private class NullablesMetricsPhase
	super Phase
	redef fun process_mainmodule(mainmodule, given_mmodules)
	do
		if not toolcontext.opt_nullables.value and not toolcontext.opt_all.value then return

		var csv = toolcontext.opt_csv.value
		var out = "{toolcontext.opt_dir.value or else "metrics"}/nullables"
		out.mkdir

		print toolcontext.format_h1("\n# Nullable metrics")

		var model = toolcontext.modelbuilder.model
		var filter = new ModelFilter(private_visibility)

		var metrics = new MetricSet
		metrics.register(new CNBA(model, mainmodule, filter))
		metrics.register(new CNBNA(model, mainmodule, filter))

		var mclasses = new HashSet[MClass]
		for mpackage in model.mpackages do

			print toolcontext.format_h2("\n ## package {mpackage}")

			for mgroup in mpackage.mgroups do
				if mgroup.mmodules.is_empty then continue
				metrics.clear

				# Scalar metrics
				print toolcontext.format_h3("  `- group {mgroup.full_name}")
				var mod_mclasses = new HashSet[MClass]
				for mmodule in mgroup.mmodules do mod_mclasses.add_all(mmodule.intro_mclasses)
				if mod_mclasses.is_empty then continue
				mclasses.add_all(mod_mclasses)
				metrics.collect(new HashSet[MClass].from(mod_mclasses))
				metrics.to_console(1, not toolcontext.opt_nocolors.value)
				if csv then metrics.to_csv.write_to_file("{out}/{mgroup}.csv")
			end
		end
		if not mclasses.is_empty then
			metrics.clear
			# Global metrics
			print toolcontext.format_h2("\n ## global metrics")
			metrics.collect(mclasses)
			metrics.to_console(1, not toolcontext.opt_nocolors.value)
			if csv then metrics.to_csv.write_to_file("{out}/summary.csv")
		end

		compute_nullables_metrics(toolcontext.modelbuilder)
	end
end