# A Metric that collects float datas
#
# Used sor summarization
class FloatMetric
	super Metric

	redef type VAL: Float

	# `FloatMetric` uses a Map to store values in intern.
	protected var values_cache = new HashMap[ELM, VAL]

	redef fun values do return values_cache

	redef fun clear do values_cache.clear


	redef fun sum do
		var sum = 0.0
		for v in values.values do
			if v.is_nan then continue
			sum += v
		end
		return sum
	end

	redef fun max do
		assert not values.is_empty
		var max: nullable Float = null
		var elem: nullable ELM = null
		for e, v in values do
			if max == null or v > max then
				max = v
				elem = e
			end
		end
		return elem.as(not null)
	end

	redef fun min do
		assert not values.is_empty
		var min: nullable Float = null
		var elem: nullable ELM = null
		for e, v in values do
			if min == null or v < min then
				min = v
				elem = e
			end
		end
		return elem.as(not null)
	end

	redef fun avg do
		if values.is_empty then return 0.0
		return sum / values.length.to_f
	end

	redef fun std_dev do
		var sum = 0.0
		for value in values.values do
			if value.is_nan then continue
			sum += (value - avg).pow(2.to_f)
		end
		return (sum / values.length.to_f).sqrt
	end

	redef fun above_threshold do
		var above = new HashSet[ELM]
		var threshold = threshold
		for element, value in values do
			if value > threshold then above.add(element)
		end
		return above
	end

	redef fun to_console(indent, colors) do
		super
		if colors then
			print "{"\t" * indent}  sum: {sum}".light_gray
		else
			print "{"\t" * indent}  sum: {sum}"
		end
	end
end