function LevelLoadTiles()

	LevelData = dofile("Mothback/data/levels/"..currLevel..".lua")

	-- tiles data
	TileData = dofile("Mothback/data/tileset/library.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 or, if multiple tiles {id, id, id,}, choose at random
		overlay_depth = foreground/background overlay depth
		type = collision type
	]]
	LevelTiles = LevelData.tiles
	LevelUpdateDimensions()
	LevelIndexTiles()
	TileCreateObjects()
end

function LevelReloadTiles()
	LevelUpdateDimensions()
	TileCreateObjects()
end

function LevelUpdateDimensions()
	LevelData.Width = LevelGetWidth()
	LevelData.Height = LevelGetHeight()
end

function LevelGetTileHeight()
	return #LevelTiles
end

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

function LevelGetHeight()
	return LevelGetTileHeight() * tileProperties.height
end

function LevelGetWidth()
	return LevelGetTileWidth() * tileProperties.width
end

function LevelIndexTiles()
	TileIndex = {}

	-- index from tileset
	local width = LevelData.tileset:getPixelWidth()/tileProperties.width
	local height = LevelData.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,
														LevelData.tileset:getDimensions()
													)
		end
	end
	TileDataInitialize()

-- instance level tiles according to the Properties
	for i = 1, #LevelTiles do
		for j = 1, #LevelTiles[i] do
			InstanceTile(i,j,LevelTiles[i][j])
		end
	end
end

function TileDataInitialize()
	for _, Properties in pairs(TileData) 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 InstanceTile(i,j,id)
		LevelTiles[i][j] = {}
		local tile = LevelTiles[i][j]
		tile.id = id

		for _, Properties in pairs(TileData) do
			if Properties.id == tile.id then
				if type(Properties.overlay) == "table" then
					tile.display_overlay = Properties.overlay[math.random(#Properties.overlay)]
				else
					tile.display_overlay = Properties.overlay
				end

				if type(Properties.force) == "table" then
					tile.display = Properties.force[math.random(#Properties.force)]
				else
					tile.display = Properties.force
				end
			end
		end
end

function TileGetType(tile)
	for _, Properties in pairs(TileData) do
		if Properties.id == tile.id then
			return Properties.type
		end
	end
end

function TileGetDepth(tile)
	for _, Properties in pairs(TileData) do
		if Properties.id == tile.id then
			return Properties.depth
		end
	end
end

function TileGetLight(tile)
	for _, Properties in pairs(TileData) do
		if Properties.id == tile.id then
			return Properties.light
		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 + (levelProperties.offset.x - tileProperties.width)) - Camera.pos.x,
				tileProperties.scale * (i * tileProperties.height + (levelProperties.offset.y - tileProperties.height)) - Camera.pos.y,
				tileProperties.scale * tileProperties.width,
				tileProperties.scale * tileProperties.height
			)
		end
	end
end

function TileCreateObjects()
	LoadedObjects.Collisions = {}
	LoadedObjects.Platforms = {}
	LoadedObjects.Ladders = {}

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

				local type = TileGetType(LevelTiles[i][j])
				local light = TileGetLight(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 light ~= 0 and light ~= nil then
					CreateLight(
						base_x + tileProperties.width/2 * tileProperties.scale,
						base_y + tileProperties.height/2 * tileProperties.scale,
						light
					)
				end

				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(LoadedObjects.Collisions,col)

				elseif type == "half_bottom" 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(LoadedObjects.Collisions,col)

				elseif type == "half_top" then

					local col = Collision:New(
						base_x,
						base_y ,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height/2 * tileProperties.scale
					)
					table.insert(LoadedObjects.Collisions,col)

				elseif type == "half_right" then

					local col = Collision:New(
						base_x + tileProperties.height/2 * tileProperties.scale,
						base_y,
						base_x + tileProperties.width * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(LoadedObjects.Collisions,col)

				elseif type == "half_left" then

					local col = Collision:New(
						base_x,
						base_y,
						base_x + tileProperties.height/2 * tileProperties.scale,
						base_y + tileProperties.height * tileProperties.scale
					)
					table.insert(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.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(LoadedObjects.Platforms,plat)

				end
			end
		end
	end
end

function AnimateTiles()
	for _, Properties in pairs(TileData) 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,x,y,depth)
	for _, Properties in pairs(TileData) 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
					if Properties.force ~= 0 then
					love.graphics.draw(
						LevelData.tileset,
						TileIndex[tile.display],
						x,
						y,
						0,
						tileProperties.scale,
						tileProperties.scale
					)
					end
				else
					love.graphics.draw(
						LevelData.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(TileData) 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(
							LevelData.tileset,
							TileIndex[tile.display_overlay],
							x,
							y,
							0,
							tileProperties.scale,
							tileProperties.scale
						)
					end
				end
			end
			--[[
			love.graphics.setColor(0,0,1)
			love.graphics.print(tostring(tile.display),x+16,y)
			love.graphics.setColor(1,1,1)
			]]
		end
	end
end