task16

using System;

public class Program
{
    public static void Main(string[] args)
    {
        Random random = new Random();

        Library library = new Library(random);
        library.Enter();
    }
}

public class Book
{
    public string Title { get; private set; }
    public string Author { get; private set; }
    public int Year { get; private set; }

    public Book(string title, string author, int year)
    {
        Title = title;
        Author = author;
        Year = year;
    }

    public bool Equals(Book book)
    {
        if(book.Title == Title ||
           book.Author == Author ||
           book.Year == Year)
            return true;
        else
            return false;
    }
}

public class Library
{
    private List<Book> _books;
    private Random _random;

    public Library(Random random)
    {
        _books = new List<Book>();
        _random = random;
    }

    public void Enter()
    {
        bool isChoosed = true;

        int answerShowAllBooks = 1;
        int answerSearchBooks = 2;
        int answerAddBook = 3;
        int answerRemoveBook = 4;
        int answerExit = 5;

        int answer;

        Console.WriteLine("Welcome to the Library");

        while(isChoosed)
        {
            Console.Clear();
            Console.WriteLine("\nWhat you want to do?");
            Console.WriteLine("{0}. Show all books.", answerShowAllBooks);
            Console.WriteLine("{0}. Search books.", answerSearchBooks);
            Console.WriteLine("{0}. Add book.", answerAddBook);
            Console.WriteLine("{0}. Remove book.", answerRemoveBook);
            Console.WriteLine("{0}. Exit.", answerExit);

            bool isDigit = Int32.TryParse(Console.ReadLine(), out answer);

            if(isDigit)
            {
                if(answer == answerShowAllBooks)
                {
                    ShowAllBooks();
                    Console.ReadLine();
                }
                else if(answer == answerSearchBooks)
                {
                    SearchBooks();
                }
                else if(answer == answerAddBook)
                {
                    CreateBook();
                }
                else if(answer == answerRemoveBook)
                {
                    RemoveBook();
                }
                else if(answer == answerExit)
                {
                    isChoosed = false;
                }
            }
        }

        Console.WriteLine("You exit library");
    }

    private void CreateBook()
    {
        bool isChoosed = true;

        int answerCreateRandom = 1;
        int answerCreateManual = 2;
        int answerBack = 3;

        int answer;

        while(isChoosed)
        {
            Console.WriteLine("\nWhat you want to do?");
            Console.WriteLine("{0}. Create book by random.", answerCreateRandom);
            Console.WriteLine("{0}. Create book by manual.", answerCreateManual);
            Console.WriteLine("{0}. Back.", answerBack);

            bool isDigit = Int32.TryParse(Console.ReadLine(), out answer);

            if(isDigit)
            {
                if(answer == answerCreateRandom)
                {
                    _books.Add(CreateBookRandom());
                    isChoosed = false;
                }
                else if(answer == answerCreateManual)
                {
                    _books.Add(CreateBookManual());
                    isChoosed = false;
                }
                else if(answer == answerBack)
                {
                    isChoosed = false;
                }
            }
        }
    }

    private Book CreateBookRandom()
    {
        string[] titles = {"Thus Spoke Zarathustra", "Moby Dick", "Organon", "Republic"};
        string[] authors = {"Spinoza", "Aristotle", "Plato", "Socrates"};
        int yearStart = 1800;
        int yearEnd = 2022;

        string title = titles[_random.Next(titles.Length)];
        string author = authors[_random.Next(authors.Length)];
        int year = _random.Next(yearStart, yearEnd);

        Book book = new Book(title, author, year);
        return book;
    }

    private Book CreateBookManual()
    {
        bool isInput = true;

        string title = "";
        string author = "";
        int year = 0;

        while(isInput)
        {
            Console.WriteLine("Input a title of book : ");
            title = Console.ReadLine();

            Console.WriteLine("Input an author of book : ");
            author = Console.ReadLine();

            Console.WriteLine("Input a year of book : ");
            bool isDigit = Int32.TryParse(Console.ReadLine(), out year);

            if(isDigit)
                isInput = false;
        }

        Book book = new Book(title, author, year);
        return book;
    }

    private void RemoveBook()
    {
        Book book = CreateBookManual();
        int booksRemoved = 0;

        for (int start = 0; start < _books.Count;)
        {
            if(_books[start].Equals(book))
            {
                ++booksRemoved;
                _books.RemoveAt(start);
            }
            else
            {
                ++start;
            }
        }

        Console.WriteLine("{0} books removed.", booksRemoved);
        Console.ReadLine();
    }

    private void ShowAllBooks()
    {
        Console.WriteLine("\nList of all books : ");

        for(int start = 0; start < _books.Count; start++)
            Console.WriteLine("{0}. {1} {2} {3}",
                              start, _books[start].Title, _books[start].Author, _books[start].Year);
    }

    private void SearchBooks()
    {
        Book book = CreateBookManual();
        PrintSearchedBooks(book);
    }

    private void PrintSearchedBooks(Book book)
    {
        Console.WriteLine("\nList of searched books : ");

        for(int start = 0; start < _books.Count; start++)
            if(_books[start].Equals(book))
                Console.WriteLine("{0}. {1} {2} {3}",
                              start, _books[start].Title, _books[start].Author, _books[start].Year);

        Console.ReadLine();
    }
}