# Compute the bounding box of a Logo program
#
# See Part 3
module bound

import visitor
import turtle

redef class Logo
	# Compute the bounding box of the program
	fun bounding_box: BoundBox do
		var v = new BoundVisitor
		v.visit(self)
		return v.bounding_box
	end
end

# An Axis-aligned minimum bounding box that grows to enclose all the given points.
class BoundBox
	# Current minimum x coordinate
	var xmin: Float = inf

	# Current minimum y coordinate
	var ymin: Float = inf

	# Current maximum x coordinate
	var xmax: Float = -inf

	# Current maximum y coordinate
	var ymax: Float = -inf

	redef fun to_s do return "({xmin},{ymin})--({xmax},{ymax})"

	# Update the current min&max coordinate to include the given point.
	fun update(x,y: Float) do
		if x > xmax then xmax = x
		if x < xmin then xmin = x
		if y > ymax then ymax = y
		if y < ymin then ymin = y
	end
end

# Visitor that interprets a Logo program and update the associated bounding box
class BoundVisitor
	super Visitor

	# The moving turtle
	var turtle = new Turtle

	# The growing bounding box
	var bounding_box = new BoundBox

	# TODO Finish the class
end

print logo.fd(10).main.bounding_box
print logo_star.bounding_box
print logo_home.bounding_box