const app = document.getElementById('app');
const view = document.getElementById('view');
let countdownTimer = null;
let renderedState = null;     // which runtime_state the DOM currently shows
let dismissedNudge = null;    // text of the nudge the user has dismissed

function post(path, body) {
  return fetch(path, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: body ? JSON.stringify(body) : undefined,
  });
}

function fmt(secs) {
  secs = Math.max(0, Math.floor(secs));
  const m = String(Math.floor(secs / 60)).padStart(2, '0');
  const s = String(secs % 60).padStart(2, '0');
  return `${m}:${s}`;
}

// stateKey maps server state to the data-state accent bucket. Drift outranks
// a nudge, and a nudge the user already dismissed reverts to plain active.
function stateKey(state) {
  const rs = state.runtime_state;
  if (rs !== 'active') return rs || 'locked';
  const d = state.drift || {};
  if (d.status === 'drifting') return 'drift';
  if (d.nudge && d.nudge !== dismissedNudge) return 'nudge';
  return 'active';
}

function setStateAttr(state) {
  app.dataset.state = stateKey(state);
}

function evidenceBlock(ev) {
  if (!ev) return '';
  const health = ev.available
    ? `<span class="health-ok">tracking</span>`
    : `<span class="health-bad">evidence unavailable: ${ev.reason || 'unknown'}</span>`;
  const now = ev.current && (ev.current.class || ev.current.title)
    ? `${ev.current.class || '?'} · ${ev.current.title || ''}` : '—';
  const rows = (ev.buckets || []).map(b =>
    `<li><span>${(b.class || '?')} · ${b.title || ''}</span><span>${fmt(b.seconds)}</span></li>`).join('');
  return `<div class="band evidence">
    <div class="now">now ${now} &nbsp; ${health}</div>
    <ul class="buckets">${rows}</ul>
    <div class="switches">context switches: ${ev.switch_count || 0}</div>
  </div>`;
}

// reviewSummary renders a presentational recap from already-available state:
// the commitment plus the per-window evidence buckets. No new backend data.
function reviewSummary(ev) {
  if (!ev) return '';
  const rows = (ev.buckets || []).map(b =>
    `<div class="summary-row"><span>${(b.class || '?')} · ${b.title || ''}</span><span>${fmt(b.seconds)}</span></div>`).join('');
  const switches = `<div class="summary-row"><span>context switches</span><span>${ev.switch_count || 0}</span></div>`;
  return `<div class="band summary">${switches}${rows}</div>`;
}

// updateActiveDrift owns the active status band: it renders on-task, nudge,
// drift, or pending content into #statusband and rebinds the buttons.
function updateActiveDrift(state) {
  const el = document.getElementById('statusband');
  if (!el) return;
  setStateAttr(state);
  const drift = state.drift || {};
  const switches = (state.evidence && state.evidence.switch_count) || 0;

  if (drift.status === 'drifting') {
    el.className = 'band statusband col';
    el.innerHTML = `<div><span class="pill">Drift</span></div>
      <div class="drift-reason">${drift.reason || 'This looks off task.'}</div>
      <div class="band-actions">
        <button id="refocus" type="button" class="btn btn-primary">Back to task</button>
        <button id="ontask" type="button" class="btn btn-ghost">This is on task</button>
        <button id="enddrift" type="button" class="btn btn-ghost">End session</button>
      </div>`;
    document.getElementById('refocus').onclick = () => post('/refocus');
    document.getElementById('ontask').onclick = () => post('/ontask');
    document.getElementById('enddrift').onclick = () => post('/complete');
    return;
  }

  const nudge = drift.nudge || '';
  if (!nudge) dismissedNudge = null; // trajectory recovered; allow future nudges
  if (nudge && nudge !== dismissedNudge) {
    el.className = 'band statusband col';
    el.innerHTML = `<div><span class="pill">Heads up</span></div>
      <div class="nudge-msg">${nudge}</div>
      <div class="band-actions">
        <button id="dismissnudge" type="button" class="btn btn-ghost">Dismiss</button>
      </div>`;
    document.getElementById('dismissnudge').onclick = () => {
      dismissedNudge = nudge;
      setStateAttr(state);
      updateActiveDrift(state);
    };
    return;
  }

  if (drift.status === 'pending') {
    el.className = 'band statusband';
    el.innerHTML = `<span class="pill">Active</span><span class="status-meta">checking focus…</span>`;
    return;
  }

  el.className = 'band statusband';
  el.innerHTML = `<span class="pill">Active</span>
    <span class="status-meta">on task · ${switches} switches</span>`;
}

function updatePlanningCoach(coach) {
  const statusEl = document.getElementById('coachStatus');
  if (!statusEl) return;
  if (!coach || coach.status === 'idle') { statusEl.textContent = ''; return; }
  if (coach.status === 'pending') { statusEl.textContent = 'Sharpening…'; return; }
  if (coach.status === 'error') { statusEl.textContent = coach.error || 'coach unavailable'; return; }
  if (coach.status === 'ready' && coach.proposal) {
    statusEl.textContent = 'AI suggestion applied — edit freely.';
    const stamp = JSON.stringify(coach.proposal);
    if (statusEl.dataset.applied === stamp) return;
    statusEl.dataset.applied = stamp;
    const na = document.getElementById('na'), sc = document.getElementById('sc'),
          mins = document.getElementById('mins'), start = document.getElementById('start');
    if (na && !na.value.trim()) na.value = coach.proposal.next_action || '';
    if (sc && !sc.value.trim()) sc.value = coach.proposal.success_condition || '';
    if (mins && coach.proposal.timebox_secs) mins.value = Math.round(coach.proposal.timebox_secs / 60);
    if (start) start.disabled = !(na.value.trim() && sc.value.trim() && +mins.value > 0);
    const apps = document.getElementById('apps');
    if (apps && !apps.value.trim() && Array.isArray(coach.proposal.allowed_window_classes)) {
      apps.value = coach.proposal.allowed_window_classes.join(', ');
    }
  }
}

// updatePlanningTasks renders today's Marvin tasks as clickable seed chips.
// Clicking a chip fills the intent field; the coach pipeline is unchanged.
// idle/error/empty render nothing; pending shows a quiet loading line.
function updatePlanningTasks(tasks) {
  const el = document.getElementById('tasksBand');
  if (!el) return;
  if (!tasks || tasks.status === 'idle' || tasks.status === 'error') { el.innerHTML = ''; return; }
  if (tasks.status === 'pending') { el.innerHTML = `<div class="meta">loading tasks…</div>`; return; }
  const list = tasks.tasks || [];
  if (!list.length) { el.innerHTML = ''; return; }
  const chips = list.map((t, i) =>
    `<button type="button" class="task-chip" data-i="${i}">${t.title}</button>`).join('');
  el.innerHTML = `<label>Today</label><div class="tasklist">${chips}</div>`;
  el.querySelectorAll('.task-chip').forEach(btn => {
    btn.onclick = () => {
      const intent = document.getElementById('intent');
      if (intent) { intent.value = list[+btn.dataset.i].title; intent.focus(); }
    };
  });
}

function render(state) {
  setStateAttr(state);
  const rs = state.runtime_state;
  if (rs === 'planning' && renderedState === 'planning') {
    updatePlanningCoach(state.coach);
    updatePlanningTasks(state.tasks);
    return;
  }
  if (rs === 'active' && renderedState === 'active') {
    updateActiveDrift(state);
    return;
  }
  if (countdownTimer) { clearInterval(countdownTimer); countdownTimer = null; }
  renderedState = rs;

  if (rs === 'locked') {
    view.innerHTML = `<div class="band statusband"><span class="pill">Locked</span></div>
      <div class="band">
        <p class="meta">No active commitment.</p>
        <button id="plan" class="btn btn-primary">Start planning</button>
      </div>`;
    document.getElementById('plan').onclick = () => post('/planning');

  } else if (rs === 'planning') {
    view.innerHTML = `<div class="band statusband"><span class="pill">Planning</span></div>
      <div class="band">
        <label>Rough intent</label>
        <input id="intent" placeholder="e.g. work on the quarterly report">
        <button id="sharpen" type="button" class="btn btn-ghost">Sharpen</button>
        <div id="coachStatus" class="meta"></div>
      </div>
      <div class="band" id="tasksBand"></div>
      <div class="band">
        <label>Next action</label><input id="na" placeholder="What exactly will you do?">
        <label>Success condition</label><input id="sc" placeholder="How do you know it's done?">
        <label>Minutes</label><input id="mins" type="number" min="1" value="25">
        <label>Allowed apps (comma-separated window classes)</label>
        <input id="apps" placeholder="e.g. code, firefox">
        <button id="start" class="btn btn-primary" disabled>Start commitment</button>
      </div>`;
    const na = document.getElementById('na'), sc = document.getElementById('sc'),
          mins = document.getElementById('mins'), start = document.getElementById('start');
    const check = () => { start.disabled = !(na.value.trim() && sc.value.trim() && +mins.value > 0); };
    [na, sc, mins].forEach(el => el.oninput = check);
    start.onclick = () => post('/commitment', {
      next_action: na.value.trim(),
      success_condition: sc.value.trim(),
      timebox_secs: Math.round(+mins.value * 60),
      allowed_window_classes: (document.getElementById('apps').value || '')
        .split(',').map(s => s.trim()).filter(Boolean),
    });
    document.getElementById('sharpen').onclick = () => {
      const intent = document.getElementById('intent').value.trim();
      if (intent) post('/coach', { intent });
    };
    updatePlanningCoach(state.coach);
    updatePlanningTasks(state.tasks);

  } else if (rs === 'active') {
    const c = state.commitment || {};
    view.innerHTML = `<div class="band statusband" id="statusband"></div>
      <div class="band"><div class="timer" id="t">--:--</div></div>
      <div class="band">
        <div class="action">${c.next_action || ''}</div>
        <p class="meta">done when: ${c.success_condition || ''}</p>
      </div>
      ${evidenceBlock(state.evidence)}
      <div class="band"><button id="done" class="btn btn-primary">Complete</button></div>`;
    document.getElementById('done').onclick = () => post('/complete');
    const t = document.getElementById('t');
    const tick = () => { t.textContent = fmt((c.deadline_unix_secs || 0) - Date.now() / 1000); };
    tick();
    countdownTimer = setInterval(tick, 250);
    updateActiveDrift(state);

  } else if (rs === 'review') {
    const c = state.commitment || {};
    view.innerHTML = `<div class="band statusband"><span class="pill">Review</span></div>
      <div class="band">
        <div class="action">Session ended</div>
        <p class="meta">${c.next_action || ''}</p>
        <p class="meta">done when: ${c.success_condition || ''}</p>
      </div>
      ${reviewSummary(state.evidence)}
      <div class="band"><button id="end" class="btn btn-primary">End</button></div>`;
    document.getElementById('end').onclick = () => post('/end');

  } else {
    view.textContent = rs;
  }
}

const es = new EventSource('/events');
es.onmessage = (e) => render(JSON.parse(e.data));
es.onerror = () => { view.textContent = 'disconnected — is antidriftd running?'; };