# world_boss_ai_system.gd —— Metin2 40250 野外世界首领动态巡逻与仇恨反击 AI 1:1
# 对照 40250 服务端 char_battle.cpp, battle.cpp, mob_manager.cpp, char_state.cpp
class_name WorldBossAISystem
extends RefCounted

signal state_changed(old_state: String, new_state: String)
signal target_acquired(target_id: String, distance: float)
signal skill_cast(skill_name: String, damage: int, aoe_radius: float)
signal boss_enraged(atk_multiplier: float)
signal leash_reset_started()
signal leash_reset_completed()

const STATE_IDLE := "idle"
const STATE_PATROL := "patrol"
const STATE_CHASE := "chase"
const STATE_ATTACK := "attack"
const STATE_SKILL := "skill"
const STATE_ENRAGED := "enraged"
const STATE_LEASH_RETURN := "leash_return"
const STATE_DEAD := "dead"

const AGGRO_RADIUS: float = 18.0       # 索敌警戒范围 (米)
const ATTACK_RANGE: float = 3.5       # 普通近战攻击距离 (米)
const SKILL_RANGE: float = 9.0        # 首领大招攻击距离 (米)
const LEASH_DISTANCE: float = 35.0    # 脱战最远距离 (米)
const PATROL_RADIUS: float = 12.0     # 巡逻游荡半径 (米)
const SKILL_COOLDOWN: float = 8.0     # 技能冷却时间 (秒)
const ENRAGE_HP_RATIO: float = 0.30   # 30% 残血狂暴触发线

const BOSS_CONFIG: Dictionary = {
	1901: {
		"name": "九尾妖狐",
		"level": 72,
		"max_hp": 280000,
		"atk": 850,
		"def": 450,
		"skill_name": "暴风雪呼啸",
		"skill_mult": 1.8,
		"skill_aoe": 8.0
	},
	1304: {
		"name": "黄虎领主",
		"level": 75,
		"max_hp": 320000,
		"atk": 920,
		"def": 480,
		"skill_name": "神虎震地啸",
		"skill_mult": 2.0,
		"skill_aoe": 7.5
	},
	2191: {
		"name": "巨龟仙人",
		"level": 67,
		"max_hp": 350000,
		"atk": 780,
		"def": 600,
		"skill_name": "地刺岩崩",
		"skill_mult": 1.6,
		"skill_aoe": 9.0
	},
	2206: {
		"name": "烈焰之王",
		"level": 73,
		"max_hp": 300000,
		"atk": 980,
		"def": 420,
		"skill_name": "地狱火海",
		"skill_mult": 2.2,
		"skill_aoe": 8.5
	}
}

var vnum: int = 0
var boss_name: String = ""
var level: int = 1
var max_hp: int = 100000
var current_hp: int = 100000
var base_atk: int = 500
var base_def: int = 300
var skill_name: String = ""
var skill_mult: float = 1.8
var skill_aoe: float = 8.0

var spawn_position: Vector3 = Vector3.ZERO
var current_position: Vector3 = Vector3.ZERO
var patrol_destination: Vector3 = Vector3.ZERO

var current_state: String = STATE_IDLE
var is_enraged: bool = false
var skill_timer: float = 0.0
var patrol_wait_timer: float = 0.0
var current_target_id: String = ""
var aggro_table: Dictionary = {} # target_id -> threat_points

# 初始化世界首领
func init_boss(boss_vnum: int, pos: Vector3 = Vector3.ZERO) -> Dictionary:
	if not BOSS_CONFIG.has(boss_vnum):
		return {"ok": false, "reason": "INVALID_BOSS_VNUM", "msg": "未知的世界 Boss 代码！"}

	var cfg = BOSS_CONFIG[boss_vnum]
	vnum = boss_vnum
	boss_name = cfg["name"]
	level = cfg["level"]
	max_hp = cfg["max_hp"]
	current_hp = cfg["max_hp"]
	base_atk = cfg["atk"]
	base_def = cfg["def"]
	skill_name = cfg["skill_name"]
	skill_mult = cfg["skill_mult"]
	skill_aoe = cfg["skill_aoe"]

	spawn_position = pos
	current_position = pos
	patrol_destination = pos

	current_state = STATE_IDLE
	is_enraged = false
	skill_timer = 0.0
	patrol_wait_timer = 2.0
	current_target_id = ""
	aggro_table.clear()

	return {
		"ok": true,
		"vnum": vnum,
		"name": boss_name,
		"level": level,
		"hp": current_hp,
		"pos": current_position
	}

# 改变当前状态
func _change_state(new_state: String) -> void:
	if current_state == new_state:
		return
	var old = current_state
	current_state = new_state
	state_changed.emit(old, new_state)

# 核心 AI 帧心跳更新驱动 (对照 40250 char_state.cpp)
func update_ai(delta: float, target_pos: Vector3, target_id: String = "player", is_target_alive: bool = true) -> Dictionary:
	if current_state == STATE_DEAD:
		return {"state": STATE_DEAD, "action": "none"}

	# 技能冷却计时
	if skill_timer > 0.0:
		skill_timer = max(0.0, skill_timer - delta)

	# 1. 脱战判定：如果距离出生点超出 LEASH_DISTANCE，强制触发回拉
	var dist_from_spawn = current_position.distance_to(spawn_position)
	if dist_from_spawn > LEASH_DISTANCE and current_state != STATE_LEASH_RETURN:
		_start_leash_return()
		return {"state": STATE_LEASH_RETURN, "action": "leashing", "msg": "超出脱战范围，首领无敌回满血并返回出生点！"}

	# 2. 回拉返回出生点过程
	if current_state == STATE_LEASH_RETURN:
		var step = 12.0 * delta # 高速回跑
		current_position = current_position.move_toward(spawn_position, step)
		if current_position.distance_to(spawn_position) < 0.5:
			current_position = spawn_position
			current_hp = max_hp
			aggro_table.clear()
			current_target_id = ""
			is_enraged = false
			_change_state(STATE_IDLE)
			leash_reset_completed.emit()
			return {"state": STATE_IDLE, "action": "reset_done"}
		return {"state": STATE_LEASH_RETURN, "action": "moving_home"}

	# 3. 仇恨目标存活与索敌检测
	var dist_to_target = current_position.distance_to(target_pos)
	var has_aggro = is_target_alive and (dist_to_target <= AGGRO_RADIUS or aggro_table.has(target_id))

	if not has_aggro or not is_target_alive:
		# 失去仇恨或目标死亡 -> 回归巡逻/待机
		current_target_id = ""
		_handle_patrol_idle(delta)
		return {"state": current_state, "action": "wandering"}

	# 确认锁定仇恨目标
	if current_target_id != target_id:
		current_target_id = target_id
		target_acquired.emit(target_id, dist_to_target)

	# 4. 处于战斗追击 / 攻击决策
	if dist_to_target > SKILL_RANGE:
		# 距离过远，快速追赶
		_change_state(STATE_CHASE)
		var move_speed = 6.0 if not is_enraged else 7.8
		current_position = current_position.move_toward(target_pos, move_speed * delta)
		return {"state": STATE_CHASE, "action": "chasing", "dist": dist_to_target}

	# 5. 技能大招释放判定
	if skill_timer <= 0.0 and dist_to_target <= SKILL_RANGE:
		skill_timer = SKILL_COOLDOWN
		_change_state(STATE_SKILL)
		var dmg_mult = skill_mult * (1.5 if is_enraged else 1.0)
		var skill_dmg = int(float(base_atk) * dmg_mult)
		skill_cast.emit(skill_name, skill_dmg, skill_aoe)
		return {
			"state": STATE_SKILL,
			"action": "skill",
			"skill_name": skill_name,
			"damage": skill_dmg,
			"aoe": skill_aoe
		}

	# 6. 普通攻击判定
	if dist_to_target <= ATTACK_RANGE:
		_change_state(STATE_ATTACK)
		var atk_dmg = int(float(base_atk) * (1.5 if is_enraged else 1.0))
		return {
			"state": STATE_ATTACK,
			"action": "basic_attack",
			"damage": atk_dmg
		}
	else:
		# 在技能范围内但未到普攻范围 -> 继续靠近
		_change_state(STATE_CHASE)
		var move_speed = 5.0 if not is_enraged else 6.5
		current_position = current_position.move_toward(target_pos, move_speed * delta)
		return {"state": STATE_CHASE, "action": "closing_in", "dist": dist_to_target}

# 待机与路点漫步巡逻处理
func _handle_patrol_idle(delta: float) -> void:
	if current_state != STATE_PATROL:
		_change_state(STATE_PATROL)

	patrol_wait_timer -= delta
	if patrol_wait_timer <= 0.0:
		# 选取出生点周围随机路点
		var angle = randf_range(0, TAU)
		var r = randf_range(2.0, PATROL_RADIUS)
		patrol_destination = spawn_position + Vector3(cos(angle) * r, 0.0, sin(angle) * r)
		patrol_wait_timer = randf_range(4.0, 7.0)

	if current_position.distance_to(patrol_destination) > 0.5:
		current_position = current_position.move_toward(patrol_destination, 2.5 * delta)

# 开始拉回重置
func _start_leash_return() -> void:
	_change_state(STATE_LEASH_RETURN)
	leash_reset_started.emit()

# 受到攻击与伤害结算
func receive_damage(raw_dmg: int, attacker_id: String = "player") -> Dictionary:
	if current_state == STATE_DEAD:
		return {"ok": false, "reason": "ALREADY_DEAD"}

	if current_state == STATE_LEASH_RETURN:
		# 脱战回跑期间无敌
		return {"ok": true, "immune": true, "net_dmg": 0, "msg": "首领脱战回归中，处于神圣免疫状态！"}

	var net_dmg = max(1, raw_dmg - base_def)
	current_hp = max(0, current_hp - net_dmg)

	# 累计仇恨度
	aggro_table[attacker_id] = aggro_table.get(attacker_id, 0) + net_dmg

	# 狂暴判定：HP <= 30%
	var hp_ratio = float(current_hp) / float(max_hp)
	if hp_ratio <= ENRAGE_HP_RATIO and not is_enraged:
		is_enraged = true
		boss_enraged.emit(1.5)

	# 死亡判定
	if current_hp <= 0:
		_change_state(STATE_DEAD)
		return {
			"ok": true,
			"dead": true,
			"net_dmg": net_dmg,
			"remaining_hp": 0,
			"msg": "【%s】发出震天哀鸣，轰然倒地！" % boss_name
		}

	return {
		"ok": true,
		"dead": false,
		"net_dmg": net_dmg,
		"remaining_hp": current_hp,
		"hp_ratio": hp_ratio,
		"is_enraged": is_enraged
	}

# 获取当前首领状态摘要
func get_boss_status() -> Dictionary:
	return {
		"vnum": vnum,
		"name": boss_name,
		"level": level,
		"state": current_state,
		"current_hp": current_hp,
		"max_hp": max_hp,
		"is_enraged": is_enraged,
		"pos": current_position,
		"spawn_pos": spawn_position
	}