// =============================================================================
// SLA Calculator - Script
// All business rules loaded from config.json. Zero hard-coded logic.
// =============================================================================

let CONFIG = null;

// ── API fetch helper ──────────────────────────────────────────────────────────
// Automatically includes the in-memory access token as a Bearer header.
// On 401, attempts one silent token refresh before giving up.
async function apiFetch(path, options = {}) {
  const url = `/loreal-sla-calculator/api${path}`;
  const headers = { ...(options.headers || {}) };
  if (currentAccessToken) headers['Authorization'] = `Bearer ${currentAccessToken}`;

  let res = await fetch(url, { ...options, credentials: 'include', headers });

  if (res.status === 401) {
    // Try to refresh and retry once
    const refreshed = await tryRefresh();
    if (refreshed && currentAccessToken) {
      headers['Authorization'] = `Bearer ${currentAccessToken}`;
      res = await fetch(url, { ...options, credentials: 'include', headers });
    }
  }
  return res;
}
let currentStep = 1;
let activeStages = [false, false, false, false, false, false, false, false];
let lastCalculationData = null;

// ---- Usage Tracking ----
const TRACK_API = (() => {
  if (location.hostname === 'localhost' || location.hostname === '127.0.0.1') return null;
  const base = location.pathname.replace(/\/[^/]*$/, '');
  return `${base}/api/events`;
})();

async function getVisitorId() {
  const raw = [
    navigator.language,
    screen.width + 'x' + screen.height,
    screen.colorDepth,
    Intl.DateTimeFormat().resolvedOptions().timeZone,
    navigator.hardwareConcurrency || '',
  ].join('|');
  const buf = await crypto.subtle.digest('SHA-256', new TextEncoder().encode(raw));
  return Array.from(new Uint8Array(buf)).map(b => b.toString(16).padStart(2, '0')).join('');
}

function trackEvent(event, metadata = {}) {
  if (!TRACK_API) return;
  getVisitorId().then(visitor_id => {
    fetch(TRACK_API, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ event, page: 'calculator', visitor_id, metadata }),
    }).catch(() => {});
  });
}

// ---- Bootstrap ----
document.addEventListener('DOMContentLoaded', async () => {
  await initAuth();
  await loadConfig();
  initDarkMode();
  initStepper();
  initDatePickers();
  bindEvents();
  trackEvent('page_view');
});

async function loadConfig() {
  try {
    const res = await fetch('config.json?v=2026050801');
    CONFIG = await res.json();
    populateBriefTypes();
    populateStageDropdowns();
  } catch (e) {
    console.error('Failed to load config.json:', e);
    alert('Error loading configuration. Please ensure config.json is in the same directory.');
  }
}

// ---- Populate Dropdowns from Config ----
function populateBriefTypes() {
  const sel = document.getElementById('briefType');
  CONFIG.briefTypes.forEach(bt => {
    const opt = document.createElement('option');
    opt.value = bt.id;
    opt.textContent = bt.label;
    sel.appendChild(opt);
  });
}

function populateStageDropdowns() {
  const cfg = CONFIG.stageConfigs;

  // Stage 1 complexity
  populateSelect('stage1Complexity', cfg.stage1.fields.complexity.options, 'value', 'label');

  // Stage 2
  populateSelect('stage2MasteringComplexity', cfg.stage2.fields.masteringComplexity.options, 'value', 'label');
  populateSelect('stage2CopyComplexity', cfg.stage2.fields.copyComplexity.options, 'value', 'label');

  // Stage 4/5 word count
  populateSelect('stage45WordCount', cfg.stage4_5.fields.wordCount.options, 'value', 'label');

  // Stage 6
  populateSelect('stage6Complexity', cfg.stage6.fields.complexity.options, 'value', 'label');
  populateSelect('stage6AssetVolume', cfg.stage6.fields.assetVolume.options, 'value', 'label');

  // Stage 8
  populateSelect('stage8SyndicationType', cfg.stage8.fields.syndicationType.options, 'value', 'label');
  document.getElementById('stage8SyndicationType').value = cfg.stage8.fields.syndicationType.default;
}

function populateSelect(id, options, valueKey, labelKey) {
  const sel = document.getElementById(id);
  if (!sel) return;
  sel.innerHTML = '';
  options.forEach(opt => {
    const o = document.createElement('option');
    o.value = opt[valueKey];
    o.textContent = opt[labelKey];
    sel.appendChild(o);
  });
}

// ---- Dark Mode ----
function initDarkMode() {
  const saved = localStorage.getItem('sla-dark-mode');
  if (saved === 'true' || (!saved && window.matchMedia('(prefers-color-scheme: dark)').matches)) {
    document.documentElement.classList.add('dark');
  }
  document.getElementById('darkModeToggle').addEventListener('click', () => {
    document.documentElement.classList.toggle('dark');
    localStorage.setItem('sla-dark-mode', document.documentElement.classList.contains('dark'));
  });
}

// ---- Stepper ----
function initStepper() {
  document.querySelectorAll('.step-item').forEach(item => {
    item.addEventListener('click', () => {
      const step = parseInt(item.dataset.step);
      if (step <= currentStep || canAdvanceTo(step)) {
        goToStep(step);
      }
    });
  });
}

function canAdvanceTo(step) {
  if (step >= 2 && !document.getElementById('briefType').value) return false;
  if (step >= 4 && !document.getElementById('kickOffDate').value) return false;
  return true;
}

function goToStep(step) {
  if (step > currentStep + 1) return;

  // Validation gates
  if (step >= 2 && !document.getElementById('briefType').value) return;
  if (step >= 4 && !document.getElementById('kickOffDate').value) {
    alert('Please enter the Project Kick-Off Date before proceeding.');
    return;
  }

  currentStep = step;

  // Show/hide step content
  document.querySelectorAll('.step-content').forEach(s => s.classList.add('hidden'));
  const target = document.getElementById('step' + step);
  if (target) {
    target.classList.remove('hidden');
    target.classList.add('fade-in');
  }

  // Update stepper UI
  document.querySelectorAll('.step-item').forEach(item => {
    const s = parseInt(item.dataset.step);
    const num = item.querySelector('.step-number');
    if (s < step || (s === step && step === 4)) {
      num.className = 'step-number flex items-center justify-center w-8 h-8 rounded-full bg-green-500 text-white text-sm font-semibold shrink-0';
      num.innerHTML = '<svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="3" d="M5 13l4 4L19 7"/></svg>';
    } else if (s === step) {
      num.className = 'step-number flex items-center justify-center w-8 h-8 rounded-full bg-brand-600 text-white text-sm font-semibold shrink-0';
      num.textContent = s;
    } else {
      num.className = 'step-number flex items-center justify-center w-8 h-8 rounded-full bg-gray-300 dark:bg-gray-600 text-gray-600 dark:text-gray-300 text-sm font-semibold shrink-0';
      num.textContent = s;
    }
  });

  // Run calculation when entering step 4
  if (step === 4) {
    calculateSLA();
  }

  window.scrollTo({ top: 0, behavior: 'smooth' });
}

// ---- Date Pickers ----
function initDatePickers() {
  const fpConfig = {
    dateFormat: 'Y-m-d',
    altInput: true,
    altFormat: 'd M Y',
    disableMobile: true,
    minDate: 'today',
    disable: [
      function(date) {
        // Disable weekends (Sat=6, Sun=0)
        return date.getDay() === 0 || date.getDay() === 6;
      }
    ]
  };
  flatpickr('#kickOffDate', { ...fpConfig, onChange: () => validateStep3() });
  flatpickr('#goLiveDate', { ...fpConfig, onChange: () => validateStep3() });
}

function validateStep3() {
  const kick = document.getElementById('kickOffDate').value;
  const btn = document.getElementById('btnStep3Next');
  btn.disabled = !kick;
}

// ---- Event Bindings ----
function bindEvents() {
  // Brief type change
  document.getElementById('briefType').addEventListener('change', onBriefTypeChange);

  // Stage toggles
  document.querySelectorAll('.stage-toggle').forEach(toggle => {
    toggle.addEventListener('change', onStageToggle);
  });

  // Production complexity/volume change -> update base days and opera days
  const stage6Inputs = ['stage6Complexity', 'stage6AssetVolume'];
  stage6Inputs.forEach(id => {
    document.getElementById(id).addEventListener('change', () => {
      updateProductionBaseDays();
      updateOperaDays();
    });
  });

  // Syndication type change -> update base days
  document.getElementById('stage8SyndicationType').addEventListener('change', updateSyndicationBaseDays);
}

// ---- Brief Type Change ----
function onBriefTypeChange() {
  const briefId = document.getElementById('briefType').value;
  if (!briefId) {
    document.getElementById('projectTypeDisplay').textContent = 'Select a Brief Type first';
    document.getElementById('briefDescription').classList.add('hidden');
    document.getElementById('stageMatrixPreview').classList.add('hidden');
    document.getElementById('btnStep1Next').disabled = true;
    return;
  }

  const bt = CONFIG.briefTypes.find(b => b.id === briefId);
  document.getElementById('projectTypeDisplay').textContent = bt.projectType;
  document.getElementById('projectTypeDisplay').classList.remove('text-gray-500');
  document.getElementById('projectTypeDisplay').classList.add('font-semibold');

  // Description
  const descEl = document.getElementById('briefDescription');
  if (Array.isArray(bt.description)) {
    descEl.innerHTML = '<ul class="list-disc list-inside space-y-1">' +
      bt.description.map(item => `<li>${item}</li>`).join('') + '</ul>';
  } else {
    descEl.textContent = bt.description;
  }
  descEl.classList.remove('hidden');

  // Stage matrix
  const matrix = CONFIG.stageMatrix[briefId];
  activeStages = [...matrix];

  // Force always-active stages (e.g. Opera Upload)
  CONFIG.stages.forEach((stage, i) => {
    const cfg = CONFIG.stageConfigs['stage' + stage.number];
    if (cfg && cfg.alwaysActive) activeStages[i] = true;
  });

  renderStageMatrixBadges(activeStages);
  document.getElementById('stageMatrixPreview').classList.remove('hidden');
  document.getElementById('btnStep1Next').disabled = false;

  // Update stage cards visibility and toggles
  updateStageCards();
  updateProductionBaseDays();
  updateOperaDays();
  updateSyndicationBaseDays();
}

function renderStageMatrixBadges(matrix) {
  const container = document.getElementById('stageMatrixBadges');
  container.innerHTML = '';
  CONFIG.stages.forEach((stage, i) => {
    const active = matrix[i];
    const cfg = CONFIG.stageConfigs['stage' + stage.number];
    const locked = cfg && cfg.alwaysActive;
    const badge = document.createElement('div');
    badge.className = `flex items-center gap-2 px-3 py-2 rounded-lg text-xs font-medium select-none transition-colors ${
      locked ? 'cursor-default' : 'cursor-pointer'
    } ${
      active
        ? 'bg-green-50 dark:bg-green-900/20 text-green-700 dark:text-green-400 border border-green-200 dark:border-green-800 hover:bg-green-100 dark:hover:bg-green-900/40'
        : 'bg-gray-50 dark:bg-gray-700/50 text-gray-400 dark:text-gray-500 border border-gray-200 dark:border-gray-600 hover:bg-gray-100 dark:hover:bg-gray-600/50'
    }`;
    badge.innerHTML = `
      <span class="w-5 h-5 flex items-center justify-center rounded-full text-[10px] font-bold ${
        active ? 'bg-green-500 text-white' : 'bg-gray-300 dark:bg-gray-600 text-gray-500 dark:text-gray-400'
      }">${active ? 'Y' : 'N'}</span>
      ${stage.shortLabel}${locked ? ' <span class="text-[9px] opacity-60">(Required)</span>' : ''}
    `;
    if (!locked) {
      badge.addEventListener('click', () => {
        // Stages 4 & 5 (Translation) toggle together
        if (i === 3 || i === 4) {
          activeStages[3] = !activeStages[3];
          activeStages[4] = activeStages[3];
        } else {
          activeStages[i] = !activeStages[i];
        }
        renderStageMatrixBadges(activeStages);
        updateStageCards();
        updateProductionBaseDays();
        updateOperaDays();
        updateSyndicationBaseDays();
      });
    }
    container.appendChild(badge);
  });
}

// ---- Stage Cards ----
function updateStageCards() {
  const cardMap = {
    0: 'stage1Card',
    1: 'stage2Card',
    2: 'stage3Card',
    3: 'stage45Card', // stage 4
    4: 'stage45Card', // stage 5 (same card)
    5: 'stage6Card',
    6: 'stage7Card',
    7: 'stage8Card'
  };

  // Show/hide and set toggles
  const shownCards = new Set();
  for (let i = 0; i < 8; i++) {
    const cardId = cardMap[i];
    if (shownCards.has(cardId)) continue;
    shownCards.add(cardId);

    const card = document.getElementById(cardId);
    if (!card) continue;

    // Determine if this card's stages are active
    let isActive;
    if (cardId === 'stage45Card') {
      isActive = activeStages[3] || activeStages[4];
    } else {
      isActive = activeStages[i];
    }

    card.classList.remove('hidden');

    // Check if this stage is always-active (locked)
    const stageNum = CONFIG.stages[i] ? CONFIG.stages[i].number : null;
    const stageCfg = stageNum ? CONFIG.stageConfigs['stage' + stageNum] : null;
    const locked = stageCfg && stageCfg.alwaysActive;

    // Set toggle
    const toggle = card.querySelector('.stage-toggle');
    if (toggle) {
      toggle.checked = isActive;
      // Disable toggle for always-active stages
      if (locked) {
        toggle.disabled = true;
        toggle.closest('label').classList.add('opacity-50', 'cursor-not-allowed');
        toggle.closest('label').classList.remove('cursor-pointer');
      }
      // Update card appearance
      const fields = card.querySelector('.stage-fields');
      if (fields) {
        if (isActive) {
          card.classList.remove('inactive');
          fields.style.display = '';
        } else {
          card.classList.add('inactive');
          fields.style.display = 'none';
        }
      }
    }
  }
}

function onStageToggle(e) {
  const stageKey = e.target.dataset.stage;
  const checked = e.target.checked;

  // Prevent disabling always-active stages
  if (!checked) {
    const idx = parseInt(stageKey);
    const stageNum = CONFIG.stages[idx] ? CONFIG.stages[idx].number : null;
    const cfg = stageNum ? CONFIG.stageConfigs['stage' + stageNum] : null;
    if (cfg && cfg.alwaysActive) {
      e.target.checked = true;
      return;
    }
  }

  if (stageKey === '3_4') {
    // Translation stages 4 and 5
    activeStages[3] = checked;
    activeStages[4] = checked;
  } else {
    const idx = parseInt(stageKey);
    activeStages[idx] = checked;
  }

  // Update card appearance
  const card = e.target.closest('.stage-card');
  const fields = card.querySelector('.stage-fields');
  if (fields) {
    if (checked) {
      card.classList.remove('inactive');
      fields.style.display = '';
    } else {
      card.classList.add('inactive');
      fields.style.display = 'none';
    }
  }

  // Update badges
  renderStageMatrixBadges(activeStages);
}

// ---- Dynamic Lookups ----
function updateProductionBaseDays() {
  const complexity = document.getElementById('stage6Complexity').value;
  const volume = document.getElementById('stage6AssetVolume').value;
  const key = complexity + '_' + volume;
  const table = CONFIG.stageConfigs.stage6.fields.crossReferenceTable;
  const days = table[key];
  document.getElementById('stage6BaseDays').textContent = days !== undefined ? days + ' days' : '--';
}

function updateOperaDays() {
  const volume = document.getElementById('stage6AssetVolume').value;
  const daysMap = CONFIG.stageConfigs.stage7.daysByAssetVolume;
  const days = daysMap[volume] || CONFIG.stageConfigs.stage7.defaultDays;
  document.getElementById('stage7Days').textContent = days + ' day' + (days > 1 ? 's' : '');
}

function updateSyndicationBaseDays() {
  const value = document.getElementById('stage8SyndicationType').value;
  const opt = CONFIG.stageConfigs.stage8.fields.syndicationType.options.find(o => o.value === value);
  const days = opt ? opt.days : undefined;
  document.getElementById('stage8BaseDays').textContent = days !== undefined ? days + ' days' : '--';
}

// ---- Business Day Arithmetic ----
function addBusinessDays(startDate, days) {
  const result = new Date(startDate);
  let added = 0;
  while (added < days) {
    result.setDate(result.getDate() + 1);
    const dow = result.getDay();
    if (dow !== 0 && dow !== 6) {
      added++;
    }
  }
  return result;
}

function businessDaysBetween(start, end) {
  let count = 0;
  const d = new Date(start);
  while (d < end) {
    d.setDate(d.getDate() + 1);
    const dow = d.getDay();
    if (dow !== 0 && dow !== 6) count++;
  }
  return count;
}

function formatDate(date) {
  if (!date) return 'n.a.';
  const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
  return date.getDate().toString().padStart(2, '0') + '-' + months[date.getMonth()];
}

function formatDateLong(date) {
  if (!date) return '--';
  const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
  return date.getDate() + ' ' + months[date.getMonth()] + ' ' + date.getFullYear();
}

// ---- SLA Calculation Engine ----
function calculateSLA() {
  const kickOffStr = document.getElementById('kickOffDate').value;
  const goLiveStr = document.getElementById('goLiveDate').value;
  const briefName = document.getElementById('briefName').value || 'Unnamed Brief';

  if (!kickOffStr) return;

  const kickOff = new Date(kickOffStr + 'T00:00:00');
  const goLive = goLiveStr ? new Date(goLiveStr + 'T00:00:00') : null;
  const cfg = CONFIG.stageConfigs;
  const results = [];
  let currentDate = new Date(kickOff);

  // Stage 1: Missing DMI Asset Creation
  results.push(calcGenericStage(0, activeStages[0], currentDate, () => {
    const complexity = document.getElementById('stage1Complexity').value;
    const opt = cfg.stage1.fields.complexity.options.find(o => o.value === complexity);
    const wip = opt ? opt.days : 0;
    const feedback = intVal('stage1MarketApproval');
    const rounds = intVal('stage1RevisionRounds');
    const revDays = intVal('stage1RevisionDays');
    return { handover: 0, wip, feedback, revisions: rounds * revDays, rounds };
  }));
  currentDate = results[0].completeDate;

  // Stage 2: Mastering, Copy Creation / Extraction
  results.push(calcGenericStage(1, activeStages[1], currentDate, () => {
    const masterOpt = cfg.stage2.fields.masteringComplexity.options.find(o => o.value === document.getElementById('stage2MasteringComplexity').value);
    const copyOpt = cfg.stage2.fields.copyComplexity.options.find(o => o.value === document.getElementById('stage2CopyComplexity').value);
    const masterDays = masterOpt ? masterOpt.days : 0;
    const copyDays = copyOpt ? copyOpt.days : 0;
    const wip = masterDays + copyDays;
    return { handover: 0, wip, feedback: 0, revisions: 0, rounds: 0 };
  }));
  currentDate = results[1].completeDate;

  // Stage 3: Global Rollout Invitation
  results.push(calcGenericStage(2, activeStages[2], currentDate, () => {
    const wip = intVal('stage3RolloutDays');
    return { handover: 0, wip, feedback: 0, revisions: 0, rounds: 0, noFeedback: true };
  }));
  currentDate = results[2].completeDate;

  // Stages 4 & 5: Translation (run in parallel, so counted once)
  const translationActive = activeStages[3] || activeStages[4];
  const translationResult = calcGenericStage(3, translationActive, currentDate, () => {
    const wcOpt = cfg.stage4_5.fields.wordCount.options.find(o => o.value === document.getElementById('stage45WordCount').value);
    const wip = wcOpt ? wcOpt.days : 0;
    const feedback = intVal('stage45MarketApproval');
    const rounds = intVal('stage45RevisionRounds');
    const revDays = intVal('stage45RevisionDays');
    return { handover: 0, wip, feedback, revisions: rounds * revDays, rounds };
  });
  // Stage 4 result
  results.push({
    ...translationResult,
    stageIndex: 3,
    label: CONFIG.stages[3].label
  });
  // Stage 5 result (same dates since parallel)
  results.push({
    ...translationResult,
    stageIndex: 4,
    label: CONFIG.stages[4].label,
    active: activeStages[4]
  });
  currentDate = translationResult.completeDate;

  // Stage 6: Production
  results.push(calcGenericStage(5, activeStages[5], currentDate, () => {
    const complexity = document.getElementById('stage6Complexity').value;
    const volume = document.getElementById('stage6AssetVolume').value;
    const key = complexity + '_' + volume;
    const table = cfg.stage6.fields.crossReferenceTable;
    let wip = table[key] || 0;

    // Apply speed-up
    const speedUp = intVal('stage6SpeedUp');
    if (speedUp > 0) {
      wip = Math.ceil(wip * (1 - speedUp / 100));
    }

    const feedback = intVal('stage6MarketApproval');
    const rounds = intVal('stage6RevisionRounds');
    const revDays = intVal('stage6RevisionDays');
    return { handover: 0, wip, feedback, revisions: rounds * revDays, rounds };
  }));
  currentDate = results[5].completeDate;

  // Stage 7: Opera Upload
  results.push(calcGenericStage(6, activeStages[6], currentDate, () => {
    const volume = document.getElementById('stage6AssetVolume').value;
    const daysMap = cfg.stage7.daysByAssetVolume;
    const wip = daysMap[volume] || cfg.stage7.defaultDays;
    return { handover: 0, wip, feedback: 0, revisions: 0, rounds: 0, noFeedback: true };
  }));
  currentDate = results[6].completeDate;

  // Stage 8: Syndication
  results.push(calcGenericStage(7, activeStages[7], currentDate, () => {
    const value = document.getElementById('stage8SyndicationType').value;
    const opt = cfg.stage8.fields.syndicationType.options.find(o => o.value === value);
    const wip = opt ? opt.days : 0;
    return { handover: 0, wip, feedback: 0, revisions: 0, rounds: 0, noFeedback: true };
  }));

  const projectEndDate = results[7].completeDate;

  // Suggested go-live: add syndication buffer if syndication is active
  let suggestedGoLive = new Date(projectEndDate);
  if (activeStages[7]) {
    suggestedGoLive = addBusinessDays(projectEndDate, CONFIG.meta.syndicationBufferDays);
  }

  // Verdict: compare against suggestedGoLive (includes syndication buffer)
  // so that retailer lead times are factored into the Y/N decision
  const canMeet = goLive ? suggestedGoLive <= goLive : null;

  renderResults({
    briefName,
    kickOff,
    goLive,
    projectEndDate,
    suggestedGoLive,
    canMeet,
    stages: results
  });
}

function calcGenericStage(stageIndex, isActive, prevDate, getParams) {
  const stage = CONFIG.stages[stageIndex];
  if (!isActive) {
    return {
      stageIndex,
      label: stage.label,
      active: false,
      handover: 0,
      wip: 0,
      feedback: 0,
      revisions: 0,
      rounds: 0,
      noFeedback: false,
      completeDate: new Date(prevDate),
      kickOffDate: null,
      wipCompleteDate: null,
      feedbackByDate: null
    };
  }

  const params = getParams();
  const totalDays = params.handover + params.wip + params.feedback + params.revisions;

  const kickOffDate = addBusinessDays(prevDate, 0); // Next business day check not needed; start from prev
  // Actually kickoff is the day after previous stage completes
  const stageKickOff = addBusinessDays(prevDate, params.handover);
  const wipComplete = addBusinessDays(stageKickOff, params.wip);
  const feedbackBy = params.feedback > 0 ? addBusinessDays(wipComplete, params.feedback) : null;
  const completeDate = addBusinessDays(prevDate, totalDays);

  // Build sub-phase array for Gantt detail view
  const phases = [];
  if (params.handover > 0) {
    phases.push({ label: 'Handover', type: 'handover', start: new Date(prevDate), end: new Date(stageKickOff) });
  }
  if (params.wip > 0) {
    phases.push({ label: 'WIP 1', type: 'wip', start: new Date(stageKickOff), end: new Date(wipComplete) });
  }
  if (!params.noFeedback && params.rounds > 0) {
    const revDaysPerRound = params.revisions / params.rounds;
    let cursor = new Date(wipComplete);
    // First feedback period
    phases.push({ label: 'Feedback 1', type: 'feedback', start: new Date(cursor), end: new Date(feedbackBy) });
    cursor = new Date(feedbackBy);
    // Each revision round (WIP 2, WIP 3, ...)
    for (let r = 1; r <= params.rounds; r++) {
      const revEnd = addBusinessDays(cursor, revDaysPerRound);
      phases.push({ label: `WIP ${r + 1}`, type: 'revision', start: new Date(cursor), end: revEnd });
      cursor = revEnd;
    }
  } else if (!params.noFeedback && params.feedback > 0) {
    phases.push({ label: 'Feedback', type: 'feedback', start: new Date(wipComplete), end: new Date(completeDate) });
  }

  return {
    stageIndex,
    label: stage.label,
    active: true,
    handover: params.handover,
    wip: params.wip,
    feedback: params.feedback,
    revisions: params.revisions,
    rounds: params.rounds || 0,
    noFeedback: params.noFeedback || false,
    completeDate,
    kickOffDate: stageKickOff,
    wipCompleteDate: wipComplete,
    feedbackByDate: feedbackBy,
    phases
  };
}

function intVal(id) {
  const el = document.getElementById(id);
  return el ? parseFloat(el.value) || 0 : 0;
}

// ---- Render Results ----
function renderResults(data) {
  lastCalculationData = data;
  const briefType = document.getElementById('briefType').selectedOptions[0]?.text;
  trackEvent('show_results', { briefType });

  // Verdict banner
  const banner = document.getElementById('verdictBanner');
  const badge = document.getElementById('verdictBadge');
  const msg = document.getElementById('verdictMessage');
  document.getElementById('verdictBriefName').textContent = data.briefName;

  const roundel = 'w-20 h-20 sm:w-24 sm:h-24 rounded-full flex items-center justify-center flex-shrink-0 shadow-lg';
  const icon = 'w-10 h-10 sm:w-12 sm:h-12';

  if (data.canMeet === null) {
    banner.className = 'rounded-xl shadow-sm border p-6 mb-4 bg-gray-100 dark:bg-gray-800 border-gray-300 dark:border-gray-600';
    badge.className = `${roundel} bg-gray-300 dark:bg-gray-600`;
    badge.innerHTML = `<span class="text-3xl sm:text-4xl font-black text-white">?</span>`;
    msg.textContent = 'Enter a Go-Live Date to see the verdict.';
  } else if (data.canMeet) {
    banner.className = 'rounded-xl shadow-sm border p-6 mb-4 bg-green-50 dark:bg-green-900/20 border-green-300 dark:border-green-800';
    badge.className = `${roundel} bg-green-500 dark:bg-green-600`;
    badge.innerHTML = `<svg class="${icon}" fill="none" stroke="white" stroke-width="3" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7"/></svg>`;
    msg.textContent = CONFIG.verdictMessages.canMeet;
  } else {
    banner.className = 'rounded-xl shadow-sm border p-6 mb-4 bg-red-50 dark:bg-red-900/20 border-red-300 dark:border-red-800';
    badge.className = `${roundel} bg-red-500 dark:bg-red-600`;
    badge.innerHTML = `<svg class="${icon}" fill="none" stroke="white" stroke-width="3" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12"/></svg>`;
    const gap = businessDaysBetween(data.goLive, data.suggestedGoLive);
    const prodGap = businessDaysBetween(data.goLive, data.projectEndDate);
    if (prodGap > 0) {
      msg.textContent = CONFIG.verdictMessages.cannotMeet + ` (${gap} business day${gap !== 1 ? 's' : ''} over deadline)`;
    } else {
      msg.textContent = CONFIG.verdictMessages.cannotMeet + ` (production completes in time, but ${gap} business day${gap !== 1 ? 's' : ''} short for syndication retailer lead times)`;
    }
  }

  // Key dates
  document.getElementById('resultKickOff').textContent = formatDateLong(data.kickOff);
  document.getElementById('resultGoLive').textContent = data.goLive ? formatDateLong(data.goLive) : 'Not set';
  document.getElementById('resultEndDate').textContent = formatDateLong(data.projectEndDate);
  document.getElementById('resultSuggestedGoLive').textContent = formatDateLong(data.suggestedGoLive);

  // PM instruction
  const pmEl = document.getElementById('pmInstruction');
  if (data.canMeet === null) {
    pmEl.textContent = 'Enter a Required Go-Live Date to see the full verdict and PM instructions.';
  } else {
    pmEl.textContent = data.canMeet ? CONFIG.pmInstructions.canMeet : CONFIG.pmInstructions.cannotMeet;
  }

  // Calculation table
  const calcBody = document.getElementById('calculationTable');
  calcBody.innerHTML = '';
  data.stages.forEach(s => {
    const tr = document.createElement('tr');
    tr.className = 'border-b border-gray-100 dark:border-gray-700/50' + (!s.active ? ' text-gray-400 dark:text-gray-500' : '');
    tr.innerHTML = `
      <td class="py-2 pr-3 text-xs sm:text-sm">${s.label}</td>
      <td class="py-2 px-2 text-center"><span class="inline-flex items-center justify-center w-6 h-6 rounded-full text-xs font-bold ${s.active ? 'bg-green-100 dark:bg-green-900/30 text-green-700 dark:text-green-400' : 'bg-gray-100 dark:bg-gray-700 text-gray-400'}">${s.active ? 'Y' : 'N'}</span></td>

      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? s.wip : 0}</td>
      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? (s.noFeedback ? 'n/r' : s.feedback) : 0}</td>
      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? (s.noFeedback ? 'n/r' : s.revisions) : 0}</td>
      <td class="py-2 pl-2 text-center text-xs sm:text-sm font-medium">${formatDate(s.completeDate)}</td>
    `;
    calcBody.appendChild(tr);
  });

  // Key dates table
  const datesBody = document.getElementById('keyDatesTable');
  datesBody.innerHTML = '';
  data.stages.forEach(s => {
    const tr = document.createElement('tr');
    tr.className = 'border-b border-gray-100 dark:border-gray-700/50' + (!s.active ? ' text-gray-400 dark:text-gray-500' : '');
    tr.innerHTML = `
      <td class="py-2 pr-3 text-xs sm:text-sm">${s.label}</td>
      <td class="py-2 px-2 text-center"><span class="inline-flex items-center justify-center w-6 h-6 rounded-full text-xs font-bold ${s.active ? 'bg-green-100 dark:bg-green-900/30 text-green-700 dark:text-green-400' : 'bg-gray-100 dark:bg-gray-700 text-gray-400'}">${s.active ? 'Y' : 'N'}</span></td>
      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? formatDate(s.kickOffDate) : 'n.a.'}</td>
      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? (s.noFeedback ? 'n/r' : formatDate(s.wipCompleteDate)) : 'n.a.'}</td>
      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? (s.noFeedback ? 'n/r' : (s.feedbackByDate ? formatDate(s.feedbackByDate) : formatDate(s.wipCompleteDate))) : 'n.a.'}</td>
      <td class="py-2 px-2 text-center text-xs sm:text-sm">${s.active ? (s.noFeedback ? 'n/r' : s.rounds) : 'n.a.'}</td>
      <td class="py-2 pl-2 text-center text-xs sm:text-sm font-medium">${s.active ? formatDate(s.completeDate) : 'n.a.'}</td>
    `;
    datesBody.appendChild(tr);
  });
}

// ---- View Toggle (List / Gantt) ----
function setView(view) {
  const listView = document.getElementById('listView');
  const ganttView = document.getElementById('ganttView');
  const btnList = document.getElementById('btnViewList');
  const btnGantt = document.getElementById('btnViewGantt');

  const activeClass = 'px-4 py-2 rounded-md font-medium text-sm transition-colors bg-white dark:bg-gray-800 text-gray-900 dark:text-white shadow-sm';
  const inactiveClass = 'px-4 py-2 rounded-md font-medium text-sm transition-colors text-gray-500 dark:text-gray-400 hover:text-gray-700 dark:hover:text-gray-200';

  if (view === 'gantt') {
    listView.classList.add('hidden');
    ganttView.classList.remove('hidden');
    btnGantt.className = activeClass;
    btnList.className = inactiveClass;
    renderGantt();
  } else {
    listView.classList.remove('hidden');
    ganttView.classList.add('hidden');
    btnList.className = activeClass;
    btnGantt.className = inactiveClass;
  }
}

function renderGantt() {
  if (!lastCalculationData) return;
  const data = lastCalculationData;
  const container = document.getElementById('ganttChart');

  // Filter active stages
  const activeStgs = data.stages.filter(s => s.active);
  if (activeStgs.length === 0) {
    container.innerHTML = '<p class="text-gray-500 text-sm">No active stages to display.</p>';
    return;
  }

  // ── Day-grid setup ──────────────────────────────────────────────────────────
  const DAY_W = 28; // px per calendar day
  const LABEL_W = 192; // px for left stage-label column

  const minDate = data.kickOff;
  const maxDate = data.suggestedGoLive > data.projectEndDate ? data.suggestedGoLive : data.projectEndDate;

  // Snap grid start to the Sunday of the kick-off week
  const gridStart = new Date(minDate);
  gridStart.setHours(0, 0, 0, 0);
  gridStart.setDate(gridStart.getDate() - gridStart.getDay());

  // Pad end by one full week
  const gridEnd = new Date(maxDate);
  gridEnd.setHours(0, 0, 0, 0);
  gridEnd.setDate(gridEnd.getDate() + 7);

  // All calendar days in range
  const days = [];
  const cur = new Date(gridStart);
  while (cur <= gridEnd) {
    days.push(new Date(cur));
    cur.setDate(cur.getDate() + 1);
  }
  const timelineWidth = days.length * DAY_W;

  // Day-index from gridStart (0-based)
  const toDayIdx = (date) => {
    const d = new Date(date);
    d.setHours(0, 0, 0, 0);
    return Math.max(0, Math.round((d - gridStart) / 86400000));
  };

  // ── Phase colours ───────────────────────────────────────────────────────────
  const phaseColors = {
    wip:      'bg-violet-600 dark:bg-violet-700',
    revision: 'bg-violet-400 dark:bg-violet-500',
    feedback: 'bg-amber-400 dark:bg-amber-500',
  };

  // ── Header rows ─────────────────────────────────────────────────────────────
  const MONTHS = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];
  const DAY_LETTERS = ['S','M','T','W','T','F','S']; // Sun=0

  // Row 1: week-start date labels (every 7 days)
  let weekRow = '';
  for (let i = 0; i < days.length; i += 7) {
    const day = days[i];
    weekRow += `<div class="absolute border-l border-gray-200 dark:border-gray-600 text-[10px] font-semibold text-gray-500 dark:text-gray-400 pl-1 truncate leading-4" style="left:${i * DAY_W}px;width:${7 * DAY_W}px">${day.getDate()} ${MONTHS[day.getMonth()]}</div>`;
  }

  // Row 2: individual day letters + weekend band collector
  let dayRow = '';
  let weekendBands = '';
  days.forEach((day, i) => {
    const isWeekend = day.getDay() === 0 || day.getDay() === 6;
    const letter = DAY_LETTERS[day.getDay()];
    const textCls = isWeekend
      ? 'text-gray-300 dark:text-gray-600 font-medium'
      : 'text-gray-400 dark:text-gray-500 font-medium';
    dayRow += `<div class="absolute border-l border-gray-100 dark:border-gray-700/60 text-[9px] text-center leading-4 ${textCls}" style="left:${i * DAY_W}px;width:${DAY_W}px">${letter}</div>`;
    if (isWeekend) {
      weekendBands += `<div class="absolute top-0 bottom-0 bg-gray-50 dark:bg-gray-800/40 pointer-events-none" style="left:${i * DAY_W}px;width:${DAY_W}px"></div>`;
    }
  });

  // ── Stage rows ──────────────────────────────────────────────────────────────
  let rows = '';
  activeStgs.forEach((s, idx) => {
    let barsHtml = '';
    if (s.phases && s.phases.length > 0) {
      s.phases.forEach(phase => {
        const leftPx = toDayIdx(phase.start) * DAY_W;
        const widthDays = Math.max(toDayIdx(phase.end) - toDayIdx(phase.start), 1);
        const widthPx = widthDays * DAY_W;
        const color = phaseColors[phase.type] || 'bg-violet-600 dark:bg-violet-700';
        barsHtml += `<div class="absolute ${color} rounded h-full flex items-center px-1.5 text-white text-[10px] font-semibold shadow-sm overflow-hidden" style="left:${leftPx}px;width:${widthPx}px" title="${phase.label}: ${formatDate(phase.start)} → ${formatDate(phase.end)}">${phase.label}</div>`;
      });
    } else {
      const leftPx = toDayIdx(s.kickOffDate || minDate) * DAY_W;
      const widthPx = Math.max((toDayIdx(s.completeDate) - toDayIdx(s.kickOffDate || minDate)) * DAY_W, DAY_W);
      barsHtml = `<div class="absolute bg-violet-600 dark:bg-violet-700 rounded h-full flex items-center px-1.5 text-white text-[10px] font-semibold shadow-sm overflow-hidden" style="left:${leftPx}px;width:${widthPx}px" title="${s.label}: ${formatDate(s.kickOffDate)} → ${formatDate(s.completeDate)}">${formatDate(s.kickOffDate)}</div>`;
    }

    rows += `
      <div class="flex items-center ${idx > 0 ? 'border-t border-gray-100 dark:border-gray-700/50' : ''}">
        <div class="shrink-0 text-right pr-3 py-2" style="width:${LABEL_W}px">
          <span class="text-[11px] font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wide leading-tight">${s.label}</span>
        </div>
        <div class="relative overflow-hidden" style="width:${timelineWidth}px;height:28px">
          ${weekendBands}
          ${barsHtml}
        </div>
      </div>`;
  });

  // ── Suggested go-live marker ────────────────────────────────────────────────
  const suggestedGoLivePx = LABEL_W + toDayIdx(data.suggestedGoLive) * DAY_W;
  const goLiveMarker = `
    <div class="absolute top-0 bottom-0 z-10 pointer-events-none" style="left:${suggestedGoLivePx}px">
      <div class="w-0 h-full border-l-2 border-dashed border-red-400 dark:border-red-500"></div>
      <div class="absolute -top-5 -translate-x-1/2 text-[9px] font-bold text-red-500 dark:text-red-400 whitespace-nowrap">SUGGESTED LIVE</div>
    </div>`;

  container.innerHTML = `
    <div class="overflow-x-auto">
      <div style="min-width:${LABEL_W + timelineWidth}px">
        <!-- Header row 1: week dates -->
        <div class="flex items-stretch">
          <div class="shrink-0" style="width:${LABEL_W}px"></div>
          <div class="relative" style="width:${timelineWidth}px;height:16px">${weekRow}</div>
        </div>
        <!-- Header row 2: day letters -->
        <div class="flex items-stretch mb-1">
          <div class="shrink-0" style="width:${LABEL_W}px"></div>
          <div class="relative" style="width:${timelineWidth}px;height:14px">${dayRow}</div>
        </div>
        <!-- Stage rows -->
        <div class="relative border-t border-gray-200 dark:border-gray-700">
          ${goLiveMarker}
          ${rows}
        </div>
      </div>
    </div>
    <div class="flex flex-wrap items-center gap-4 mt-4 pt-3 border-t border-gray-200 dark:border-gray-700 text-xs text-gray-400 dark:text-gray-500">
      <span class="flex items-center gap-1.5"><span class="w-3 h-3 rounded bg-violet-600 inline-block"></span> WIP</span>
      <span class="flex items-center gap-1.5"><span class="w-3 h-3 rounded bg-amber-400 inline-block"></span> Feedback</span>
      <span class="flex items-center gap-1.5"><span class="w-3 h-3 rounded bg-violet-400 inline-block"></span> Revision WIP</span>

      <span class="flex items-center gap-1.5"><span class="w-3 h-3 rounded bg-gray-100 border border-gray-200 inline-block"></span> Weekend</span>
      <span class="flex items-center gap-1.5"><span class="w-4 border-t-2 border-dashed border-red-400 inline-block"></span> Suggested Live</span>
    </div>
  `;
}

// ---- CSV Export ----
function exportCSV() {
  if (!lastCalculationData) return;
  const data = lastCalculationData;
  const lines = [];

  // Summary section
  lines.push('SLA Calculator Report');
  lines.push('');
  lines.push('Brief Name,' + csvEscape(data.briefName));
  lines.push('Brief Type,' + csvEscape(document.getElementById('briefType').selectedOptions[0]?.text || ''));
  lines.push('Kick-Off Date,' + formatDateLong(data.kickOff));
  lines.push('Required Go-Live Date,' + (data.goLive ? formatDateLong(data.goLive) : 'Not set'));
  lines.push('Planned End Date (SLA),' + formatDateLong(data.projectEndDate));
  lines.push('Suggested Go-Live (SLA),' + formatDateLong(data.suggestedGoLive));
  lines.push('Can Meet Deadline?,' + (data.canMeet === null ? 'N/A' : data.canMeet ? 'YES' : 'NO'));
  if (data.canMeet === false && data.goLive) {
    const gap = businessDaysBetween(data.goLive, data.suggestedGoLive);
    lines.push('Business Days Over Deadline,' + gap);
  }

  // Calculation of Days table
  lines.push('');
  lines.push('Calculation of Days');
  lines.push('Stage,Active,WIP 1,Feedback,Revisions,Complete By');
  data.stages.forEach(s => {
    lines.push([
      csvEscape(s.label),
      s.active ? 'Y' : 'N',
      s.active ? s.wip : 0,
      s.active ? (s.noFeedback ? 'n/r' : s.feedback) : 0,
      s.active ? (s.noFeedback ? 'n/r' : s.revisions) : 0,
      formatDate(s.completeDate)
    ].join(','));
  });

  // Key Dates table
  lines.push('');
  lines.push('Key Dates');
  lines.push('Stage,Active,Stage Kick-Off,WIP 1 To Approval,Receive Feedback By,Rounds,Stage Complete By');
  data.stages.forEach(s => {
    lines.push([
      csvEscape(s.label),
      s.active ? 'Y' : 'N',
      s.active ? formatDate(s.kickOffDate) : 'n.a.',
      s.active ? (s.noFeedback ? 'n/r' : formatDate(s.wipCompleteDate)) : 'n.a.',
      s.active ? (s.noFeedback ? 'n/r' : (s.feedbackByDate ? formatDate(s.feedbackByDate) : formatDate(s.wipCompleteDate))) : 'n.a.',
      s.active ? (s.noFeedback ? 'n/r' : s.rounds) : 'n.a.',
      s.active ? formatDate(s.completeDate) : 'n.a.'
    ].join(','));
  });

  const blob = new Blob([lines.join('\r\n')], { type: 'text/csv;charset=utf-8' });
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = (data.briefName || 'SLA_Report').replace(/\s+/g, '_') + '_SLA.csv';
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
}

// ---- Download Gantt as PNG ----
function downloadGanttPNG() {
  const el = document.getElementById('ganttChart');
  if (!el || !lastCalculationData) return;

  const isDark = document.documentElement.classList.contains('dark');
  const btn = el.closest('#ganttView').querySelector('button');
  if (btn) btn.style.visibility = 'hidden'; // hide button from screenshot

  html2canvas(el, {
    backgroundColor: isDark ? '#1f2937' : '#ffffff',
    scale: 2,
    useCORS: true,
    logging: false,
  }).then(canvas => {
    if (btn) btn.style.visibility = '';
    const a = document.createElement('a');
    a.download = (lastCalculationData.briefName || 'SLA_Gantt').replace(/\s+/g, '_') + '_Gantt.png';
    a.href = canvas.toDataURL('image/png');
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
  }).catch(() => {
    if (btn) btn.style.visibility = '';
    alert('Could not generate image. Please try again.');
  });
}

function csvEscape(str) {
  if (!str) return '';
  str = String(str);
  if (str.includes(',') || str.includes('"') || str.includes('\n')) {
    return '"' + str.replace(/"/g, '""') + '"';
  }
  return str;
}

// ---- Copy for Email (Rich HTML) ----
function copyForEmail() {
  if (!lastCalculationData) return;
  const briefType = document.getElementById('briefType').selectedOptions[0]?.text || '';
  trackEvent('copy_email', { briefType });
  const data = lastCalculationData;

  // Inline styles for Outlook compatibility
  const tbl = 'border-collapse:collapse;width:100%;font-family:Calibri,Arial,sans-serif;font-size:13px;';
  const th = 'border:1px solid #d1d5db;padding:6px 10px;background:#f3f4f6;font-weight:600;text-align:center;';
  const thL = 'border:1px solid #d1d5db;padding:6px 10px;background:#f3f4f6;font-weight:600;text-align:left;';
  const td = 'border:1px solid #d1d5db;padding:5px 10px;text-align:center;';
  const tdL = 'border:1px solid #d1d5db;padding:5px 10px;text-align:left;';
  const tdActive = 'border:1px solid #d1d5db;padding:5px 10px;text-align:center;color:#16a34a;font-weight:600;';
  const tdInactive = 'border:1px solid #d1d5db;padding:5px 10px;text-align:center;color:#9ca3af;';

  // Verdict
  let verdictText, verdictColor;
  if (data.canMeet === null) {
    verdictText = 'N/A — No Go-Live date set';
    verdictColor = '#6b7280';
  } else if (data.canMeet) {
    verdictText = 'YES — Can meet the deadline';
    verdictColor = '#16a34a';
  } else {
    const gap = businessDaysBetween(data.goLive, data.suggestedGoLive);
    verdictText = `NO — Cannot meet deadline (${gap} business days over)`;
    verdictColor = '#dc2626';
  }

  let html = `<div style="font-family:Calibri,Arial,sans-serif;font-size:14px;color:#1f2937;">`;
  html += `<h2 style="margin:0 0 12px 0;font-size:18px;">SLA Summary — ${data.briefName || 'Untitled'}</h2>`;
  html += `<p style="margin:3px 0;"><strong>Brief Type:</strong> ${briefType}</p>`;
  html += `<p style="margin:3px 0;"><strong>Kick-Off Date:</strong> ${formatDateLong(data.kickOff)}</p>`;
  html += `<p style="margin:3px 0;"><strong>Required Go-Live:</strong> ${data.goLive ? formatDateLong(data.goLive) : 'Not set'}</p>`;
  html += `<p style="margin:3px 0;"><strong>Planned End Date (SLA):</strong> ${formatDateLong(data.projectEndDate)}</p>`;
  html += `<p style="margin:3px 0;"><strong>Suggested Go-Live (SLA):</strong> ${formatDateLong(data.suggestedGoLive)}</p>`;
  html += `<p style="margin:3px 0 16px 0;"><strong>Verdict:</strong> <span style="color:${verdictColor};font-weight:700;">${verdictText}</span></p>`;

  // Key Dates table
  html += `<h3 style="margin:0 0 6px 0;font-size:15px;">Key Dates</h3>`;
  html += `<table style="${tbl}">`;
  html += `<tr><th style="${thL}">Stage</th><th style="${th}">Active</th><th style="${th}">Stage Kick-Off</th><th style="${th}">WIP 1 To Approval</th><th style="${th}">Receive Feedback By</th><th style="${th}">Rounds</th><th style="${th}">Stage Complete By</th></tr>`;
  data.stages.forEach(s => {
    const aStyle = s.active ? tdActive : tdInactive;
    const aText = s.active ? 'Y' : 'N';
    const kickOff = s.active ? formatDate(s.kickOffDate) : 'n.a.';
    const wip = s.active ? (s.noFeedback ? 'n/r' : formatDate(s.wipCompleteDate)) : 'n.a.';
    const feedback = s.active ? (s.noFeedback ? 'n/r' : (s.feedbackByDate ? formatDate(s.feedbackByDate) : formatDate(s.wipCompleteDate))) : 'n.a.';
    const rounds = s.active ? (s.noFeedback ? 'n/r' : s.rounds) : 'n.a.';
    const complete = s.active ? formatDate(s.completeDate) : 'n.a.';
    html += `<tr><td style="${tdL}">${s.label}</td><td style="${aStyle}">${aText}</td><td style="${td}">${kickOff}</td><td style="${td}">${wip}</td><td style="${td}">${feedback}</td><td style="${td}">${rounds}</td><td style="${td}">${complete}</td></tr>`;
  });
  html += `</table>`;

  // Calculation of Days table
  html += `<h3 style="margin:16px 0 6px 0;font-size:15px;">Calculation of Days</h3>`;
  html += `<table style="${tbl}">`;
  html += `<tr><th style="${thL}">Stage</th><th style="${th}">Active</th><th style="${th}">WIP 1</th><th style="${th}">Feedback</th><th style="${th}">Revisions</th><th style="${th}">Complete By</th></tr>`;
  data.stages.forEach(s => {
    const aStyle = s.active ? tdActive : tdInactive;
    const aText = s.active ? 'Y' : 'N';
    const wip = s.active ? s.wip : 0;
    const feedback = s.active ? (s.noFeedback ? 'n/r' : s.feedback) : 0;
    const revisions = s.active ? (s.noFeedback ? 'n/r' : s.revisions) : 0;
    const complete = formatDate(s.completeDate);
    html += `<tr><td style="${tdL}">${s.label}</td><td style="${aStyle}">${aText}</td><td style="${td}">${wip}</td><td style="${td}">${feedback}</td><td style="${td}">${revisions}</td><td style="${td}">${complete}</td></tr>`;
  });
  html += `</table></div>`;

  // Plain text fallback
  let plain = `SLA Summary — ${data.briefName || 'Untitled'}\n`;
  plain += `Brief Type: ${briefType}\n`;
  plain += `Kick-Off: ${formatDateLong(data.kickOff)}\n`;
  plain += `Go-Live: ${data.goLive ? formatDateLong(data.goLive) : 'Not set'}\n`;
  plain += `Planned End: ${formatDateLong(data.projectEndDate)}\n`;
  plain += `Verdict: ${verdictText}\n`;

  const showCopied = () => {
    const btn = document.getElementById('btnCopyEmail');
    const originalHTML = btn.innerHTML;
    btn.innerHTML = `<svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M5 13l4 4L19 7"/></svg> Copied!`;
    setTimeout(() => { btn.innerHTML = originalHTML; }, 2000);
  };

  // Use ClipboardItem API for rich HTML copy
  if (navigator.clipboard && typeof ClipboardItem !== 'undefined') {
    const htmlBlob = new Blob([html], { type: 'text/html' });
    const textBlob = new Blob([plain], { type: 'text/plain' });
    navigator.clipboard.write([new ClipboardItem({ 'text/html': htmlBlob, 'text/plain': textBlob })]).then(showCopied).catch(() => {
      fallbackCopyHtml(html);
      showCopied();
    });
  } else {
    fallbackCopyHtml(html);
    showCopied();
  }
}

function fallbackCopyHtml(html) {
  const el = document.createElement('div');
  el.innerHTML = html;
  el.style.position = 'fixed';
  el.style.left = '-9999px';
  document.body.appendChild(el);
  const range = document.createRange();
  range.selectNodeContents(el);
  const sel = window.getSelection();
  sel.removeAllRanges();
  sel.addRange(range);
  document.execCommand('copy');
  sel.removeAllRanges();
  document.body.removeChild(el);
}

// ---- iCal Export ----
function exportICal() {
  if (!lastCalculationData) return;
  const data = lastCalculationData;

  const formatICalDate = (date) => {
    const y = date.getFullYear();
    const m = String(date.getMonth() + 1).padStart(2, '0');
    const d = String(date.getDate()).padStart(2, '0');
    return y + m + d;
  };

  const now = new Date();
  const stamp = now.toISOString().replace(/[-:]/g, '').replace(/\.\d+/, '');
  const uid = () => 'sla-' + Math.random().toString(36).substr(2, 9) + '@ecf';

  let events = [];

  // Project kick-off event
  events.push({
    summary: `[Kick-Off] ${data.briefName}`,
    date: formatICalDate(data.kickOff),
    description: `Project kick-off for ${data.briefName}\\nBrief Type: ${document.getElementById('briefType').value.replace(/_/g, ' ')}`
  });

  // Active stage completion milestones
  data.stages.forEach(s => {
    if (s.active && s.completeDate) {
      events.push({
        summary: `[${s.label} Complete] ${data.briefName}`,
        date: formatICalDate(s.completeDate),
        description: `Stage "${s.label}" estimated completion for ${data.briefName}`
      });
    }
  });

  // Go-live deadline (if set)
  if (data.goLive) {
    events.push({
      summary: `[Go-Live Deadline] ${data.briefName}`,
      date: formatICalDate(data.goLive),
      description: `Required go-live date for ${data.briefName}\\nVerdict: ${data.canMeet ? 'CAN meet deadline' : 'CANNOT meet deadline'}`
    });
  }

  // Project planned end date
  events.push({
    summary: `[SLA End Date] ${data.briefName}`,
    date: formatICalDate(data.projectEndDate),
    description: `Planned end date based on SLA calculation for ${data.briefName}`
  });

  // Build .ics content
  let ics = [
    'BEGIN:VCALENDAR',
    'VERSION:2.0',
    'PRODID:-//eCom Content Factory//SLA Calculator//EN',
    'CALSCALE:GREGORIAN',
    'METHOD:PUBLISH'
  ];

  events.forEach(evt => {
    ics.push(
      'BEGIN:VEVENT',
      `DTSTART;VALUE=DATE:${evt.date}`,
      `DTEND;VALUE=DATE:${evt.date}`,
      `DTSTAMP:${stamp}`,
      `UID:${uid()}`,
      `SUMMARY:${evt.summary}`,
      `DESCRIPTION:${evt.description}`,
      'END:VEVENT'
    );
  });

  ics.push('END:VCALENDAR');

  const blob = new Blob([ics.join('\r\n')], { type: 'text/calendar;charset=utf-8' });
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = (data.briefName || 'SLA_Milestones').replace(/\s+/g, '_') + '.ics';
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
}