using System;
using System.Collections.Generic;
using System.IO;
using JetBrains.Annotations;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace Module.NavigationTool.Editor.Toolbar
{
    [UsedImplicitly]
    internal sealed class ToolScenePicker : AbstractToolbarDrawer
    {
        public override bool Visible => ToolbarScenePickerSettings.IsSceneEnabled;
        public override bool Enabled => !EditorApplication.isPlaying && !EditorApplication.isPlayingOrWillChangePlaymode;
        public override EToolbarPlacement Placement => EToolbarPlacement.Right;
        public override int Priority => (int)EToolbarPriority.Medium;

        private static bool IS_DIRTY = true;
        private static int SELECTED_INDEX = -1;
        private static string[] OPTIONS = new string[0];
        private static string[] PATHS = new string[0];
        
        private static void Initialize()
        {
            if (!IS_DIRTY)
                return;
            
            var listNames = new List<string>();
            var listPaths = new List<string>();
            
            InitializeBuildSettingsScenes(listNames, listPaths);
            InitializeRemainingScenes(listNames, listPaths);

            OPTIONS = listNames.ToArray();
            PATHS = listPaths.ToArray();

            Scene activeScene = SceneManager.GetActiveScene();
            SELECTED_INDEX = listPaths.IndexOf(activeScene.path);
            IS_DIRTY = false;
        }

        private static void InitializeBuildSettingsScenes(List<string> listNames, List<string> listPaths)
        {
            EditorBuildSettingsScene[] scenes = EditorBuildSettings.scenes;

            for (var i = 0; i < scenes.Length; i++)
            {
                if (string.IsNullOrEmpty(scenes[i].path))
                    continue;

                listNames.Add($"{Path.GetFileNameWithoutExtension(scenes[i].path)}");
                listPaths.Add(scenes[i].path);
            }
        }
        
        private static void InitializeRemainingScenes(List<string> listNames, List<string> listPaths)
        {
            List<string> sortByAssetLabels = ToolbarScenePickerSettings.SceneAssetLabels;
            var assetLabelToScenes = new SceneSortElement[sortByAssetLabels.Count + 1];
            string[] guids = AssetDatabase.FindAssets("t:scene");
            
            for (var i = 0; i < guids.Length; i++)
            {
                string path = AssetDatabase.GUIDToAssetPath(guids[i]);
                
                if (listPaths.Contains(path) || !path.StartsWith("Assets"))
                    continue;

                var scene = AssetDatabase.LoadAssetAtPath<SceneAsset>(path);

                if (scene == null)
                    continue;
                
                string sceneName = path.Substring(7, path.Length - 13)
                                       .Replace('/', '\\');

                string[] assetLabels = AssetDatabase.GetLabels(scene);
                int index = -1;

                for (var j = 0; j < assetLabels.Length; j++)
                {
                    index = sortByAssetLabels.IndexOf(assetLabels[j]);

                    if (index != -1)
                        break;
                }

                if (index == -1)
                    index = sortByAssetLabels.Count;
                if (assetLabelToScenes[index] == null)
                    assetLabelToScenes[index] = new SceneSortElement();

                assetLabelToScenes[index].names.Add(sceneName);
                assetLabelToScenes[index].paths.Add(path);
            }

            for (var i = 0; i < assetLabelToScenes.Length; i++)
            {
                SceneSortElement e = assetLabelToScenes[i];

                if (e == null)
                    continue;

                listNames.Add(string.Empty);
                listPaths.Add(string.Empty);
                
                listNames.AddRange(e.names);
                listPaths.AddRange(e.paths);
            }
        }
        
        public override void Update()
        {
            Initialize();
        }

        protected override void Draw(Rect rect)
        {
            Initialize();
            int temp = EditorGUI.Popup(rect, SELECTED_INDEX, OPTIONS, styles.popup);

            if (temp <= -1 || temp == SELECTED_INDEX || OPTIONS.Length == 0)
                return;
            if (string.IsNullOrEmpty(PATHS[temp]))
                return;

            try
            {
                Scene scene = EditorSceneManager.OpenScene(PATHS[temp], OpenSceneMode.Single);
                    
                if (scene.isLoaded)
                    SELECTED_INDEX = temp;
            }
            catch (Exception e)
            {
                Debug.LogWarningFormat("Failed to load scene ({0}), due to exception: {1}", PATHS[temp], e.Message);
            }
        }
        
        public override float CalculateWidth()
        {
            return 100.0f;
        }

        public static void SetAsDirty()
        {
            IS_DIRTY = true;
        }

        private sealed class SceneSortElement
        {
            public readonly List<string> names = new List<string>();
            public readonly List<string> paths = new List<string>();
        }
    }
}