(() => {
  'use strict';

  // -------- helpers ----------
  const log  = (...a) => console.log('[Classic]', ...a);
  const fail = (msg) => {
    console.error('[Classic ERROR]', msg);
    const d = document.getElementById('classic-display');
    if (d) d.innerHTML = `<div style="padding:1rem;color:#b91c1c;font-family:system-ui,Arial">
      <strong>Classic failed:</strong> ${String(msg)}
    </div>`;
  };
  const normHex = (h) => (String(h || '')).trim().toLowerCase();

  // -------- persistent color selection (now supports image textures) ----------
  const PALETTE_KEY = 'classic:colors:v2';
  const TOPPER_COLOR_KEY = 'classic:topperColor:v2';

  const defaultColors = () => [
    { hex: '#d92e3a', image: null }, { hex: '#ffffff', image: null },
    { hex: '#0055a4', image: null }, { hex: '#40e0d0', image: null },
    { hex: '#fcd34d', image: null }
  ];
  const defaultTopper = () => ({ hex: '#a18b67', image: 'images/chrome-gold.webp' });

  function getClassicColors() {
    let arr = defaultColors();
    try {
      const savedJSON = localStorage.getItem(PALETTE_KEY);
      if (!savedJSON) return arr;
      const saved = JSON.parse(savedJSON);
      if (Array.isArray(saved) && saved.length > 0) {
        if (typeof saved[0] === 'string') {
          arr = saved.slice(0, 5).map(hex => ({ hex: normHex(hex), image: null }));
        } else if (typeof saved[0] === 'object' && saved[0] !== null) {
          arr = saved.slice(0, 5);
        }
        while (arr.length < 5) arr.push({ hex: '#ffffff', image: null });
      }
    } catch (e) { console.error('Failed to parse classic colors:', e); }
    return arr;
  }

  function setClassicColors(arr) {
    const clean = (arr || []).slice(0, 5).map(c => ({
      hex: normHex(c.hex), image: c.image || null
    }));
    while (clean.length < 5) clean.push({ hex: '#ffffff', image: null });
    try { localStorage.setItem(PALETTE_KEY, JSON.stringify(clean)); } catch {}
    return clean;
  }

  function getTopperColor() {
    try {
      const saved = JSON.parse(localStorage.getItem(TOPPER_COLOR_KEY));
      return (saved && saved.hex) ? saved : defaultTopper();
    } catch { return defaultTopper(); }
  }

  function setTopperColor(colorObj) {
    const clean = { hex: normHex(colorObj.hex), image: colorObj.image || null };
    try { localStorage.setItem(TOPPER_COLOR_KEY, JSON.stringify(clean)); } catch {}
  }

  function buildClassicPalette() {
    const colors = getClassicColors();
    const palette = { 0: { colour: '#FFFFFF', name: 'No Colour', image: null } };
    colors.forEach((c, i) => {
      palette[i + 1] = { colour: c.hex, image: c.image };
    });
    return palette;
  }

  function flattenPalette() {
    const out = [];
    if (Array.isArray(window.PALETTE)) {
      window.PALETTE.forEach(group => {
        (group.colors || []).forEach(c => {
          if (!c?.hex) return;
          out.push({
            hex: normHex(c.hex), name: c.name || c.hex,
            family: group.family || '', image: c.image || null
          });
        });
      });
    }
    const seen = new Set();
    return out.filter(c => (seen.has(c.hex) ? false : (seen.add(c.hex), true)));
  }

  // -------- tiny grid engine (Mithril) ----------
  function GridCalculator() {
    if (typeof window.m === 'undefined') throw new Error('Mithril (m) not loaded');

    let pxUnit = 10;
    let clusters = 10;
    let reverse  = false;
    let topperEnabled = false;
    let topperType = 'round';
    let topperOffsetX_Px = 0;
    let topperOffsetY_Px = 0;
    let topperSizeMultiplier = 1;
    let shineEnabled = true;

    const patterns = {};
    const api = {
      patterns,
      initialPattern: 'Arch 4',
      controller: (el) => makeController(el),
      setClusters(n) { clusters = Math.max(1, (Number(n)|0) || 10); },
      setReverse(on){ reverse = !!on; },
      setTopperEnabled(on) { topperEnabled = !!on; },
      setTopperType(type) { topperType = type || 'round'; },
      setTopperOffsetX(val) { topperOffsetX_Px = (Number(val) || 0) * 5; },
      setTopperOffsetY(val) { topperOffsetY_Px = (Number(val) || 0) * -5; },
      setTopperSize(multiplier) { topperSizeMultiplier = Number(multiplier) || 1; },
      setShineEnabled(on) { shineEnabled = !!on; }
    };

    const svg = (tag, attrs, children) => m(tag, attrs, children);

    function extend(p){
      const parentName = p.deriveFrom; if (!parentName) return;
      const base = patterns[parentName]; if (!base) return;
      if (base.deriveFrom) extend(base);
      Object.keys(base).forEach(k => { if (!(k in p)) p[k] = base[k]; });
      p.parent = base;
    }

    function BBox(){ this.min={x:Infinity,y:Infinity}; this.max={x:-Infinity,y:-Infinity}; }
    BBox.prototype.add = function(x,y){ if(isNaN(x)||isNaN(y)) return this;
      this.min.x=Math.min(this.min.x,x); this.min.y=Math.min(this.min.y,y);
      this.max.x=Math.max(this.max.x,x); this.max.y=Math.max(this.max.y,y); return this; };
    BBox.prototype.w=function(){return this.max.x-this.min.x;};
    BBox.prototype.h=function(){return this.max.y-this.min.y;};

    const balloonSize = (cell)=> (cell.shape.size ?? 1);
    const cellScale   = (cell)=> balloonSize(cell) * pxUnit;

    function cellView(cell, id, explicitFill, model){
        const shape = cell.shape;
        const scale = cellScale(cell);
        const transform = [(shape.base.transform||''), `scale(${scale})`].join(' ');
        const commonAttrs = {
            'vector-effect': 'non-scaling-stroke', stroke: '#111827',
            'stroke-width': 2, 'paint-order': 'stroke fill', class: 'balloon',
            fill: explicitFill || '#cccccc'
        };
        if (cell.isTopper) {
            commonAttrs['data-is-topper'] = true;
        } else {
            commonAttrs['data-color-code'] = cell.colorCode || 0;
            commonAttrs['data-quad-number'] = cell.y + 1;
        }

        let shapeEl;
        if (shape.base.type === 'path') shapeEl = svg('path', { ...commonAttrs, d: shape.base.d });
        else shapeEl = svg('ellipse', { ...commonAttrs, cx:0, cy:0, rx:0.5, ry:0.5 });

        const kids = [shapeEl];
        const applyShine = model.shineEnabled && (!cell.isTopper || (cell.isTopper && model.topperType === 'round'));
        if (applyShine) {
            kids.push(svg('ellipse', {
                class: 'shine', cx: -0.15, cy: -0.15, rx: 0.22, ry: 0.13,
                fill: '#ffffff', opacity: 0.45, transform: 'rotate(-25)', 'pointer-events': 'none'
            }));
        }
        return svg('g', { id, transform }, kids);
    }

    function gridPos(x,y,z,inflate,pattern,model){
      const base = patterns[model.patternName].parent || patterns[model.patternName];
      const rel  = (pattern.baseBalloonSize && base.baseBalloonSize) ? pattern.baseBalloonSize/base.baseBalloonSize : 1;
      let p = { x: pattern.gridX(model.pattern.cellsPerRow > 1 ? y : x, x), y: pattern.gridY(y,x) };
      if (pattern.transform) p = pattern.transform(p,x,y,model);
      return { x: p.x * rel * pxUnit, y: p.y * rel * pxUnit };
    }

    // === Spiral coloring helpers (shared by 4- and 5-balloon clusters) ===
function distinctPaletteSlots(palette) {
  // Collapse visually identical slots so 3-color spirals work even if you filled 5 slots.
  const seen = new Set(), out = [];
  for (let s = 1; s <= 5; s++) {
    const c = palette[s];
    if (!c) continue;
    const key = (c.image || '') + '|' + String(c.colour || '').toLowerCase();
    if (!seen.has(key)) { seen.add(key); out.push(s); }
  }
  return out.length ? out : [1,2,3,4,5];
}



    function newGrid(pattern, cells, container, model){
      const kids = [], layers = [], bbox = new BBox();
      const balloonsPerCluster = pattern.balloonsPerCluster || 4;
      const reversed = !!(pattern._reverse || (pattern.parent && pattern.parent._reverse));
      const rowColorPatterns = {};

      const colorBlock4 = [[1, 2, 3, 4], [3, 1, 4, 2], [4, 3, 2, 1], [2, 4, 1, 3]];
      const colorBlock5 = 
      [
        [5, 2, 3, 4, 1], 
        [2, 3, 4, 5, 1], 
        [2, 4, 5, 1, 3], 
        [4, 5, 1, 2, 3], 
        [4, 1, 2, 3, 5],
      ];

      for (let cell of cells) {
          let c, fill;
          if (cell.isTopper) {
              const topRowYIndex = 0, topClusterY = pattern.gridY(topRowYIndex, 0) * pxUnit;
              const regularBalloonRadius = (pattern.balloonShapes['front'] || pattern.balloonShapes['penta'] || pattern.balloonShapes['middle']).size * pxUnit * 0.5;
              const highestPoint = topClusterY - regularBalloonRadius;
              const topperRadius = cell.shape.size * pxUnit * cell.shape.base.radius;
              const topperY = highestPoint - topperRadius - (pxUnit * 0.5) + topperOffsetY_Px;
              c = { x: topperOffsetX_Px, y: topperY };
              fill = model.topperColor.image ? `url(#classic-pattern-topper)` : model.topperColor.hex;
          } else {
              c = gridPos(cell.x, cell.y, cell.shape.zIndex, cell.inflate, pattern, model);
              
              const rowIndex = cell.y;
              if (!rowColorPatterns[rowIndex]) {
                  const qEff = rowIndex + 1;
                  let pat;

                  if (balloonsPerCluster === 5) {
                      const base = (qEff - 1) % 5;
                      pat = colorBlock5[base].slice();
                  } else {
                      const base = Math.floor((qEff - 1) / 2);
                      pat = colorBlock4[base % 4].slice();
                      if (qEff % 2 === 0) {
                          pat = [pat[0], pat[2], pat[1], pat[3]];
                      }
                  }
                  
                  if (reversed && pat.length > 1) {
                      const first = pat.shift();
                      pat.reverse();
                      pat.unshift(first);
                  }

                  // --- NEW: swap left/right after every 5 clusters ---
const SWAP_EVERY = 5;                    // clusters per block
const blockIndex = Math.floor(rowIndex / SWAP_EVERY);

// swap on blocks #2, #4, #6, ... (i.e., rows 6–10, 16–20, ...)
if (blockIndex % 2 === 1) {
  if (balloonsPerCluster === 5) {
    // [leftMid, leftBack, front, rightBack, rightMid]
    [pat[0], pat[4]] = [pat[4], pat[0]];
    // [pat[1], pat[3]] = [pat[3], pat[1]];
  } 
}
                  rowColorPatterns[rowIndex] = pat;
              }

              const colorCode = rowColorPatterns[rowIndex][cell.balloonIndexInCluster];
              cell.colorCode = colorCode;
              const colorInfo = model.palette[colorCode];
              fill = colorInfo ? (colorInfo.image ? `url(#classic-pattern-slot-${colorCode})` : colorInfo.colour) : 'transparent';
          }

          const scale = cellScale(cell), shapeRadius = cell.shape.base.radius || 0.5, size = shapeRadius * scale;
          bbox.add(c.x - size, c.y - size);
          bbox.add(c.x + size, c.y + size);
          const v = cellView(cell, `balloon_${cell.x}_${cell.y}`, fill, model);
          v.attrs.transform = `translate(${c.x},${c.y}) ${v.attrs.transform || ''}`;
          const zi = cell.isTopper ? 100 + 2 : (100 + (cell.shape.zIndex || 0));
          (layers[zi] ||= []).push(v);
      };

      layers.forEach(layer => layer && layer.forEach(v => kids.push(v)));
      const margin = 20;
      const vb = [ bbox.min.x - margin, bbox.min.y - margin, Math.max(1,bbox.w()) + margin*2, Math.max(1,bbox.h()) + margin*2 ].join(' ');
      
      const patternsDefs = [];
      const SVG_PATTERN_ZOOM = 2.5;
      const offset = (1 - SVG_PATTERN_ZOOM) / 2;

      Object.entries(model.palette).forEach(([slot, colorInfo]) => {
          if (colorInfo.image) {
              patternsDefs.push(svg('pattern', {id: `classic-pattern-slot-${slot}`, patternContentUnits: 'objectBoundingBox', width: 1, height: 1}, 
                [ svg('image', { href: colorInfo.image, x: offset, y: offset, width: SVG_PATTERN_ZOOM, height: SVG_PATTERN_ZOOM, preserveAspectRatio: 'xMidYMid slice' }) ]
              ));
          }
      });
      if (model.topperColor.image) {
          patternsDefs.push(svg('pattern', {id: 'classic-pattern-topper', patternContentUnits: 'objectBoundingBox', width: 1, height: 1}, 
            [ svg('image', { href: model.topperColor.image, x: offset, y: offset, width: SVG_PATTERN_ZOOM, height: SVG_PATTERN_ZOOM, preserveAspectRatio: 'xMidYMid slice' }) ]
          ));
      }
      const svgDefs = svg('defs', {}, patternsDefs);

      const mainGroup = svg('g', null, kids);
      m.render(container, svg('svg', { xmlns: 'http://www.w3.org/2000/svg', width:'100%', height:'100%', viewBox: vb, preserveAspectRatio:'xMidYMid meet', style: 'isolation:isolate' }, [svgDefs, mainGroup]));
    }

    function makeController(displayEl){
      const models = [];
      function buildModel(name){
        const pattern = patterns[name];
        if (patterns['Column 4']) patterns['Column 4']._reverse = reverse;
        if (patterns['Arch 4'])   patterns['Arch 4']._reverse   = reverse;
        if (patterns['Column 5']) patterns['Column 5']._reverse = reverse;
        if (patterns['Arch 5'])   patterns['Arch 5']._reverse   = reverse;

        const model = { patternName: name, pattern, cells: [], rowCount: clusters, palette: buildClassicPalette(), topperColor: getTopperColor(), topperType, shineEnabled };
        const rows = pattern.cellsPerRow * model.rowCount, cols = pattern.cellsPerColumn;
        for (let y=0; y<rows; y++){
          let balloonIndexInCluster = 0;
          for (let x=0; x<cols; x++) {
              const cellData = pattern.createCell(x,y);
              if (cellData) model.cells.push({ ...cellData, x, y, balloonIndexInCluster: balloonIndexInCluster++ });
          }
        }
        if (name === 'Column 4' && topperEnabled) {
            const shapeName = `topper-${topperType}`;
            const originalShape = pattern.balloonShapes[shapeName];
            if (originalShape) {
                const shape = {...originalShape};
                shape.size *= topperSizeMultiplier;
                model.cells.push({ isTopper: true, shape, inflate: 0, x:0, y:rows });
            }
        }
        return model;
      }
      function selectPattern(name){
        const m = buildModel(name); models.push(m);
        newGrid(m.pattern, m.cells, displayEl, m); return m;
      }
      return { selectPattern };
    }

    function roundedStarPath({ points = 5, outerR = 0.5, innerR = 0.22, round = 0.28, rotate = -90 }) {
      const toRad = Math.PI / 180; const rot = rotate * toRad; const verts = [];
      for (let i = 0; i < points * 2; i++) { const ang = rot + i * Math.PI / points; const R = (i % 2 === 0) ? outerR : innerR; verts.push([Math.cos(ang) * R, Math.sin(ang) * R]); }
      const t = Math.max(0, Math.min(0.49, round));
      const lerp = (a, b, u) => [a[0] + (b[0] - a[0]) * u, a[1] + (b[1] - a[1]) * u];
      let v0 = verts[0], v1 = verts[1]; let p0 = lerp(v0, v1, t);
      let d = `M ${p0[0].toFixed(4)} ${p0[1].toFixed(4)}`;
      for (let i = 0; i < verts.length; i++) { const v = verts[(i + 1) % verts.length], vNext = verts[(i + 2) % verts.length]; const p = lerp(v, vNext, t); d += ` Q ${v[0].toFixed(4)} ${v[1].toFixed(4)} ${p[0].toFixed(4)} ${p[1].toFixed(4)}`; }
      return d + ' Z';
    }

    // --- Column 4: This is the existing logic from classic.js, which matches your template file ---
    patterns['Column 4'] = {
      baseBalloonSize: 25, _reverse: false, balloonsPerCluster: 4,
      balloonShapes: {
        'front':{zIndex:4, base:{radius:0.5}, size:3}, 'front-inner':{zIndex:3, base:{radius:0.5}, size:3}, 'back-inner':{zIndex:2, base:{radius:0.5}, size:3}, 'back':{zIndex:1, base:{radius:0.5}, size:3},
        'topper-round':{base:{type:'ellipse', radius:0.5}, size:8}, 'topper-star':{base:{type:'path', d:roundedStarPath({}), radius:0.5}, size:8}, 'topper-heart':{base:{type:'path', d:'M0,0.35 C-0.5,0, -0.14,-0.35, 0,-0.14 C0.14,-0.35, 0.5,0, 0,0.35 Z', radius:0.5}, size:20}
      },
      tile: { size:{x:5,y:1} }, cellsPerRow: 1, cellsPerColumn: 5,
      gridX(row, col){ return col + [0, -0.12, -0.24, -0.36, -0.48][col % 5]; },
      gridY(row, col){ return 2.2 * (1 - 1/5) * (Math.floor(row/2) + Math.floor((row+1)/2)); },
      createCell(x, y) {
        const odd = !!(y % 2);
        const A = ['front-inner','back','', 'front','back-inner'], B = ['back-inner', 'front','', 'back', 'front-inner'];
        const arr = this._reverse ? (odd ? B : A) : (odd ? A : B);
        const shapeName = arr[x % 5];
        const shape = this.balloonShapes[shapeName];
        return shape ? { shape:{...shape} } : null;
      }
    };
    
    // --- Arch 4: This is the existing logic from classic.js, which matches your template file ---
    patterns['Arch 4'] = { 
      deriveFrom: 'Column 4', 
      transform(point, col, row, model){ 
        const len = this.gridY(model.rowCount*this.tile.size.y, 0) - this.gridY(0, 0); 
        const r = (len / Math.PI) + point.x;
        const y = point.y - this.gridY(0, 0);
        const a = Math.PI * (y / len); 
        return { x: -r*Math.cos(a), y: -r*Math.sin(a) }; 
      } 
    };
    
    // --- START: MODIFIED SECTION ---
    // This is the new 'Column 5' definition, adapted from your template file.
    patterns['Column 5'] = {
      baseBalloonSize: 25,
      _reverse: false,
      balloonsPerCluster: 5, // Kept this from classic.js to ensure 5-color spiral
      tile: { size: { x: 5, y: 1 } },
      cellsPerRow: 1,
      cellsPerColumn: 5,
    
      // Balloon shapes from your template, converted to classic.js format
      // (type: "qlink" is approx size: 3.0)
      balloonShapes: {
        "front":   { zIndex:5, base:{radius:0.5}, size:3.0 },
        "front2":  { zIndex:4, base:{radius:0.5}, size:3.0 },
        "middle":  { zIndex:3, base:{radius:0.5}, size:3.0 },
        "middle2": { zIndex:2, base:{radius:0.5}, size:3.0 },
        "back":    { zIndex:1, base:{radius:0.5}, size:3.0 },
        "back2":   { zIndex:0, base:{radius:0.5}, size:3.0 }
      },
    
      // gridX function from your template
      // (I've hard-coded `this.exploded` to false, as it's not in classic.js)
      gridX(row, col) {
            var mid = 0.6; // this.exploded ? 0.2 : 0.6
            return (0.9) * (col + (0 === col % 5 && -0.5) + (1 === col % 5 && -mid) + (3 === col % 5 && mid) + (4 === col % 5 && 0.5) - 0.5);
      },
      
      // gridY function is inherited from Column 4 via `deriveFrom` in your template.
      // So, we use the gridY function from this file's 'Column 4'.
      gridY(row, col){ 
        return 2.2 * (1 - 1/5) * (Math.floor(row/2) + Math.floor((row+1)/2)); 
      },
    
      // createCell function from your template, adapted for classic.js
      createCell(x, y) {
            var yOdd = !!(y % 2);
            
            // Re-created logic from template's createCell
            const shapePattern = yOdd ?
                ['middle', 'back', 'front', 'back', 'middle'] :
                ['middle2', 'front2', 'back2', 'front2', 'middle2'];
            
            var shapeName = shapePattern[x % 5];
            var shape = this.balloonShapes[shapeName];
            
            // Return in classic.js format
            return shape ? { shape: {...shape} } : null;
      }
    };
    
    // This is the new 'Arch 5' definition.
    // It derives from the new 'Column 5' and uses the same arching logic as 'Arch 4'.
    patterns['Arch 5'] = {
      deriveFrom: 'Column 5',
      transform(point, col, row, model){
        // This transform logic is standard and will work with the new Column 5's gridY
        const len = this.gridY(model.rowCount * this.tile.size.y, 0) - this.gridY(0, 0);
        const r   = (len / Math.PI) + point.x;
        const y   = point.y - this.gridY(0, 0);
        const a   = Math.PI * (y / len);
        return { x: -r * Math.cos(a), y: -r * Math.sin(a) };
      }
    };
    // --- END: MODIFIED SECTION ---


    Object.keys(patterns).forEach(n => extend(patterns[n]));
    return api;
  }

  function initClassicColorPicker(onColorChange) {
      const slots = Array.from(document.querySelectorAll('#classic-slots .slot-btn')), topperSwatch = document.getElementById('classic-topper-color-swatch'), swatchGrid = document.getElementById('classic-swatch-grid'), activeLabel = document.getElementById('classic-active-label'), randomizeBtn = document.getElementById('classic-randomize-colors');
      if (!slots.length || !topperSwatch || !swatchGrid || !activeLabel) return;
      topperSwatch.classList.add('tab-btn');
      let classicColors = getClassicColors(), activeTarget = '1';

      function updateUI() {
          [...slots, topperSwatch].forEach(el => { const id = el.dataset.slot || 'T'; el.classList.toggle('tab-active', activeTarget === id); el.classList.toggle('tab-idle', activeTarget !== id); });
          
          slots.forEach((slot, i) => { 
            const color = classicColors[i]; 
            if (!color) return; // Safeguard against errors
            slot.style.backgroundImage = color.image ? `url("${color.image}")` : 'none';
            slot.style.backgroundColor = color.hex;
            slot.style.backgroundSize = '200%';
            slot.style.backgroundPosition = 'center';
          });
          
          const topperColor = getTopperColor(); 
          topperSwatch.style.backgroundImage = topperColor.image ? `url("${topperColor.image}")` : 'none';
          topperSwatch.style.backgroundColor = topperColor.hex;
          topperSwatch.style.backgroundSize = '200%';
          topperSwatch.style.backgroundPosition = 'center';

          activeLabel.textContent = activeTarget === 'T' ? 'Topper' : `Slot #${activeTarget}`;
      }

      const allPaletteColors = flattenPalette(); swatchGrid.innerHTML = '';
      (window.PALETTE || []).forEach(group => {
          const title = document.createElement('div'); title.className = 'family-title'; title.textContent = group.family; swatchGrid.appendChild(title);
          const row = document.createElement('div'); row.className = 'swatch-row';
          (group.colors || []).forEach(colorItem => {
              const sw = document.createElement('div'); sw.className = 'swatch'; sw.title = colorItem.name;
              
              sw.style.backgroundImage = colorItem.image ? `url("${colorItem.image}")` : 'none';
              sw.style.backgroundColor = colorItem.hex;
              sw.style.backgroundSize = '500%';
              sw.style.backgroundPosition = 'center';

              sw.addEventListener('click', () => {
                  const selectedColor = { hex: colorItem.hex, image: colorItem.image };
                  if (activeTarget === 'T') setTopperColor(selectedColor);
                  else {
                      const index = parseInt(activeTarget, 10) - 1;
                      if (index >= 0 && index < 5) { classicColors[index] = selectedColor; setClassicColors(classicColors); }
                  }
                  updateUI(); onColorChange();
                  if (window.updateExportButtonVisibility) window.updateExportButtonVisibility();
              });
              row.appendChild(sw);
          });
          swatchGrid.appendChild(row);
      });
      slots.forEach(slot => { slot.addEventListener('click', () => { activeTarget = slot.dataset.slot; updateUI(); }); });
      topperSwatch.addEventListener('click', () => { activeTarget = 'T'; updateUI(); });
      randomizeBtn?.addEventListener('click', () => {
          const pool = allPaletteColors.slice(); const picks = [];
          const colorCount = (patterns[document.getElementById('classic-pattern')?.value] || {}).balloonsPerCluster || 5;
          for (let i = 0; i < colorCount && pool.length; i++) { picks.push(pool.splice(Math.floor(Math.random() * pool.length), 1)[0]); }
          classicColors = setClassicColors(picks.map(c => ({ hex: c.hex, image: c.image })));
          updateUI(); onColorChange();
          if (window.updateExportButtonVisibility) window.updateExportButtonVisibility();
      });
      updateUI();
  }

  function initClassic() {
    try {
      if (typeof window.m === 'undefined') return fail('Mithril not loaded');
      const display = document.getElementById('classic-display'), patSel = document.getElementById('classic-pattern'), lengthInp = document.getElementById('classic-length-ft'), clusterHint = document.getElementById('classic-cluster-hint'), reverseCb = document.getElementById('classic-reverse'), rebuildBtn = document.getElementById('classic-rerender'), topperControls = document.getElementById('topper-controls'), topperEnabledCb = document.getElementById('classic-topper-enabled'), topperTypeSelect = document.getElementById('classic-topper-type'), topperOffsetX_Inp = document.getElementById('classic-topper-offset-x'), topperOffsetY_Inp = document.getElementById('classic-topper-offset-y'), topperSizeInp = document.getElementById('classic-topper-size'), shineEnabledCb = document.getElementById('classic-shine-enabled');
      if (!display) return fail('#classic-display not found');
      if (window.setupAccordionPanel) { window.setupAccordionPanel({ panelId: 'classic-controls-panel', expandBtnId: 'classic-expand-all', collapseBtnId: 'classic-collapse-all', reorderBtnId: 'classic-toggle-reorder', storagePrefix: 'cbd' }); }
      const GC = GridCalculator(), ctrl = GC.controller(display);

      function updateClassicDesign() {
        if (!lengthInp || !patSel) return;
        const patternName = patSel.value || 'Arch 4';
        const isColumn = patternName.toLowerCase().includes('column');
        const hasTopper = patternName.includes('4');

        topperControls.classList.toggle('hidden', !isColumn || !hasTopper);
        topperTypeSelect.disabled = !topperEnabledCb.checked;
        
        GC.setTopperEnabled(isColumn && hasTopper && topperEnabledCb.checked); 
        GC.setClusters(Math.round((parseFloat(lengthInp.value) || 0) * 2));
        GC.setReverse(!!reverseCb?.checked); 
        GC.setTopperType(topperTypeSelect.value); 
        GC.setTopperOffsetX(topperOffsetX_Inp?.value); 
        GC.setTopperOffsetY(topperOffsetY_Inp?.value); 
        GC.setTopperSize(topperSizeInp?.value); 
        GC.setShineEnabled(!!shineEnabledCb?.checked);
        if(clusterHint) clusterHint.textContent = `≈ ${Math.round((parseFloat(lengthInp.value) || 0) * 2)} clusters (rule: 2 clusters/ft)`;
        ctrl.selectPattern(patternName);
      }
      
      window.ClassicDesigner = window.ClassicDesigner || {};
      window.ClassicDesigner.api = GC;
      window.ClassicDesigner.redraw = updateClassicDesign;
      window.ClassicDesigner.getColors = getClassicColors;
      window.ClassicDesigner.getTopperColor = getTopperColor;

      document.querySelector('#mode-tabs')?.addEventListener('click', () => setTimeout(() => { if (window.updateExportButtonVisibility) window.updateExportButtonVisibility() }, 50));
      patSel?.addEventListener('change', () => { 
        const isArch = patSel.value.toLowerCase().includes('arch');
        lengthInp.value = isArch ? 25 : 5; 
        updateClassicDesign(); 
      });
      [lengthInp, reverseCb, topperEnabledCb, topperTypeSelect, topperOffsetX_Inp, topperOffsetY_Inp, topperSizeInp, rebuildBtn]
      .forEach(el => { if (!el) return; const eventType = (el.type === 'range' || el.type === 'number') ? 'input' : 'change'; el.addEventListener((el === rebuildBtn) ? 'click' : eventType, updateClassicDesign); });
      shineEnabledCb?.addEventListener('change', (e) => { const on = !!e.target.checked; GC.setShineEnabled(on); updateClassicDesign(); window.syncAppShine?.(on); });
      initClassicColorPicker(updateClassicDesign);
      try { const saved = localStorage.getItem('app:shineEnabled:v1'); if (saved !== null && shineEnabledCb) shineEnabledCb.checked = JSON.parse(saved); } catch {}
      updateClassicDesign();
      if (window.updateExportButtonVisibility) window.updateExportButtonVisibility();
      log('Classic ready');
    } catch (e) { fail(e.message || e); }
  }

  window.ClassicDesigner = window.ClassicDesigner || { init: initClassic, api: null, redraw: null };
  document.addEventListener('DOMContentLoaded', () => { if (document.getElementById('classic-display') && !window.__classicInit) { window.__classicInit = true; initClassic(); } });
})();