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
#   2. PlanetSurfaceController._compose_surface() actually swaps the
#      background material's shader when landing on a gas giant
#   3. landing on a rocky planet ends up on rocky's own declared shader
#
# Rocky's background_shader used to be left null, meaning "keep whatever the
# hosting scene already had". That convention is gone: it resolved to a
# different shader in the game than in the setup editor, which is exactly how
# the two came apart (see tests/test_surface_background_shared.gd). Every
# profile now names its shader, so this checks rocky lands on ITS OWN rather
# than on whatever PlanetSurface.tscn shipped with.
#
# 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 scene_shader: Shader
var rocky_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")
	# Whatever PlanetSurface.tscn itself ships with, read from the scene
	# rather than named by path. The property under test is "a null
	# background_shader leaves the scene's own background alone" - naming a
	# specific file here instead made this fail the moment the lunar
	# background changed implementation (#68 swapped the per-pixel
	# procedural shader for a baked, tiled one), which is a change this test
	# has no business having an opinion about.
	var packed: PackedScene = load("res://surface/PlanetSurface.tscn")
	var probe: Node = packed.instantiate()
	scene_shader = probe.get_node("BackgroundLayer/Background").material.shader
	probe.free()


	# 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://surface/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 has no background_shader set)")
		quit(1)
		return
	rocky_shader = rocky_profile.background_shader
	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 == scene_shader:
		print("TEST_SURFACE_PROFILES: FAIL (gas profile points at the scene's own shader, not its own)")
		quit(1)
		return

	game_state.planet_definition_id = "rocky"
	scene = load("res://surface/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/Background").material
			rocky_shader_after_compose = rocky_bg.shader
			scene.free()

			game_state.planet_definition_id = "gas_giant"
			scene = load("res://surface/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/Background").material
			scene.free()

			if rocky_shader_after_compose != rocky_shader:
				print("TEST_SURFACE_PROFILES: FAIL (landing on a rocky planet did not put rocky's own declared shader on the background)")
				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 == scene_shader:
				print("TEST_SURFACE_PROFILES: FAIL (gas surface still uses the scene's own lunar background)")
				quit(1)
				return true

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