require 'gtk3'
require 'pp'

DELTA_X=20
DELTA_Y=20

RED  = [0.7,0.0,0.1]
GREEN= [0.1,0.9,0.1]
BLUE = [0.1,0.0,0.7]
BLACK= [0.0,0.0,0.0]

class Rectangle
	attr_accessor :x,:y,:w,:h
	attr_accessor :color
	def initialize x,y,w,h
		@x,@y,@w,@h= x,y,w,h
		@color=BLUE
	end

	def draw ctx
		ctx.set_source_rgb *color
		ctx.rectangle x,y,w,h
		ctx.fill
	end
end

class Drawer

	def initialize
		init_gui
		@grobs=[]
		@on_rect=nil
	end

	def init_gui
		builder = Gtk::Builder.new
		builder.add_from_file('drawing.glade')
		@window = builder['applicationwindow2']
		@window.signal_connect('destroy'){Gtk.main_quit}

		@drawingArea = builder['drawingarea']
		init_event_handlers
		@window.present
	end

	def init_event_handlers

		@drawingArea.signal_connect "draw" do
			ctx=@drawingArea.window.create_cairo_context
			redraw
		end

		@drawingArea.signal_connect("button-press-event") do |widget, event|
			puts "mouse pressed"
			if @on_rect
				@moving=true
			else
				@grobs << Rectangle.new(event.x,event.y,50,50)
				redraw
			end
		end

		@drawingArea.signal_connect("motion-notify-event") do |widget, event|
			puts "moving rect" if @moving
			if @moving
				@on_rect.x=event.x+@dx
				@on_rect.y=event.y+@dy
				@drawingArea.queue_draw
			else
				@on_rect=on_rect?(event)
				if @on_rect
					@dx,@dy=@on_rect.x-event.x,@on_rect.y-event.y
					w,h=@on_rect.w,@on_rect.h
					@drawingArea.queue_draw
				end
			end
		end

		@drawingArea.signal_connect("button-release-event") do |widget, event|
			puts "mouse released"
			@moving=false
			@on_rect=nil
			redraw
		end

		def on_rect? event
			for rect in @grobs
				if event.x>rect.x && event.x < rect.x+rect.w
					if event.y>rect.y && event.y < rect.y+rect.h
						return rect
					end
				end
			end
			nil
		end
	end

	def redraw
		ctx=@drawingArea.window.create_cairo_context
		@grobs.each{|grob| grob.draw(ctx)}
	end


end #class

Drawer.new
Gtk.main