Modeling data with associations

interface.rb

require_relative "patients_repository"
require_relative "rooms_repository"
require_relative "room"
require 'csv'

rooms_repository = RoomsRepository.new("rooms.csv")
patient_repository = PatientsRepository.new("patients.csv", rooms_repository)

room = Room.new(capacity: 10)
rooms_repository.add(room)

another_room = Room.new(capacity: 6)
rooms_repository.add(another_room)

p patient_repository.all

patient.rb

class Patient
	def initialize(attributes = {})
		@name = attributes[:name]
		@discharged = attributes[:discharged] || false
		@room = attributes[:room]
	end

	def room=(room)
		@room = room
	end

	def name
		@name
	end
end

patients.csv

patients_repository.rb

require_relative "patient"

class PatientsRepository
	def initialize(csv_file_path, rooms_repository)
		@csv_file_path = csv_file_path
		@rooms_repository = rooms_repository
		@patients = []
		load_csv
	end

	def all
		@patients
	end

	def add(patient)
		@patients << patient
		save_csv
	end

	def load_csv
		options = { headers: :first_row, header_converters: :symbol }
		CSV.foreach("patients.csv", options) do |row|
			patient = Patient.new(row)
			room_id = row[:room_id].to_i
			room = @rooms_repository.all.find { |room| room.id == room_id }

			patient.room = room
			room.add_patient(patient)

			@patients << patient
		end
	end
end

room.rb

class Room
	class RoomFullError < Exception
	end

	attr_accessor :id
	attr_reader :capacity

	def initialize(attributes = {})
		@capacity = attributes[:capacity]
		@patients = attributes[:patients] || []
	end

	def full?
		@capacity <= @patients.size
	end

	def add_patient(patient)
		if full?
			fail RoomFullError, "Room is full!"
		else
			@patients << patient
		end
	end
end

rooms.csv

rooms_repository.rb

require_relative "room"

class RoomsRepository
	def initialize(csv_file_path)
		@csv_file_path = csv_file_path
		@rooms = []
		load_csv
		@next_id = all.last.id + 1
	end

	def all
		@rooms
	end

	def add(room)
		room.id = @next_id
		@rooms << room
		save_csv
		@next_id += 1
	end

	def load_csv
		options = { headers: :first_row, header_converters: :symbol }
		CSV.foreach(@csv_file_path, options) do |row|
			row[:capacity] = row[:capacity].to_i

			room = Room.new(row)
			room.id = row[:id].to_i

			@rooms << room
		end
	end

	def save_csv
		CSV.open(@csv_file_path, "wb") do |csv|
			csv << ["id", "capacity"]

			all.each do |room|
				p room.capacity
				csv << [room.id, room.capacity]
			end
		end
	end
end