using UnityEngine;
using UnityEditor;
using System;
using UnityEngine.Rendering;

#if UNITY_EDITOR
public class BrewMonsterUnlitShaderGUI : ShaderGUI
{
    // Properties
    private MaterialProperty colorProp;
    private MaterialProperty baseMapProp;
    private MaterialProperty shadowStrengthProp;
    private MaterialProperty alphaClipProp;
    private MaterialProperty cutoffProp;
    private MaterialProperty alphaModulateProp;
    private MaterialProperty surfaceProp;
    private MaterialProperty srcBlendProp;
    private MaterialProperty dstBlendProp;
    private MaterialProperty zWriteProp;
    private MaterialProperty cullProp;

    // UI Labels
    private static readonly GUIContent baseMapLabel = new GUIContent("Base Map");
    private static readonly GUIContent colorLabel = new GUIContent("Base Color");
    private static readonly GUIContent shadowStrengthLabel = new GUIContent("Shadow Strength");
    private static readonly GUIContent surfaceOptionsLabel = new GUIContent("Surface Options");
    private static readonly GUIContent alphaOptionsLabel = new GUIContent("Alpha Options");
    private static readonly string[] surfaceNames = Enum.GetNames(typeof(SurfaceType));

    // Enums
    private enum SurfaceType
    {
        Opaque,
        Transparent
    }

    public override void OnGUI(MaterialEditor materialEditor, MaterialProperty[] properties)
    {
        // Find properties
        colorProp = FindProperty("_Color", properties);
        baseMapProp = FindProperty("_BaseMap", properties);
        shadowStrengthProp = FindProperty("_ShadowStrength", properties);
        alphaClipProp = FindProperty("_AlphaClip", properties);
        cutoffProp = FindProperty("_Cutoff", properties);
        alphaModulateProp = FindProperty("_AlphaModulate", properties);
        surfaceProp = FindProperty("_Surface", properties);
        srcBlendProp = FindProperty("_SrcBlend", properties);
        dstBlendProp = FindProperty("_DstBlend", properties);
        zWriteProp = FindProperty("_ZWrite", properties);
        cullProp = FindProperty("_Cull", properties);

        Material material = materialEditor.target as Material;

        // Draw UI
        EditorGUILayout.Space();
        EditorGUILayout.LabelField(surfaceOptionsLabel, EditorStyles.boldLabel);
        DoSurfaceTypePopup(material);
        materialEditor.ShaderProperty(cullProp, "Cull Mode");
        
        EditorGUILayout.Space();
        materialEditor.TexturePropertySingleLine(baseMapLabel, baseMapProp, colorProp);
        materialEditor.ShaderProperty(shadowStrengthProp, shadowStrengthLabel);
        
        EditorGUILayout.Space();
        EditorGUILayout.LabelField(alphaOptionsLabel, EditorStyles.boldLabel);
        materialEditor.ShaderProperty(alphaClipProp, "Alpha Clipping");
        if (material.HasProperty("_AlphaClip") && material.GetFloat("_AlphaClip") > 0)
        {
            materialEditor.ShaderProperty(cutoffProp, "Alpha Cutoff", 1);
        }
        
        SurfaceType surfaceType = (SurfaceType)material.GetFloat("_Surface");
        if (surfaceType == SurfaceType.Transparent)
        {
            materialEditor.ShaderProperty(alphaModulateProp, "Multiply Color by Alpha");
        }

        EditorGUILayout.Space();
        materialEditor.RenderQueueField();
        materialEditor.EnableInstancingField();
        materialEditor.DoubleSidedGIField();
    }

    private void DoSurfaceTypePopup(Material material)
    {
        EditorGUI.BeginChangeCheck();
        SurfaceType surfaceType = (SurfaceType)material.GetFloat("_Surface");
        var selectedSurfaceType = (SurfaceType)EditorGUILayout.Popup("Surface Type", (int)surfaceType, surfaceNames);
        
        if (EditorGUI.EndChangeCheck())
        {
            material.SetFloat("_Surface", (float)selectedSurfaceType);
            SetupMaterialBlendMode(material, selectedSurfaceType);
        }
    }

    private void SetupMaterialBlendMode(Material material, SurfaceType surfaceType)
    {
        switch (surfaceType)
        {
            case SurfaceType.Opaque:
                material.SetOverrideTag("RenderType", "Opaque");
                material.SetInt("_SrcBlend", (int)BlendMode.One);
                material.SetInt("_DstBlend", (int)BlendMode.Zero);
                material.SetInt("_ZWrite", 1);
                material.renderQueue = (int)RenderQueue.Geometry;
                material.DisableKeyword("_ALPHAMODULATE_ON");
                break;
                
            case SurfaceType.Transparent:
                material.SetOverrideTag("RenderType", "Transparent");
                material.SetInt("_SrcBlend", (int)BlendMode.SrcAlpha);
                material.SetInt("_DstBlend", (int)BlendMode.OneMinusSrcAlpha);
                material.SetInt("_ZWrite", 0);
                material.renderQueue = (int)RenderQueue.Transparent;
                break;
        }
    }
}
#endif