extends SceneTree

var failures: Array[String] = []


func _initialize() -> void:
	call_deferred("_run")


func _run() -> void:
	var viewport := root as Viewport
	var original_msaa := viewport.msaa_3d
	var camera := Camera3D.new()
	camera.current = true
	root.add_child(camera)
	var world: JajceWorld = load("res://world/jajce/JajceWorld.tscn").instantiate()
	root.add_child(world)
	await process_frame
	await physics_frame

	var environment: Environment = (
		(world.get_node("WorldEnvironment") as WorldEnvironment).environment
	)
	var light := world.get_node("DirectionalLight3D") as DirectionalLight3D
	var grass := world.get_node("TerrainRoot/Terrain3D/CozyGrassField") as Node3D
	var grass_controller := world.get_node("TerrainRoot/GrassInteractionController") as Node
	var meadow := world.get_node("PainterlyMeadow") as PainterlyMeadow
	var balanced_meadow := meadow.get_presentation_stats()
	var world_grass_material := grass.get("mesh_material_override") as ShaderMaterial
	var world_process_material := grass.get("process_material") as ShaderMaterial
	var world_sky: Sky = environment.sky
	var world_sky_material: Material = world_sky.sky_material
	var balanced_particle_count := int(grass.get("particle_count"))
	var balanced_render_scale := viewport.scaling_3d_scale

	_check(
		world.get_active_presentation_quality() == JajceWorld.PresentationQuality.BALANCED,
		"Balanced should be the default presentation tier"
	)
	_check(
		balanced_render_scale <= JajceWorld.BALANCED_RENDER_SCALE + 0.001,
		(
			"Balanced should reduce 3D render resolution while leaving UI resolution untouched"
			+ " (found %.2f)" % balanced_render_scale
		)
	)
	_check(
		viewport.msaa_3d == mini(original_msaa, Viewport.MSAA_2X),
		"Balanced should cap authored multisample antialiasing at 2x"
	)
	_check(
		(
			light.directional_shadow_max_distance <= JajceWorld.BALANCED_SHADOW_DISTANCE
			and light.directional_shadow_mode == DirectionalLight3D.SHADOW_PARALLEL_2_SPLITS
			and environment.fog_enabled
			and not environment.volumetric_fog_enabled
		),
		"Balanced should bound shadows and use cheap valley fog instead of volumetric fog"
	)
	_check(
		world_grass_material == grass_controller.get("grass_material"),
		"Grass rendering and interaction should share this world's isolated material"
	)
	_check(
		(
			int(balanced_meadow["multimesh_batch_count"]) == 4
			and int(balanced_meadow["flower_clump_count"]) in range(1, 1801)
			and _meadow_has_finite_placements(meadow)
		),
		"Meadow batches should retain neutral instance colors, finite placement and their clump budget"
	)

	_check(
		world.apply_presentation_quality(JajceWorld.PresentationQuality.HIGH),
		"High presentation tier should be selectable"
	)
	await physics_frame
	var high_particle_count := int(grass.get("particle_count"))
	var high_render_scale := viewport.scaling_3d_scale
	var high_shadow_distance := light.directional_shadow_max_distance
	_check(
		viewport.msaa_3d == original_msaa,
		"High should restore the authored multisample antialiasing setting"
	)
	var high_meadow := meadow.get_presentation_stats()
	_check(
		(
			int(high_meadow["visible_flower_clump_count"]) == int(high_meadow["flower_clump_count"])
			and (
				int(balanced_meadow["visible_flower_clump_count"])
				< int(high_meadow["visible_flower_clump_count"])
			)
		),
		"High should restore every flower clump while Balanced reduces meadow density"
	)
	_check(
		high_particle_count in range(9000, 15001),
		"High should restore the authored grass population"
	)
	_check(
		balanced_particle_count < high_particle_count,
		"Balanced should materially reduce grass density relative to High"
	)
	_check(
		(
			environment.glow_enabled
			and (environment.volumetric_fog_enabled == world.call("_supports_volumetric_fog"))
			and environment.adjustment_enabled
		),
		"High should preserve supported authored effects without enabling unsupported fog"
	)
	_check(
		is_equal_approx(high_shadow_distance, 180.0),
		"High should preserve the authored 180 metre shadow range"
	)
	_check(_all_grass_particles_emitting(grass), "High should render every authored grass cell")

	_check(
		world.apply_presentation_quality(JajceWorld.PresentationQuality.LOW),
		"Low presentation tier should be selectable"
	)
	await physics_frame
	_check(
		viewport.scaling_3d_scale <= JajceWorld.LOW_RENDER_SCALE + 0.001,
		"Low should reduce 3D render resolution"
	)
	_check(
		viewport.msaa_3d == Viewport.MSAA_DISABLED, "Low should disable multisample antialiasing"
	)
	_check(
		(
			environment.fog_enabled
			and not environment.glow_enabled
			and not environment.volumetric_fog_enabled
			and not environment.adjustment_enabled
		),
		"Low should retain cheap valley fog while disabling costly post-processing"
	)
	_check(
		(
			light.directional_shadow_max_distance <= JajceWorld.LOW_SHADOW_DISTANCE
			and light.directional_shadow_mode == DirectionalLight3D.SHADOW_ORTHOGONAL
		),
		"Low should shorten shadows and use one orthogonal shadow region"
	)
	_check(
		int(grass.get("particle_count")) <= high_particle_count / 4,
		"Low should reduce the latent grass population by at least 75 percent"
	)
	_check(
		not grass.visible and not grass.is_physics_processing(),
		"Low should hide grass and stop its camera-grid physics work"
	)
	_check(not grass_controller.is_processing(), "Low should stop grass interaction scans")
	_check(_not_any_grass_particle_emitting(grass), "Low should stop every grass particle emitter")
	var low_meadow := meadow.get_presentation_stats()
	_check(
		(
			int(low_meadow["visible_flower_clump_count"]) > 0
			and (
				int(low_meadow["visible_flower_clump_count"])
				< int(balanced_meadow["visible_flower_clump_count"])
			)
			and low_meadow["flower_clump_count"] == high_meadow["flower_clump_count"]
		),
		"Low should retain a reduced flower population without regenerating placements"
	)
	_check(
		(
			world_grass_material != null
			and int(world_grass_material.get_shader_parameter("interactor_count")) == 0
		),
		"Low should clear grass shader interactors"
	)

	_check(
		world.apply_presentation_quality(JajceWorld.PresentationQuality.HIGH),
		"High should be restorable after Low"
	)
	await physics_frame
	_check(
		(
			is_equal_approx(viewport.scaling_3d_scale, high_render_scale)
			and viewport.msaa_3d == original_msaa
			and environment.glow_enabled
			and (environment.volumetric_fog_enabled == world.call("_supports_volumetric_fog"))
			and environment.adjustment_enabled
			and is_equal_approx(light.directional_shadow_max_distance, high_shadow_distance)
		),
		"Returning to High should restore the authored environment contract"
	)
	_check(
		(
			grass.visible
			and grass.is_physics_processing()
			and grass_controller.is_processing()
			and int(grass.get("particle_count")) == high_particle_count
			and _all_grass_particles_emitting(grass)
		),
		"Returning to High should restore grass rendering and processing"
	)
	_check(
		meadow.get_presentation_stats() == high_meadow,
		"Returning to High should restore the same complete flower batches"
	)

	var world_base_scale := float(world.get("_authored_render_scale"))
	world.free()
	_check(
		(
			is_equal_approx(viewport.scaling_3d_scale, world_base_scale)
			and viewport.msaa_3d == original_msaa
		),
		"An exiting world should restore the viewport scale and antialiasing it originally owned"
	)
	_check(
		(
			world_grass_material.resource_local_to_scene
			and world_process_material.resource_local_to_scene
			and environment.resource_local_to_scene
			and world_sky.resource_local_to_scene
			and world_sky_material.resource_local_to_scene
		),
		"Every mutable environment, sky, and grass resource should be local to one world"
	)
	var fresh_world: JajceWorld = load("res://world/jajce/JajceWorld.tscn").instantiate()
	root.add_child(fresh_world)
	await process_frame
	await physics_frame
	var fresh_environment: Environment = (
		(fresh_world.get_node("WorldEnvironment") as WorldEnvironment).environment
	)
	var fresh_grass := fresh_world.get_node("TerrainRoot/Terrain3D/CozyGrassField") as Node3D
	var fresh_grass_material := fresh_grass.get("mesh_material_override") as ShaderMaterial
	var fresh_process_material := fresh_grass.get("process_material") as ShaderMaterial
	_check(
		(
			fresh_world.get_active_presentation_quality() == JajceWorld.PresentationQuality.BALANCED
			and viewport.msaa_3d == mini(original_msaa, Viewport.MSAA_2X)
			and fresh_environment.fog_enabled
			and not fresh_environment.volumetric_fog_enabled
			and fresh_grass.visible
			and fresh_grass.is_physics_processing()
			and int(fresh_grass.get("particle_count")) == balanced_particle_count
		),
		"A fresh world after Low should start from an isolated Balanced presentation"
	)
	_check(
		(
			environment != fresh_environment
			and environment.sky != fresh_environment.sky
			and environment.sky.sky_material != fresh_environment.sky.sky_material
			and world_grass_material != fresh_grass_material
			and world_process_material != fresh_process_material
			and _all_grass_particles_use_process_material(fresh_grass, fresh_process_material)
		),
		"Sequential Jajce worlds should not share mutable environment, sky, or grass resources"
	)
	var original_scale := float(fresh_world.get("_authored_render_scale"))
	fresh_world.free()
	_check(
		(
			is_equal_approx(viewport.scaling_3d_scale, original_scale)
			and viewport.msaa_3d == original_msaa
		),
		"A sequential world should release its viewport scale and antialiasing ownership"
	)

	var older_owner := _create_presentation_only_world(JajceWorld.PresentationQuality.LOW)
	root.add_child(older_owner)
	await process_frame
	var newer_owner := _create_presentation_only_world(JajceWorld.PresentationQuality.BALANCED)
	root.add_child(newer_owner)
	await process_frame
	_check(
		(
			is_equal_approx(float(newer_owner.get("_authored_render_scale")), original_scale)
			and int(newer_owner.get("_authored_msaa")) == original_msaa
		),
		"Concurrent owners should inherit the viewport's base scale and antialiasing"
	)
	older_owner.free()
	_check(
		(
			is_equal_approx(viewport.scaling_3d_scale, JajceWorld.BALANCED_RENDER_SCALE)
			and viewport.msaa_3d == mini(original_msaa, Viewport.MSAA_2X)
		),
		"A stale owner exiting should preserve the active owner's scale and antialiasing"
	)
	newer_owner.free()
	_check(
		(
			is_equal_approx(viewport.scaling_3d_scale, original_scale)
			and viewport.msaa_3d == original_msaa
		),
		"The final viewport owner should restore the original scale and antialiasing on exit"
	)
	await _check_msaa_previous_owner_and_external_change(viewport)

	var main_scene: Node = load("res://main.tscn").instantiate()
	var time_dial := main_scene.get_node("UI/TimeDial") as Control
	_check(
		(
			is_equal_approx(time_dial.anchor_left, 0.5)
			and is_equal_approx(time_dial.anchor_right, 0.5)
			and is_equal_approx(time_dial.offset_left, -30.0)
			and is_equal_approx(time_dial.offset_right, 30.0)
		),
		"Time dial should remain horizontally centered at weaker-PC window sizes"
	)
	main_scene.free()

	camera.free()
	if failures.is_empty():
		print("Jajce presentation quality checks passed")
		quit(0)
	else:
		for failure in failures:
			push_error(failure)
		quit(1)


func _all_grass_particles_emitting(grass: Node3D) -> bool:
	var particles: Array = grass.get("particle_nodes")
	if particles.is_empty():
		return false
	for value in particles:
		var particle := value as GPUParticles3D
		if particle == null or not particle.emitting:
			return false
	return true


func _meadow_has_finite_placements(meadow: PainterlyMeadow) -> bool:
	var terrain := meadow.get_node(meadow.terrain_path) as Terrain3D
	# The dummy headless renderer returns black for every instance-color readback.
	var can_read_instance_colors := DisplayServer.get_name() != "headless"
	for child in meadow.get_children():
		var batch := child as MultiMeshInstance3D
		if batch == null or batch.multimesh == null:
			return false
		if not batch.multimesh.use_colors or not batch.multimesh.use_custom_data:
			return false
		for index in batch.multimesh.instance_count:
			if (
				can_read_instance_colors
				and not batch.multimesh.get_instance_color(index).is_equal_approx(Color.WHITE)
			):
				return false
			var placement := batch.multimesh.get_instance_transform(index)
			if not placement.is_finite():
				return false
			var point := batch.to_global(placement.origin)
			var height := terrain.data.get_height(point)
			if is_nan(height) or absf(point.y - height) > 0.025:
				return false
	return true


func _create_presentation_only_world(quality: int) -> JajceWorld:
	var world: JajceWorld = load("res://world/jajce/JajceWorld.tscn").instantiate()
	# Stable simulation-facing IDs deliberately allow only one loaded authority
	# world. The ownership test needs only the presentation subtree.
	world.get_node("WorldObjects").free()
	world.presentation_quality = quality
	return world


func _check_msaa_previous_owner_and_external_change(viewport: Viewport) -> void:
	var original_msaa := viewport.msaa_3d
	viewport.msaa_3d = Viewport.MSAA_8X
	var previous_owner := _create_presentation_only_world(JajceWorld.PresentationQuality.LOW)
	root.add_child(previous_owner)
	await process_frame
	var active_owner := _create_presentation_only_world(JajceWorld.PresentationQuality.HIGH)
	root.add_child(active_owner)
	await process_frame
	_check(
		viewport.msaa_3d == Viewport.MSAA_8X,
		"A High owner should inherit authored antialiasing even when the previous owner uses Low"
	)
	active_owner.free()
	_check(
		viewport.msaa_3d == Viewport.MSAA_DISABLED,
		"An exiting active owner should restore the surviving previous owner's antialiasing"
	)
	viewport.msaa_3d = Viewport.MSAA_2X
	previous_owner.free()
	_check(
		viewport.msaa_3d == Viewport.MSAA_2X,
		"Releasing the final owner should preserve an external antialiasing change"
	)
	viewport.msaa_3d = original_msaa


func _not_any_grass_particle_emitting(grass: Node3D) -> bool:
	var particles: Array = grass.get("particle_nodes")
	for value in particles:
		var particle := value as GPUParticles3D
		if particle != null and particle.emitting:
			return false
	return true


func _all_grass_particles_use_process_material(grass: Node3D, material: ShaderMaterial) -> bool:
	var particles: Array = grass.get("particle_nodes")
	if particles.is_empty():
		return false
	for value in particles:
		var particle := value as GPUParticles3D
		if particle == null or particle.process_material != material:
			return false
	return true


func _check(condition: bool, message: String) -> void:
	if not condition:
		failures.append(message)