// ComparisonTray.jsx
export function ComparisonTray({ selectedProducts, onRemove, onClear }) {
  if (selectedProducts.length === 0) return null;

  const compareUrl = `/compare?${selectedProducts.map(p => `compare=${p.id}`).join('&')}`;

  return (
    <div className="comparison-tray" aria-live="polite" aria-label="Products selected for comparison">
      <div className="tray-products">
        {selectedProducts.map(product => (
          <div key={product.id} className="tray-product">
            <img src={product.image} alt={product.name} width="48" height="48" />
            <button onClick={() => onRemove(product.id)} aria-label={`Remove ${product.name} from comparison`}>&times;</button>
          </div>
        ))}
        {Array.from({ length: Math.max(0, 4 - selectedProducts.length) }).map((_, i) => (
          <div key={`empty-${i}`} className="tray-placeholder" aria-hidden="true">+</div>
        ))}
      </div>
      <div className="tray-actions">
        <a href={compareUrl} className="btn-primary" aria-disabled={selectedProducts.length < 2}>
          Compare ({selectedProducts.length})
        </a>
        <button onClick={onClear}>Clear all</button>
      </div>
    </div>
  );
}

export function ProductComparisonTable({ products, attributeGroups, showOnlyDifferences }) {
  function isRowIdentical(attrKey) {
    const values = products.map(p => p.attributes[attrKey]);
    return values.every(v => v === values[0]);
  }

  return (
    <div className="comparison-wrapper" style={{ overflowX: 'auto' }}>
      <table className="comparison-table">
        <caption className="sr-only">
          Side-by-side comparison of {products.map(p => p.name).join(', ')}
        </caption>
        <thead>
          <tr>
            <th scope="col" className="attr-col">Attribute</th>
            {products.map(product => (
              <th key={product.id} scope="col">
                <img src={product.image} alt={product.name} width="80" height="80" />
                <a href={product.url}>{product.name}</a>
                <strong>${product.price}</strong>
                <button className="btn-primary">Add to Cart</button>
              </th>
            ))}
          </tr>
        </thead>
        <tbody>
          {attributeGroups.map(group => (
            <>
              <tr key={`group-${group.label}`}>
                <th scope="rowgroup" colSpan={products.length + 1}>{group.label}</th>
              </tr>
              {group.attributes.map(attrKey => {
                if (showOnlyDifferences && isRowIdentical(attrKey)) return null;
                return (
                  <tr key={attrKey} className={isRowIdentical(attrKey) ? 'identical-row' : 'different-row'}>
                    <th scope="row">{attrKey.replace(/_/g, ' ')}</th>
                    {products.map(p => (
                      <td key={p.id}>{p.attributes[attrKey] ?? 'N/A'}</td>
                    ))}
                  </tr>
                );
              })}
            </>
          ))}
        </tbody>
      </table>
    </div>
  );
}

function toggleCompare(productId) {
  const params = new URLSearchParams(window.location.search);
  const current = params.getAll('compare');
  if (current.includes(productId)) {
    params.delete('compare');
    current.filter(id => id !== productId).forEach(id => params.append('compare', id));
  } else if (current.length < 4) {
    params.append('compare', productId);
  }
  window.history.replaceState({}, '', `${window.location.pathname}?${params.toString()}`);
}