# mob_drop_scatter.gd —— 40250 怪物死亡爆装与辐射散射 1:1 规则引擎
# 严格对照：
#   metin2/src/server/game/src/char_battle.cpp:840-930 (pos.x = number(-7, 7) * 20)
#   metin2/src/server/game/src/item.cpp:SetOwnership (ITEM_OWNERSHIP_TIME = 30)
extends RefCounted

const ITEM_OWNERSHIP_DURATION := 30.0 # 40250 官方 30 秒拾取归属保护期
const CM_TO_METERS := 0.01

# 单个掉落物基础散射偏移区间：[-140cm, +140cm]，即 [-1.4m, +1.4m]
const MIN_SCATTER_CM := -140
const MAX_SCATTER_CM := 140

const SOUND_MONEY := "sound/ui/money.wav"
const SOUND_DROP := "sound/ui/drop.wav"

# 计算第 index 个掉落物相对于怪物中心的世界偏移量
# 1:1 对齐 char_battle.cpp: number(-7, 7) * 20cm
static func calculate_scatter_offset(index: int, total_count: int, seed_val := -1) -> Vector3:
	if total_count <= 1:
		# 单个物品：在 [-1.4m, +1.4m] 范围内轻微偏移
		var rng := RandomNumberGenerator.new()
		if seed_val >= 0:
			rng.seed = seed_val
		else:
			rng.randomize()
		var dx: float = (rng.randi_range(-7, 7) * 20) * CM_TO_METERS
		var dz: float = (rng.randi_range(-7, 7) * 20) * CM_TO_METERS
		return Vector3(dx, 0.0, dz)

	# 多个物品（首领爆装）：360 度环状辐射发散，半径 1.0m ~ 1.8m
	var angle_step := TAU / float(maxi(1, total_count))
	var base_angle := angle_step * float(index)
	var rng := RandomNumberGenerator.new()
	if seed_val >= 0:
		rng.seed = seed_val + index * 37
	else:
		rng.randomize()

	# 半径在 1.0m ~ 1.6m 之间带微量抖动
	var radius := 1.0 + rng.randf_range(0.0, 0.6)
	var jitter_angle := rng.randf_range(-0.2, 0.2)
	var angle := base_angle + jitter_angle

	var dx: float = cos(angle) * radius
	var dz: float = sin(angle) * radius
	return Vector3(dx, 0.0, dz)

# 计算最终落地世界坐标
static func calculate_drop_position(center_pos: Vector3, index: int, total_count: int, seed_val := -1) -> Vector3:
	var offset := calculate_scatter_offset(index, total_count, seed_val)
	return center_pos + offset

# 归属保护期判定
static func is_ownership_protected(drop_time: float, current_time: float) -> bool:
	return (current_time - drop_time) < ITEM_OWNERSHIP_DURATION

# 剩余归属秒数
static func remaining_ownership_time(drop_time: float, current_time: float) -> float:
	return maxf(0.0, ITEM_OWNERSHIP_DURATION - (current_time - drop_time))

# 匹配掉落音效
static func get_drop_sound(is_gold: bool) -> String:
	return SOUND_MONEY if is_gold else SOUND_DROP