Интерфейс администратора

Часть раздела Object Oriented Programming путешествия по Python на Coddy — урок 59 из 64.

Задание

Средне

В этом задании вам предстоит реализовать административные функции для системы управления библиотекой.

Вам необходимо изменить файл library.py, чтобы добавить метод get_statistics в класс Library, который возвращает словарь (dictionary) с ключевой статистикой о состоянии (state) библиотеки. Детали реализации приведены в комментариях TODO внутри файла.

Статистика должна включать:

Общее количество книг
Количество доступных книг
Количество выданных книг
Общее количество пользователей
Количество пользователей с выданными книгами

Файлы book.py и user.py содержат предварительно реализованные классы, с которыми будет взаимодействовать ваше решение. Хотя вы можете изучить эти файлы, чтобы понять структуру системы, ваша реализация должна быть сосредоточена на файле library.py.

Попробуйте сами

from book import Book
from user import User
from library import Library

# Обработчик тестовых случаев
test_case = input()

if test_case == "empty_library":
    library = Library("Empty Library")
    stats = library.get_statistics()
    
    print(f"Total Books: {stats['total_books']}")
    print(f"Available Books: {stats['available_books']}")
    print(f"Borrowed Books: {stats['borrowed_books']}")
    print(f"Total Users: {stats['total_users']}")
    print(f"Users with Books: {stats['users_with_books']}")

elif test_case == "with_borrowed_books":
    library = Library("Community Library")
    
    # Добавить книги и пользователей
    library.add_book(Book("The Great Gatsby", "F. Scott Fitzgerald", "123456"))
    library.add_book(Book("To Kill a Mockingbird", "Harper Lee", "789012"))
    library.add_book(Book("1984", "George Orwell", "345678"))
    
    library.add_user(User("U001", "Alice"))
    library.add_user(User("U002", "Bob"))
    library.add_user(User("U003", "Charlie"))
    
    # Взять несколько книг
    library.borrow_book("123456", "U001")
    library.borrow_book("789012", "U001") # Alice берёт 2 книги
    library.borrow_book("345678", "U002") # Bob берёт 1 книгу
    
    stats = library.get_statistics()
    print(f"Total Books: {stats['total_books']}")
    print(f"Available Books: {stats['available_books']}")
    print(f"Borrowed Books: {stats['borrowed_books']}")
    print(f"Total Users: {stats['total_users']}")
    print(f"Users with Books: {stats['users_with_books']}")

elif test_case == "return_books":
    library = Library("Return Test Library")
    
    # Добавить книги и пользователей
    library.add_book(Book("Python Programming", "John Smith", "111222"))
    library.add_book(Book("Data Structures", "Jane Doe", "333444"))
    
    library.add_user(User("U101", "David"))
    library.add_user(User("U102", "Emma"))
    
    # Взять книгу
    library.borrow_book("111222", "U101")
    
    # Get statistics before returning
    stats_before = library.get_statistics()
    print("Before returning:")
    print(f"Total Books: {stats_before['total_books']}")
    print(f"Available Books: {stats_before['available_books']}")
    print(f"Borrowed Books: {stats_before['borrowed_books']}")
    print(f"Users with Books: {stats_before['users_with_books']}")
    
    # Реализация возврата книги (должна быть в классе Library)
    book = next((book for book in library.books if book.isbn == "111222"), None)
    user = next((user for user in library.users if user.user_id == "U101"), None)
    
    if book and user:
        book.available = True
        book.borrower = None
        user.books_borrowed.remove(book)
        print("Book returned successfully")
    
    # Get statistics after returning
    stats_after = library.get_statistics()
    print("\
After returning:")
    print(f"Total Books: {stats_after['total_books']}")
    print(f"Available Books: {stats_after['available_books']}")
    print(f"Borrowed Books: {stats_after['borrowed_books']}")
    print(f"Users with Books: {stats_after['users_with_books']}")

elif test_case == "edge_cases":
    # Empty library
    empty_library = Library("Empty Library")
    empty_stats = empty_library.get_statistics()
    print("Empty library statistics:")
    print(f"Total Books: {empty_stats['total_books']}")
    print(f"Available Books: {empty_stats['available_books']}")
    print(f"Borrowed Books: {empty_stats['borrowed_books']}")
    print(f"Total Users: {empty_stats['total_users']}")
    print(f"Users with Books: {empty_stats['users_with_books']}")
    
    # Books but no users
    books_only = Library("Books Only")
    books_only.add_book(Book("Book 1", "Author 1", "B001"))
    books_only.add_book(Book("Book 2", "Author 2", "B002"))
    books_stats = books_only.get_statistics()
    print("\
Library with books but no users:")
    print(f"Total Books: {books_stats['total_books']}")
    print(f"Available Books: {books_stats['available_books']}")
    print(f"Total Users: {books_stats['total_users']}")
    print(f"Users with Books: {books_stats['users_with_books']}")
    
    # Users but no books
    users_only = Library("Users Only")
    users_only.add_user(User("U201", "User 1"))
    users_only.add_user(User("U202", "User 2"))
    users_stats = users_only.get_statistics()
    print("\
Library with users but no books:")
    print(f"Total Books: {users_stats['total_books']}")
    print(f"Available Books: {users_stats['available_books']}")
    print(f"Total Users: {users_stats['total_users']}")
    print(f"Users with Books: {users_stats['users_with_books']}")
    
    # Случаи ошибок
    error_library = Library("Error Test")
    error_library.add_book(Book("Error Book", "Error Author", "E001"))
    error_library.add_user(User("E101", "Error User"))
    
    print("\
Error cases:")
    print(f"Borrow non-existent book: {error_library.borrow_book('NONEXISTENT', 'E101')}")
    print(f"Borrow with non-existent user: {error_library.borrow_book('E001', 'NONEXISTENT')}")

elif test_case == "large_library":
    large_library = Library("Large Library")
    
    # Добавить 100 книг
    for i in range(1, 101):
        large_library.add_book(Book(f"Book {i}", f"Author {i}", f"ISBN{i:06d}"))
    
    # Добавить 100 пользователей
    for i in range(1, 101):
        large_library.add_user(User(f"U{i:03d}", f"User {i}"))
    
    # Пусть 50 пользователей возьмут книги
    for i in range(1, 51):
        large_library.borrow_book(f"ISBN{i:06d}", f"U{i:03d}")
    
    # Пусть некоторые пользователи возьмут несколько книг
    for i in range(1, 11):
        large_library.borrow_book(f"ISBN{i+50:06d}", f"U{i:03d}")
    
    stats = large_library.get_statistics()
    print("Large library statistics:")
    print(f"Total Books: {stats['total_books']}")
    print(f"Available Books: {stats['available_books']}")
    print(f"Borrowed Books: {stats['borrowed_books']}")
    print(f"Total Users: {stats['total_users']}")
    print(f"Users with Books: {stats['users_with_books']}")
    
    # Проверить расчёты
    print("\
Verification:")
    print(f"Total books should be 100: {stats['total_books'] == 100}")
    print(f"Borrowed books should be 60: {stats['borrowed_books'] == 60}")
    print(f"Available books should be 40: {stats['available_books'] == 40}")
    print(f"Users with books should be 50: {stats['users_with_books'] == 50}")

elif test_case == "statistics_accuracy":
    accuracy_library = Library("Accuracy Test")
    
    # Добавить ровно 10 книг
    for i in range(1, 11):
        accuracy_library.add_book(Book(f"Book {i}", f"Author {i}", f"A{i:03d}"))
    
    # Добавить ровно 5 пользователей
    for i in range(1, 6):
        accuracy_library.add_user(User(f"AU{i}", f"Accuracy User {i}"))
    
    # Книги ещё не взяты
    stats1 = accuracy_library.get_statistics()
    print("Initial state:")
    print(f"Total Books: {stats1['total_books']} (Expected: 10)")
    print(f"Available Books: {stats1['available_books']} (Expected: 10)")
    print(f"Borrowed Books: {stats1['borrowed_books']} (Expected: 0)")
    print(f"Total Users: {stats1['total_users']} (Expected: 5)")
    print(f"Users with Books: {stats1['users_with_books']} (Expected: 0)")
    
    # Пусть 3 пользователя возьмут книги
    accuracy_library.borrow_book("A001", "AU1")
    accuracy_library.borrow_book("A002", "AU1")  # Пользователь 1 берёт 2 книги
    accuracy_library.borrow_book("A003", "AU2")  # Пользователь 2 берёт 1 книгу
    accuracy_library.borrow_book("A004", "AU3")  # Пользователь 3 берёт 1 книгу
    
    stats2 = accuracy_library.get_statistics()
    print("\
After borrowing:")
    print(f"Total Books: {stats2['total_books']} (Expected: 10)")
    print(f"Available Books: {stats2['available_books']} (Expected: 6)")
    print(f"Borrowed Books: {stats2['borrowed_books']} (Expected: 4)")
    print(f"Total Users: {stats2['total_users']} (Expected: 5)")
    print(f"Users with Books: {stats2['users_with_books']} (Expected: 3)")