# Model loaded from a file in the asset folder
#
# In case of error, `error` is set accordingly.
# If the error is on the mesh, `mesh` is set to a default `new Cube`.
# If the material is missing or it failed to load, `material` is set to the blueish `new Material`.
class ModelAsset
	super Model
	super Asset

	init do models.add self

	private var loaded = false

	redef fun load
	do
		if loaded then return

		var ext = path.file_extension
		if ext == "obj" then
			load_obj_file
		else
			errors.add new Error("Model at '{path}' failed to load: Extension '{ext or else "null"}' unrecognized")
		end

		if leaves_cache.is_empty then
			# Nothing was loaded, use a cube with the default material
			var leaf = placeholder_model
			leaves_cache.add leaf
		end

		loaded = true
	end

	private fun lazy_load
	do
		if loaded then return

		# Lazy load
		load

		# Print errors when lazy loading only
		if errors.length == 1 then
			print_error errors.first
		else if errors.length > 1 then
			print_error "Loading model at '{path}' raised {errors.length} errors:\n* "
			print_error errors.join("\n* ")
		end
	end

	private fun load_obj_file
	do
		# Read .obj description from assets
		var text_asset = new TextAsset(path)
		var content = text_asset.to_s
		if content.is_empty then
			errors.add new Error("Model failed to load: Asset empty at '{self.path}'")
			leaves_cache.add new LeafModel(new Cube, new Material)
			return
		end

		# Parse .obj description
		var parser = new ObjFileParser(content)
		var obj_def = parser.parse
		if obj_def == null then
			errors.add new Error("Model failed to load: .obj format error on '{self.path}'")
			leaves_cache.add new LeafModel(new Cube, new Material)
			return
		end

		# Check for errors
		if debug_gamnit then assert obj_def.is_coherent

		# Build models
		var converter = new BuildModelFromObj(path, obj_def)
		converter.fill_leaves self
		errors.add_all converter.errors
	end

	redef fun leaves
	do
		lazy_load
		return leaves_cache
	end

	private var leaves_cache = new Array[LeafModel]

	redef fun named_parts
	do
		lazy_load
		return named_leaves_cache
	end

	private var named_leaves_cache = new Map[String, Model]
end