class Book:
    def __init__(self, title, author, status="在馆"):
        self.title = title
        self.author = author
        self.status = status

    def to_dict(self):
        """把对象转成字典，方便存JSON"""
        return {"title": self.title, "author": self.author, "status": self.status}

    @classmethod
    def from_dict(cls, data):
        """从字典恢复成对象"""
        return cls(data['title'], data['author'], data['status'])

import json
import os
from models import Book

class LibrarySystem:
    def __init__(self):
        self.books = []
        self.load_data()

    def load_data(self):
        """从文件加载数据"""
        if os.path.exists('books.json'):
            try:
                with open('books.json', 'r', encoding='utf-8') as f:
                    data = json.load(f)
                    self.books = [Book.from_dict(item) for item in data]
            except Exception as e:
                print(f"数据加载失败: {e}")

    def save_data(self):
        """保存数据到文件"""
        with open('books.json', 'w', encoding='utf-8') as f:
            json.dump([b.to_dict() for b in self.books], f, ensure_ascii=False, indent=4)

    def add_book(self, title, author):
        self.books.append(Book(title, author))
        self.save_data()
        print(f"《{title}》入库成功！")

    def borrow_book(self, title):
        for book in self.books:
            if book.title == title:
                if book.status == "在馆":
                    book.status = "借出"
                    self.save_data()
                    print(f"借阅成功！请按时归还《{title}》。")
                else:
                    print(f"抱歉，《{title}》已经被借走了。")
                return
        print("查无此书！")

    def show_books(self):
        print("-" * 30)
        for book in self.books:
            print(f"书名：{book.title} | 作者：{book.author} | 状态：{book.status}")
        print("-" * 30)

# 交互入口
if __name__ == "__main__":
    lib = LibrarySystem()
    while True:
        print("\n1. 查看图书 2. 添加图书 3. 借阅图书 4. 退出")
        choice = input("请输入操作编号：")
        if choice == '1': lib.show_books()
        elif choice == '2': 
            t = input("书名：")
            a = input("作者：")
            lib.add_book(t, a)
        elif choice == '3':
            t = input("请输入想借的书名：")
            lib.borrow_book(t)
        elif choice == '4': break