using UnityEngine;

/// <summary>
/// 音频空间控制器（精简版）
/// 职责：管理 3D 空间音效和位置跟随
/// 设计：最小化字段，直接操作 AudioSource
/// </summary>
public class AudioSpatialController
{
    #region Constants
    
    private const float DEFAULT_MAX_DISTANCE = 150f;
    private const float DEFAULT_MIN_DISTANCE = 1f;
    
    #endregion
    
    #region Fields
    
    private readonly Transform _audioTransform;
    private readonly AudioSource _audioSource;
    private GameObject _followTarget;
    
    #endregion
    
    #region Properties
    
    /// <summary>
    /// 是否启用 3D 音效（从 AudioSource 读取）
    /// </summary>
    public bool Is3DEnabled => _audioSource != null && _audioSource.spatialBlend > 0f;
    
    /// <summary>
    /// 当前跟随的目标
    /// </summary>
    public GameObject FollowTarget => _followTarget;
    
    /// <summary>
    /// 是否正在跟随对象
    /// </summary>
    public bool IsFollowing => _followTarget != null;
    
    /// <summary>
    /// 当前位置
    /// </summary>
    public Vector3 Position 
    {
        get => _audioTransform?.position ?? Vector3.zero;
        set
        {
            if (_audioTransform != null)
                _audioTransform.position = value;
        }
    }
    
    #endregion
    
    #region Constructor
    
    /// <summary>
    /// 创建空间音频控制器
    /// </summary>
    public AudioSpatialController(Transform audioTransform, AudioSource audioSource)
    {
        _audioTransform = audioTransform;
        _audioSource = audioSource;
    }
    
    #endregion
    
    #region Public Methods - 3D Control
    
    /// <summary>
    /// 设置 3D 模式（统一接口）
    /// </summary>
    /// <param name="enable">是否启用 3D</param>
    /// <param name="maxDistance">最大听音距离</param>
    public void Set3D(bool enable, float maxDistance = DEFAULT_MAX_DISTANCE)
    {
        if (_audioSource == null) return;
        
        if (enable)
        {
            _audioSource.spatialBlend = 1f;
            _audioSource.dopplerLevel = 0f;
            _audioSource.rolloffMode = AudioRolloffMode.Linear;
            _audioSource.minDistance = DEFAULT_MIN_DISTANCE;
            _audioSource.maxDistance = maxDistance;
        }
        else
        {
            _audioSource.spatialBlend = 0f;
        }
    }
    
    /// <summary>
    /// 启用 3D 空间音效
    /// </summary>
    public void Enable3D(float maxDistance = DEFAULT_MAX_DISTANCE) 
        => Set3D(true, maxDistance);
    
    /// <summary>
    /// 禁用 3D 空间音效（改为 2D）
    /// </summary>
    public void Disable3D() 
        => Set3D(false);
    
    #endregion
    
    #region Public Methods - Position Control
    
    /// <summary>
    /// 设置跟随目标（自动启用/禁用 3D）
    /// </summary>
    /// <param name="target">跟随目标，null 则停止跟随并禁用 3D</param>
    /// <param name="maxDistance">最大听音距离</param>
    public void SetFollowTarget(GameObject target, float maxDistance = DEFAULT_MAX_DISTANCE)
    {
        _followTarget = target;
        
        if (target != null)
        {
            // 立即同步位置并启用 3D
            Position = target.transform.position;
            Enable3D(maxDistance);
        }
        else
        {
            // 停止跟随并禁用 3D
            Disable3D();
        }
    }
    
    /// <summary>
    /// 设置静态位置（不跟随，可选择是否 3D）
    /// </summary>
    /// <param name="position">世界坐标位置</param>
    /// <param name="enable3D">是否启用 3D 音效</param>
    /// <param name="maxDistance">最大听音距离</param>
    public void SetStaticPosition(Vector3 position, bool enable3D = true, float maxDistance = DEFAULT_MAX_DISTANCE)
    {
        _followTarget = null;
        Position = position;
        Set3D(enable3D, maxDistance);
    }
    
    /// <summary>
    /// 更新位置跟随（在 Update 循环中调用）
    /// </summary>
    public void Update()
    {
        if (_followTarget != null && _audioTransform != null)
        {
            _audioTransform.position = _followTarget.transform.position;
        }
    }
    
    #endregion
    
    #region Public Methods - Advanced
    
    /// <summary>
    /// 高级配置：自定义所有 3D 参数
    /// </summary>
    /// <param name="spatialBlend">空间混合度 (0=2D, 1=3D)</param>
    /// <param name="minDistance">最小距离（全音量范围）</param>
    /// <param name="maxDistance">最大距离（衰减到 0）</param>
    /// <param name="rolloffMode">衰减模式</param>
    /// <param name="dopplerLevel">多普勒效应强度</param>
    public void ConfigureAdvanced(
        float spatialBlend,
        float minDistance = DEFAULT_MIN_DISTANCE,
        float maxDistance = DEFAULT_MAX_DISTANCE,
        AudioRolloffMode rolloffMode = AudioRolloffMode.Linear,
        float dopplerLevel = 0f)
    {
        if (_audioSource == null) return;
        
        _audioSource.spatialBlend = Mathf.Clamp01(spatialBlend);
        _audioSource.minDistance = Mathf.Max(0.01f, minDistance);
        _audioSource.maxDistance = Mathf.Max(minDistance, maxDistance);
        _audioSource.rolloffMode = rolloffMode;
        _audioSource.dopplerLevel = Mathf.Max(0f, dopplerLevel);
    }
    
    /// <summary>
    /// 重置到初始状态（2D、不跟随、位置归零）
    /// </summary>
    public void Reset()
    {
        _followTarget = null;
        Disable3D();
        
        if (_audioTransform != null)
        {
            _audioTransform.localPosition = Vector3.zero;
        }
    }
    
    #endregion
    
    #region Debug
    
    /// <summary>
    /// 获取调试信息
    /// </summary>
    public override string ToString()
    {
        if (_audioSource == null) 
            return "SpatialController: [Invalid]";
        
        return $"SpatialController: " +
               $"Mode={(Is3DEnabled ? "3D" : "2D")}, " +
               $"Following={(_followTarget?.name ?? "None")}, " +
               $"Position={Position:F1}, " +
               $"SpatialBlend={_audioSource.spatialBlend:F2}, " +
               $"MaxDist={_audioSource.maxDistance:F0}";
    }
    
    #endregion
}