const DEFAULT_PROBE_NAMES = ['Probe 1', 'Probe 2', 'Probe 3', 'Probe 4'];
const PRESETS = [
  { label: 'Brisket', temp: 203 },
  { label: 'Pork Butt', temp: 205 },
  { label: 'Poultry (breast)', temp: 165 },
  { label: 'Poultry (thigh)', temp: 175 },
  { label: 'Ribs', temp: 203 },
];

let activeSession = null;
let viewedSession = null;
let allSessions = [];
let latestReading = null;
let setpoints = [];
let chartInstance = null;
let cardsInitialized = false;
let probeNames = [...DEFAULT_PROBE_NAMES];

async function api(path, options = {}) {
  const resp = await fetch(path, options);
  if (!resp.ok) throw new Error(`${resp.status} ${resp.statusText}`);
  return resp.json();
}

function formatTime(iso) {
  if (!iso) return '--';
  const d = new Date(iso + (iso.endsWith('Z') ? '' : 'Z'));
  return d.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit', second: '2-digit' });
}

function statusClass(connected) {
  return connected ? 'ok' : 'danger';
}

function createProbeCards() {
  const container = document.getElementById('probe-cards');
  container.innerHTML = '';

  for (let i = 0; i < 4; i++) {
    const card = document.createElement('div');
    card.className = 'probe-card';
    card.dataset.probe = i + 1;

    card.innerHTML = `
      <div class="header">
        <span class="name" data-probe="${i + 1}" title="Click to rename">${DEFAULT_PROBE_NAMES[i]}</span>
        <span class="number">#${i + 1}</span>
      </div>
      <div class="target">No target set</div>
      <div class="temp">---</div>
      <div class="footer">
        <span class="status">Disconnected</span>
      </div>
      <div class="setpoint-editor">
        <select class="preset-select" data-probe="${i + 1}">
          <option value="">Preset...</option>
          ${PRESETS.map(p => `<option value="${p.temp}">${p.label}</option>`).join('')}
          <option value="custom">Custom...</option>
        </select>
        <input type="number" class="custom-target" data-probe="${i + 1}" placeholder="Target">
        <input type="text" class="target-label" data-probe="${i + 1}" placeholder="Label">
        <button class="save-setpoint" data-probe="${i + 1}">Save</button>
      </div>
    `;

    container.appendChild(card);
  }

  // Wire up preset selectors and save buttons once.
  document.querySelectorAll('.preset-select').forEach(sel => {
    sel.addEventListener('change', () => {
      const probe = sel.dataset.probe;
      const customInput = document.querySelector(`.custom-target[data-probe="${probe}"]`);
      if (sel.value && sel.value !== 'custom') {
        customInput.value = sel.value;
      }
    });
  });

  document.querySelectorAll('.save-setpoint').forEach(btn => {
    btn.addEventListener('click', async () => {
      const probe = parseInt(btn.dataset.probe, 10);
      const target = parseFloat(document.querySelector(`.custom-target[data-probe="${probe}"]`).value);
      const label = document.querySelector(`.target-label[data-probe="${probe}"]`).value;
      if (isNaN(target)) return;
      await saveSetpoint(probe, label, target);
    });
  });

  // Click the probe name to rename it (writes through to the CYD).
  document.querySelectorAll('.probe-card .name').forEach(el => {
    el.addEventListener('click', () => beginRename(el));
  });

  cardsInitialized = true;
}

async function beginRename(el) {
  if (el.querySelector('input')) return; // already editing
  const probe = parseInt(el.dataset.probe, 10);
  const current = el.textContent;
  el.innerHTML = '';
  const input = document.createElement('input');
  input.type = 'text';
  input.className = 'rename-input';
  input.value = current;
  input.maxLength = 24;
  el.appendChild(input);
  input.focus();
  input.select();

  let done = false;
  const finish = async (commit) => {
    if (done) return;
    done = true;
    const newName = (commit ? input.value.trim() : current) || current;
    el.textContent = newName;
    if (commit && newName !== current) {
      await saveProbeName(probe, newName);
    }
  };
  input.addEventListener('keydown', (e) => {
    if (e.key === 'Enter') { e.preventDefault(); input.blur(); }
    if (e.key === 'Escape') { e.preventDefault(); input.value = current; input.blur(); }
  });
  input.addEventListener('blur', () => finish(true));
}

async function saveProbeName(probeNumber, name) {
  const next = [...probeNames];
  next[probeNumber - 1] = name;
  try {
    const result = await api('/api/probes', {
      method: 'PUT',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ names: next }),
    });
    if (result.names) probeNames = result.names;
    await refreshDashboard(); // pick up the new name in the latest reading
  } catch (e) {
    console.error('Rename failed:', e);
    alert(`Failed to rename probe: ${e.message}`);
  }
}

async function loadProbeNames() {
  try {
    const result = await api('/api/probes');
    if (result.names) probeNames = result.names;
  } catch (e) {
    console.warn('Probe names fetch failed, using defaults:', e);
  }
}

function updateProbeCards(reading, setpoints) {
  const probes = reading?.probes || [];
  const unit = reading?.unit || 'F';

  for (let i = 0; i < 4; i++) {
    const card = document.querySelector(`.probe-card[data-probe="${i + 1}"]`);
    if (!card) continue;

    const probe = probes[i] || { id: i + 1, name: probeNames[i] || DEFAULT_PROBE_NAMES[i], temperature: null, connected: false };
    const setpoint = setpoints.find(s => s.probe_number === (i + 1));

    card.classList.toggle('connected', probe.connected);
    // Don't overwrite the name while the user is editing it.
    const nameEl = card.querySelector('.name');
    if (!nameEl.querySelector('input')) {
      nameEl.textContent = probe.name || probeNames[i] || DEFAULT_PROBE_NAMES[i];
    }

    const targetEl = card.querySelector('.target');
    if (setpoint) {
      const labelText = setpoint.label ? setpoint.label : `Probe ${i + 1}`;
      targetEl.textContent = `${labelText}: ${setpoint.target_temp.toFixed(0)}°${unit}`;
    } else {
      targetEl.textContent = 'No target set';
    }

    const tempEl = card.querySelector('.temp');
    if (probe.connected) {
      tempEl.classList.remove('disconnected');
      tempEl.innerHTML = `${probe.temperature.toFixed(1)}<span>°${unit}</span>`;
    } else {
      tempEl.classList.add('disconnected');
      tempEl.textContent = '---';
    }

    card.querySelector('.status').textContent = probe.connected ? 'Connected' : 'Disconnected';

    // Only update setpoint placeholders, never overwrite values while typing.
    const customInput = card.querySelector('.custom-target');
    const labelInput = card.querySelector('.target-label');
    const presetSelect = card.querySelector('.preset-select');
    if (!customInput.matches(':focus') && !labelInput.matches(':focus')) {
      customInput.placeholder = `Target °${unit}`;
      if (!customInput.value && setpoint) {
        customInput.value = setpoint.target_temp;
      }
      if (!labelInput.value && setpoint) {
        labelInput.value = setpoint.label || '';
      }
      // Update preset option labels with current unit.
      Array.from(presetSelect.options).forEach((opt, idx) => {
        if (idx > 0 && idx <= PRESETS.length) {
          const p = PRESETS[idx - 1];
          opt.textContent = `${p.label} (${p.temp}°${unit})`;
        }
      });
    }
  }
}

async function saveSetpoint(probeNumber, label, targetTemp) {
  if (!viewedSession) return;
  await api(`/api/setpoints/${viewedSession.id}`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ probe_number: probeNumber, label, target_temp: targetTemp }),
  });
  await loadSetpoints();
  // Do not call refreshDashboard here; it would clear the input the user just used.
  // The next periodic poll will pick up the new setpoint from /api/status.
}

function renderStatusBar(reading) {
  const cydEl = document.getElementById('cyd-status');
  const battEl = document.getElementById('battery-status');
  const sigEl = document.getElementById('signal-status');

  if (!reading) {
    cydEl.textContent = 'CYD unreachable';
    cydEl.className = 'danger';
    return;
  }

  const connected = reading.connected;
  cydEl.textContent = connected ? 'CYD connected' : 'CYD: BLE disconnected';
  cydEl.className = connected ? 'ok' : 'warn';

  battEl.textContent = `Battery: ${reading.battery ?? '--'}%`;

  const rssi = reading.rssi;
  sigEl.textContent = rssi !== undefined ? `Signal: ${rssi} dBm` : 'Signal: WiFi only';
}

async function loadSessions() {
  allSessions = await api('/api/sessions');
  activeSession = allSessions.find(s => !s.ended_at) || null;
  // Default the viewed session to the active one, or the most recent past one.
  if (!viewedSession || !allSessions.find(s => s.id === viewedSession.id)) {
    viewedSession = activeSession || allSessions[0] || null;
  }

  const activeEl = document.getElementById('active-session');
  const endBtn = document.getElementById('end-session-btn');

  if (activeSession) {
    activeEl.innerHTML = `
      <strong>${activeSession.name}</strong> started at ${formatTime(activeSession.started_at)}
      <br><small>${activeSession.notes || 'No notes'}</small>
    `;
    endBtn.disabled = false;
  } else {
    activeEl.textContent = 'No active session. Start one above to begin recording.';
    endBtn.disabled = true;
  }

  renderSessionList();
}

function renderSessionList() {
  const listEl = document.getElementById('past-sessions');
  if (!listEl) return;
  const past = allSessions.filter(s => s.ended_at);
  if (past.length === 0) {
    listEl.innerHTML = '<p class="muted">No past sessions yet.</p>';
    return;
  }
  listEl.innerHTML = past.map(s => {
    const isViewed = viewedSession && viewedSession.id === s.id;
    const started = formatTime(s.started_at);
    const ended = formatTime(s.ended_at);
    return `
      <button type="button" class="session-row ${isViewed ? 'viewed' : ''}" data-id="${s.id}">
        <span class="session-name">${escapeHtml(s.name)}</span>
        <span class="session-times">${started} – ${ended}</span>
      </button>
    `;
  }).join('');

  listEl.querySelectorAll('.session-row').forEach(btn => {
    btn.addEventListener('click', () => {
      const id = parseInt(btn.dataset.id, 10);
      viewedSession = allSessions.find(s => s.id === id) || null;
      renderSessionList();
      loadSetpoints();
      refreshChart();
      updateChartHeader();
    });
  });
}

function escapeHtml(s) {
  return String(s).replace(/[&<>"']/g, c => ({
    '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;',
  }[c]));
}

function updateChartHeader() {
  const headerEl = document.getElementById('chart-session-label');
  if (!headerEl) return;
  if (!viewedSession) {
    headerEl.textContent = 'No session';
    return;
  }
  if (activeSession && viewedSession.id === activeSession.id) {
    headerEl.textContent = `Live — ${viewedSession.name}`;
  } else {
    headerEl.textContent = `Viewing past — ${viewedSession.name}`;
  }
}

async function loadSetpoints() {
  if (!viewedSession) {
    setpoints = [];
    updateChartHeader();
    return;
  }
  setpoints = await api(`/api/setpoints/${viewedSession.id}`);
  updateChartHeader();
}

async function refreshDashboard() {
  try {
    const status = await api('/api/status');
    latestReading = status.latest_reading;

    if (!cardsInitialized) {
      createProbeCards();
    }
    updateProbeCards(status.latest_reading, setpoints);

    renderStatusBar(status.latest_reading);
    document.getElementById('last-updated').textContent = `Last updated: ${formatTime(new Date().toISOString())}`;
  } catch (e) {
    console.error('Refresh failed:', e);
    renderStatusBar(null);
  }
}

async function refreshChart() {
  if (!chartInstance) return;
  if (!viewedSession) {
    chartInstance.data.labels = [];
    chartInstance.data.datasets = [];
    chartInstance.update();
    return;
  }
  const range = parseInt(document.getElementById('chart-range').value, 10);
  const data = await api(`/api/readings/${viewedSession.id}?minutes=${range}`);

  const labels = data.map(r => formatTime(r.received_at));
  const datasets = [1, 2, 3, 4].map((num, idx) => ({
    label: probeNames[idx] || (latestReading?.probes?.[idx]?.name) || `Probe ${num}`,
    data: data.map(r => r[`probe${num}_temp`]),
    borderColor: ['#ff6b35', '#4caf50', '#2196f3', '#9c27b0'][idx],
    backgroundColor: ['rgba(255,107,53,0.1)', 'rgba(76,175,80,0.1)', 'rgba(33,150,243,0.1)', 'rgba(156,39,176,0.1)'][idx],
    fill: true,
    tension: 0.3,
    spanGaps: true,
  }));

  chartInstance.data.labels = labels;
  chartInstance.data.datasets = datasets;
  chartInstance.update();
}

function initChart() {
  const ctx = document.getElementById('temp-chart').getContext('2d');
  chartInstance = new Chart(ctx, {
    type: 'line',
    data: { labels: [], datasets: [] },
    options: {
      responsive: true,
      maintainAspectRatio: false,
      scales: {
        y: {
          title: { display: true, text: 'Temperature' },
          grid: { color: '#333' },
          ticks: { color: '#aaa' },
        },
        x: {
          grid: { color: '#333' },
          ticks: { color: '#aaa', maxTicksLimit: 8 },
        },
      },
      plugins: {
        legend: { labels: { color: '#f0f0f0' } },
      },
    },
  });
}

document.getElementById('new-session-form').addEventListener('submit', async (e) => {
  e.preventDefault();
  const name = document.getElementById('session-name').value;
  const notes = document.getElementById('session-notes').value;
  const result = await api('/api/sessions', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ name, notes }),
  });
  document.getElementById('session-name').value = '';
  document.getElementById('session-notes').value = '';
  await loadSessions();
  // Switch the chart to the newly created active session.
  viewedSession = allSessions.find(s => s.id === result.session_id) || activeSession;
  await loadSetpoints();
  await refreshChart();
  renderSessionList();
});

document.getElementById('end-session-btn').addEventListener('click', async () => {
  if (!activeSession) return;
  await api(`/api/sessions/${activeSession.id}`, {
    method: 'PUT',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ end: true }),
  });
  await loadSessions();
  // If we were viewing the just-ended session, keep viewing it (now a past session).
  await loadSetpoints();
  await refreshChart();
});

document.getElementById('refresh-chart-btn').addEventListener('click', refreshChart);
document.getElementById('chart-range').addEventListener('change', refreshChart);

async function init() {
  initChart();
  await loadProbeNames();
  await loadSessions();
  await loadSetpoints();
  // First call creates the cards; subsequent calls only update values.
  await refreshDashboard();
  await refreshChart();

  setInterval(refreshDashboard, 5000);
  setInterval(() => { if (viewedSession) refreshChart(); }, 30000);
}

init();