// ===============================================================================
// ReferenceFinderTool - Deep Dependency Analysis for Unity Assets
//
// Creator: Scove
// Last Updated: 2024-05-08
// Version: 2.0
//
// Purpose:
// Finds every asset in the project that references the selected item by 
// scanning GUIDs inside Unity's YAML-based files (Scenes, Prefabs, Materials, etc.).
//
// Key Features:
// 1. Interactive Result List: Click any result to highlight the asset in Project window.
// 2. Wide Scope: Scans all text-based assets (Mat, PhysMat, Controller, Asset, etc.).
// 3. Optimized Search: Faster file reading and progress bar with Cancel support.
// 4. Clean UI: Integrated as a professional Editor Window.
//
// How to Use:
// 1. Right-click any asset in the Project window.
// 2. Select "Find References (Deep Scan)".
// 3. View the results in the pop-up window.
// ===============================================================================

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

namespace Editor
{
    public class ReferenceFinderTool : EditorWindow
    {
        private static List<string> foundPaths = new List<string>();
        private static string targetAssetName = "";
        private static string targetAssetGUID = "";
        private Vector2 scrollPosition;

        [MenuItem("Assets/Find References (Deep Scan)", false, 25)]
        public static void FindReferences()
        {
            Object selected = Selection.activeObject;
            if (selected == null) return;

            string path = AssetDatabase.GetAssetPath(selected);
            targetAssetGUID = AssetDatabase.AssetPathToGUID(path);
            targetAssetName = selected.name;

            if (string.IsNullOrEmpty(targetAssetGUID)) return;

            PerformDeepScan();

            // Open the results window
            ReferenceFinderTool window = GetWindow<ReferenceFinderTool>("Reference Finder");
            window.minSize = new Vector2(400, 300);
            window.Show();
        }

        private static void PerformDeepScan()
        {
            foundPaths.Clear();

            // We look for all assets that are usually saved in Text/YAML format
            // Added: Materials, Animators, ScriptableObjects, etc.
            string[] allGuids = AssetDatabase.FindAssets("t:Prefab t:Scene t:Material t:PhysicMaterial t:RuntimeAnimatorController t:ScriptableObject t:AnimatorOverrideController");
            
            int total = allGuids.Length;
            
            for (int i = 0; i < total; i++)
            {
                string assetPath = AssetDatabase.GUIDToAssetPath(allGuids[i]);

                // Update Progress Bar
                bool isCanceled = EditorUtility.DisplayCancelableProgressBar(
                    "Searching References", 
                    $"Scanning: {Path.GetFileName(assetPath)}", 
                    (float)i / total);

                if (isCanceled) break;

                // Check if the asset file contains the Target GUID
                if (FileContainsGUID(assetPath, targetAssetGUID))
                {
                    foundPaths.Add(assetPath);
                }
            }

            EditorUtility.ClearProgressBar();
        }

        private static bool FileContainsGUID(string path, string guid)
        {
            if (!File.Exists(path)) return false;

            // Using StreamReader is faster than File.ReadAllText for very large files
            using (StreamReader reader = new StreamReader(path))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    if (line.Contains(guid)) return true;
                }
            }
            return false;
        }

        private void OnGUI()
        {
            GUILayout.Label($"References for: {targetAssetName}", EditorStyles.boldLabel);
            EditorGUILayout.LabelField($"GUID: {targetAssetGUID}", EditorStyles.miniLabel);
            EditorGUILayout.Space();

            if (foundPaths.Count == 0)
            {
                EditorGUILayout.HelpBox("No references found. Note: Ensure 'Asset Serialization' is set to 'Force Text' in Project Settings.", MessageType.Info);
            }
            else
            {
                GUILayout.Label($"Found {foundPaths.Count} items:", EditorStyles.label);
                
                scrollPosition = EditorGUILayout.BeginScrollView(scrollPosition);
                
                for (int i = 0; i < foundPaths.Count; i++)
                {
                    DrawResultItem(foundPaths[i]);
                }

                EditorGUILayout.EndScrollView();
            }

            EditorGUILayout.Space();
            if (GUILayout.Button("Rescan", GUILayout.Height(30)))
            {
                PerformDeepScan();
            }
        }

        private void DrawResultItem(string path)
        {
            EditorGUILayout.BeginHorizontal("box");

            // Get the asset icon
            Texture icon = AssetDatabase.GetCachedIcon(path);
            GUILayout.Label(icon, GUILayout.Width(16), GUILayout.Height(16));

            // Display path
            GUILayout.Label(path, EditorStyles.wordWrappedLabel);

            GUILayout.FlexibleSpace();

            // Ping Button
            if (GUILayout.Button("Ping", GUILayout.Width(50)))
            {
                Object obj = AssetDatabase.LoadAssetAtPath<Object>(path);
                EditorGUIUtility.PingObject(obj);
                Selection.activeObject = obj;
            }

            EditorGUILayout.EndHorizontal();
        }
    }
}