using UnityEditor;
using UnityEditorInternal;
using UnityEngine;

namespace Amanotes
{
    internal class PresetTab
    {
        private Core.AmaDevSettings settings;
        private bool needsRefresh = true;
        private Vector2 scrollPos;
        private SerializedObject serializedSettings;
        private ReorderableList presetList;
        private SerializedProperty entriesProp;

        internal void Refresh() => needsRefresh = true;

        private void EnsureData()
        {
            if (!needsRefresh && settings != null) return;
            needsRefresh = false;
            settings = Core.AmaDevSettings.Instance;
            if (settings == null) return;

            serializedSettings = new SerializedObject(settings);
            entriesProp = serializedSettings.FindProperty("presetGenerator.entries");
            presetList = new ReorderableList(serializedSettings, entriesProp, true, true, true, true)
            {
                drawHeaderCallback = rect => EditorGUI.LabelField(rect, "Preset Folder Entries"),
                elementHeightCallback = GetElementHeight,
                drawElementCallback = DrawElement,
            };
        }

        internal void OnGUI()
        {
            EnsureData();

            if (settings == null)
            {
                EditorGUILayout.HelpBox("No AmaDevSettings asset found.", MessageType.Info);
                if (GUILayout.Button("Create AmaDevSettings", GUILayout.Height(30)))
                { settings = Core.AmaDevSettings.GetOrCreate(); needsRefresh = true; }
                return;
            }
            if (EditorApplication.isCompiling)
            { EditorGUILayout.HelpBox("Compiling...", MessageType.Info); return; }

            serializedSettings.Update();
            scrollPos = EditorGUILayout.BeginScrollView(scrollPos);
            presetList.DoLayoutList();
            EditorGUILayout.EndScrollView();
            serializedSettings.ApplyModifiedProperties();

            GUILayout.FlexibleSpace();
            DrawFooter();
        }

        private void DrawFooter()
        {
            var sep = GUILayoutUtility.GetRect(0, 1, GUILayout.ExpandWidth(true));
            EditorGUI.DrawRect(sep, new Color(0.3f, 0.3f, 0.3f, 1f));
            bool anyValid = HasAnyValidEntry();
            GUI.enabled = anyValid;
            var oldBg = GUI.backgroundColor;
            GUI.backgroundColor = new Color(0.3f, 0.7f, 1f, 1f);
            if (GUILayout.Button("Generate All", GUILayout.Height(26)))
            { serializedSettings.ApplyModifiedProperties(); settings.presetGenerator.GenerateAll(settings); }
            GUI.backgroundColor = oldBg;
            GUI.enabled = true;
            GUILayout.Space(2);
        }

        private float GetElementHeight(int index)
        {
            var entryProp = entriesProp.GetArrayElementAtIndex(index);
            bool showClassName = entryProp.FindPropertyRelative("generatedScript").objectReferenceValue == null;
            bool showTemplate = entryProp.FindPropertyRelative("templateAsset").objectReferenceValue != null;
            // Fields: sourceFolder, (template if assigned), namespace, generatedScript, (className if no script)
            int fieldCount = 3; // sourceFolder + namespace + generatedScript
            if (showTemplate) fieldCount++;
            if (showClassName) fieldCount++;
            float lineH = EditorGUIUtility.singleLineHeight + EditorGUIUtility.standardVerticalSpacing;
            return fieldCount * lineH + lineH + 30f + 12f;
        }

        private void DrawElement(Rect rect, int index, bool isActive, bool isFocused)
        {
            var entryProp = entriesProp.GetArrayElementAtIndex(index);
            float lineH = EditorGUIUtility.singleLineHeight + EditorGUIUtility.standardVerticalSpacing;
            float y = rect.y + 4f;

            // --- Source Folder (with change detection for auto-namespace) ---
            var sourceFolderProp = entryProp.FindPropertyRelative("sourceFolder");
            var prevFolder = sourceFolderProp.objectReferenceValue;
            EditorGUI.PropertyField(new Rect(rect.x, y, rect.width, EditorGUIUtility.singleLineHeight),
                sourceFolderProp, new GUIContent("Source Folder"));
            y += lineH;

            // Auto-detect namespace when folder changes
            if (sourceFolderProp.objectReferenceValue != prevFolder && sourceFolderProp.objectReferenceValue != null)
            {
                var namespaceProp = entryProp.FindPropertyRelative("nameSpace");
                if (string.IsNullOrEmpty(namespaceProp.stringValue))
                {
                    var folderPath = AssetDatabase.GetAssetPath(sourceFolderProp.objectReferenceValue);
                    var detected = Core.AmaDevSettings.PresetGeneratorConfig.DetectNamespaceNearFolder(folderPath);
                    if (detected != null)
                        namespaceProp.stringValue = detected;
                }
            }

            // --- Template (only show if explicitly assigned; uses default otherwise) ---
            var templateProp = entryProp.FindPropertyRelative("templateAsset");
            if (templateProp.objectReferenceValue != null)
            {
                EditorGUI.PropertyField(new Rect(rect.x, y, rect.width, EditorGUIUtility.singleLineHeight),
                    templateProp, new GUIContent("Template (override)"));
                y += lineH;
            }

            // --- Namespace ---
            EditorGUI.PropertyField(new Rect(rect.x, y, rect.width, EditorGUIUtility.singleLineHeight),
                entryProp.FindPropertyRelative("nameSpace"), new GUIContent("Namespace"));
            y += lineH;

            // --- Generated Script OR Class Name ---
            var scriptProp = entryProp.FindPropertyRelative("generatedScript");
            EditorGUI.PropertyField(new Rect(rect.x, y, rect.width, EditorGUIUtility.singleLineHeight),
                scriptProp, new GUIContent("Generated Script"));
            y += lineH;

            if (scriptProp.objectReferenceValue == null)
            {
                EditorGUI.PropertyField(new Rect(rect.x, y, rect.width, EditorGUIUtility.singleLineHeight),
                    entryProp.FindPropertyRelative("generatedClassName"), new GUIContent("Class Name"));
                y += lineH;
            }

            serializedSettings.ApplyModifiedProperties();
            var cfg = settings.presetGenerator;
            var entry = cfg.entries[index];
            EditorGUI.LabelField(new Rect(rect.x, y, rect.width, EditorGUIUtility.singleLineHeight),
                GetEntryInfo(cfg, entry, index), EditorStyles.miniLabel);
            y += lineH;

            GUI.enabled = IsEntryValid(cfg, entry, index);
            if (GUI.Button(new Rect(rect.x, y, rect.width, 24f), $"Generate [{index}]"))
            { serializedSettings.ApplyModifiedProperties(); cfg.GenerateEntry(index, settings); }
            GUI.enabled = true;
        }

        private bool HasAnyValidEntry()
        {
            var cfg = settings.presetGenerator;
            for (int i = 0; i < cfg.entries.Count; i++)
                if (IsEntryValid(cfg, cfg.entries[i], i)) return true;
            return false;
        }

        private static bool IsEntryValid(Core.AmaDevSettings.PresetGeneratorConfig cfg, Core.AmaDevSettings.PresetFolderEntry entry, int index)
        {
            if (entry.sourceFolder == null) return false;
            var path = AssetDatabase.GetAssetPath(entry.sourceFolder);
            return AssetDatabase.IsValidFolder(path) && cfg.GetClassName(entry, index) != null;
        }

        private static string GetEntryInfo(Core.AmaDevSettings.PresetGeneratorConfig cfg, Core.AmaDevSettings.PresetFolderEntry entry, int index)
        {
            var folderPath = entry.sourceFolder != null ? AssetDatabase.GetAssetPath(entry.sourceFolder) : null;
            if (folderPath == null || !AssetDatabase.IsValidFolder(folderPath)) return "⚠ No valid source folder";
            var templateLabel = entry.templateAsset != null ? "custom" : "default";
            return $"Prefabs: {cfg.GetPrefabsInFolder(folderPath).Count}   Class: {cfg.GetClassName(entry, index) ?? "?"}   Template: {templateLabel}";
        }
    }
}