/**
 * 首页商品列表「当次登录」会话 —— 切 tab 不重复拉商品；
 * 城市 / 登录态变化或下拉刷新时再请求。logout 时 clear。
 */

import Taro from '@tarojs/taro';

export type HomeCatalogCache = {
  cityCode: string;
  authKey: string;
  products: unknown[];
};

type HomeSession = {
  bootstrapped: boolean;
  cache: HomeCatalogCache | null;
};

const STORAGE_KEY = 'dukang_home_catalog_session_v1';

let memory: HomeSession | null = null;

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

function readSession(): HomeSession {
  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<HomeSession>;
    memory = {
      bootstrapped: !!parsed.bootstrapped,
      cache: (parsed.cache as HomeCatalogCache | null) ?? null,
    };
    return memory;
  } catch {
    memory = emptySession();
    return memory;
  }
}

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

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

export function getHomeCatalogCache(): HomeCatalogCache | null {
  return readSession().cache;
}

export function setHomeCatalogCache(cache: HomeCatalogCache): void {
  writeSession({ bootstrapped: true, cache });
}

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