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;
}

const SCORE_NUTRIENTS: { key: NutrientKey; weight: number }[] = [
  { key: 'protein_g', weight: 12 },
  { key: 'fiber_g', weight: 10 },
  { key: 'omega_3_mg', weight: 10 },
  { key: 'vitamin_d_mcg', weight: 8 },
  { key: 'b12_mcg', weight: 7 },
  { key: 'iron_mg', weight: 7 },
  { key: 'calcium_mg', weight: 7 },
  { key: 'magnesium_mg', weight: 7 },
  { key: 'choline_mg', weight: 6 },
  { key: 'dha_mg', weight: 6 },
  { key: 'epa_mg', weight: 6 },
  { key: 'potassium_mg', weight: 5 },
  { key: 'zinc_mg', weight: 5 },
  { key: 'c_mg', weight: 5 },
  { key: 'a_mcg', weight: 5 },
  { key: 'b9_mcg', weight: 5 },
  { key: 'selenium_mcg', weight: 5 },
  { key: 'iodine_mcg', weight: 5 },
  { key: 'b6_mg', weight: 4 },
  { key: 'e_mg', weight: 4 },
  { key: 'k_mcg', weight: 4 },
  { key: 'copper_mg', weight: 4 },
  { key: 'manganese_mg', weight: 4 },
  { key: 'b1_mg', weight: 3 },
  { key: 'b2_mg', weight: 3 },
  { key: 'b3_mg', weight: 3 },
  { key: 'b5_mg', weight: 3 },
  { key: 'biotin_mcg', weight: 3 },
  { key: 'phosphorus_mg', weight: 3 },
  { key: 'chromium_mcg', weight: 3 },
  { key: 'molybdenum_mcg', weight: 3 },
  { key: 'ala_mg', weight: 3 },
  { key: 'soluble_fiber_g', weight: 3 },
  { key: 'insoluble_fiber_g', weight: 3 },
  { key: 'retinol_mcg', weight: 2 },
  { key: 'dpa_mg', weight: 2 },
  { key: 'omega_6_mg', weight: 2 },
  { key: 'monounsaturated_fat_g', weight: 2 },
  { key: 'polyunsaturated_fat_g', weight: 2 },
  { key: 'tryptophan_mg', weight: 2 },
  { key: 'tyrosine_mg', weight: 2 },
  { key: 'valine_g', weight: 2 },
  { key: 'glutamine_g', weight: 2 },
  { key: 'lycopene_mcg', weight: 2 },
  { key: 'lutein_zeaxanthin_mcg', weight: 2 },
  { key: 'beta_carotene_mcg', weight: 2 },
  { key: 'alpha_carotene_mcg', weight: 1 },
  { key: 'cryptoxanthin_mcg', weight: 1 },
  { key: 'anthocyanins_mg', weight: 2 },
  { key: 'phytosterols_mg', weight: 1 },
  { key: 'betaine_mg', weight: 1 },
  { key: 'probiotics_cfu', weight: 2 },
  { key: 'collagen_g', weight: 1 },
  { key: 'coq10_mg', weight: 1 },
  { key: 'curcumin_mg', weight: 1 },
  { key: 'creatine_g', weight: 1 },
  { key: 'resveratrol_mg', weight: 1 },
  { key: 'astaxanthin_mcg', weight: 1 },
  { key: 'water_ml', weight: 2 },
  { key: 'caffeine_mg', weight: 1 },
  { key: 'theobromine_mg', weight: 1 },
  { key: 'taurine_mg', weight: 1 },
];

const SCORE_FOOD_GROUPS: { key: NutrientKey; weight: number }[] = [
  { key: 'usa_gov_dga_vegetables_cup_eq', weight: 8 },
  { key: 'usa_gov_dga_fruits_cup_eq', weight: 5 },
  { key: 'usa_gov_dga_protein_g', weight: 5 },
  { key: 'usa_gov_dga_whole_grains_oz_eq', weight: 4 },
  { key: 'usa_gov_dga_dairy_cup_eq', weight: 3 },
  { key: 'usa_gov_dga_healthy_fats_tsp_eq', weight: 3 },
  { key: 'usa_gov_dga_dark_green_veg_cup_eq', weight: 4 },
  { key: 'usa_gov_dga_red_orange_veg_cup_eq', weight: 3 },
  { key: 'usa_gov_dga_beans_peas_lentils_veg_cup_eq', weight: 3 },
  { key: 'usa_gov_dga_starchy_veg_cup_eq', weight: 2 },
  { key: 'usa_gov_dga_other_veg_cup_eq', weight: 2 },
];

function fillRatio(consumed: number, target: number): number {
  if (target <= 0) return 0;
  const ratio = consumed / target;
  return Math.min(ratio, 1.5) / 1.5;
}

export function calculateNutritionScore(
  consumed: Nutrition,
  targets: Nutrition,
  uniqueIngredientCount: number
): number {
  const nutrientTotal = SCORE_NUTRIENTS.reduce((sum, n) => sum + n.weight, 0);
  const foodGroupTotal = SCORE_FOOD_GROUPS.reduce((sum, n) => sum + n.weight, 0);

  let nutrientScore = 0;
  for (const { key, weight } of SCORE_NUTRIENTS) {
    const c = consumed[key] ?? 0;
    const t = targets[key] ?? BASE_DAILY_TARGETS[key] ?? 1;
    nutrientScore += fillRatio(c, t) * weight;
  }
  const nutrientPct = nutrientScore / nutrientTotal;

  let foodGroupScore = 0;
  for (const { key, weight } of SCORE_FOOD_GROUPS) {
    const c = consumed[key] ?? 0;
    const t = targets[key] ?? BASE_DAILY_TARGETS[key] ?? 1;
    foodGroupScore += fillRatio(c, t) * weight;
  }
  const foodGroupPct = foodGroupScore / foodGroupTotal;

  const diversityBonus = Math.min(uniqueIngredientCount / 15, 1);

  const rawScore = nutrientPct * 45 + foodGroupPct * 45 + diversityBonus * 10;

  return Math.min(Math.max(rawScore, 0), 100);
}