# Phase that assign a `FFILanguage` to all `AExternCodeBlock`
#
# It will also report errors when using an unknown foreign langages.
class FFILanguageAssignationPhase
	super Phase

	# All supported languages
	var languages = new Array[FFILanguage]

	redef fun process_nmodule(nmodule)
	do
		for block in nmodule.n_extern_code_blocks do
			verify_foreign_code_on_node( block )
		end
	end

	redef fun process_npropdef(npropdef)
	do
		if npropdef isa AMethPropdef then
			var code_block = npropdef.n_extern_code_block
			if code_block != null then
				verify_foreign_code_on_node( code_block )
			end
		end
	end

	redef fun process_nclassdef(nclassdef)
	do
		if nclassdef isa AStdClassdef and nclassdef.n_extern_code_block != null then
			verify_foreign_code_on_node( nclassdef.n_extern_code_block.as(not null) )
		end
	end

	private fun verify_foreign_code_on_node(n: AExternCodeBlock)
	do
		var found = false
		for v in languages do
			var identified = v.identify_language(n)
			if identified then
				if found and identified then
					toolcontext.error(n.location, "FFI Error: two languages identified as possible handlers.")
				end
				n.language = v
				found = true
			end
		end

		if not found then toolcontext.error(n.location, "FFI Error: unsupported language.")
	end
end