using UnityEditor;
using UnityEngine;

namespace EditorTools
{

    public class SubsurfaceLookupTextureIntegratorWindow : EditorWindow
    {
        [MenuItem("Tools/Subsurface LUT Integrator", false, 1000)]
        static void ShowIntegratorWindow()
        {
            GetWindow(typeof(SubsurfaceLookupTextureIntegratorWindow), false, "Subsurface LUT Integrator");
        }

        private Color FalloffColor = new Color(1.0f, 0.3f, 0.2f);
        private float Radius = 4;
        private bool KeepDirectBounce = false;
        [SerializeField]
        private ComputeShader IntegratorShader;
        private RenderTexture IntegratedLUT = null;
        private int resolution = 512;

        private void OnEnable()
        {
            //IntegratorShader = AssetDatabase.LoadAssetAtPath<ComputeShader>("Assets/Scripts/Tools/Editor/SSS/SubsurfaceLookupTextureIntegrator.compute");
        }

        private void OnDestroy()
        {
            if (IntegratedLUT != null)
            {
                RenderTexture.ReleaseTemporary(IntegratedLUT);
            }
        }

        void OnGUI()
        {
            GUILayout.Label("Base Settings", EditorStyles.boldLabel);

            EditorGUI.BeginChangeCheck();
            FalloffColor = EditorGUILayout.ColorField("Fallof Color", FalloffColor);
            Radius = EditorGUILayout.Slider("Radius", Radius, 0, 20);
            KeepDirectBounce = EditorGUILayout.Toggle("Keep Direct Bounce", KeepDirectBounce);
            resolution = EditorGUILayout.IntField("Resolution", resolution);
            if (EditorGUI.EndChangeCheck())
            {
                Bake();
            }

            EditorGUILayout.BeginHorizontal();
            if (GUILayout.Button("Bake") && IntegratorShader != null)
            {
                Bake();
            }
            if (GUILayout.Button("Save") && IntegratedLUT != null)
            {
                IntegratorShader.SetFloat("_Resoultion", (float)resolution);

                RenderTexture rt = RenderTexture.GetTemporary(resolution, resolution, 0, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Linear);
                Graphics.Blit(IntegratedLUT, rt);

                RenderTexture.active = rt;
                Texture2D tex = new Texture2D(resolution, resolution, TextureFormat.ARGB32, false, true);
                tex.ReadPixels(new Rect(0, 0, resolution, resolution), 0, 0);
                RenderTexture.active = null;

                RenderTexture.ReleaseTemporary(rt);

                string path = EditorUtility.SaveFilePanel("Export Texture", Application.dataPath, "SSS_Lut", "png");
                if (path == null) return;
                System.IO.File.WriteAllBytes(path, tex.EncodeToPNG());
                AssetDatabase.Refresh();

                IntegratorShader.SetFloat("_Resoultion", (float)resolution);
            }
            EditorGUILayout.EndHorizontal();
            EditorGUILayout.Space();

            float width = position.width - 100;
            float height = position.height - 189;

            float sacle = width > height ? height / resolution : width / resolution;
            Rect rect = new Rect(50, 150, resolution * sacle, resolution * sacle);
            if (IntegratedLUT != null)
            {
                EditorGUI.DrawPreviewTexture(rect, IntegratedLUT);
            }
            else
            {
                EditorGUI.DrawRect(rect, Color.black);
            }
        }

        private void Bake()
        {
            if (IntegratedLUT != null)
            {
                RenderTexture.ReleaseTemporary(IntegratedLUT);
            }
            IntegratedLUT = RenderTexture.GetTemporary(resolution, resolution, 0, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Linear);
            IntegratedLUT.enableRandomWrite = true;
            if (KeepDirectBounce)
            {
                IntegratorShader.EnableKeyword("KEEP_DIRECT_BOUNCE");
            }
            else
            {
                IntegratorShader.DisableKeyword("KEEP_DIRECT_BOUNCE");
            }
            IntegratorShader.SetTexture(0, "_IntegratedLUT", IntegratedLUT);
            IntegratorShader.SetVector("_FalloffColor", FalloffColor);
            IntegratorShader.SetFloat("_Radius", Radius);
            IntegratorShader.SetFloat("_Resoultion", (float)resolution);
            IntegratorShader.Dispatch(0, resolution / 8, resolution / 8, 1);
        }


    }
}