import {
  BASE_DAILY_TARGETS,
  LEVEL1_NUTRITION_KEYS,
  LEVEL2_NUTRITION_KEYS,
  LEVEL3_NUTRITION_KEYS,
  NUTRIENT_META,
  USA_GOV_DGA_KEYS,
} from '@/common/constants/nutrition';
import { NutrientKey, Nutrition, NutritionDisplayMode, NutritionSortMode } from '@/types/nutrition';

export type NutrientsByLevel = {
  level1: NutrientKey[];
  level2: NutrientKey[];
  level3: NutrientKey[];
};

export function getNutrientsByMode(mode: NutritionDisplayMode): NutrientsByLevel {
  if (mode === 'usa_gov_dga') {
    return { level1: USA_GOV_DGA_KEYS, level2: [], level3: [] };
  }
  return {
    level1: LEVEL1_NUTRITION_KEYS,
    level2: LEVEL2_NUTRITION_KEYS,
    level3: LEVEL3_NUTRITION_KEYS,
  };
}

export function sortNutrients(
  keys: NutrientKey[],
  sortMode: NutritionSortMode,
  consumed?: Nutrition,
  target?: Nutrition
): NutrientKey[] {
  if (sortMode === 'default') {
    return [...keys].sort((a, b) => NUTRIENT_META[a].importance - NUTRIENT_META[b].importance);
  }
  if (!consumed || !target) {
    return [...keys].sort((a, b) => NUTRIENT_META[a].importance - NUTRIENT_META[b].importance);
  }
  return [...keys].sort((a, b) => {
    const fillA = (consumed[a] ?? 0) / (target[a] || 1);
    const fillB = (consumed[b] ?? 0) / (target[b] || 1);
    return fillA - fillB;
  });
}

export function sumNutrition(items: Nutrition[]): Nutrition {
  const result: Nutrition = {};
  for (const item of items) {
    for (const key of Object.keys(item) as NutrientKey[]) {
      const val = item[key];
      if (val != null) {
        result[key] = (result[key] ?? 0) + val;
      }
    }
  }
  return result;
}

export function emptyNutrition(): Nutrition {
  return {};
}

export function getDailyTargets(date: Date): Nutrition {
  const dayOfYear = Math.floor(
    (date.getTime() - new Date(date.getFullYear(), 0, 0).getTime()) / 86400000
  );
  const seed = dayOfYear * 7 + date.getFullYear();
  const result: Nutrition = {};
  for (const [key, base] of Object.entries(BASE_DAILY_TARGETS)) {
    const hash = ((seed * 31 + key.charCodeAt(0)) * 17) % 100;
    const variation = 0.9 + (hash / 100) * 0.2;
    result[key as NutrientKey] = Math.round(base * variation * 100) / 100;
  }
  return result;
}