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)

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

		if (modified) {
			solve_rects()
			builder.tube("clipper:update")
		}
		draw_ruler()
		draw_regions(base.regions)
		draw_mouse(mouse)
		z = false
	}

	var rects = base.rects = []

	this.creating = false
	this.dragging = false

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

	function bind(){
		canvas.addEventListener("mousedown", function(e){
			var x = e.pageX, y = e.pageY
			mouse = new rect (x,y)
			if (e.shiftKey) {
				mouse.quantize(10)
			}

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

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

	function solve_rects(){
		var rects = sort_rects_by_position(base.rects)

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

		var left, right
		for (var i = 0; i < rects.length; i++) {
			left = rects[i]
			for (var j = i+1; j < rects.length; j++) {
				right = rects[j]
				if (left.intersects(right)) {
					left.clipTo(right)
					right.clipTo(left)
				}
				if (left.x.b < right.x.a) {
					break
				}
			}
		}
		for (var i = 0; i < rects.length; i++) {
			regions = regions.concat(rects[i].regions)
		}

		regions = sort_rects_by_area( regions.filter(function(r){ return !!r }) )

		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)

		modified = false
	//	document.getElementById("intersects").innerHTML = sort_rects_by_position(regions).join("<br>")
	}

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

	return base
}