using UnityEngine;
using UnityEditor;
using System.Collections.Generic;
using System.IO;

    /**
    这是替换全局材质shader的脚本不要删
    Default Lit在Package/Universal RP下面
    By:Shiraka
    **/

public class ChangeShaderTool : EditorWindow
{
    private Shader sourceShader;
    private Shader targetShader;
    private List<Material> materialsToChange = new List<Material>();

    [MenuItem("Tools/ShirakaTool/Change Shader Tool")]
    public static void ShowWindow()
    {
        GetWindow<ChangeShaderTool>("Change Shader Tool");
    }

    private void OnGUI()
    {
        GUILayout.Label("批量替换 Shader 工具", EditorStyles.boldLabel);
        sourceShader = EditorGUILayout.ObjectField("原始 Shader", sourceShader, typeof(Shader), false) as Shader;
        targetShader = EditorGUILayout.ObjectField("目标 Shader", targetShader, typeof(Shader), false) as Shader;

        if (GUILayout.Button("查找使用源 Shader 的材质"))
        {
            FindMaterialsUsingSourceShader();
        }

        if (materialsToChange.Count > 0)
        {
            GUILayout.Label($"找到 {materialsToChange.Count} 个材质使用了源 Shader。", EditorStyles.label);

            if (GUILayout.Button("执行替换"))
            {
                ReplaceShaders();
            }
        }
    }

    private void FindMaterialsUsingSourceShader()
    {
        materialsToChange.Clear();

        string[] materialGuids = AssetDatabase.FindAssets("t:Material");
        foreach (string guid in materialGuids)
        {
            string path = AssetDatabase.GUIDToAssetPath(guid);
            Material mat = AssetDatabase.LoadAssetAtPath<Material>(path);
            if (mat != null && mat.shader == sourceShader)
            {
                materialsToChange.Add(mat);
            }
        }

        Debug.Log($"找到 {materialsToChange.Count} 个材质使用了源 Shader。");
    }

    private void ReplaceShaders()
    {
        if (targetShader == null)
        {
            Debug.LogError("请指定目标 Shader。");
            return;
        }

        foreach (Material mat in materialsToChange)
        {
            Undo.RecordObject(mat, "Change Shader");
            mat.shader = targetShader;
            EditorUtility.SetDirty(mat);
        }

        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();

        Debug.Log("Shader 替换完成。");
    }
}