using UnityEngine;
using UnityEngine.Rendering.Universal;
using UnityEngine.SceneManagement;

namespace NLD
{
    /// <summary>
    /// 在特定相机和特定场景上启用depth texture
    /// 用于支持需要深度信息的shader（如雾效soft particles）
    /// </summary>
    [RequireComponent(typeof(UnityEngine.Camera))]
    public class EnableDepthTextureForCamera : MonoBehaviour
    {
        [Header("场景限制")]
        [Tooltip("指定在哪些场景中启用depth texture，留空则在所有场景生效")]
        [SerializeField] private string[] targetSceneNames = new string[0];

        [Header("调试信息")]
        [Tooltip("是否输出调试日志")]
        [SerializeField] private bool showDebugLog = true;

        private UnityEngine.Camera _camera;
        private UniversalAdditionalCameraData _cameraData;
        private bool _originalRequireDepth;
        private bool _isDepthEnabled = false;

        private void OnEnable()
        {
            // 检查是否在目标场景中
            if (!IsInTargetScene())
            {
                if (showDebugLog)
                {
                    Debug.Log($"[EnableDepthTexture] 相机 '{gameObject.name}' 不在目标场景中，跳过启用");
                }
                return;
            }

            InitializeCamera();
            EnableDepthTexture();
            CheckRenderTextureConfiguration();
        }

        private void OnDisable()
        {
            RestoreOriginalSettings();
        }

        private void InitializeCamera()
        {
            _camera = GetComponent<UnityEngine.Camera>();
            _cameraData = _camera.GetUniversalAdditionalCameraData();

            if (_cameraData == null)
            {
                Debug.LogError($"[EnableDepthTexture] 相机 '{gameObject.name}' 没有UniversalAdditionalCameraData组件！");
            }
        }

        private void EnableDepthTexture()
        {
            if (_cameraData == null) return;

            _originalRequireDepth = _cameraData.requiresDepthTexture;

            _cameraData.requiresDepthTexture = true;
            _isDepthEnabled = true;

            if (showDebugLog)
            {
                Debug.Log($"[EnableDepthTexture] 已在相机 '{gameObject.name}' 上启用depth texture");
            }
        }

        private void RestoreOriginalSettings()
        {
            if (_isDepthEnabled && _cameraData != null)
            {
                _cameraData.requiresDepthTexture = _originalRequireDepth;
                _isDepthEnabled = false;

                if (showDebugLog)
                {
                    Debug.Log($"[EnableDepthTexture] 已恢复相机 '{gameObject.name}' 的原始depth texture设置");
                }
            }
        }

        private bool IsInTargetScene()
        {
            if (targetSceneNames == null || targetSceneNames.Length == 0)
            {
                return true;
            }

            string currentSceneName = SceneManager.GetActiveScene().name;

            foreach (string sceneName in targetSceneNames)
            {
                if (string.IsNullOrEmpty(sceneName))
                {
                    continue;
                }

                if (currentSceneName.Equals(sceneName, System.StringComparison.OrdinalIgnoreCase))
                {
                    return true;
                }
            }

            return false;
        }

        private void CheckRenderTextureConfiguration()
        {
            if (_camera == null || _camera.targetTexture == null)
            {
                return;
            }

            RenderTexture rt = _camera.targetTexture;

            if (rt.depth == 0)
            {
                Debug.LogWarning(
                    $"[EnableDepthTexture] 警告：相机 '{gameObject.name}' 渲染到RenderTexture '{rt.name}'，" +
                    $"但该RT没有depth buffer (depthBufferBits = 0)！\n"
                );
            }
            else if (showDebugLog)
            {
                Debug.Log(
                    $"[EnableDepthTexture] RenderTexture '{rt.name}' 配置正确 " +
                    $"(depthBufferBits = {rt.depth})"
                );
            }
        }

        public void SetDepthTextureEnabled(bool enabled)
        {
            if (_cameraData != null && IsInTargetScene())
            {
                _cameraData.requiresDepthTexture = enabled;
                _isDepthEnabled = enabled;

                if (showDebugLog)
                {
                    Debug.Log($"[EnableDepthTexture] 运行时设置depth texture为: {enabled}");
                }
            }
        }

        public bool IsDepthTextureEnabled()
        {
            return _isDepthEnabled && _cameraData != null && _cameraData.requiresDepthTexture;
        }
    }
}