deckhearth/lib/deck-builder-stats.js

/** Basic land names for Commander singleton rule checks. */
export const BASIC_LAND_NAMES = ['Plains', 'Island', 'Swamp', 'Mountain', 'Forest'];

export function isBasicLand(card) {
  return BASIC_LAND_NAMES.includes(card.name);
}

/**
 * Aggregate deck list metrics from deck card rows (quantity-weighted).
 * @param {Array<{ quantity: number, cmc?: number, colors?: string, card_type?: string }>} deckCards
 */
export function computeDeckStats(deckCards) {
  const totalCards = deckCards.reduce((sum, card) => sum + card.quantity, 0);
  const avgCmc =
    deckCards.length > 0
      ? (
          deckCards.reduce((sum, card) => sum + (card.cmc || 0) * card.quantity, 0) /
          totalCards
        ).toFixed(1)
      : 0;

  const colorCounts = deckCards.reduce((counts, card) => {
    if (card.colors) {
      try {
        const colors = JSON.parse(card.colors);
        colors.forEach((color) => {
          counts[color] = (counts[color] || 0) + card.quantity;
        });
      } catch {
        // Handle non-JSON color format
      }
    }
    return counts;
  }, {});

  const typeCounts = deckCards.reduce((counts, card) => {
    if (card.card_type) {
      const types = card.card_type.split(' — ')[0].split(' ');
      types.forEach((type) => {
        counts[type] = (counts[type] || 0) + card.quantity;
      });
    }
    return counts;
  }, {});

  return { totalCards, avgCmc, colorCounts, typeCounts };
}