class Async::HTTP::Cache::Store::Memory

def close
	@gardener.stop
end

def initialize(limit: 1024, maximum_size: 1024*64, prune_interval: 60)
	@index = {}
	@limit = limit
	@maximum_size = maximum_size
	
	@hit = 0
	@miss = 0
	@pruned = 0
	
	@gardener = Async(transient: true, annotation: self.class) do |task|
		while true
			task.sleep(prune_interval)
			
			pruned = self.prune
			@pruned += pruned
			
			Console.logger.debug(self) do |buffer|
				if pruned > 0
					buffer.puts "Pruned #{pruned} entries."
				end
				
				buffer.puts "Hits: #{@hit} Misses: #{@miss} Pruned: #{@pruned} Ratio: #{(100.0*@hit/@miss).round(2)}%"
				
				body_usage = @index.sum{|key, value| value.body.length}
				buffer.puts "Index size: #{@index.size} Memory usage: #{(body_usage / 1024.0**2).round(2)}MiB"
				
				# @index.each do |key, value|
				# 	buffer.puts "#{key.join('-')}: #{value.body.length}B"
				# end
			end
		end
	end
end

def insert(key, request, response)
	if @index.size < @limit
		length = response.body&.length
		if length.nil? or length < @maximum_size
			@index[key] = response
		end
	end
end

def lookup(key, request)
	if response = @index[key]
		if response.expired?
			@index.delete(key)
			
			@pruned += 1
			
			return nil
		end
		
		if etags = request.headers[IF_NONE_MATCH]
			if etags.include?(response.etag)
				return NOT_MODIFIED
			end
		end
		
		@hit += 1
		
		return response.dup
	else
		@miss += 1
		
		return nil
	end
end

def prune
	initial_count = @index.size
	
	@index.delete_if do |key, value|
		value.expired?
	end
	
	return initial_count - @index.size
end