using System;
using System.IO;
using System.Linq;
using JetBrains.Annotations;
using UnityEditor;
using UnityEditor.Animations;
using UnityEditor.UIElements;
using UnityEngine;
using UnityEngine.UIElements;
using Object = UnityEngine.Object;

namespace AibisDream.SystemEditor
{
    public class AnimatorClipLink : EditorWindow
    {
        [SerializeField] private VisualTreeAsset visualTreeAsset;

        private ObjectField _animatorField;
        private Label _animatorMessage;
        private ListView _stateInfoView;

        private TextField _clipsPathField;
        private Label _clipsMessage;
        private ListView _clipsNameList;

        private HelpBox _matchMessageBox;

        #region 部分缓存

        private static AnimatorController _animatorCache;
        private static string _clipsPathCache;

        private ChildAnimatorState[] _statesCache;
        private string[] _clipsCache;

        private bool _isChecked;
        private bool _allMatched;
        private bool _isAllLoad;

        #endregion

        [MenuItem("Tools/AnimatorClipLink")]
        public static void ShowExample()
        {
            AnimatorClipLink wnd = GetWindow<AnimatorClipLink>();
            wnd.titleContent = new GUIContent("AnimatorClipLink");
        }

        public void CreateGUI()
        {
            // Each editor window contains a root VisualElement object
            VisualElement root = rootVisualElement;

            // Instantiate UXML
            root.Add(visualTreeAsset.Instantiate());

            // 注册一些事件
            _animatorField = root.Q<ObjectField>("animator-field");
            _animatorField.RegisterValueChangedCallback(OnAnimatorChanged);
            _animatorMessage = root.Q<Label>("animator-message");
            _stateInfoView = root.Q<ListView>("state-info-list");

            _clipsPathField = root.Q<TextField>("clips-path-field");
            _clipsPathField.RegisterValueChangedCallback(OnClipsPathChanged);
            _clipsMessage = root.Q<Label>("clips-message");
            _clipsNameList = root.Q<ListView>("clips-name-list");

            _matchMessageBox = root.Q<HelpBox>("match-message-box");

            root.Q<Button>("import-merge-button").clicked += ImportMerge;

            // 初始化
            _animatorMessage.text = "请添加AnimatorController";
            _clipsMessage.text = "请输入Clips路径";
            // 加载AnimatorState
            if (_animatorCache != null)
            {
                _animatorField.value = _animatorCache;
                LoadAnimatorController(_animatorCache);
            }
            else
            {
                UpdateStateInfos(Array.Empty<ChildAnimatorState>());
            }

            // 加载路径下的Clips
            if (!string.IsNullOrWhiteSpace(_clipsPathCache))
            {
                _clipsPathField.value = _clipsPathCache;
                LoadClipPath(_clipsPathCache);
            }
            else
            {
                UpdateClipInFolder(Array.Empty<string>());
            }
        }

        private void UpdateStateInfos(ChildAnimatorState[] states)
        {
            _statesCache = states;
            // 总条目
            var stateList = states.ToList();

            _stateInfoView.makeItem = MakeItem;
            _stateInfoView.bindItem = BindItem;
            _stateInfoView.itemsSource = stateList;
            _stateInfoView.selectionType = UnityEngine.UIElements.SelectionType.None;

            MatchStateAndClip();
            return;

            // 链接
            void BindItem(VisualElement item, int index)
            {
                if (index >= stateList.Count) return;

                var state = stateList[index];
                if (item is ObjectField field)
                {
                    field.value = state.state.motion;
                    field.label = state.state.name;
                }
            }

            // 创建
            VisualElement MakeItem()
            {
                var item = new ObjectField
                {
                    objectType = typeof(AnimationClip)
                };
                item.SetEnabled(false);
                return item;
            }
        }

        private void OnAnimatorChanged(ChangeEvent<Object> evt)
        {
            if (evt.newValue is AnimatorController animatorController)
            {
                LoadAnimatorController(animatorController);
            }
            else
            {
                LoadAnimatorController(null);
            }
        }

        private void LoadAnimatorController([CanBeNull] AnimatorController animatorController)
        {
            // 判断新的值是不是空的，是就清空State信息
            if (animatorController == null)
            {
                _animatorCache = null;
                _animatorMessage.text = "AnimatorController 为空";
                // 清空State信息
                UpdateStateInfos(Array.Empty<ChildAnimatorState>());
                return;
            }

            _animatorCache = animatorController;
            // 值更新的时候，更新State信息
            var states = animatorController.layers[0].stateMachine.states;
            _animatorMessage.text = $"BaseLayer共有{states.Length}个State";
            UpdateStateInfos(states);
        }

        private void OnClipsPathChanged(ChangeEvent<string> evt)
        {
            LoadClipPath(evt.newValue);
        }

        private void LoadClipPath([CanBeNull] string clipsPath)
        {
            _clipsPathCache = clipsPath;
            // 先判断路径是否存在
            if (!AssetDatabase.IsValidFolder(clipsPath))
            {
                _clipsMessage.text = "路径不存在";
                // 清空Clip信息
                UpdateClipInFolder(Array.Empty<string>());
                return;
            }

            // 从路径中获取Clip
            var clipIds = AssetDatabase.FindAssets("t:AnimationClip", new[] { clipsPath });
            // 获取名称
            var clipNames = clipIds.Select(AssetDatabase.GUIDToAssetPath)
                .Where(item => item.EndsWith(".anim"))
                .ToArray();

            _clipsMessage.text = $"共有{clipNames.Length}个Clip";
            UpdateClipInFolder(clipNames);
        }

        private void UpdateClipInFolder(string[] clipNames)
        {
            _clipsCache = clipNames;
            var clipNameList = clipNames.Select(Path.GetFileNameWithoutExtension).ToList();

            _clipsNameList.makeItem = MakeItem;
            _clipsNameList.bindItem = BindItem;
            _clipsNameList.itemsSource = clipNameList;

            MatchStateAndClip();
            return;

            void BindItem(VisualElement item, int index)
            {
                if (index >= clipNameList.Count) return;

                var clipName = clipNameList[index];
                if (item is Label label)
                {
                    label.text = clipName;
                }
            }

            VisualElement MakeItem() => new Label();
        }

        private void MatchStateAndClip()
        {
            if (_statesCache is not { Length: > 0 } || _clipsCache is not { Length: > 0 })
            {
                _matchMessageBox.text = "请先选择AnimatorController和Clips路径";
                _matchMessageBox.messageType = HelpBoxMessageType.Warning;
                _allMatched = false;
                _isAllLoad = false;
                return;
            }

            var clipNames = _clipsCache.Select(Path.GetFileNameWithoutExtension).ToArray();
            // 匹配state和clips
            var notMatchStates =
                (from state in _statesCache where !clipNames.Contains(state.state.name) select state.state.name)
                .ToList();

            if (notMatchStates.Count == 0)
            {
                _matchMessageBox.messageType = HelpBoxMessageType.Info;
                _matchMessageBox.text = "所有State都已经匹配";
                _allMatched = true;
            }
            else
            {
                _matchMessageBox.messageType = HelpBoxMessageType.Warning;
                _matchMessageBox.text = $"未匹配的State有{notMatchStates.Count}个：\n{string.Join(", ", notMatchStates)}";
                _allMatched = false;
            }

            _isAllLoad = true;
            _isChecked = false;
        }

        private void ImportMerge()
        {
            if (!_isAllLoad)
            {
                _matchMessageBox.messageType = HelpBoxMessageType.Warning;
                _matchMessageBox.text = "请先选择AnimatorController和Clips路径";
                return;
            }

            if (_isChecked || _allMatched)
            {
                MergeClips();
                _isChecked = false;

                _matchMessageBox.messageType = HelpBoxMessageType.Info;
                _matchMessageBox.text = "匹配完成";
            }
            else
            {
                _matchMessageBox.messageType = HelpBoxMessageType.Warning;
                _matchMessageBox.text = "仍有未匹配到Clip的State，确认要继续吗？";
                _isChecked = true;
            }
        }

        private void MergeClips()
        {
            var clipNames = _clipsCache.Select(Path.GetFileNameWithoutExtension).ToArray();
            foreach (var state in _statesCache)
            {
                var idx = Array.IndexOf(clipNames, state.state.name);
                if (idx != -1)
                {
                    var newClip = AssetDatabase.LoadAssetAtPath<AnimationClip>(_clipsCache[idx]);
                    var oldClip = state.state.motion;
                    
                    var settings = AnimationUtility.GetAnimationClipSettings(newClip);
                    settings.loopTime = oldClip.isLooping;
                    AnimationUtility.SetAnimationClipSettings(newClip, settings);
                    
                    state.state.motion = newClip;
                }
            }

            LoadAnimatorController(_animatorCache);
        }
    }
}