extends SceneTree

# Headless gameplay test: run with
#   godot --headless -s res://tests/test_surface_profiles.gd
# Forgejo #51: a landed gas giant needs its own background shader instead of
# lunar_surface.gdshader recoloured (craters reading as regolith, not
# atmosphere). Verifies:
#   1. the gas profile resolves a background_shader different from rocky's
#      (rocky's stays null - "keep the scene's existing shader")
#   2. PlanetSurfaceController._compose_surface() actually swaps the
#      background material's shader when landing on a gas giant
#   3. landing on a rocky planet leaves the scene's own lunar shader in
#      place - a null background_shader is a no-op, not a forced reset
#
# PlanetSurfaceController's _ready() (which calls _compose_surface()) does
# not fire synchronously inside add_child() for a -s entry-point script -
# it's deferred to the next frame, same as ResourceReadout's was for #49 -
# so every read of the composed shader below waits a frame after add_child()
# rather than checking on the same one.

var game_state: Node
var lunar_shader: Shader
var gas_shader: Shader
var rocky_shader_after_compose: Shader
var scene: Node
var stage: int = 0
var elapsed: float = 0.0


func _initialize() -> void:
	game_state = root.get_node("GameState")
	lunar_shader = load("res://lunar_surface.gdshader")

	# Loaded by path into a local, not referenced by its bare global
	# class_name - same load-order hazard PlanetSetups.gd and
	# PlanetSurfaceController.gd already work around: the class_name cache
	# isn't guaranteed warm before an import pass has run.
	var surface_profiles: Script = load("res://PlanetSurfaceProfiles.gd")
	var rocky_profile: Resource = surface_profiles.get_profile("rocky")
	var gas_profile: Resource = surface_profiles.get_profile("gas")
	if rocky_profile.background_shader != null:
		print("TEST_SURFACE_PROFILES: FAIL (rocky profile sets a background_shader - it should stay null)")
		quit(1)
		return
	if gas_profile.background_shader == null:
		print("TEST_SURFACE_PROFILES: FAIL (gas profile has no background_shader set)")
		quit(1)
		return
	gas_shader = gas_profile.background_shader
	if gas_shader == lunar_shader:
		print("TEST_SURFACE_PROFILES: FAIL (gas profile points at the lunar shader, not its own)")
		quit(1)
		return

	game_state.planet_definition_id = "rocky"
	scene = load("res://PlanetSurface.tscn").instantiate()
	root.add_child(scene)


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if elapsed < 0.2:
				return false
			var rocky_bg: ShaderMaterial = scene.get_node("BackgroundLayer/LunarBackground").material
			rocky_shader_after_compose = rocky_bg.shader
			scene.free()

			game_state.planet_definition_id = "gas_giant"
			scene = load("res://PlanetSurface.tscn").instantiate()
			root.add_child(scene)
			elapsed = 0.0
			stage = 1
			return false
		1:
			if elapsed < 0.2:
				return false
			var gas_bg: ShaderMaterial = scene.get_node("BackgroundLayer/LunarBackground").material
			scene.free()

			if rocky_shader_after_compose != lunar_shader:
				print("TEST_SURFACE_PROFILES: FAIL (landing on a rocky planet changed the background shader)")
				quit(1)
				return true
			if gas_bg.shader != gas_shader:
				print("TEST_SURFACE_PROFILES: FAIL (landing on a gas giant did not swap in gas_surface.gdshader)")
				quit(1)
				return true
			if gas_bg.shader == lunar_shader:
				print("TEST_SURFACE_PROFILES: FAIL (gas surface still uses the lunar shader)")
				quit(1)
				return true

			print("TEST_SURFACE_PROFILES: PASS")
			quit(0)
			return true
	return false