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

namespace Editor.Utilities
{
    public class BatchComponentAdder : EditorWindow
    {
        private Vector2 scrollPosition;
        private List<GameObject> selectedPrefabs = new List<GameObject>();
        private string searchText = "";
        private List<Type> availableComponentTypes = new List<Type>();
        private List<Type> filteredComponentTypes = new List<Type>();
        private int selectedComponentIndex = -1;
        private bool showScriptsOnly = true;
        private bool showBuiltInComponents = false;

        [MenuItem("Tools/Batch Component Adder")]
        public static void ShowWindow()
        {
            GetWindow<BatchComponentAdder>("Batch Component Adder");
        }

        private void OnEnable()
        {
            // Get all component types when the window is opened
            RefreshComponentTypes();
        }

        private void RefreshComponentTypes()
        {
            // Get all types that derive from Component
            availableComponentTypes = AppDomain.CurrentDomain.GetAssemblies()
                .SelectMany(assembly => assembly.GetTypes())
                .Where(type => type.IsSubclassOf(typeof(Component)) && !type.IsAbstract)
                .OrderBy(type => type.Name)
                .ToList();

            // Apply initial filtering
            FilterComponentTypes();
        }

        private void FilterComponentTypes()
        {
            filteredComponentTypes = availableComponentTypes
                .Where(type => {
                    if (!showBuiltInComponents && type.Namespace != null && type.Namespace.StartsWith("UnityEngine"))
                        return false;
                        
                    if (showScriptsOnly && type.Namespace != null && type.Namespace.StartsWith("UnityEngine"))
                        return false;
                        
                    if (!string.IsNullOrEmpty(searchText))
                        return type.Name.ToLower().Contains(searchText.ToLower());
                        
                    return true;
                })
                .ToList();
                
            // Reset selection if it's no longer valid
            if (selectedComponentIndex >= filteredComponentTypes.Count)
                selectedComponentIndex = -1;
        }

        private void OnGUI()
        {
            EditorGUILayout.BeginVertical();
            
            EditorGUILayout.LabelField("Batch Component Adder", EditorStyles.boldLabel);
            EditorGUILayout.HelpBox("Select multiple prefabs, choose a component type, and add it to the root of all selected prefabs.", MessageType.Info);
            
            EditorGUILayout.Space();
            
            // Prefab selection section
            EditorGUILayout.LabelField("Selected Prefabs", EditorStyles.boldLabel);
            
            if (GUILayout.Button("Add Selected Assets"))
            {
                AddSelectedAssets();
            }
            
            scrollPosition = EditorGUILayout.BeginScrollView(scrollPosition, GUILayout.Height(150));
            
            for (int i = 0; i < selectedPrefabs.Count; i++)
            {
                EditorGUILayout.BeginHorizontal();
                
                selectedPrefabs[i] = (GameObject)EditorGUILayout.ObjectField(selectedPrefabs[i], typeof(GameObject), false);
                
                if (GUILayout.Button("X", GUILayout.Width(20)))
                {
                    selectedPrefabs.RemoveAt(i);
                    i--;
                }
                
                EditorGUILayout.EndHorizontal();
            }
            
            EditorGUILayout.EndScrollView();
            
            if (GUILayout.Button("Clear All"))
            {
                selectedPrefabs.Clear();
            }
            
            EditorGUILayout.Space();
            
            // Component selection section
            EditorGUILayout.LabelField("Component to Add", EditorStyles.boldLabel);
            
            EditorGUILayout.BeginHorizontal();
            showScriptsOnly = EditorGUILayout.Toggle("Scripts Only", showScriptsOnly);
            showBuiltInComponents = EditorGUILayout.Toggle("Show Built-in Components", showBuiltInComponents);
            EditorGUILayout.EndHorizontal();
            
            string newSearchText = EditorGUILayout.TextField("Search", searchText);
            if (newSearchText != searchText)
            {
                searchText = newSearchText;
                FilterComponentTypes();
            }
            
            string[] componentNames = filteredComponentTypes.Select(t => t.Name).ToArray();
            
            selectedComponentIndex = EditorGUILayout.Popup("Component Type", selectedComponentIndex, componentNames);
            
            EditorGUILayout.Space();
            
            // Validate and add the component
            GUI.enabled = selectedPrefabs.Count > 0 && selectedComponentIndex >= 0 && selectedComponentIndex < filteredComponentTypes.Count;
            
            if (GUILayout.Button("Add Component to Prefabs"))
            {
                AddComponentToPrefabs();
            }
            
            GUI.enabled = true;
            
            EditorGUILayout.EndVertical();
        }

        private void AddSelectedAssets()
        {
            UnityEngine.Object[] selectedObjects = Selection.objects;
            
            foreach (var obj in selectedObjects)
            {
                if (obj is GameObject go)
                {
                    string path = AssetDatabase.GetAssetPath(go);
                    if (!string.IsNullOrEmpty(path) && path.EndsWith(".prefab"))
                    {
                        if (!selectedPrefabs.Contains(go))
                        {
                            selectedPrefabs.Add(go);
                        }
                    }
                }
            }
        }

        private void AddComponentToPrefabs()
        {
            if (selectedComponentIndex < 0 || selectedComponentIndex >= filteredComponentTypes.Count)
                return;
                
            Type componentType = filteredComponentTypes[selectedComponentIndex];
            int successCount = 0;
            List<string> failedPrefabs = new List<string>();
            
            // For undo operations
            Undo.RecordObjects(selectedPrefabs.ToArray(), "Add Component To Prefabs");
            
            foreach (GameObject prefab in selectedPrefabs)
            {
                // Skip null entries
                if (prefab == null) continue;
                
                try
                {
                    // Open the prefab for editing
                    string prefabPath = AssetDatabase.GetAssetPath(prefab);
                    GameObject prefabRoot = PrefabUtility.LoadPrefabContents(prefabPath);
                    
                    // Check if the component already exists
                    if (prefabRoot.GetComponent(componentType) == null)
                    {
                        // Add the component
                        prefabRoot.AddComponent(componentType);
                        
                        // Save the prefab
                        PrefabUtility.SaveAsPrefabAsset(prefabRoot, prefabPath);
                        successCount++;
                    }
                    else
                    {
                        failedPrefabs.Add($"{prefab.name} (already has component)");
                    }
                    
                    // Unload the prefab
                    PrefabUtility.UnloadPrefabContents(prefabRoot);
                }
                catch (Exception e)
                {
                    Debug.LogError($"Error adding component to {prefab.name}: {e.Message}");
                    failedPrefabs.Add($"{prefab.name} (error)");
                }
            }
            
            // Show results
            if (successCount > 0)
            {
                Debug.Log($"Successfully added {componentType.Name} to {successCount} prefabs.");
            }
            
            if (failedPrefabs.Count > 0)
            {
                Debug.LogWarning($"Failed to add component to {failedPrefabs.Count} prefabs: {string.Join(", ", failedPrefabs)}");
            }
            
            // Refresh the asset database to show changes
            AssetDatabase.Refresh();
        }
    }
}