import { useLocalStorage, createSharedComposable } from "@vueuse/core";

export type Item = {
  id: number;
  name: string;
  imageUrl?: string | null;
  description?: string | null;
  tags?: string[] | null;
  createdAt: Date;
  updatedAt: Date;
};

const _useItems = () => {
  const stored = useLocalStorage<Item[]>("item-database", [], {
    serializer: {
      read: (v) => {
        if (!v) return [];
        const parsed = JSON.parse(v);
        return parsed.map((item: any) => ({
          ...item,
          createdAt: new Date(item.createdAt),
          updatedAt: new Date(item.updatedAt),
        }));
      },
      write: (v) => JSON.stringify(v),
    },
  });

  // 直接使用 stored（Ref<Item[]>）。模板会自动解包，其他逻辑也简单。
  const items = stored; // Ref<Item[]>

  // 统计项使用 items.value
  const stats = {
    totalItems: computed(() => (items.value ?? []).length),
    addedThisMonth: computed(() => {
      const now = new Date();
      const thisMonth = now.getMonth();
      const thisYear = now.getFullYear();
      return (items.value ?? []).filter(
        (item) =>
          item.createdAt.getMonth() === thisMonth &&
          item.createdAt.getFullYear() === thisYear
      ).length;
    }),
    latestId: computed(() => {
      const arr = items.value ?? [];
      if (arr.length === 0) return 1;
      return Math.max(...arr.map((i) => i.id)) + 1;
    }),
  };

  const isNameAvailable = (name: string) =>
    !(items.value ?? []).some((item) => item.name === name);

  const addItem = (item: Item) => {
    items.value = [...(items.value ?? []), item]; // <-- 替换数组引用
  };

  const editItem = (item: Item) => {
    const index = (items.value ?? []).findIndex((i) => i.id === item.id);
    if (index === -1) return; // 未找到则直接返回

    // 生成一个新的数组（保持响应式）
    const updatedItems = [...(items.value ?? [])];
    updatedItems[index] = {
      ...updatedItems[index],
      ...item,
      updatedAt: new Date(), // 自动更新时间戳
    };

    items.value = updatedItems; // 替换引用，触发 UI 更新
  };

  const removeItem = (id: number) => {
    items.value = (items.value ?? []).filter((i) => i.id !== id); // <-- 替换数组引用
  };

  return { items, stats, isNameAvailable, addItem, editItem, removeItem };
};

export const useItemsStore = createSharedComposable(_useItems);