extends SceneTree

const SonarMaterial = preload("res://game/domain/sonar/sonar_material.gd")
const SiteTerrainBaker = preload("res://tools/site_terrain_baker.gd")
const VehicleTestRecipe = preload("res://tools/sites/vehicle_test_terrain_recipe.gd")
const Zone1Recipe = preload("res://tools/sites/zone1_vigilant_recipe.gd")
const SiteTerrainData = preload("res://game/domain/sites/site_terrain_data.gd")

const ZONE1_TERRAIN_PATH := "res://content/sites/zone1_vigilant_terrain.res"

const TEST_COUNT := 16

var _failures: Array[String] = []


func _init() -> void:
	_test_plane_and_blob()
	_test_materials_and_determinism()
	_test_modifiers_and_primitive_materials()
	_test_zone1_artefact_is_stable()

	if _failures.is_empty():
		print("Site baker unit tests: %d passed, 0 failed." % TEST_COUNT)
		quit(0)
	else:
		for failure: String in _failures:
			push_error(failure)
		print("Site baker unit tests: %d failed." % _failures.size())
		quit(1)


func _small_recipe() -> SiteTerrainBaker.Recipe:
	var recipe := SiteTerrainBaker.Recipe.new()
	recipe.columns = 21
	recipe.rows = 21
	recipe.cell_size_m = 2.0
	recipe.origin_x_m = -20.0
	recipe.origin_z_m = -20.0
	recipe.floor_elevation_m = -80.0
	recipe.rock_slope_degrees = 20.0
	return recipe


func _test_plane_and_blob() -> void:
	var recipe := _small_recipe()
	recipe.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 0.0, 0.1, 0.0, 0.0))
	var data := SiteTerrainBaker.bake(recipe)
	_expect(data != null and data.validation_error().is_empty(), "plane recipe bakes valid data")
	_expect(is_equal_approx(data.elevations_m[data.index_of(10, 10)], -30.0), "plane depth at the reference point")
	_expect(is_equal_approx(data.elevations_m[data.index_of(10, 20)], -28.0), "plane slopes along +Z")
	_expect(data.materials[data.index_of(10, 10)] == SonarMaterial.Value.SAND, "gentle plane is sand")

	recipe.primitives.append(SiteTerrainBaker.Blob.new(Vector2(0.0, 0.0), 4.0, 4.0, 10.0))
	data = SiteTerrainBaker.bake(recipe)
	_expect(is_equal_approx(data.elevations_m[data.index_of(10, 10)], -20.0), "blob adds its amplitude at the centre")
	_expect(data.materials[data.index_of(12, 10)] == SonarMaterial.Value.ROCK, "steep blob flank is rock")


func _test_materials_and_determinism() -> void:
	var recipe := _small_recipe()
	recipe.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 0.0, 0.0, 0.0, 0.0))
	recipe.primitives.append(SiteTerrainBaker.Roughness.new(1933, 0.05, 0.5))
	recipe.material_patches.append(
		SiteTerrainBaker.MaterialPatch.new(Vector2(10.0, 10.0), 3.0, SonarMaterial.Value.ROCK)
	)
	var first := SiteTerrainBaker.bake(recipe)
	var second := SiteTerrainBaker.bake(recipe)
	_expect(first.elevations_m == second.elevations_m, "same recipe bakes identical elevations")
	_expect(first.materials == second.materials, "same recipe bakes identical materials")
	_expect(first.materials[first.index_of(15, 15)] == SonarMaterial.Value.ROCK, "material patch overrides the slope rule")
	var calibration := SiteTerrainBaker.bake(VehicleTestRecipe.recipe())
	_expect(calibration != null and calibration.validation_error().is_empty(), "calibration recipe bakes valid data")


## Test doubles for the extension points: a modifier that lifts the field by one metre
## and a primitive that forces rock on a flat plane.
class Lift extends SiteTerrainBaker.Modifier:
	func modify(_x_m: float, _z_m: float, elevation_m: float, _gradient: Vector2) -> float:
		return elevation_m + 1.0


class GradientProbe extends SiteTerrainBaker.Modifier:
	var gradient_at_centre := Vector2.ZERO

	func modify(x_m: float, z_m: float, elevation_m: float, gradient: Vector2) -> float:
		if is_zero_approx(x_m) and is_zero_approx(z_m):
			gradient_at_centre = gradient
		return elevation_m


class RockDisc extends SiteTerrainBaker.Primitive:
	func material_at(x_m: float, z_m: float) -> int:
		if Vector2(x_m, z_m).length() <= 5.0:
			return SonarMaterial.Value.ROCK
		return SiteTerrainBaker.NO_MATERIAL


func _test_modifiers_and_primitive_materials() -> void:
	var recipe := _small_recipe()
	recipe.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 0.2, 0.0, 0.0, 0.0))
	var probe := GradientProbe.new()
	recipe.modifiers.append(probe)
	recipe.modifiers.append(Lift.new())
	var data := SiteTerrainBaker.bake(recipe)
	_expect(is_equal_approx(data.elevations_m[data.index_of(10, 10)], -29.0), "modifier runs after the primitive sum")
	_expect(probe.gradient_at_centre.is_equal_approx(Vector2(0.2, 0.0)), "modifier receives the local gradient (%s)" % probe.gradient_at_centre)

	var flat := _small_recipe()
	flat.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 0.0, 0.0, 0.0, 0.0))
	flat.primitives.append(RockDisc.new())
	var flat_data := SiteTerrainBaker.bake(flat)
	_expect(flat_data.materials[flat_data.index_of(10, 10)] == SonarMaterial.Value.ROCK, "primitive material wins over the slope rule")
	_expect(flat_data.materials[flat_data.index_of(0, 0)] == SonarMaterial.Value.SAND, "primitive material is local")


func _test_zone1_artefact_is_stable() -> void:
	var versioned := load(ZONE1_TERRAIN_PATH) as SiteTerrainData
	_expect(versioned != null, "versioned zone 1 terrain loads")
	if versioned == null:
		return
	var baked := SiteTerrainBaker.bake(Zone1Recipe.recipe())
	_expect(
		baked.elevations_m == versioned.elevations_m and baked.materials == versioned.materials,
		"zone 1 recipe still bakes the versioned artefact byte for byte"
	)


func _expect(condition: bool, label: String) -> void:
	if not condition:
		_failures.append(label)