require "benchmark"
require "./utilities.cr"
require "../src/lru.cr"

def add(lru : LRU(Int32) | EfficientLRU(Int32), nb : UInt32)
	i = 0
	while i < nb
		lru << i
		i += 1
	end
end

def report_add(lru : LRU(Int32) | EfficientLRU(Int32), nb : UInt32, fname : String)
	File.open("#{Context.report_dir}/#{fname}.raw", "w") do |file|
		i = 0
		while i < nb
			elapsed_time = perform_something { lru << i }
			i += 1
			file.puts "#{i} #{elapsed_time.total_nanoseconds}"
		end
	end
end

class Context
	class_property nb_values  : UInt32 = 100_000
	class_property lru_size   : UInt32 = 10_000
	class_property report_dir = "results"
end

if nb_values = ENV["NBVAL"]?
	Context.nb_values = nb_values.to_u32
end

if lru_size = ENV["LRUSIZE"]?
	Context.lru_size = lru_size.to_u32
end

if ARGV.size > 0
	puts "Usage: benchmark-lru"
	puts ""
	puts "envvar: REPORT_DIR=<directory> where to put the results"
	puts "envvar: REPORT_EACH_ADD=<any> to report the duration of each addition of a value in the structure"
	puts "envvar: NBVAL=<nb> (default: 100_000) nb of values to add to the structure"
	puts "envvar: LRUSIZE=<nb> (default: 10_000) max number of values in the structure"
	exit 0
end

ENV["REPORT_DIR"]?.try { |report_dir| Context.report_dir = report_dir }
Dir.mkdir_p Context.report_dir

if ENV["REPORT_EACH_ADD"]?
	LRU(Int32).new(Context.lru_size).tap do |lru|
		report_add lru, Context.nb_values, "lru_#{Context.lru_size}_#{Context.nb_values}"
	end
	EfficientLRU(Int32).new(Context.lru_size).tap do |lru|
		report_add lru, Context.nb_values, "efficientlru_#{Context.lru_size}_#{Context.nb_values}"
	end
else
	Benchmark.ips do |x|
		x.report("adding #{Context.nb_values} values, LRU limited to #{Context.lru_size}") do
			lru = LRU(Int32).new Context.lru_size
			add lru, Context.nb_values
		end

		x.report("adding #{Context.nb_values} values, EfficientLRU limited to #{Context.lru_size}") do
			lru = EfficientLRU(Int32).new Context.lru_size
			add lru, Context.nb_values
		end
	end
end