import AsyncStorage from '@react-native-async-storage/async-storage';
import * as Crypto from 'expo-crypto';
import type { UserProfileV1_2_Extended } from '@/src/features/userProfileScoring';

/**
 * 本地存储 key 统一管理，避免 UI 里散落硬编码
 */
const KEY_CLIENT_USER_ID = 'client.userId';
const KEY_ONBOARDING_COMPLETED = 'onboarding.completed';
const KEY_PUSH_PROMPT_STATE = 'push.promptState';
const KEY_CONTENT_REACTIONS = 'content.reactions';
const KEY_FAVORITES_ITEMS = 'favorites.items';
const KEY_CONSENT_ACCEPTED = 'consent.accepted';
const KEY_USER_PROFILE = 'user.profile';
const KEY_USER_PROFILE_SCORING = 'user.profileScoring';
const KEY_RECO_FEED_CACHE = 'reco.feedCache';
const KEY_RECO_FEED_HISTORY = 'reco.feedHistory';
const KEY_UI_THEME_MODE = 'ui.theme.mode';
const KEY_UI_THEME_SUIXIN_STATE = 'ui.theme.suixin.state';
const KEY_DAILY_REMINDER_SETTINGS = 'dailyReminder.settings';

export type PushPromptState = 'enabled' | 'skipped' | 'unknown';
export type Reaction = 'like' | 'dislike';
export type ReactionsMap = Record<string, Reaction>;
export type ThemeMode = 'scenery' | 'color' | 'suixin';
export type UserProfile = {
  name?: string;
  intents?: string[];
};

export type SuixinBaseThemeId =
  | 'neutral'
  | 'emotional_support'
  | 'parenting_pressure'
  | 'self_worth'
  | 'anxiety_relief'
  | 'rest_balance';

export type SuixinThemeStateV1 = {
  schema_version: 1;
  saved_at: string; // ISO8601
  /**
   * 冷启动会话标记（进程级）。
   * 用于确保：仅在冷启动时重置 base theme/seed。
   */
  boot_id: string;
  base_theme_id: SuixinBaseThemeId;
  seed: string;
  step_index: number;
  last_color: string; // "#RRGGBB"
};

/**
 * 用户画像（问卷打分输出）
 * 说明：用于推荐/Push/Widget 统一复用；结构以 `src/features/userProfileScoring` 输出为准。
 */
export type UserProfileScoring = UserProfileV1_2_Extended;
export type DailyReminderSettings = {
  /**
   * 每天推送次数：
   * - 0：关闭
   * - 1～5：每天推送 1～5 次
   */
  timesPerDay: number;
  /**
   * 仅用于 UI 展示与交互（开关）。
   * 后端偏好建议使用：enabled = pushEnabled && timesPerDay > 0
   */
  pushEnabled: boolean;
};

export type RecoFeedCacheItem = {
  content_id: number;
  text: string;
};

export type RecoFeedCache = {
  saved_at: string; // ISO8601
  /**
   * 缓存文案的语言（后端目前只区分 en / tc）
   * - en: English
   * - tc: 繁体中文
   */
  lang?: 'en' | 'tc';
  items: RecoFeedCacheItem[];
  meta?: Record<string, unknown>;
};

/**
 * Feed 链路可观测输入（用于下一次请求携带给后端）
 *
 * - already_recommended_ids：本设备已下发过的内容（避免重复下发）
 * - touched_or_viewed_ids：本设备用户已看过/划过的内容（用于频控/去重/降重复）
 *
 * 说明：后端不需要“实时知道”，只要在下一次拉取时带上即可。
 */
export type RecoFeedHistory = {
  updated_at: string; // ISO8601
  already_recommended_ids: number[];
  touched_or_viewed_ids: number[];
};


async function getJson<T>(key: string, fallback: T): Promise<T> {
  const raw = await AsyncStorage.getItem(key);
  if (!raw) return fallback;
  try {
    return JSON.parse(raw) as T;
  } catch {
    return fallback;
  }
}

async function setJson<T>(key: string, value: T): Promise<void> {
  await AsyncStorage.setItem(key, JSON.stringify(value));
}

function looksLikeUuid(v: string): boolean {
  // 宽松校验：8-4-4-4-12（不强依赖大小写）
  return /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(v);
}

function uuidV4FromBytes(bytes: Uint8Array): string {
  // RFC 4122 v4：设置 version 与 variant
  const b = new Uint8Array(bytes);
  b[6] = (b[6] & 0x0f) | 0x40;
  b[8] = (b[8] & 0x3f) | 0x80;

  const hex = Array.from(b)
    .map((x) => x.toString(16).padStart(2, '0'))
    .join('');
  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
}

async function generateUuidV4(): Promise<string> {
  // 1) 优先使用运行时提供的 randomUUID（如可用）
  const maybeCrypto = (globalThis as unknown as { crypto?: { randomUUID?: () => string } }).crypto;
  if (maybeCrypto?.randomUUID) return maybeCrypto.randomUUID();

  // 2) 使用 expo-crypto 生成安全随机数（推荐）
  const bytes = await Crypto.getRandomBytesAsync(16);
  return uuidV4FromBytes(bytes);
}

/**
 * 获取或生成客户端用户标识（UUID）。
 *
 * 说明：
 * - `client_user_id` 用于与后端关联 Push Token 与用户推送偏好
 * - 它是“安装实例标识”，不等同真实用户账号
 */
export async function getOrCreateClientUserId(): Promise<string> {
  const raw = await AsyncStorage.getItem(KEY_CLIENT_USER_ID);
  if (raw && looksLikeUuid(raw)) return raw;

  const next = await generateUuidV4();
  await AsyncStorage.setItem(KEY_CLIENT_USER_ID, next);
  return next;
}

export async function getOnboardingCompleted(): Promise<boolean> {
  const raw = await AsyncStorage.getItem(KEY_ONBOARDING_COMPLETED);
  return raw === 'true';
}

export async function setOnboardingCompleted(completed: boolean): Promise<void> {
  await AsyncStorage.setItem(KEY_ONBOARDING_COMPLETED, completed ? 'true' : 'false');
}

export async function getPushPromptState(): Promise<PushPromptState> {
  const raw = await AsyncStorage.getItem(KEY_PUSH_PROMPT_STATE);
  if (raw === 'enabled' || raw === 'skipped' || raw === 'unknown') return raw;
  return 'unknown';
}

export async function setPushPromptState(state: PushPromptState): Promise<void> {
  await AsyncStorage.setItem(KEY_PUSH_PROMPT_STATE, state);
}

export async function getReactions(): Promise<ReactionsMap> {
  return await getJson<ReactionsMap>(KEY_CONTENT_REACTIONS, {});
}

export async function setReaction(contentId: string, reaction: Reaction): Promise<void> {
  const next = await getReactions();
  next[contentId] = reaction;
  await setJson(KEY_CONTENT_REACTIONS, next);
}

export type FavoriteItem = {
  favId: string; // 唯一标识，支持重复点赞同一文案
  id: string;
  /**
   * 收藏时的文案快照（强烈建议写入，避免后续 cache 覆盖导致无法还原文案）
   */
  text?: string;
  date: string;
  themeMode: ThemeMode;
  background: string; // 颜色值或图片路径
};

export async function getFavorites(): Promise<FavoriteItem[]> {
  return await getJson<FavoriteItem[]>(KEY_FAVORITES_ITEMS, []);
}

export async function addFavorite(item: FavoriteItem): Promise<void> {
  const list = await getFavorites();
  // 允许重复点赞，不再根据 id 去重
  const newList = [item, ...list];
  console.log('Adding to favorites:', JSON.stringify(item));
  await setJson(KEY_FAVORITES_ITEMS, newList);
}

export async function removeFavorite(favId: string): Promise<void> {
  const list = await getFavorites();
  const next = list.filter(item => item.favId !== favId);
  await setJson(KEY_FAVORITES_ITEMS, next);
}

export async function getConsentAccepted(): Promise<boolean> {
  const raw = await AsyncStorage.getItem(KEY_CONSENT_ACCEPTED);
  return raw === 'true';
}

export async function setConsentAccepted(accepted: boolean): Promise<void> {
  await AsyncStorage.setItem(KEY_CONSENT_ACCEPTED, accepted ? 'true' : 'false');
}

export async function getThemeMode(): Promise<ThemeMode> {
  const raw = await AsyncStorage.getItem(KEY_UI_THEME_MODE);
  if (raw === 'scenery' || raw === 'color' || raw === 'suixin') return raw;
  return 'scenery';
}

export async function setThemeMode(mode: ThemeMode): Promise<void> {
  await AsyncStorage.setItem(KEY_UI_THEME_MODE, mode);
}

export async function getSuixinThemeState(): Promise<SuixinThemeStateV1 | null> {
  const raw = await AsyncStorage.getItem(KEY_UI_THEME_SUIXIN_STATE);
  if (!raw) return null;
  try {
    const parsed = JSON.parse(raw) as Partial<SuixinThemeStateV1>;
    if (parsed.schema_version !== 1) return null;
    if (typeof parsed.boot_id !== 'string') return null;
    if (typeof parsed.base_theme_id !== 'string') return null;
    if (typeof parsed.seed !== 'string') return null;
    if (typeof parsed.step_index !== 'number') return null;
    if (typeof parsed.last_color !== 'string') return null;
    if (typeof parsed.saved_at !== 'string') return null;
    return parsed as SuixinThemeStateV1;
  } catch {
    return null;
  }
}

export async function setSuixinThemeState(state: SuixinThemeStateV1): Promise<void> {
  await setJson(KEY_UI_THEME_SUIXIN_STATE, state);
}

export async function getUserProfile(): Promise<UserProfile> {
  return await getJson<UserProfile>(KEY_USER_PROFILE, {});
}

export async function setUserProfile(profile: UserProfile): Promise<void> {
  const current = await getUserProfile();
  await setJson(KEY_USER_PROFILE, { ...current, ...profile });
}

export async function getUserProfileScoring(): Promise<UserProfileScoring | null> {
  const raw = await AsyncStorage.getItem(KEY_USER_PROFILE_SCORING);
  if (!raw) return null;
  try {
    return JSON.parse(raw) as UserProfileScoring;
  } catch {
    return null;
  }
}

export async function setUserProfileScoring(profile: UserProfileScoring): Promise<void> {
  await setJson(KEY_USER_PROFILE_SCORING, profile);
}

export async function getRecoFeedCache(): Promise<RecoFeedCache | null> {
  const raw = await AsyncStorage.getItem(KEY_RECO_FEED_CACHE);
  if (!raw) return null;
  try {
    return JSON.parse(raw) as RecoFeedCache;
  } catch {
    return null;
  }
}

export async function setRecoFeedCache(cache: RecoFeedCache): Promise<void> {
  await setJson(KEY_RECO_FEED_CACHE, cache);
}

export async function getRecoFeedHistory(): Promise<RecoFeedHistory> {
  const raw = await AsyncStorage.getItem(KEY_RECO_FEED_HISTORY);
  if (!raw) {
    return {
      updated_at: new Date().toISOString(),
      already_recommended_ids: [],
      touched_or_viewed_ids: [],
    };
  }
  try {
    const parsed = JSON.parse(raw) as Partial<RecoFeedHistory>;
    return {
      updated_at: typeof parsed.updated_at === 'string' ? parsed.updated_at : new Date().toISOString(),
      already_recommended_ids: Array.isArray(parsed.already_recommended_ids)
        ? parsed.already_recommended_ids.filter((x) => Number.isFinite(x)).map((x) => Number(x))
        : [],
      touched_or_viewed_ids: Array.isArray(parsed.touched_or_viewed_ids)
        ? parsed.touched_or_viewed_ids.filter((x) => Number.isFinite(x)).map((x) => Number(x))
        : [],
    };
  } catch {
    return {
      updated_at: new Date().toISOString(),
      already_recommended_ids: [],
      touched_or_viewed_ids: [],
    };
  }
}

export async function setRecoFeedHistory(history: RecoFeedHistory): Promise<void> {
  await setJson(KEY_RECO_FEED_HISTORY, history);
}

function uniqKeepLatest(list: number[], max: number): number[] {
  const seen = new Set<number>();
  const out: number[] = [];
  for (let i = list.length - 1; i >= 0; i -= 1) {
    const v = list[i];
    if (!Number.isFinite(v)) continue;
    if (seen.has(v)) continue;
    seen.add(v);
    out.push(v);
    if (out.length >= max) break;
  }
  return out.reverse();
}

export async function recordRecoFeedServed(contentIds: number[]): Promise<void> {
  if (!contentIds?.length) return;
  const h = await getRecoFeedHistory();
  const next = {
    ...h,
    updated_at: new Date().toISOString(),
    already_recommended_ids: uniqKeepLatest([...h.already_recommended_ids, ...contentIds], 500),
  };
  await setRecoFeedHistory(next);
}

export async function recordRecoFeedTouched(contentId: number): Promise<void> {
  if (!Number.isFinite(contentId)) return;
  const h = await getRecoFeedHistory();
  const next = {
    ...h,
    updated_at: new Date().toISOString(),
    touched_or_viewed_ids: uniqKeepLatest([...h.touched_or_viewed_ids, contentId], 500),
  };
  await setRecoFeedHistory(next);
}

export async function getDailyReminderSettings(): Promise<DailyReminderSettings> {
  const s = await getJson<DailyReminderSettings>(KEY_DAILY_REMINDER_SETTINGS, {
    timesPerDay: 3,
    pushEnabled: false,
  });
  const timesPerDay = Number.isFinite(s.timesPerDay) ? s.timesPerDay : 3;
  return {
    // 需求：0～5（0 表示关闭）
    timesPerDay: Math.min(5, Math.max(0, Math.round(timesPerDay))),
    pushEnabled: Boolean(s.pushEnabled),
  };
}

export async function setDailyReminderSettings(settings: DailyReminderSettings): Promise<void> {
  // 需求：0～5（0 表示关闭）
  const timesPerDay = Math.min(5, Math.max(0, Math.round(settings.timesPerDay)));
  await setJson(KEY_DAILY_REMINDER_SETTINGS, {
    timesPerDay,
    pushEnabled: Boolean(settings.pushEnabled),
  });
}