window.ctx = window.w = window.h = null;

var clipper = new function(){
	var base = this
	var canvas = document.createElement("canvas")
	var ctx = window.ctx = canvas.getContext("2d")
	var w = window.w = canvas.width = 500
	var h = window.h = canvas.height = 500
	var regions = []
	document.querySelector("#map").appendChild(canvas)

	var rooms = base.rooms = []

	base.creating = false
	base.dragging = false

	var modified = true
	base.mouse = new rect(0,0,0,0)

	base.init = function (){
		base.bind()
	}
	base.animate = function(){
		clear_canvas()

		if (modified) {
			solve_rects()
			builder.tube("clipper:update")
		}
		draw_ruler()
		draw_regions(base.regions)
		draw_mouse(base.mouse)
		modified = z = false
	}
	
	base.add_room = function(r){
		rooms.push( new room({
			id: base.rooms.length,
			rect: r,
		}) )
	}
	
	base.bind = function(){
		canvas.addEventListener("mousedown", function(e){
			e.stopPropagation()
			var x = e.pageX, y = e.pageY
			base.mouse = new rect (x,y)
			if (e.shiftKey) {
				base.mouse.quantize(10)
			}

			var intersects = rooms.filter(function(r){
				return r.focused = r.rect.contains(x,y)
			})
	
			if (intersects.length){
				clipper.dragging = intersects[0]
			}
			else {
				clipper.creating = true
			}
			if (e.shiftKey && clipper.dragging) {
				clipper.dragging.rect.quantize(10)
			}
		})
		canvas.addEventListener("mousemove", function(e){
			e.stopPropagation()
			var x, y
			if (e.shiftKey) {
				x = quantize( e.pageX, 10 )
				y = quantize( e.pageY, 10 )
			}
			else {
				x = e.pageX
				y = e.pageY
			}

			base.mouse.x.b = x
			base.mouse.y.b = y
	
			if (clipper.dragging) {
				clipper.dragging.rect.translation.a = base.mouse.x.magnitude()
				clipper.dragging.rect.translation.b = base.mouse.y.magnitude()
			}
			else if (clipper.creating) {
				base.mouse.x.b = x
				base.mouse.y.b = y
			}
			else {
				base.mouse.x.a = base.mouse.x.b
				base.mouse.y.a = base.mouse.y.b
			}
		})
		document.addEventListener("mouseup", function(e){
			e.stopPropagation()
			if (clipper.creating) {
				if (base.mouse.height() != 0 && base.mouse.width() != 0) {
					base.add_room( base.mouse.translate() )
				}
			}
			if (clipper.dragging) {
				clipper.dragging.rect.translate()
			}
			base.mouse = new rect(e.pageX, e.pageY)
			clipper.creating = clipper.dragging = false
			modified = true
		})
	}

	function solve_rects(){

		for (var i = 0; i < base.rooms.length; i++) {
			base.rooms[i].id = i
			base.rooms[i].reset()
		}

		var rooms = sort_rooms_by_position( base.rooms )

		var regions = []

		var left, right
		for (var i = 0; i < rooms.length; i++) {
			left = rooms[i]
			for (var j = i+1; j < rooms.length; j++) {
				right = rooms[j]
				if (left.rect.intersects(right.rect)) {
					left.clipTo(right.rect)
					right.clipTo(left.rect)
				}
				if (left.rect.x.b < right.rect.x.a) {
					break
				}
			}
		}
		for (var i = 0; i < rooms.length; i++) {
			rooms[i].regions = rooms[i].regions.filter(function(r){ return !!r })
			regions = regions.concat(rooms[i].regions)
		}

		regions = sort_rects_by_area( regions )

		var ty = new tree (regions[0].y.a, [regions[0]])
		var tx = new tree (regions[0].x.a, ty)
		var ttx, tty
	
		for (var i = 1; i < regions.length; i++) {
			ttx = tx.add (regions[i].x.a, null)
			if (ttx.data) {
				tty = ttx.data.add (regions[i].y.a, null)
				// duplicate polygon?
				if (tty.data) {
					tty.data.forEach(function(yy, ii){
						if (yy.intersects(regions[i])) {
							if (yy.area() > regions[i].area()) {
								regions[i].dupe = true
							}
							else {
								yy.dupe = true
								tty.data[ii] = regions[i]
							}
						}
					})
				}
				else {
					tty.data = [regions[i]]
				}
			}
			else {
				ttx.data = new tree (regions[i].y.a, [regions[i]])
			}
		}

		base.regions = sort_rects_by_position(regions)
	}

	// generate floor and ceiling for some regions
	// generate walls from surviving regions
	// generate ceiling-walls where ceiling has discontinuity

	return base
}