using UnityEngine;
using UnityEngine.Rendering;

namespace Thousandto.Launcher.ExternalLibs
{
    /// <summary>
    /// 一个简单的扭曲效果脚本
    /// </summary>
    [RequireComponent(typeof(Camera))]
    public class DistortEffectSimpleScript: MonoBehaviour
    {
        //触发事件
        private const CameraEvent CN_TRIGGER_EVENT = CameraEvent.BeforeImageEffects;

        [Range(0.0f, 1.0f)]
        public float DistortTimeFactor = 0.15f;
        //扭曲的强度
        [Range(0.0f, 0.2f)]
        public float DistortStrength = 0.01f;
        //噪声图
        public Texture NoiseTexture = null;


        private Camera _camera;
        private CommandBuffer _cmd;
        private Material _mat;
        

        private void Start()
        {
            InitCamera();
            InitMat();
            InitCmd();
        }

        private void OnEnable()
        {
            if (_cmd != null && _camera != null)
            {
                _camera.AddCommandBuffer(CN_TRIGGER_EVENT, _cmd);
            }
            RefreshMat();
        }

        private void OnDisable()
        {
            if (_cmd != null && _camera != null)
            {
                _camera.RemoveCommandBuffer(CN_TRIGGER_EVENT, _cmd);
            }
        }

        private void OnDestroy()
        {
            if (_cmd != null)
            {
                if (_camera != null)
                {
                    _camera.RemoveCommandBuffer(CN_TRIGGER_EVENT, _cmd);
                }
                _cmd.Release();
                _cmd = null;
            }

            if (_mat != null)
            {
                GameObject.Destroy(_mat);
                _mat = null;
            }
        }

        private void OnValidate()
        {
            RefreshMat();
        }

        private void InitCamera()
        {
            _camera = GetComponent<Camera>();
            _camera.forceIntoRenderTexture = true;
        }

        private void InitCmd()
        {
            if (_cmd == null)
            {
                _cmd = new CommandBuffer();
                _cmd.name = "DistortEffect";
                var _tmpTexID = Shader.PropertyToID("_TmpTex");
                _cmd.GetTemporaryRT(_tmpTexID, -1, -1,0,FilterMode.Bilinear);

                _cmd.SetRenderTarget(_tmpTexID);
                _cmd.SetGlobalTexture(CmdBufferUtils.MainTexID, BuiltinRenderTextureType.CameraTarget);
                _cmd.DrawMesh(CmdBufferUtils.QuadMesh, Matrix4x4.identity, CmdBufferUtils.BlitMat, 0, 0);

                _cmd.SetRenderTarget(BuiltinRenderTextureType.CameraTarget);
                _cmd.SetGlobalTexture(CmdBufferUtils.MainTexID, _tmpTexID);
                _cmd.DrawMesh(CmdBufferUtils.QuadMesh, Matrix4x4.identity, _mat,0,0);

                _cmd.ReleaseTemporaryRT(_tmpTexID);

                if (_camera != null)
                {
                    _camera.AddCommandBuffer(CN_TRIGGER_EVENT, _cmd);
                }
                
            }
        }

        private void InitMat()
        {
            var sh = RuntimeUtilities.FindShader("Hidden/Ares/PostEffect/DistortEffect");
            if (sh != null)
            {
                _mat = new Material(sh);
                _mat.hideFlags = HideFlags.DontSave;
                RefreshMat();
            }
            else
            {
                Debug.LogError("没有找到Shader:Hidden/Ares/PostEffect/DistortEffect");
            }
        }

        private void RefreshMat()
        {
            if (_mat != null)
            { 
                _mat.SetVector("_Params", new Vector4(DistortTimeFactor, DistortStrength, 0, 0));
                _mat.SetTexture("_NoiseTex", NoiseTexture);
            }
        }

        private void OnPostEffectActive(int val)
        {
            if (_camera != null && _cmd != null)
            {
                //根据激活状态来处理
                if (val > 0)
                {   
                    _camera.RemoveCommandBuffer(CN_TRIGGER_EVENT, _cmd);
                    _camera.AddCommandBuffer(CN_TRIGGER_EVENT, _cmd);
                }
                else
                {
                    _camera.RemoveCommandBuffer(CN_TRIGGER_EVENT, _cmd);
                }
            }
        }
    }
}