# HitReaction —— CLIENT-GAP §3.7 受击方视图（PlayerView / MobView）共用的受击状态机。
#   __HitGood / __HitGreate / __HitStone（ActorInstanceBattle.cpp）的分支判定、
#   __Shake + ShakeProcess（世界矩阵平移 ±rand()%10 cm）、CGraphicThingInstance::InsertDelay、
#   InterceptOnceMotion + PushOnceMotion + PushLoopMotion 的动作链。
# 视图只提供「按状态名绑定一段一次性动作」的 Callable（bind(step) -> bool，资源缺失 = false，
# 等同 GetMotionKey 失败时 InterceptOnceMotion / PushOnceMotion 返回 FALSE）。
extends RefCounted

const SHAKE_TIME := 0.1              # __Shake(100)：m_dwShakeTime = now + 100 ms
const SHAKE_RAND_CM := 10            # ShakeProcess：rand() % 10
const LOOP_STATES := ["wait", "walk", "run"]
const DAMAGE_STATES := ["damage", "damage_back"]                  # IsDamage 类
const KNOCKDOWN_STATES := ["knockdown", "knockdown_back"]          # IsKnockDown：DAMAGE_FLYING(_BACK)
const STANDUP_STATES := ["standup", "standup_back"]               # __IsStandUpMotion：STAND_UP(_BACK)
# CActorInstance::isLock：NORMAL_ATTACK / COMBO_ATTACK_* / SPECIAL_* / 钓鱼 / 表情跳舞等
const LOCK_STATES := ["attack", "combo", "skill", "__motion", "emotion", "dig",
		"fishing", "fishing_react", "fishing_catch", "fishing_fail"]
const SKILL_STATES := ["skill"]      # IsUsingSkill：SKILL 段 / SPECIAL_1..6

var delay_left := 0.0
var speed := 1.0                     # 当前动作的 fSpeedRatio（InsertDelay 结束后恢复）
var shake_left := 0.0
var queue: Array = []                # 剩余的 PushOnceMotion 步
var resume := "wait"                 # 链尾 PushLoopMotion 的循环动作
var active := false                  # 受击动作链正在播
var real_dead := false               # m_isRealDead：晕眩击倒后不起身
var _shaking := false
var _shake_base := Vector3.ZERO

static func is_reaction(state: String) -> bool:
	return state in DAMAGE_STATES or state in KNOCKDOWN_STATES or state in STANDUP_STATES

# __HitGood：返回候选动作链（按顺序尝试，首步绑定成功的那条生效）。
func good(state: String, scalar: float, stunned: bool) -> Array:
	if state in KNOCKDOWN_STATES:
		return []
	if stunned:
		return []            # IsStun() -> Die()：死亡动作由服务器驱动（seam）
	shake()
	if state in LOCK_STATES:
		return []
	if scalar < 0.0:
		return [["damage"]]
	return [["damage_back"], ["damage"]]

# __HitGreate
func greate(state: String, scalar: float, stunned: bool) -> Array:
	if state in KNOCKDOWN_STATES or state in STANDUP_STATES:
		return []
	shake()
	if state in SKILL_STATES:
		return []
	if stunned:
		if scalar < 0.0:
			return [["knockdown"]]
		return [["knockdown_back"], ["knockdown"]]
	if scalar < 0.0:
		return [["knockdown", "standup"]]
	return [["knockdown_back", "standup_back"], ["knockdown", "standup"]]

# __HitStone
func stone(stunned: bool) -> void:
	if not stunned:
		shake()

func shake() -> void:
	shake_left = SHAKE_TIME

func insert_delay(d: float, anim: Object) -> void:
	if d <= 0.0:
		return
	delay_left = d
	if anim:
		anim.set("time_scale", 0.0)

# 绑定新动作时的 time_scale：InsertDelay 期间保持冻结。
func scale_for(ratio: float) -> float:
	speed = ratio
	return 0.0 if delay_left > 0.0 else ratio

# 首步绑定成功 -> 记下链尾要回的循环动作，剩余步入队。
func start(chains: Array, current: String, bind: Callable, dead_after := false) -> bool:
	for chain: Array in chains:
		if chain.is_empty() or not bool(bind.call(String(chain[0]))):
			continue
		if not is_reaction(current):
			resume = current if current in LOOP_STATES else "wait"
		queue = chain.slice(1)
		active = true
		real_dead = dead_after
		return true
	return false

# 一段受击动作播完：绑下一步（缺资源的步跳过）；返回 false = 链结束。
func advance(bind: Callable) -> bool:
	while not queue.is_empty():
		if bool(bind.call(String(queue.pop_front()))):
			return true
	active = false
	return false

func cancel() -> void:
	active = false
	queue.clear()
	real_dead = false

func tick(dt: float, anim: Object, model: Node3D) -> void:
	if delay_left > 0.0:
		delay_left -= dt
		if delay_left <= 0.0 and anim:
			anim.set("time_scale", speed)
	if shake_left > 0.0:
		shake_left -= dt
	if model == null:
		return
	if shake_left > 0.0:
		if not _shaking:
			_shaking = true
			_shake_base = model.position
		model.position = _shake_base + Vector3(_rand_cm(), _rand_cm(), _rand_cm()) / 100.0
	elif _shaking:
		_shaking = false
		model.position = _shake_base

static func _rand_cm() -> float:
	var v := float(randi() % SHAKE_RAND_CM)
	return v if randi() % 2 == 0 else -v