/**
 * 门店列表「当次登录」会话 —— 用 Taro Storage 持久化，
 * 避免模块多实例 / globalThis 不可靠导致切 tab 后当成首次进入。
 * 仅 logout 时 clear。
 */

import Taro from '@tarojs/taro';

export type StoresSessionRegion = {
  province: string;
  city: string;
  district: string;
};

export type StoresSessionCategory = {
  parentId: string;
  parentName: string;
  childId: string;
  childName: string;
};

export type StoresListCache = {
  cityKey: string;
  cityCode: string;
  /** 登录态指纹：token 变化时需重新拉取（白名单） */
  authKey: string;
  listRegion: StoresSessionRegion;
  items: unknown[];
  filterRegion: StoresSessionRegion;
  keyword: string;
  keywordInput: string;
  category: StoresSessionCategory;
};

type StoresSession = {
  bootstrapped: boolean;
  cache: StoresListCache | null;
};

const STORAGE_KEY = 'dukang_stores_session_v1';

let memory: StoresSession | null = null;

function emptySession(): StoresSession {
  return { bootstrapped: false, cache: null };
}

function readSession(): StoresSession {
  if (memory) return memory;
  try {
    const raw = Taro.getStorageSync(STORAGE_KEY);
    if (!raw) {
      memory = emptySession();
      return memory;
    }
    const parsed = (typeof raw === 'string' ? JSON.parse(raw) : raw) as Partial<StoresSession>;
    memory = {
      bootstrapped: !!parsed.bootstrapped,
      cache: (parsed.cache as StoresListCache | null) ?? null,
    };
    return memory;
  } catch {
    memory = emptySession();
    return memory;
  }
}

function writeSession(next: StoresSession) {
  memory = next;
  try {
    Taro.setStorageSync(STORAGE_KEY, JSON.stringify(next));
  } catch {
    /* ignore quota */
  }
}

export function isStoresSessionBootstrapped(): boolean {
  return readSession().bootstrapped;
}

export function markStoresSessionBootstrapped(): void {
  const cur = readSession();
  writeSession({ ...cur, bootstrapped: true });
}

export function getStoresListCache(): StoresListCache | null {
  return readSession().cache;
}

export function setStoresListCache(cache: StoresListCache | null): void {
  const cur = readSession();
  writeSession({ ...cur, bootstrapped: true, cache });
}

export function patchStoresFilterCache(
  patch: Partial<
    Pick<StoresListCache, 'filterRegion' | 'keyword' | 'keywordInput' | 'category'>
  >,
): void {
  const cur = readSession();
  if (!cur.cache) {
    // 列表尚未写入时也要记下用户筛选，避免切回丢失
    writeSession({
      bootstrapped: true,
      cache: {
        cityKey: '',
        cityCode: '',
        listRegion: patch.filterRegion ?? { province: '', city: '', district: '' },
        items: [],
        filterRegion: patch.filterRegion ?? { province: '', city: '', district: '' },
        keyword: patch.keyword ?? '',
        keywordInput: patch.keywordInput ?? '',
        category: patch.category ?? {
          parentId: '',
          parentName: '',
          childId: '',
          childName: '',
        },
      },
    });
    return;
  }
  writeSession({
    ...cur,
    bootstrapped: true,
    cache: { ...cur.cache, ...patch },
  });
}

export function resetStoresSessionBootstrap(): void {
  memory = emptySession();
  try {
    Taro.removeStorageSync(STORAGE_KEY);
  } catch {
    /* ignore */
  }
}