'connected';
      retryDelay = 1000;
    });

    ws.addEventListener('message', (event) => {
      try {
        update(JSON.parse(event.data));
      } catch (e) {
        console.error('llamagochi: bad message', e);
      }
    });

    ws.addEventListener('close', () => {
      startPolling();
      setTimeout(connect, retryDelay);
      retryDelay = Math.min(retryDelay * 2, MAX_DELAY);
    });

    ws.addEventListener('error', () => {
      ws.close();
    });
  }

  connect();
})();