import {
  type CustomWorldThemeMode,
  detectCustomWorldThemeMode,
  resolveCustomWorldCompatibilityTemplateWorldType,
} from '../services/customWorldTheme';
import { CustomWorldItem, CustomWorldProfile, InventoryItem, WorldTemplateType, WorldType } from '../types';

let runtimeCustomWorldProfile: CustomWorldProfile | null = null;

export function setRuntimeCustomWorldProfile(profile: CustomWorldProfile | null) {
  runtimeCustomWorldProfile = profile;
}

export function getRuntimeCustomWorldProfile() {
  return runtimeCustomWorldProfile;
}

export function resolveCompatibilityTemplateWorldType(
  worldType: WorldType | null | undefined,
  customWorldProfile: CustomWorldProfile | null | undefined = runtimeCustomWorldProfile,
): WorldTemplateType | null {
  if (!worldType) return null;
  if (worldType === WorldType.CUSTOM) {
    return customWorldProfile
      ? resolveCustomWorldCompatibilityTemplateWorldType(customWorldProfile)
      : WorldType.WUXIA;
  }
  return worldType;
}

export function isCustomWorldType(worldType: WorldType | null | undefined) {
  return worldType === WorldType.CUSTOM;
}

function hashText(value: string) {
  let hash = 0;
  for (let index = 0; index < value.length; index += 1) {
    hash = (hash * 31 + value.charCodeAt(index)) >>> 0;
  }
  return hash >>> 0;
}

function compactStrings(values: Array<string | null | undefined | false>) {
  return [...new Set(
    values
      .map(value => typeof value === 'string' ? value.trim() : '')
      .filter(Boolean),
  )];
}

function pickCyclic<T>(items: readonly T[], index: number, fallback: T): T {
  return items[index % items.length] ?? fallback;
}

function normalizeInventoryItemId(item: CustomWorldItem, quantity: number, seedKey: string) {
  return `custom:${item.id}:${quantity}:${hashText(seedKey).toString(36)}`;
}

function toInventoryItem(item: CustomWorldItem, quantity: number, seedKey: string): InventoryItem {
  return {
    id: normalizeInventoryItemId(item, quantity, seedKey),
    category: item.category,
    name: item.name,
    quantity,
    rarity: item.rarity,
    tags: [...item.tags],
    iconSrc: item.iconSrc,
    description: item.description,
    equipmentSlotId: item.equipmentSlotId ?? null,
    statProfile: item.statProfile ?? null,
    useProfile: item.useProfile ?? null,
    value: item.value,
    runtimeMetadata: {
      origin: 'procedural',
      generationChannel: 'discovery',
      seedKey,
      sourceReason: `围绕自定义世界 ${runtimeCustomWorldProfile?.name ?? '未知世界'} 的主题即时生成。`,
    },
  };
}

export interface RuntimeCustomWorldItemQueryOptions {
  categories?: string[];
  tags?: string[];
  preferredTags?: string[];
  keywords?: string[];
  count?: number;
  quantity?: number;
  rarityFloor?: CustomWorldItem['rarity'];
}

const RARITY_ORDER: CustomWorldItem['rarity'][] = ['common', 'uncommon', 'rare', 'epic', 'legendary'];
const DEFAULT_RUNTIME_CATEGORIES = ['武器', '护甲', '饰品', '消耗品', '材料', '稀有品', '专属物'] as const;
const CATEGORY_DEFAULT_TAGS: Record<string, string[]> = {
  武器: ['weapon', '战斗'],
  护甲: ['armor', '防护'],
  饰品: ['relic', 'mana'],
  消耗品: ['healing', '补给'],
  材料: ['material', '采集'],
  稀有品: ['rare', '线索'],
  专属物: ['rare', '剧情关键'],
};
const WORLD_ITEM_PREFIXES: Record<CustomWorldThemeMode, string[]> = {
  mythic: ['远岸', '回声', '曙迹', '长旅', '微光', '新铭'],
  martial: ['风雨', '断桥', '青锋', '旧案', '夜行', '残影'],
  arcane: ['灵纹', '道痕', '云篆', '星芒', '界辉', '玉简'],
  machina: ['铁脊', '脉冲', '新星', '等离', '钢律', '核列'],
  tide: ['潮纹', '霜浪', '天澜', '海晕', '潮歌', '沧流'],
  rift: ['裂痕', '灰域', '界桥', '断层', '回响', '前哨'],
};
const WORLD_ITEM_NOUNS: Record<string, string[]> = {
  武器: ['刃', '剑', '弓', '枪', '印', '锤'],
  护甲: ['甲', '衣', '护符', '披风', '战铠', '护腕'],
  饰品: ['坠', '环', '佩', '珠', '印记', '信物'],
  消耗品: ['药', '露', '符', '瓶', '包', '散'],
  材料: ['砂', '石', '铁', '木', '羽', '晶'],
  稀有品: ['残页', '密卷', '古钥', '图录', '印匣', '秘函'],
  专属物: ['遗物', '核心', '母印', '真符', '遗钥', '界核'],
};

function normalizeLookupText(value: string) {
  return value.trim().toLowerCase();
}

function getRarityFloorValue(rarityFloor?: CustomWorldItem['rarity']) {
  return rarityFloor ? RARITY_ORDER.indexOf(rarityFloor) : -1;
}

function sanitizeNameFragment(value: string) {
  return value.replace(/[^\u4e00-\u9fa5a-z0-9]/giu, '').slice(0, 4);
}

function getWorldSeedLabel(profile: CustomWorldProfile) {
  const fromName = sanitizeNameFragment(profile.name);
  if (fromName) return fromName;

  const fromSetting = sanitizeNameFragment(profile.settingText);
  if (fromSetting) return fromSetting;

  return '旅境';
}

function buildRuntimeItemTags(
  category: string,
  options: RuntimeCustomWorldItemQueryOptions,
  seed: number,
) {
  const baseTags = [...(CATEGORY_DEFAULT_TAGS[category] ?? ['world-item'])];
  const preferredTags = [...new Set((options.preferredTags ?? []).map(tag => tag.trim()).filter(Boolean))];
  const keywordTags = [...new Set((options.keywords ?? []).map(tag => tag.trim()).filter(Boolean))];
  const selectedPreferredTag = preferredTags.length > 0
    ? preferredTags[seed % preferredTags.length]
    : undefined;
  const selectedKeywordTag = keywordTags.length > 0
    ? keywordTags[(seed >>> 3) % keywordTags.length]
    : undefined;

  if (category === '消耗品' && preferredTags.some(tag => /mana|法力|灵气|内息/u.test(tag))) {
    baseTags.push('mana');
  }
  if (category === '消耗品' && preferredTags.some(tag => /heal|疗|血|恢复/u.test(tag))) {
    baseTags.push('healing');
  }

  return compactStrings([...baseTags, selectedPreferredTag, selectedKeywordTag]).slice(0, 5);
}

function inferRuntimeItemRarity(seed: number, rarityFloorValue: number): CustomWorldItem['rarity'] {
  const rolledRarity = [0, 1, 1, 2, 2, 2, 3, 3, 4][seed % 9] ?? 0;
  return RARITY_ORDER[Math.max(rarityFloorValue, rolledRarity)] ?? 'common';
}

function inferRuntimeItemMechanics(
  category: string,
  rarity: CustomWorldItem['rarity'],
  tags: string[],
  seed: number,
) {
  const rarityTier = Math.max(1, RARITY_ORDER.indexOf(rarity) + 1);

  if (category === '武器') {
    return {
      equipmentSlotId: 'weapon' as const,
      statProfile: {
        outgoingDamageBonus: 2 * rarityTier + (seed % 3),
      },
      useProfile: null,
      value: 28 * rarityTier,
    };
  }

  if (category === '护甲') {
    return {
      equipmentSlotId: 'armor' as const,
      statProfile: {
        maxHpBonus: 10 * rarityTier + (seed % 8),
        incomingDamageMultiplier: Math.max(0.72, Number((1 - rarityTier * 0.04).toFixed(2))),
      },
      useProfile: null,
      value: 26 * rarityTier,
    };
  }

  if (category === '饰品' || category === '稀有品' || category === '专属物') {
    return {
      equipmentSlotId: 'relic' as const,
      statProfile: {
        maxManaBonus: 8 * rarityTier + (seed % 7),
        outgoingDamageBonus: rarityTier >= 3 ? rarityTier : undefined,
      },
      useProfile: null,
      value: 32 * rarityTier,
    };
  }

  if (category === '消耗品') {
    return {
      equipmentSlotId: null,
      statProfile: null,
      useProfile: tags.includes('mana')
        ? { manaRestore: 12 * rarityTier, cooldownReduction: rarityTier >= 3 ? 1 : 0 }
        : { hpRestore: 16 * rarityTier },
      value: 18 * rarityTier,
    };
  }

  return {
    equipmentSlotId: null,
    statProfile: null,
    useProfile: null,
    value: 10 * rarityTier,
  };
}

function buildProceduralRuntimeItem(
  profile: CustomWorldProfile,
  seedKey: string,
  options: RuntimeCustomWorldItemQueryOptions,
  index: number,
) {
  const themeMode = detectCustomWorldThemeMode(profile);
  const seed = hashText(`${profile.id}:${seedKey}:${index}`);
  const defaultCategory = DEFAULT_RUNTIME_CATEGORIES[0] ?? 'world-item';
  const categories = compactStrings(options.categories?.length ? options.categories : [...DEFAULT_RUNTIME_CATEGORIES]);
  const category = pickCyclic(categories, seed, defaultCategory);
  const rarityFloorValue = getRarityFloorValue(options.rarityFloor);
  const rarity = inferRuntimeItemRarity(seed, rarityFloorValue);
  const tags = buildRuntimeItemTags(category, options, seed);
  const prefixPool = WORLD_ITEM_PREFIXES[themeMode];
  const nounPool = WORLD_ITEM_NOUNS[category] ?? WORLD_ITEM_NOUNS.稀有品;
  const fallbackNounPool = ['sigil', 'relic', 'token', 'seal', 'core', 'mark'];
  const resolvedNounPool = nounPool ?? fallbackNounPool;
  const worldSeed = getWorldSeedLabel(profile);
  const optionSeed = sanitizeNameFragment((options.preferredTags ?? [])[0] ?? '') || sanitizeNameFragment((options.keywords ?? [])[0] ?? '');
  const prefix = pickCyclic(prefixPool, seed >>> 2, prefixPool[0] ?? 'world');
  const noun = pickCyclic(resolvedNounPool, seed >>> 5, fallbackNounPool[0]);
  const name = `${prefix}${optionSeed || worldSeed}${noun}${index + 1}`;
  const mechanics = inferRuntimeItemMechanics(category, rarity, tags, seed);

  return {
    id: `runtime-item:${hashText(`${seedKey}:${index}`).toString(36)}`,
    name,
    category,
    rarity,
    description: `围绕“${profile.playerGoal}”即时生成的${category}，适合在 ${profile.name} 中作为掉落、交易或补给资源。`,
    tags,
    origin: 'generated' as const,
    equipmentSlotId: mechanics.equipmentSlotId,
    statProfile: mechanics.statProfile,
    useProfile: mechanics.useProfile,
    value: mechanics.value,
  } satisfies CustomWorldItem;
}

function matchesRuntimeQuery(
  item: CustomWorldItem,
  options: RuntimeCustomWorldItemQueryOptions,
  rarityFloorValue: number,
) {
  if (options.categories?.length && !options.categories.includes(item.category)) {
    return false;
  }
  if (options.tags?.length && !options.tags.some(tag => item.tags.includes(tag))) {
    return false;
  }
  if (rarityFloorValue >= 0) {
    const itemRarityValue = RARITY_ORDER.indexOf(item.rarity);
    if (itemRarityValue < rarityFloorValue) {
      return false;
    }
  }
  return true;
}

function scoreItemRelevance(item: CustomWorldItem, options: RuntimeCustomWorldItemQueryOptions) {
  const haystack = normalizeLookupText([
    item.name,
    item.category,
    item.description,
    ...(item.tags ?? []),
  ].join(' '));
  const itemTags = new Set((item.tags ?? []).map(tag => normalizeLookupText(tag)));
  let score = 0;

  const preferredTags = [...new Set((options.preferredTags ?? []).map(normalizeLookupText).filter(Boolean))];
  preferredTags.forEach(tag => {
    if (itemTags.has(tag)) {
      score += 10;
      return;
    }
    if (haystack.includes(tag)) {
      score += 4;
    }
  });

  const keywords = [...new Set((options.keywords ?? []).map(normalizeLookupText).filter(keyword => keyword.length >= 2))];
  keywords.forEach(keyword => {
    if (!haystack.includes(keyword)) {
      return;
    }
    score += keyword.length >= 4 ? 7 : keyword.length === 3 ? 5 : 3;
  });

  if (options.categories?.includes(item.category)) {
    score += 2;
  }
  if (item.origin === 'generated') {
    score += 1;
  }

  return score;
}

function rankItems(items: CustomWorldItem[], seedKey: string, options: RuntimeCustomWorldItemQueryOptions = {}) {
  const seed = hashText(seedKey);
  return [...items].sort((left, right) => {
    const relevanceDelta = scoreItemRelevance(right, options) - scoreItemRelevance(left, options);
    if (relevanceDelta !== 0) {
      return relevanceDelta;
    }

    const leftScore = hashText(`${left.id}:${seed}`) % 997;
    const rightScore = hashText(`${right.id}:${seed}`) % 997;
    return leftScore - rightScore;
  });
}

export function pickRuntimeCustomWorldItems(
  seedKey: string,
  options: RuntimeCustomWorldItemQueryOptions = {},
) {
  const profile = runtimeCustomWorldProfile;
  if (!profile) return [] as CustomWorldItem[];

  const rarityFloorValue = getRarityFloorValue(options.rarityFloor);
  const sourceItems = Array.from({ length: Math.max(16, (options.count ?? 1) * 10) }, (_, index) =>
    buildProceduralRuntimeItem(profile, seedKey, options, index),
  );

  const filtered = sourceItems.filter(item => matchesRuntimeQuery(item, options, rarityFloorValue));

  return rankItems(filtered.length > 0 ? filtered : sourceItems, seedKey, options).slice(0, options.count ?? 1);
}

export function buildRuntimeCustomWorldInventoryItems(
  seedKey: string,
  options: RuntimeCustomWorldItemQueryOptions = {},
) {
  const count = options.count ?? 1;
  return pickRuntimeCustomWorldItems(seedKey, options)
    .slice(0, count)
    .map((item, index) => toInventoryItem(item, options.quantity ?? 1, `${seedKey}:${index}`));
}