## PlayerStats — 玩家属性统计（Autoload: PlayerStats）
## 权威来源：development_plan.md S2、numerical_design.md §1.2
extends Node

signal stats_changed
signal leveled_up(new_level: int)

# ── HP ───────────────────────────────────────────────
var hp:     float = 100.0
var hp_max: float = 100.0

# ── 资源 ──────────────────────────────────────────────
var gold:   int   = 0
var xp:     int   = 0

# ── 等级 ──────────────────────────────────────────────
var level:     int = 1
var xp_to_next: int = 10  # 升级所需 XP

# ── 属性（生效值：静态类型裸字段，读取端零开销）─────────────
# 由 _recompute_attrs() 经 AttributeFormula 从 base + _modifiers 算出，勿直接赋值
var cpu_limit:      int   = 0     # 生效运算力（含法杖 "core" 加成）；MAX_OPS = 本值 × 40
var move_speed:     float = 200.0 # 像素/秒
var cast_delay_mod: float = 1.0   # 施法间隔乘算系数，越低越快
var _invuln_until_msec: int = 0   # < now 表示可受击；受击后设为 now + iframe 窗口

# 属性定义与加成来源（非热路径）
var _attr_def:  Dictionary = {}          # attributes.json 全量定义，只读
var _modifiers: Array[Dictionary] = []   # [{attr_id, mode, value, source}]

# ── 魔力（MVP）─────────────────────────────────────────
var mana:       float = 100.0
var mana_max:   float = 100.0
var mana_regen: float = 5.0    # 每秒回复
var mana_heat:  float = 0.0    # 递增蓝耗热值（0=无，1=蓝耗翻倍）
var mana_leech: float = 0.0    # 击杀回蓝量（换杖/换牌重算）

func _ready() -> void:
	_load_attr_definitions()
	_recompute_attrs()
	EventBus.subscribe(EventID.ENEMY_KILLED, _on_enemy_killed)

func _on_enemy_killed(_payload: Dictionary) -> void:
	gain_mana(mana_leech)

## 升级曲线：roundf(10 × 1.4^(level-1))，P6-N16
## Level 1→2: 10 XP; Level 5→6: ≈ 54 XP
static func xp_for_level(lv: int) -> int:
	return roundi(10.0 * pow(1.4, float(lv - 1)))

func gain_xp(amount: int) -> void:
	xp += amount
	while xp >= xp_to_next:
		xp -= xp_to_next
		level += 1
		xp_to_next = xp_for_level(level)
		leveled_up.emit(level)
		EventBus.emit(EventID.LEVEL_UP, {"level": level})
	stats_changed.emit()

func gain_gold(amount: int) -> void:
	gold += amount
	stats_changed.emit()

func spend_gold(amount: int) -> bool:
	if gold < amount:
		return false
	gold -= amount
	stats_changed.emit()
	return true

func take_damage(amount: float) -> void:
	var now: int = Time.get_ticks_msec()
	if now < _invuln_until_msec:
		return  # 无敌窗口内：忽略外部伤害（多弹同帧只扣一次）
	var applied: float = amount * SettingsManager.player_dmg_taken_mult()  # 难度减伤（初学者×0.7）
	hp = max(0.0, hp - applied)
	_invuln_until_msec = now + int(SettingsManager.player_iframe_sec() * 1000.0)
	EventBus.emit(EventID.PLAYER_DAMAGED, {"damage": applied})  # 复活 hurt 音效 / HUD 钩子
	stats_changed.emit()
	if hp <= 0.0:
		EventBus.emit(EventID.PLAYER_DIED, {})

func is_invulnerable() -> bool:
	return Time.get_ticks_msec() < _invuln_until_msec

func heal(amount: float) -> void:
	hp = min(hp_max, hp + amount)
	stats_changed.emit()

func get_hp_percent() -> float:
	return hp / max(hp_max, 0.001)

## 换杖时设定蓝池上限/回速，并把当前蓝夹到 [0, max]
func set_mana_pool(max_v: float, regen: float) -> void:
	mana_max   = max_v
	mana_regen = regen
	mana       = clampf(mana, 0.0, mana_max)
	stats_changed.emit()

## 花费魔力；够则扣除返回 true，否则不变返回 false
func spend_mana(cost: float) -> bool:
	if mana < cost:
		return false
	mana -= cost
	stats_changed.emit()
	return true

## 每帧回蓝（PlayerManager 驱动）。不 emit stats_changed —— HUD 每帧直接读 mana，
## 避免回蓝过程每帧发信号触发商店刷新。
func regen_mana(delta: float) -> void:
	if mana >= mana_max:
		return
	mana = min(mana_max, mana + mana_regen * delta)

## 击杀回蓝（魔力虹吸）
func gain_mana(n: float) -> void:
	if n <= 0.0:
		return
	mana = min(mana_max, mana + n)
	stats_changed.emit()

## 主动 HP 代价（infinite_spells / heavy_cost）——直接扣血，不走难度减伤
func spend_hp_cost(amount: float) -> void:
	if amount <= 0.0:
		return
	hp = max(0.0, hp - amount)
	stats_changed.emit()
	if hp <= 0.0:
		EventBus.emit(EventID.PLAYER_DIED, {})

func reset_for_run() -> void:
	hp        = hp_max
	mana      = mana_max
	gold      = 0
	xp        = 0
	level     = 1
	xp_to_next = xp_for_level(1)
	_invuln_until_msec = 0
	stats_changed.emit()

## hp_max / cpu_limit 不入存档：二者现为 attributes.json + _modifiers 的派生值，
## 回读会覆盖公式结果。旧存档里的同名键忽略即可，无需提升 schema 版本。
func get_save_data() -> Dictionary:
	return {"hp": hp, "gold": gold, "xp": xp, "level": level}

func load_save_data(data: Dictionary) -> void:
	hp        = float(data.get("hp",    100.0))
	gold      = int(data.get("gold",    0))
	xp        = int(data.get("xp",      0))
	level     = int(data.get("level",   1))
	xp_to_next = xp_for_level(level)
	stats_changed.emit()

# ── 属性框架 ──────────────────────────────────────────────
const _ATTR_PATH: String = "res://data/attributes.json"

func _load_attr_definitions() -> void:
	if not FileAccess.file_exists(_ATTR_PATH):
		push_error("PlayerStats: 缺少 %s" % _ATTR_PATH)
		return
	var parsed = JSON.parse_string(FileAccess.get_file_as_string(_ATTR_PATH))
	if not (parsed is Dictionary):
		push_error("PlayerStats: %s 格式错误（应为对象）" % _ATTR_PATH)
		return
	_attr_def = parsed

## 追加一条加成来源；同一 source 可对多个属性各加一条
func add_modifier(attr_id: String, mode: String, value: float, source: String) -> void:
	_modifiers.append({"attr_id": attr_id, "mode": mode, "value": value, "source": source})
	_recompute_attrs()

## 撤销某来源的全部加成（换杖、出售退款用）
func remove_modifiers_from(source: String) -> void:
	var kept: Array[Dictionary] = []
	for m in _modifiers:
		if String(m.get("source", "")) != source:
			kept.append(m)
	_modifiers = kept
	_recompute_attrs()

func _mods_for(attr_id: String) -> Array:
	var out: Array = []
	for m in _modifiers:
		if String(m.get("attr_id", "")) == attr_id:
			out.append(m)
	return out

## 逐属性按各自 combine 公式重算生效值，写回裸字段
## 留给货架 C：一旦玩家可购买属性，需要持久化的是 _modifiers（来源列表）而非
## 派生的生效值，届时 get_save_data 应加 "attr_modifiers": _modifiers 并提升
## schema 版本。source == "core" 的那条**不要**持久化——它在换杖时由
## combat_manager._rebuild_wand 重建。
func _recompute_attrs() -> void:
	if _attr_def.is_empty():
		return
	cpu_limit      = int(_compute_attr("cpu_limit"))
	move_speed     = _compute_attr("move_speed")
	cast_delay_mod = _compute_attr("cast_delay_mod")
	hp_max         = _compute_attr("hp_max")
	stats_changed.emit()

func _compute_attr(attr_id: String) -> float:
	var d: Dictionary = _attr_def.get(attr_id, {})
	if d.is_empty():
		push_error("PlayerStats: attributes.json 缺少属性「%s」" % attr_id)
		return 0.0
	return AttributeFormula.compute(float(d.get("base", 0.0)), _mods_for(attr_id), d)