# An abstract command that returns a dot graph
abstract class CmdGraph
	super DocCommand

	# Mainmodule for linearization
	var mainmodule: MModule

	# Rendering format
	#
	# Default is `dot`.
	# See `allowed_formats`.
	var format = "dot" is optional, writable

	# Allowed rendering formats.
	#
	# Can be `dot` or `svg`.
	var allowed_formats: Array[String] = ["dot", "svg"]

	# Dot to render
	var dot: nullable Writable = null is optional, writable

	# Render `dot` depending on `format`
	fun render: nullable Writable do
		var dot = self.dot
		if dot == null then return null
		if format == "svg" then
			var proc = new ProcessDuplex("dot", "-Tsvg")
			var svg = proc.write_and_read(dot.write_to_string)
			proc.close
			proc.wait
			return svg
		end
		return dot
	end

	redef fun init_command do
		if not allowed_formats.has(format) then
			return new ErrorBadGraphFormat(format, allowed_formats)
		end
		return super
	end
end