extends SceneTree

# Reusable screenshot tool - NOT run via run_tests.sh (underscore prefix).
# Loads a given scene, waits for a given number of frames to render, then
# saves a PNG and quits. Must be run WITHOUT --headless (that forces
# Godot's dummy/null renderer) - see tests/screenshot.sh for the full
# invocation (Xvfb + Mesa softpipe; llvmpipe's JIT crashes with SIGILL in
# this environment, softpipe's non-JIT rasterizer does not).
#
# Args (after `--`): <scene_res_path> <output_png_path> [wait_frames]
#                    [key=value ...]
#
# Any trailing key=value pairs are assigned onto the GameState autoload
# BEFORE the scene is instantiated. Several scenes read GameState in
# _ready() to decide what they draw - PlanetSurface.tscn picks its whole
# surface profile from planet_definition_id - so without this the tool can
# only ever photograph the default planet:
#
#   ... -- res://PlanetSurface.tscn out.png 90 planet_definition_id=gas_giant

var wait_frames: int = 60
var frames: int = 0
var scene_path: String
var output_path: String
var loaded_scene: Node


func _initialize() -> void:
	var args: PackedStringArray = OS.get_cmdline_user_args()
	if args.size() < 2:
		printerr("usage: -- <scene_res_path> <output_png_path> [wait_frames]")
		quit(1)
		return

	scene_path = args[0]
	output_path = args[1]
	if args.size() >= 3:
		wait_frames = int(args[2])
	for i in range(3, args.size()):
		var pair: PackedStringArray = args[i].split("=", true, 1)
		if pair.size() != 2:
			printerr("expected key=value, got: %s" % args[i])
			quit(1)
			return
		root.get_node("GameState").set(pair[0], pair[1])

	var packed: PackedScene = load(scene_path)
	if packed == null:
		printerr("could not load scene: %s" % scene_path)
		quit(1)
		return

	loaded_scene = packed.instantiate()
	root.add_child(loaded_scene)


func _process(_delta: float) -> bool:
	frames += 1
	if frames < wait_frames:
		return false
	var img: Image = root.get_viewport().get_texture().get_image()
	var err: int = img.save_png(output_path)
	if err != OK:
		printerr("save_png failed with error %d" % err)
		quit(1)
		return true
	print("SCREENSHOT_SAVED: %s (%s)" % [output_path, str(img.get_size())])
	quit(0)
	return true