local blocks = {}

local function tris(x, y, w, h)
	return {
		x, y,
		x+w, y,
		x+w, y+h,
		x, y,
		x, y+h,
		x+w, y+h
	}
end

local function append(t, x, y, w, h)
	for k,v in ipairs(tris(x, y, w, h)) do
		t[#t + 1] = v
	end
end

local blank = Graphics.loadImage(Misc.resolveFile("graphics/stock-0.png"))
local swap = setmetatable({}, {__index = function() return blank end})

local function swapSprites()
	for _,i in ipairs(Block.SIZEABLE) do
		swap[i], Graphics.sprites.block[i].img = Graphics.sprites.block[i].img, swap[i]
	end
end

function onDraw()
	for k,v in ipairs(Block.get(Block.SIZEABLE)) do
		if not v.isHidden then
			table.insert(blocks, v)

			local id = v.id
			local img = Graphics.sprites.block[id].img
			local vtx = {add = append}
			local tex = {add = append}
			local x, y = v.x, v.y
			local w, h = v.width, v.height

			-- size of the edges
			local tw = math.min(w/2, 32)
			local th = math.min(h/2, 32)

			-- size of the edges for tex
			local ttw = tw / 96
			local tth = th / 96

			local x2 = x + tw -- end of first corner
			local x3 = x + w - tw -- start of second corner
			local x4 = x + w --end of box

			local y2 = y + th
			local y3 = y + h - th
			local y4 = y + h
			-- top left
			vtx:add(x, y, tw, th)
			tex:add(0, 0, ttw, tth)
			-- top right
			vtx:add(x3, y, tw, th)
			tex:add(1-ttw, 0, ttw, tth)
			-- bottom left
			vtx:add(x, y3, tw, th)
			tex:add(0, 1-tth, ttw, tth)
			-- bottom right
			vtx:add(x3, y3, tw, th)
			tex:add(1-ttw, 1-tth, ttw, tth)
			local maxI
			for i = x2, x3-32, 32 do
				-- top edge
				vtx:add(i, y, 32, th)
				tex:add(1/3, 0, 1/3, tth)
				-- bottom edge
				vtx:add(i, y3, 32, th)
				tex:add(1/3, 1-tth, 1/3, tth)
				maxI = i
			end
			local maxJ
			for j = y2, y3 - 32, 32 do
				-- left edge
				vtx:add(x, j, tw, 32)
				tex:add(0, 1/3, ttw, 1/3)
				-- right edge
				vtx:add(x3, j, tw, 32)
				tex:add(1-ttw, 1/3, ttw, 1/3)
				maxJ = j
			end
			local iw, jh = 0, 0 -- size of extra fill/edge portion
			if maxI then
				iw = x3 - (maxI + 32)
			end
			if maxJ then
				jh = y3 - (maxJ + 32)
			end
			if maxI and maxJ then
				for i = x2, maxI, 32 do
					for j = y2, maxJ, 32 do
						-- fill
						vtx:add(i, j, 32, 32)
						tex:add(1/3, 1/3, 1/3, 1/3)
					end
				end
			end
			if iw > 0 then
				-- end of top edge
				vtx:add(maxI + 32, y, iw, th)
				tex:add(1/3, 0, iw/96, tth)
				-- end of bottom edge
				vtx:add(maxI + 32, y3, iw, th)
				tex:add(1/3, 1-tth, iw/96, tth)
				if maxJ then
					for j = y2, maxJ, 32 do
						-- right edge of fill
						vtx:add(maxI + 32, j, iw, 32)
						tex:add(1/3, 1/3, iw/96, 1/3)
					end
				end
			end
			if jh > 0 then
				-- end of left edge
				vtx:add(x, maxJ + 32, tw, jh)
				tex:add(0, 1/3, ttw, jh/96)
				-- end of right edge
				vtx:add(x3, maxJ + 32, tw, jh)
				tex:add(1-ttw, 1/3, ttw, jh/96)
				if maxI then
					for i = x2, maxI, 32 do
						-- bottom edge of fill
						vtx:add(i, maxJ + 32, 32, jh)
						tex:add(1/3, 1/3, 1/3, jh/96)
					end
				end
			end
			if iw > 0 and jh > 0 then
				-- bottom right of fill
				vtx:add(maxI + 32, maxJ + 32, iw, jh)
				tex:add(1/3, 1/3, iw/96, jh/96)
			end
			Graphics.glDraw{
				texture = img,
				sceneCoords = true,
				vertexCoords = vtx,
				textureCoords = tex
			}
		end
	end
	swapSprites()
end

function onDrawEnd()
	swapSprites()
end