class App
  def initialize
    @books = []
    @people = []
  end

  def list_books
    puts 'No books available' if @books.empty?
    @books.each do |bk|
      puts "title: #{bk.title}, author: #{bk.author}"
    end
  end

  def list_people
    puts 'No one has registered' if @people.empty?
    @people.each do |human|
      puts "[#{human.class}] id: #{human.id}, Name: #{human.name}, Age: #{human.age}"
    end
  end

  def create_person
    print 'Do you want to create a student (1) or a teacher (2)? [Input the number]: '
    choice = gets.chomp
    if choice == '1'
      create_student
    elsif choice == '2'
      create_teacher
    else
      puts 'Invalid choice. Please enter 1 or 2.'
    end
  end

  def create_student
    print 'Name: '
    name = gets.chomp
    print 'Age: '
    age = gets.chomp.to_i
    print 'Parent permission? [Y/N]: '
    permission = gets.chomp.upcase
    parent_permission = (permission == 'Y')
    student = Student.new(age, nil, name, parent_permission: parent_permission)
    @people.push(student)
  end

  def create_teacher
    print 'Name: '
    name = gets.chomp
    print 'Age: '
    age = gets.chomp.to_i
    print 'Specialization: '
    specialization = gets.chomp
    teacher = Teacher.new(age, specialization, name)
    @people.push(teacher)
  end

  def create_book
    print 'Title: '
    title = gets.chomp
    print 'Author: '
    author = gets.chomp
    book = Book.new(title, author)
    @books.push(book)
  end

  def create_rental
    return if @books.empty? || @people.empty?
    
    puts 'Select a book from the following list by number:'
    @books.each_with_index { |b, i| puts "#{i}: #{b.title}" }
    book_index = gets.chomp.to_i
    return unless book_index.between?(0, @books.length - 1)
    
    puts 'Select a person from the following list by number:'
    @people.each_with_index { |p, i| puts "#{i}: #{p.name}" }
    person_index = gets.chomp.to_i
    return unless person_index.between?(0, @people.length - 1)
    
    print 'Date (YYYY-MM-DD): '
    date = gets.chomp
    Rental.new(date, @books[book_index], @people[person_index])
  end

  def list_rentals
    print 'ID of person: '
    id = gets.chomp.to_i
    person = @people.find { |p| p.id == id }
    if person
      puts 'Rentals:'
      person.rentals.each { |r| puts "Date: #{r.date}, Book: #{r.book.title}" }
    else
      puts 'Person not found.'
    end
  end

  private

  def valid_indices?(p_i, b_i)
    p_i >= 0 && p_i < @people.length && b_i >= 0 && b_i < @books.length
  end
end

class Nameable
  def correct_name
    raise NotImplementedError, "#{self.class} has not implemented method '#{__method__}'"
  end
end

class Decorator < Nameable
  def initialize(nameable)
    super()
    @nameable = nameable
  end

  def correct_name
    @nameable.correct_name
  end
end

class TrimmerDecorator < Decorator
  def correct_name
    super[0..9]
  end
end

class CapitalizeDecorator < Decorator
  def correct_name
    super.capitalize
  end
end

class Rental
  attr_accessor :date, :book, :person

  def initialize(date, book, person)
    @date = date
    @book = book
    @person = person
    book.rentals << self
    person.rentals << self
  end
end

class Book
  attr_accessor :title, :author, :rentals

  def initialize(title, author)
    @title = title
    @author = author
    @rentals = []
  end

  def add_rental(person, date)
    Rental.new(date, self, person)
  end
end

class Classroom
  attr_accessor :label, :students

  def initialize(label)
    @label = label
    @students = []
  end

  def add_student(student)
    @students << student
    student.assign_classroom(self)
  end
end

class Person < Nameable
  attr_accessor :id, :name, :age, :rentals, :parent_permission

  def initialize(age, name = 'Unknown', parent_permission: true)
    super()
    @id = rand(1..1000)
    @name = name
    @age = age
    @parent_permission = parent_permission
    @rentals = []
  end

  def correct_name
    @name
  end

  def can_use_services?
    of_age? || @parent_permission
  end

  def add_rental(book, date)
    Rental.new(date, book, self)
  end

  private

  def of_age?
    @age >= 18
  end
end

class Student < Person
  attr_reader :classroom

  def initialize(age, classroom, name, parent_permission: true)
    super(age, name, parent_permission: parent_permission)
    @classroom = classroom
    classroom.add_student(self) if classroom
  end

  def play_hooky
    '╰(°▽°)╯'
  end

  def assign_classroom(room)
    @classroom = room
  end
end

class Teacher < Person
  attr_accessor :specialization

  def initialize(age, specialization, name = 'Unknown', parent_permission: true)
    super(age, name, parent_permission: parent_permission)
    @specialization = specialization
  end

  def can_use_services?
    true
  end
end