#! /usr/bin/env ruby

require 'erb'
require 'json'
require 'open3'
require 'set'

$datestr = (Time.now - 86400).strftime '%F'

class Object
	def also
		yield self
		self
	end

	def let
		yield self
	end
end

# @param [String] station_name
def normalize_station station_name
	station_name
		.downcase
		.gsub(/\s/, ' ')
		.gsub('ă', 'a')
		.gsub('â', 'a')
		.gsub('î', 'i')
		.gsub('ș', 's')
		.gsub('ț', 't')
end

$station_link_name_cache = {}

# @param [String] station_name
def get_station station_name
	# Try getting from file
	begin
		return JSON.parse(File.read(File.join($datestr, 'stations', "#{normalize_station(station_name)}.json")), symbolize_names: true)
	rescue
	end

	station_name = normalize_station station_name
	station_name = $station_link_name_cache.fetch(station_name, station_name)
	station_name = ERB::Util.url_encode(station_name)
	stdout, status = Open3.capture2('curl', '--silent', '--fail', '--show-error', "https://scraper.infotren.dcdev.ro/v3/stations/#{station_name}?date=#{$datestr}")
	if status != 0
		nil
	else
		JSON.parse stdout, symbolize_names: true
	end
end

# @param [String] train_number
def get_train train_number
	# Try getting from file
	begin
		return JSON.parse(File.read(File.join($datestr, 'trains', "#{train_number}.json")), symbolize_names: true)
	rescue
	end

	train_number = ERB::Util.url_encode(train_number)
	stdout, status = Open3.capture2('curl', '--silent', '--fail', '--show-error', "https://scraper.infotren.dcdev.ro/v3/trains/#{train_number}?date=#{$datestr}")
	if status != 0
		nil
	else
		JSON.parse stdout, symbolize_names: true
	end
end

def populate_link_name_cache train
	train[:groups].each do |g|
		g[:stations].each do |s|
			$station_link_name_cache[s[:name]] = s[:linkName]
		end
	end
end

def get_stations_from_station station
	Set.new.also do |stations|
		station[:arrivals].each do |train| 
			train[:train][:route].each do |r|
				stations << r
			end
		end
		station[:departures].each do |train| 
			train[:train][:route].each do |r|
				stations << r
			end
		end
	end
end

# @param [Integer] times
def reattempt times
	times.times do |n|
		result = yield
		unless result.nil?
			return result
		end
	end
	nil
end

def get_trains_from_station station
	Set.new.also do |trains|
		station[:arrivals].each do |train| 
			trains << train[:train][:number]
		end
		station[:departures].each do |train| 
			trains << train[:train][:number]
		end
	end
end

def get_stations_from_train train
	train[:groups].flat_map do |group|
		group[:stations].map do |station|
			station[:name]
		end
	end
end

class Log
	def initialize
		@to_erase = 0
	end

	def add message
		print "\e[1A\e[2K" * @to_erase
		@to_erase = 0
		puts message
	end

	def temporary_add message
		if $stdout.isatty
			puts message
			@to_erase += 1
		end
	end
end

def main
    File.write('./last_attempted_run.txt', $datestr)
	log = Log.new

	log.add "Creating archive for yesterday, #{$datestr}"

	existing = if Dir.exist? $datestr
		log.add 'Archive already exists. Merging.'
		true
	else
		Dir.mkdir $datestr
		Dir.mkdir(File.join $datestr, 'stations')
		Dir.mkdir(File.join $datestr, 'trains')
		false
	end

	# @type [Array<String>] 
	roots = ['București Nord', 'Brașov', 'Iași', 'Titan Sud', 'Oltenița', 'Oravița', 'Anina']
	# @type [Array<String>] 
	visited_stations = Dir.entries(File.join $datestr, 'stations')
		.filter { |entry| entry != '.' and entry != '..' }
		.map { |name| if name.end_with? ".json" then name[0...-5] else name end }
		.map { |name| get_station(name)[:stationName] }
	if existing
		log.add "#{visited_stations.count} visited stations"
	end
	# @type [Array<String>] 
	unvisited_stations = []
	# @type [Set<String>] 
	failed_stations = Set.new

	# @type [Array<String>] 
	visited_trains = Dir.entries(File.join $datestr, 'trains')
		.filter { |entry| entry != '.' and entry != '..' }
		.map { |name| if name.end_with? ".json" then name[0...-5] else name end }
	if existing
		log.add "#{visited_trains.count} visited trains"
	end
	# @type [Array<String>] 
	unvisited_trains = []
	# @type [Set<String>] 
	failed_trains = Set.new

	roots.each do |station|
		unvisited_stations.push station unless visited_stations.include? station
	end

	# Get unvisited from visited
	visited_trains.each do |train_number|
		train = get_train train_number
		populate_link_name_cache train

		get_stations_from_train(train).each do |station|
			unvisited_stations << station unless visited_stations.include? station or unvisited_stations.include? station
		end
	end
	visited_stations.each do |station_name|
		station = get_station station_name

		get_stations_from_station(station).each do |station|
			unvisited_stations << station unless visited_stations.include? station or unvisited_stations.include? station
		end
		get_trains_from_station(station).each do |train|
			unvisited_trains << train unless visited_trains.include? train or unvisited_trains.include? train
		end
	end
	unless unvisited_stations.empty?
		log.add "#{unvisited_stations.count} unvisited stations"
	end
	unless unvisited_trains.empty?
		log.add "#{unvisited_trains.count} unvisited trains"
	end

	start_time = Time.now
	File.write(File.join($datestr, 'start_time.txt'), start_time.strftime('%FT%T%:z'))
	
	until unvisited_stations.empty? and unvisited_trains.empty?
		# First visit all trains
		if not unvisited_trains.empty?
			# @type [String] 
			train_number = unvisited_trains.shift
			log.temporary_add "Getting train #{train_number}"
			train = reattempt 3 do get_train train_number end
			if train.nil?
				# Failed to get
				failed_trains << train_number
				log.add "Failed to get train #{train_number}"
			else
				populate_link_name_cache train
				visited_trains << train_number
				File.write(File.join($datestr, 'trains', "#{train_number}.json"), JSON.dump(train))
				log.add "Got train #{train_number}"
				old_ustations_cnt = unvisited_stations.count
				get_stations_from_train(train).each do |station|
					unvisited_stations << station unless visited_stations.include? station or unvisited_stations.include? station
				end
				unless unvisited_stations.count == old_ustations_cnt
					log.add "Found #{unvisited_stations.count - old_ustations_cnt} new stations"
				end
			end
			log.temporary_add "Stations: #{visited_stations.count} visited, #{failed_stations.count} failed, #{unvisited_stations.count} remaining"
			log.temporary_add "Trains: #{visited_trains.count} visited, #{failed_trains.count} failed, #{unvisited_trains.count} remaining"
		# Then visit stations
		elsif not unvisited_stations.empty?
			# @type [String] 
			station_name = unvisited_stations.shift
			log.temporary_add "Getting station #{station_name}"
			station = reattempt 3 do get_station station_name end
			if station.nil?
				# Failed to get
				failed_stations << station_name
				log.add "Failed to get station #{station_name}"
			else
				visited_stations << station_name
				filename = normalize_station(station_name)
				filename = $station_link_name_cache.fetch(filename, filename)
				File.write(File.join($datestr, 'stations', "#{filename}.json"), JSON.dump(station))
				log.add "Got station #{station_name}"
				old_ustations_cnt = unvisited_stations.count
				old_utrains_cnt = unvisited_trains.count
				get_stations_from_station(station).each do |station|
					unvisited_stations << station unless visited_stations.include? station or unvisited_stations.include? station
				end
				get_trains_from_station(station).each do |train|
					unvisited_trains << train unless visited_trains.include? train or unvisited_trains.include? train
				end
				unless unvisited_stations.count == old_ustations_cnt
					log.add "Found #{unvisited_stations.count - old_ustations_cnt} new stations"
				end
				unless unvisited_trains.count == old_utrains_cnt
					log.add "Found #{unvisited_trains.count - old_utrains_cnt} new trains"
				end
			end
			log.temporary_add "Stations: #{visited_stations.count} visited, #{failed_stations.count} failed, #{unvisited_stations.count} remaining"
			log.temporary_add "Trains: #{visited_trains.count} visited, #{failed_trains.count} failed, #{unvisited_trains.count} remaining"
		end
	end

	log.add "Stations: #{visited_stations.count} visited, #{failed_stations.count} failed, #{unvisited_stations.count} remaining"
	log.add "Trains: #{visited_trains.count} visited, #{failed_trains.count} failed, #{unvisited_trains.count} remaining"

	end_time = Time.now
	File.write(File.join($datestr, 'end_time.txt'), end_time.strftime('%FT%T%:z'))
	timespan = (end_time - start_time).to_i
	log.add "Finished in #{timespan}s (#{timespan / 3600}h #{timespan / 60 % 60}m #{timespan % 60}s)"

	# Finally, write failures log
	File.open(File.join($datestr, 'failed_stations.txt'), "w") do |f|
		failed_stations.each do |s|
			f.puts s
		end
	end
	File.open(File.join($datestr, 'failed_trains.txt'), "w") do |f|
		failed_trains.each do |s|
			f.puts s
		end
	end
	File.write(File.join($datestr, 'failures.json'), JSON.dump({
		stations: failed_stations,
		trains: failed_trains,
	}))
    File.write('./last_executed_run.txt', $datestr)
    
	if visited_stations.count == 0 and visited_trains.count == 0
		exit 1
	end
end

if __FILE__ == $0
	main
end