extends SceneTree

## 第四轮修复契约（2026-07-05，07-06 修订）：
## 1. 小怪击退：残速不再被 AI 每帧接管清零，产生实际水平滑行；
##    垂直击退后假高度轴正常积分并落地复位 Grounded（修复"被剑雨/下砸
##    打过一次后 ground_state 永久 Airborne、小怪从此不能出招"的隐藏 bug）。
## 2. 趔趄门禁：击退滑行期间 Boss/小怪不得起手新动作（EnemyActionDriver
##    钩子），否则动作突进立刻接管 velocity 冲回玩家，把击退整个吃掉
##    （真实 stage 实测净位移为负）；Boss 受击链强制撤退豁免（清残速标志）。
## 3. 关卡背景分层契约：当前整图里的地面/步道先锁在 1:1 世界层，避免脚下
##    地砖相对角色滑动；美术拆出的天空/夕阳放入 SkyParallaxLayer 后继续按
##    0.2 倍世界滚动（相机 0.8 跟随）。
## （Boss 击退 ×9 的加码钉在 test_round3_fixes。）

var failures: Array[String] = []


func _init() -> void:
	_run.call_deferred()


func _run() -> void:
	root.size = Vector2i(1152, 648)
	var settings := root.get_node_or_null("GameSettings")
	if settings != null:
		settings.call("set_difficulty", &"easy")
	await _check_minion_horizontal_knockback()
	await _check_minion_vertical_knockback_recovers()
	await _check_stagger_gates_enemy_actions()
	await _check_boss_to_player_knockback()
	await _check_background_parallax()
	_finish()


func _make_minion() -> Node2D:
	var scene: PackedScene = load("res://scenes/enemies/minion.tscn")
	var minion := scene.instantiate() as Node2D
	root.add_child(minion)
	# 与 test_minion_phase_system 同款：关 AI，排除追击/巡逻对位移的污染。
	var behavior := minion.get_node_or_null("MinionBehavior")
	if behavior != null:
		behavior.set("enabled", false)
	minion.set("approach_direction", 0.0)
	return minion


func _check_minion_horizontal_knockback() -> void:
	var minion := _make_minion()
	await process_frame
	minion.global_position = Vector2(500.0, 300.0)
	var motor := minion.get_node("MovementMotor")
	var start_x := minion.global_position.x
	motor.call("apply_knockback", Vector2(120.0, 0.0))
	await physics_frame
	await physics_frame
	await physics_frame
	_expect((minion as CharacterBody2D).velocity.x > 0.0, "小怪击退残速不再被 AI 每帧清零")
	for _index: int in range(40):
		await physics_frame
	var displacement := minion.global_position.x - start_x
	_expect(displacement > 5.0, "小怪击退产生实际水平滑行（got %.2f px）" % displacement)
	_expect(not bool(motor.call("has_knockback_stray")), "残速衰减完后 stray 标志自清（AI 可恢复接管）")
	minion.free()


func _check_minion_vertical_knockback_recovers() -> void:
	var minion := _make_minion()
	await process_frame
	minion.global_position = Vector2(500.0, 300.0)
	var motor := minion.get_node("MovementMotor")
	var state_machine := minion.get_node("StateMachine")
	motor.call("apply_knockback", Vector2(0.0, 300.0))
	await physics_frame
	_expect_equal(state_machine.call("get_ground_state"), &"Airborne", "垂直击退令小怪进入 Airborne")
	var landed := false
	for _index: int in range(180):
		await physics_frame
		if state_machine.call("get_ground_state") == &"Grounded" \
				and is_zero_approx(float(minion.get("height"))) \
				and is_zero_approx(float(minion.get("height_speed"))):
			landed = true
			break
	_expect(landed, "垂直击退后小怪应自然落地复位 Grounded（旧版永久卡 Airborne 导致无法出招）")
	minion.free()


func _check_stagger_gates_enemy_actions() -> void:
	# Boss：击退滑行期间不得起手新动作；强制撤退清残速后恢复。
	var boss_scene: PackedScene = load("res://scenes/enemies/boss.tscn")
	var boss := boss_scene.instantiate() as Node2D
	root.add_child(boss)
	await process_frame
	boss.set("combat_enabled", true)
	boss.set("stationary", false)
	# 用不解析的动作 ID 旁路 BossBehaviorTree 的相位限型分支（melee/ranged
	# 按时间相位限制与本契约无关），只隔离趔趄门禁本身。
	var boss_motor := boss.get_node("MovementMotor")
	_expect(bool(boss.call("can_start_enemy_action", &"__stagger_probe__")), "无击退时 Boss 可正常起手")
	boss_motor.call("apply_knockback", Vector2(120.0, 0.0))
	_expect(not bool(boss.call("can_start_enemy_action", &"__stagger_probe__")),
		"击退滑行（趔趄）期间 Boss 不得起手新动作——否则突进会吃掉击退位移")
	boss_motor.call("clear_knockback_stray")
	_expect(bool(boss.call("can_start_enemy_action", &"__stagger_probe__")),
		"清残速标志后恢复起手（受击链强制撤退走此豁免）")
	boss.free()

	# 小怪：同款门禁。
	var minion := _make_minion()
	await process_frame
	var minion_motor := minion.get_node("MovementMotor")
	_expect(bool(minion.call("can_start_enemy_action", &"__stagger_probe__")), "无击退时小怪可正常起手")
	minion_motor.call("apply_knockback", Vector2(120.0, 0.0))
	_expect(not bool(minion.call("can_start_enemy_action", &"__stagger_probe__")),
		"击退滑行期间小怪不得起手新动作")
	minion.free()


func _check_boss_to_player_knockback() -> void:
	# 2026-07-06 策划（连续三轮）："Boss 对玩家没有任何击退效果"。两个根因：
	# ①Boss 近战沿用默认基准 120，普通连段倍率 0.4/0.5 → 位移仅 2~3px，且相机
	#   1:1 跟随玩家把位移完全吃进视觉；②敌方弹丸基准击退 (0,0)，未来相位
	#   Boss 只用远程 → 恒为零。修复=Boss 近战基准 ×3 初速 + 敌弹补基准。
	var boss_scene: PackedScene = load("res://scenes/enemies/boss.tscn")
	var boss := boss_scene.instantiate()
	root.add_child(boss)
	await process_frame
	var emitter := boss.get_node("DamageEmitter")
	_expect((emitter.get("base_knockback") as Vector2).is_equal_approx(Vector2(360.0, 304.056)),
		"Boss 近战基准击退 ×3 初速（普通连段 2px→20~32px、重击 190~343px）")
	boss.free()

	var container: Node2D = (load("res://scenes/stage/actors_container.gd") as GDScript).new()
	root.add_child(container)
	container.call("_on_projectile_requested", null, Vector2.ZERO, Vector2.LEFT, {"team": &"enemy"})
	await process_frame
	var bullet := container.get_child(0)
	_expect((bullet.get("base_knockback") as Vector2).is_equal_approx(Vector2(360.0, 0.0)),
		"敌方弹丸补上基准击退（未来相位不再恒为零，弹丸不击飞）")
	_expect_float(float(bullet.get("speed")), 416.0, "敌弹速度保持 416 不受击退注入影响")
	container.free()


func _check_background_parallax() -> void:
	var scene: PackedScene = load("res://scenes/ground/ground1.tscn")
	var ground := scene.instantiate()
	root.add_child(ground)
	await process_frame
	await process_frame
	var art_layer := ground.get_node("ArtLayer") as Node2D
	var sky_layer := ground.get_node("SkyParallaxLayer") as Node2D

	# 无相机：世界层与可选远景层都保持原位（headless/菜单兜底）。
	_expect_float(art_layer.position.x, 896.5, "无相机时地面世界层保持基准位置")
	_expect_float(sky_layer.position.x, 896.5, "无相机时远景视差层保持基准位置")

	# 有相机：地面/步道保持 1:1 世界坐标；远景容器按
	# (相机中心 - 1734.5) × 0.8 视差移动。
	var camera := Camera2D.new()
	root.add_child(camera)
	camera.make_current()
	camera.global_position = Vector2(2547.0, 395.0)
	await process_frame
	await process_frame
	_expect_float(art_layer.position.x, 896.5, "相机右移时地面世界层不做视差")
	_expect_float(sky_layer.position.x, 896.5 + (2547.0 - 1734.5) * 0.8, "相机右移时远景层 80% 跟随")

	camera.global_position = Vector2(1547.0, 395.0)
	await process_frame
	await process_frame
	_expect_float(art_layer.position.x, 896.5, "相机左移时地面世界层仍不做视差")
	_expect_float(sky_layer.position.x, 896.5 + (1547.0 - 1734.5) * 0.8, "相机左移时远景层对称跟随")

	camera.free()
	ground.free()


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


func _expect_equal(actual: Variant, expected: Variant, label: String) -> void:
	if actual != expected:
		failures.append("%s: expected %s, got %s" % [label, expected, actual])


func _expect_float(actual: float, expected: float, label: String) -> void:
	if not is_equal_approx(actual, expected):
		failures.append("%s: expected %.4f, got %.4f" % [label, expected, actual])


func _finish() -> void:
	paused = false
	if failures.is_empty():
		print("PASS round4 fixes")
		quit(0)
	else:
		for failure: String in failures:
			push_error(failure)
		quit(1)