function LoadTiles()
	LevelInfo = {}
	Tiles = dofile("Mothback/data/tiles.lua")
	--[[
		on level format:

		id = tile identifier
		depth = order in the render
		force = rendering other tile instead of the one in this position
		overlay = render another tile id
		overlay_depth = foreground/background overlay depth
		type = collision type

	]]
	LevelTiles = json.decode(getInput("Mothback/data/levels/"..currLevel..".json"))
	LevelInfo.Width = GetLevelWidth()
	LevelInfo.Height = #LevelTiles * tileProperties.height
	IndexLevelTiles()
	LoadTileObjects()
end

function GetLevelWidth()
	local width = 0
	for i = 1, #LevelTiles do
		if width < #LevelTiles[i] then width = #LevelTiles[i] end
	end
	return width * tileProperties.width
end

function IndexLevelTiles()
	TileIndex = {}

	-- number of tiles in tileset!
	local width = tileProperties.tileset:getPixelWidth()/tileProperties.width
	local height = tileProperties.tileset:getPixelHeight()/tileProperties.height
	for i = 0, height do
		for j = 0, width do
			TileIndex[i*width+j+1] = love.graphics.newQuad(
														j*tileProperties.width,
														i*tileProperties.height,
														tileProperties.width,
														tileProperties.height,
														tileProperties.tileset:getDimensions()
													)
		end
	end


	for _, properties in pairs(Tiles) do
		if properties.animation ~= nil then
			properties.tileset = love.graphics.newImage("assets/terrain/"..properties.animation..".png")
			properties.imgs = {}
			properties.current_image = 1
			properties.current_subimage = 1

			local tileset = properties.tileset
			local width = tileset:getPixelWidth()/tileProperties.width
			local height = tileset:getPixelHeight()/tileProperties.height
			local image_count = 0

			for i = 0, height-1 do
				for j = 0, width-1 do
					local quad =
						love.graphics.newQuad(
							j*tileProperties.width,
							i*tileProperties.height,
							tileProperties.width,
							tileProperties.height,
							tileset:getDimensions()
						)
					image_count = image_count + 1

					table.insert(properties.imgs,quad)

				end
			end
			properties.image_count = image_count
		end
	end
end

function TilesDisplayFront()
	for i = 1, #LevelTiles do
		for j = 1, #LevelTiles[i] do
			if LevelTiles[i][j] ~= 0 then

				local depth = getTileDepth(LevelTiles[i][j])
				DrawTile(
					LevelTiles[i][j],
					tileProperties.scale * j * tileProperties.width	+ tileProperties.scale * (levelProperties.offset.x - tileProperties.width)	- Camera.pos.x,
					tileProperties.scale * i * tileProperties.height + tileProperties.scale * (levelProperties.offset.y - tileProperties.height) - Camera.pos.y,
					"foreground"
				)

			end
		end
	end
end

function TilesDisplayBack()
	for i = 1, #LevelTiles do
		for j = 1, #LevelTiles[i] do
			if LevelTiles[i][j] ~= 0 then

				local depth = getTileDepth(LevelTiles[i][j])
				DrawTile(
					LevelTiles[i][j],
					tileProperties.scale * j * tileProperties.width	+ tileProperties.scale * (levelProperties.offset.x - tileProperties.width)	- Camera.pos.x,
					tileProperties.scale * i * tileProperties.height + tileProperties.scale * (levelProperties.offset.y - tileProperties.height) - Camera.pos.y,
					"background"
				)

			end
		end
	end
end


function getTileType(tile_id)
	for _, properties in ipairs(Tiles) do
		if properties.id == tile_id then
			return properties.type
		end
	end
end

function getTileDepth(tile_id)
	for _, properties in ipairs(Tiles) do
		if properties.id == tile_id then
			return properties.depth
		end
	end
end

function GridDisplay()
	for i = 1, #LevelTiles do
		for j = 1, #LevelTiles[i] do
			love.graphics.rectangle(
				"line",
				tileProperties.scale * j * tileProperties.width + tileProperties.scale * (levelProperties.offset.x - tileProperties.width) - Camera.pos.x,
				tileProperties.scale * i * tileProperties.height + tileProperties.scale * (levelProperties.offset.y - tileProperties.height) - Camera.pos.y,
				tileProperties.scale * tileProperties.width,
				tileProperties.scale * tileProperties.height
			)
		end
	end
end

function LoadTileObjects()
	objects.collisions = {}
	objects.platforms = {}
	objects.ladders = {}

	for i = 1, #LevelTiles do
		for j = 1, #LevelTiles[i] do
			if LevelTiles[i][j] ~= 0 then

				local type = getTileType(LevelTiles[i][j])

				local base_x = tileProperties.scale * j * tileProperties.width + tileProperties.scale * (levelProperties.offset.x - tileProperties.height)
				local base_y = tileProperties.scale * i * tileProperties.height + tileProperties.scale * (levelProperties.offset.y - tileProperties.height)

				if type == "whole" then
					local col = Collision:new(
						base_x,
						base_y,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.collisions,col)

				elseif type == "half" then

					local col = Collision:new(
						base_x,
						base_y + tileProperties.height/2 * tileProperties.scale,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.collisions,col)

				elseif type == "platform" then
					local plat = Collision:new(
						base_x,
						base_y + tileProperties.scale * 2,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height/4 * tileProperties.scale + tileProperties.scale * 2
					)
					table.insert(objects.platforms,plat)

				elseif type == "ramp2_bot_left_whole" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x,
							base_y + k * tileProperties.scale - tileProperties.scale,
							base_x + k * 2 * tileProperties.scale,
							base_y + k * tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end
					-- fill lower half
					local col = Collision:new(
						base_x,
						base_y + tileProperties.height/2 * tileProperties.scale,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.collisions,col)

				elseif type == "ramp2_bot_left_half" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x,
							base_y + tileProperties.height/2 * tileProperties.scale + k * tileProperties.scale - tileProperties.scale,
							base_x + k * 2 * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale + k * tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end

				elseif type == "ramp2_top_left_whole" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x,
							base_y + tileProperties.height/2 * tileProperties.scale - tileProperties.scale + k * tileProperties.scale,
							base_x + tileProperties.width * tileProperties.scale - (k-1) * 2 * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale - tileProperties.scale + k * tileProperties.scale + tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end
					-- fill higher half
					local col = Collision:new(
						base_x,
						base_y,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height/2 * tileProperties.scale
					)
					table.insert(objects.collisions,col)

				elseif type == "ramp2_top_left_half" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x,
							base_y - tileProperties.scale + k * tileProperties.scale,
							base_x + tileProperties.width * tileProperties.scale - (k-1) * 2 * tileProperties.scale,
							base_y - tileProperties.scale + k * tileProperties.scale + tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end

				elseif type == "ramp2_bot_right_whole" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x + (k-8) * -2 * tileProperties.scale,
							base_y - tileProperties.scale + k * tileProperties.scale,
							base_x + tileProperties.width * tileProperties.scale,
							base_y - tileProperties.scale + k * tileProperties.scale + tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end
					-- fill lower half
					local col = Collision:new(
						base_x,
						base_y + tileProperties.height/2 * tileProperties.scale,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.collisions,col)

				elseif type == "ramp2_bot_right_half" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x + (k-8) * -2 * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale - tileProperties.scale + k * tileProperties.scale,
							base_x + tileProperties.width * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale - tileProperties.scale + k * tileProperties.scale + tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end

				elseif type == "ramp2_top_right_half" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x + (k-8) * -2 * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale - k * tileProperties.scale,
							base_x + tileProperties.width * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale - k * tileProperties.scale + tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end

				elseif type == "ramp2_top_right_whole" then
					for k = 1, 8 do
					-- do ramp owo
						local slope = Collision:new(
							base_x + (k-8) * -2 * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale + tileProperties.height/2 * tileProperties.scale - k * tileProperties.scale,
							base_x + tileProperties.width * tileProperties.scale,
							base_y + tileProperties.height/2 * tileProperties.scale + tileProperties.height/2 * tileProperties.scale - k * tileProperties.scale + tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end
					-- fill higher half
					local col = Collision:new(
						base_x,
						base_y,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height/2 * tileProperties.scale
					)
					table.insert(objects.collisions,col)

				elseif type == "ramp1_bot_left" then

					for k = 1, 16 do
					-- do ramp owo
						local slope = Collision:new(
							base_x,
							base_y + k * tileProperties.scale - tileProperties.scale,
							base_x + k * tileProperties.scale,
							base_y + k * tileProperties.scale
						)
						table.insert(objects.collisions,slope)

					end

				elseif type == "ladder_right" then

					local ladder = Collision:new(
						base_x + (tileProperties.width-4)* tileProperties.scale,
						base_y,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.ladders,ladder)

				elseif type == "ladder_platform_right" then

					local ladder = Collision:new(
						base_x + (tileProperties.width-4)* tileProperties.scale,
						base_y + tileProperties.scale * 2,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.ladders,ladder)

					local plat = Collision:new(
						base_x,
						base_y + tileProperties.scale * 2,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height/4 * tileProperties.scale + tileProperties.scale * 2
					)
					table.insert(objects.platforms,plat)

				elseif type == "ladder_left" then


					local ladder = Collision:new(
						base_x,
						base_y,
						base_x + tileProperties.scale * 4,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.ladders,ladder)

				elseif type == "ladder_platform_left" then


					local ladder = Collision:new(
						base_x,
						base_y + tileProperties.scale * 2,
						base_x + tileProperties.scale * 4,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(objects.ladders,ladder)

					local plat = Collision:new(
						base_x,
						base_y + tileProperties.scale * 2,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height/4 * tileProperties.scale + tileProperties.scale * 2
					)
					table.insert(objects.platforms,plat)

				end
			end
		end
	end
end

function AnimateTiles()
	for _, properties in pairs(Tiles) do
		if properties.animation ~= nil then
		-- calculate subimage
			properties.current_subimage = properties.current_subimage + current_dt
			-- cycle image
			if properties.current_subimage >= properties.delay then
				properties.current_subimage = properties.current_subimage - properties.delay
				properties.current_image = properties.current_image + 1
			end

			if properties.current_image > properties.image_count then
				properties.current_image = properties.current_image - properties.image_count
			end
		end
	end
end

function DrawTile(tile_id,x,y,depth)
	for _, properties in pairs(Tiles) do
		if tile_id == properties.id then
			if properties.animation ~= nil then
				if properties.imgs[properties.current_image] ~= nil
				and properties.depth == depth
				then love.graphics.draw(
					properties.tileset,
					properties.imgs[properties.current_image],
					x,
					y,
					0,
					tileProperties.scale,
					tileProperties.scale
				)	end
			elseif properties.depth == depth then
				if properties.force ~= nil then
					love.graphics.draw(
						tileProperties.tileset,
						TileIndex[properties.force],
						x,
						y,
						0,
						tileProperties.scale,
						tileProperties.scale
					)
				else
					love.graphics.draw(
						tileProperties.tileset,
						TileIndex[properties.id],
						x,
						y,
						0,
						tileProperties.scale,
						tileProperties.scale
					)
				end
			end

			if properties.overlay ~= nil then
				if properties.overlay_depth == depth or properties.overlay_depth == nil and properties.depth == depth then
					if properties.overlay_animated then
						for _, overlay_properties in pairs(Tiles) do
							if overlay_properties.id == properties.overlay then
								love.graphics.draw(
									overlay_properties.tileset,
									overlay_properties.imgs[overlay_properties.current_image],
									x,
									y,
									0,
									tileProperties.scale,
									tileProperties.scale
								)
							end
						end
					else
						love.graphics.draw(
							tileProperties.tileset,
							TileIndex[properties.overlay],
							x,
							y,
							0,
							tileProperties.scale,
							tileProperties.scale
						)
					end
				end
			end
		end
	end
end