require 'csv'

class YouTubeDataParser 

	def initialize( args )

		raise "Missing 'file1.csv'" if args[0].nil?
		raise "Missing 'file2.csv'" if args[1].nil?

		file1 = CSV.read(args[0], headers: true)
		file2 = CSV.read(args[1], headers: true)

		@file1 = file1
		@file2 = file2
		@concern = args[2]

		yt_data_checker(@file1, @file2, @concern)
	end


	#checks for concern, directs correct files.
	def yt_data_checker(file1, file2, concern)

		if concern == "channel_ownership"
			sanitize_channels(file1, file2)
			calculate_differences(@file_1_yt_channels, @file_2_yt_channels)
			print_emails(@total_difference)
		elsif concern == "subscriber_count"
			sanitize_subscriber_count(file1, file2)
			calculate_differences(@file_1_subscriber_count, @file_2_subscriber_count)
			print_emails(@total_difference)
		else
			sanitize_channels(file1, file2)
			sanitize_subscriber_count(file1, file2)
			calculate_differences(@file_1_yt_channels, @file_2_yt_channels)
			calculate_differences(@file_1_subscriber_count, @file_2_subscriber_count)
			print_emails(@total_difference)
		end
	end


	#Normalizes channels
	def sanitize_channels(file1, file2)
		@file_1_yt_channels = {}
		@file_2_yt_channels = {}

		file1.each do |row|
			@file_1_yt_channels[row[0]] = row[1].split('/').last #.gsub(/^UC/, "") -> Insert if UC is error in input 
		end

		file2.each do |row|
			@file_2_yt_channels[row[0]] = row[1].split('/').last #.gsub(/^UC/, "") -> Insert if UC is error in input
		end
	end


	#Normalizes subscriber count
	def sanitize_subscriber_count(file1, file2)
		@file_1_subscriber_count = {}
		@file_2_subscriber_count = {}

		file1.each do |row|
			@file_1_subscriber_count[row[0]] = row[2].gsub(/\W/, "").to_s
		end

		file2.each do |row|
			@file_2_subscriber_count[row[0]] = row[2].gsub(/\W/, "").to_s
		end
	end


	#Calculates between suppled channel_ownership, subscribe_count or both.
	def calculate_differences(data_set1, data_set2)
		@differences ||= []

		@differences = @differences +  (data_set1.to_a - data_set2.to_a)

		@total_difference = @differences
	end


	#Iterates through differneces, collects emails and prints them out.
	def print_emails(differences)

		emails = []

		differences.each do |difference|
			emails << difference[0]
		end

		puts "-------Emails With Discrepancies------"
		puts emails.uniq
		puts "--------------------------------------"
	end
end


YouTubeDataParser.new( ARGV )