# Tool to parse XML texture atlas and generated Nit code to access subtextures
module texture_atlas_parser

import dom
import gen_nit
import opts

# Command line options
var opts = new OptionContext
var opt_name = new OptionString("Name of the module to generate", "--name", "-n")
var opt_dir = new OptionString("Folder where to write the generated module", "--dir")
opts.add_option(opt_name, opt_dir)
opts.parse
var rest = opts.rest

if opts.errors.not_empty then
	print_error opts.errors
	exit 1
end

if rest.is_empty then
	print_error "Error: Expected the path to the XML file as argument"
	exit 2
end

# Prepare to read XML file and gather the attributes
var xml_file = rest.first
var attributes = new Array[String]

# Insert the first attribute, to load the root texture
var png_file = "images" / xml_file.basename("xml") + "png"
attributes.add """
	var root_texture = new TextureAsset("{{{png_file}}}")"""

# Read XML file
var content = xml_file.to_path.read_all
var xml = content.to_xml
if xml isa XMLError then
	print_error "RSS Parse Error: {xml.message}:{xml.location or else "null"}"
	exit 3
end

var items = xml["TextureAtlas"].first.children
for item in items do if item isa XMLOnelinerTag then
	var x = null
	var y = null
	var width = null
	var height = null
	var name = null
	for attr in item.attributes do if attr isa XMLStringAttr then
		if attr.name == "x" then
			x = attr.value.to_i
		else if attr.name == "y" then
			y = attr.value.to_i
		else if attr.name == "width" then
			width = attr.value.to_i
		else if attr.name == "height" then
			height = attr.value.to_i
		else if attr.name == "name" then
			name = attr.value
		end
	end

	if x != null and y != null and width != null and height != null and name != null then
		name = name.strip_extension(".png").to_snake_case

			var coords = "{x}, {y}, {width}, {height}"
			attributes.add """
	var {{{name}}}: Texture = root_texture.subtexture({{{coords}}})"""
	else
		print_error "Error on {item}"
	end
end

var module_name = opt_name.value
if module_name == null then module_name = "spritesheet"
var class_name = module_name.capitalized.to_camel_case

# Generate Nit code
var nit_module = new NitModule(module_name)
nit_module.header = """
# This file is generated by texture_atlas_parser
"""

nit_module.content.add """
import gamnit::display
import gamnit::textures

class {{{class_name}}}
"""

for a in attributes do nit_module.content.add a

nit_module.content.add """
end"""

var dir = opt_dir.value
if dir != null then
	var out_path = dir / module_name + ".nit"
	nit_module.write_to_file out_path
else
	printn nit_module.write_to_string
end