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

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

const _useItems = () => {
  const items = useLocalStorage<Item[]>("item-database", [], {
    serializer: {
      read: (v) => {
        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),
    },
  });

  const stats = {
    totalItems: computed(() => items.value.length),
    addedThisMonth: computed(() => {
      const now = new Date();
      const thisMonth = now.getMonth();
      const thisYear = now.getFullYear();

      let count = 0;
      for (const item of items.value) {
        const date = item.createdAt;
        if (date.getMonth() === thisMonth && date.getFullYear() === thisYear) {
          count++;
        }
      }
      return count;
    }),
    latestId: computed(
      () => (items.value[items.value.length - 1]?.id ?? 0) + 1
    ),
  };

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

  const addItem = (item: Item) => items.value.push(item);

  const removeItem = (id: number) =>
    (items.value = items.value.filter((i) => i.id !== id));

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

export const useItemsStore = createSharedComposable(_useItems);