extends CharacterBody3D
## 第三人称控制器（胶囊体占位）
##
## 场景结构：
##   Player (CharacterBody3D)          ← 只负责移动与碰撞，自身不旋转
##     ├─ Collision (CollisionShape3D, CapsuleShape3D)
##     ├─ Body (Node3D)                ← 视觉层，朝移动方向转身；换角色模型时挂在它下面
##     │    └─ Mesh (MeshInstance3D)
##     └─ CameraRig (Node3D)           ← 承担偏航 yaw，独立于本体旋转
##          └─ SpringArm (SpringArm3D)  ← 承担俯仰 pitch，自动避障
##               └─ Camera (Camera3D)
##
## 操作：WASD/方向键移动，鼠标转视角，Shift 疾跑，空格跳跃，Esc 释放/锁定鼠标

## 跳跃输入缓冲帧数（输入事件在渲染帧到达，物理帧读取，避免漏跳）
const JUMP_BUFFER_FRAMES: int = 6

@export_group("移动")
## 常规移动速度（米/秒）
@export var walk_speed: float = 5.0
## 疾跑速度（米/秒）
@export var sprint_speed: float = 8.5
## 地面加速度（米/秒²）
@export var acceleration: float = 45.0
## 空中加速度（米/秒²）
@export var air_acceleration: float = 12.0
## 起跳初速度（米/秒）
@export var jump_velocity: float = 5.0
## 视觉层转身平滑速度
@export var turn_speed: float = 10.0

@export_group("相机")
## 鼠标灵敏度（弧度/像素）
@export var mouse_sensitivity: float = 0.0025
## 最低俯角（向下看）
@export var pitch_min_deg: float = -80.0
## 最高仰角（向上看）
@export var pitch_max_deg: float = 45.0

@onready var body: Node3D = $Body
@onready var camera_rig: Node3D = $CameraRig
@onready var spring_arm: SpringArm3D = $CameraRig/SpringArm

var _gravity: float = float(ProjectSettings.get_setting("physics/3d/default_gravity", 9.8))
var _yaw: float = 0.0
var _pitch: float = 0.0
var _jump_buffer: int = 0


func _ready() -> void:
	_yaw = camera_rig.rotation.y
	_pitch = clampf(spring_arm.rotation.x, deg_to_rad(pitch_min_deg), deg_to_rad(pitch_max_deg))
	spring_arm.rotation.x = _pitch
	set_mouse_captured(true)


func _unhandled_input(event: InputEvent) -> void:
	if event is InputEventMouseMotion and Input.mouse_mode == Input.MOUSE_MODE_CAPTURED:
		_yaw -= event.relative.x * mouse_sensitivity
		_pitch = clampf(
			_pitch - event.relative.y * mouse_sensitivity,
			deg_to_rad(pitch_min_deg),
			deg_to_rad(pitch_max_deg)
		)
		camera_rig.rotation.y = _yaw
		spring_arm.rotation.x = _pitch
	elif event.is_action_pressed("jump"):
		_jump_buffer = JUMP_BUFFER_FRAMES
	elif event.is_action_pressed("ui_cancel"):
		set_mouse_captured(Input.mouse_mode != Input.MOUSE_MODE_CAPTURED)
	elif event is InputEventMouseButton and event.pressed and Input.mouse_mode != Input.MOUSE_MODE_CAPTURED:
		set_mouse_captured(true)


func set_mouse_captured(captured: bool) -> void:
	Input.mouse_mode = Input.MOUSE_MODE_CAPTURED if captured else Input.MOUSE_MODE_VISIBLE


func _physics_process(delta: float) -> void:
	# --- 重力 ---
	if is_on_floor():
		if velocity.y < 0.0:
			velocity.y = 0.0
	else:
		velocity.y -= _gravity * delta

	# --- 跳跃（读取输入缓冲）---
	if _jump_buffer > 0:
		_jump_buffer -= 1
		if is_on_floor():
			velocity.y = jump_velocity
			_jump_buffer = 0

	# --- 相对相机的水平输入 ---
	var input_dir := Input.get_vector("move_left", "move_right", "move_back", "move_forward")
	var cam_basis := camera_rig.global_transform.basis
	var wish := cam_basis.x * input_dir.x + (-cam_basis.z) * input_dir.y
	wish.y = 0.0

	var wants_move := wish.length() > 0.001
	if wants_move:
		wish = wish.normalized()
		# 只转视觉层，不动本体，也不影响相机（Godot 前进方向为 -Z）
		var target_yaw := atan2(-wish.x, -wish.z)
		body.rotation.y = lerp_angle(body.rotation.y, target_yaw, clampf(turn_speed * delta, 0.0, 1.0))

	var speed := sprint_speed if Input.is_action_pressed("sprint") else walk_speed
	if not wants_move:
		speed = 0.0
	var accel := acceleration if is_on_floor() else air_acceleration

	var horizontal := Vector2(velocity.x, velocity.z)
	horizontal = horizontal.move_toward(Vector2(wish.x, wish.z) * speed, accel * delta)
	velocity.x = horizontal.x
	velocity.z = horizontal.y

	move_and_slide()