local cargo = require("lib.cargo")
local aseLoader = require("lib.ase-loader")
local pprint = require("lib.pprint")

-- TODO: Maybe add a texture atlas library for packing frame data
-- TODO: For production maybe use another type of loader? (https://github.com/elloramir/packer, https://github.com/EngineerSmith/Runtime-TextureAtlas)
local function loadAsepriteSprite(filename)
	local sprite = {}
	local ase = aseLoader(filename)

	sprite.width = ase.header.width
	sprite.height = ase.header.height
	sprite.variants = {}

	local LAYER_CHUNK = 0x2004
	local CEL_CHUNK = 0x2005
	local TAG_CHUNK = 0x2018

	local frames = {}
	local tags = {}
	local layers = {}
	local first_tag

	for i, ase_frame in ipairs(ase.header.frames) do
		for _, chunk in ipairs(ase_frame.chunks) do
			if chunk.type == CEL_CHUNK then
				local cel = chunk.data
				local buffer = love.data.decompress("data", "zlib", cel.data)
				local data = love.image.newImageData(cel.width, cel.height, "rgba8", buffer)
				local image = love.graphics.newImage(data)
				local frame = frames[i]
				if not frame then
					frame = {
						image = love.graphics.newCanvas(sprite.width, sprite.height),
						duration = ase_frame.frame_duration / 1000
					}
					frame.image:setFilter("nearest", "nearest")
					frames[i] = frame
				end

				-- you need to draw in a canvas before.
				-- frame images can be of different sizes
				-- but never bigger than the header width and height
				love.graphics.setCanvas(frame.image)
				love.graphics.draw(image, cel.x, cel.y)
				love.graphics.setCanvas()
			elseif chunk.type == TAG_CHUNK then
				for j, tag in ipairs(chunk.data.tags) do
					-- first tag as default
					if j == 1 then
						first_tag = tag.name
					end

					-- aseprite use 0 notation to begin
					-- but in lua, everthing starts in 1
					tag.to = tag.to + 1
					tag.from = tag.from + 1
					tag.frames = tag.to - tag.from
					tags[tag.name] = tag
				end
			elseif chunk.type == LAYER_CHUNK then
				table.insert(layers, chunk.data)
			end
		end
	end

	for _, tag in pairs(tags) do
		local variant = {}
		sprite.variants[tag.name] = variant
		for i=tag.from,tag.to do
			table.insert(variant, frames[i])
		end
	end

	if not sprite.variants.default then
		sprite.variants.default = {frames[0]}
	end

	return sprite
end

return cargo.init{
	dir = "data",
	loaders = {
		aseprite = loadAsepriteSprite,
		ase = loadAsepriteSprite,
	}
}