#if UNITY_2019_4_OR_NEWER
using System;
using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEngine;
using UnityEditor.UIElements;
using UnityEngine.UIElements;

namespace YooAsset.Editor
{
    /// <summary>
    /// 帧对比查看器
    /// </summary>
    internal class DebuggerCompareViewer
    {
        /// <summary>
        /// 差异类型
        /// </summary>
        internal enum DiffType
        {
            RefIncreased,   // 引用计数增加（包括新增资源）
            RefDecreased,   // 引用计数减少（包括移除资源）
            Unchanged       // 无变化
        }

        /// <summary>
        /// 差异信息
        /// </summary>
        internal class DiffProviderInfo
        {
            public DiffType Type;
            public DebugProviderInfo ProviderInfo;
            public DebugProviderInfo OldProviderInfo; // 用于对比修改前后的值
            public int RefCountDelta; // 引用计数变化值
            public int SecondaryRefCountDelta; // 二级引用计数变化值

            public string GetDiffTypeString()
            {
                switch (Type)
                {
                    case DiffType.RefIncreased: return "[↑] 引用增加";
                    case DiffType.RefDecreased: return "[↓] 引用减少";
                    case DiffType.Unchanged: return "[=] 无变化";
                    default: return "";
                }
            }

            public Color GetDiffColor()
            {
                switch (Type)
                {
                    case DiffType.RefIncreased: return new Color(0.3f, 0.8f, 0.3f);
                    case DiffType.RefDecreased: return new Color(0.9f, 0.3f, 0.3f);
                    case DiffType.Unchanged: return Color.gray;
                    default: return Color.white;
                }
            }
        }

        private VisualElement _root;
        private ListView _diffListView;
        private Label _frame1Label;
        private Label _frame2Label;
        private Label _summaryLabel;
        private Toggle _showRefIncreasedToggle;
        private Toggle _showRefDecreasedToggle;
        private Toggle _showUnchangedToggle;

        private DebugReport _report1;
        private DebugReport _report2;
        private List<DiffProviderInfo> _allDiffInfos = new List<DiffProviderInfo>();
        private List<DiffProviderInfo> _filteredDiffInfos = new List<DiffProviderInfo>();
        private string _searchKeyWord;

        /// <summary>
        /// 初始化页面
        /// </summary>
        public void InitViewer()
        {
            _root = new VisualElement();
            _root.style.flexGrow = 1f;

            // 顶部信息栏
            var infoBar = new VisualElement();
            infoBar.style.flexDirection = FlexDirection.Row;
            infoBar.style.height = 25;
            infoBar.style.backgroundColor = new Color(0.2f, 0.2f, 0.2f);
            infoBar.style.paddingLeft = 5;
            infoBar.style.paddingRight = 5;
            _root.Add(infoBar);

            _frame1Label = new Label("Frame A: 未选择");
            _frame1Label.style.unityTextAlign = TextAnchor.MiddleLeft;
            _frame1Label.style.width = 200;
            infoBar.Add(_frame1Label);

            _frame2Label = new Label("Frame B: 未选择");
            _frame2Label.style.unityTextAlign = TextAnchor.MiddleLeft;
            _frame2Label.style.width = 200;
            infoBar.Add(_frame2Label);

            _summaryLabel = new Label("");
            _summaryLabel.style.unityTextAlign = TextAnchor.MiddleLeft;
            _summaryLabel.style.flexGrow = 1;
            infoBar.Add(_summaryLabel);

            // 过滤器栏
            var filterBar = new VisualElement();
            filterBar.style.flexDirection = FlexDirection.Row;
            filterBar.style.height = 25;
            filterBar.style.backgroundColor = new Color(0.25f, 0.25f, 0.25f);
            filterBar.style.paddingLeft = 5;
            filterBar.style.alignItems = Align.Center;
            _root.Add(filterBar);

            var filterLabel = new Label("显示过滤: ");
            filterLabel.style.unityTextAlign = TextAnchor.MiddleLeft;
            filterLabel.style.marginRight = 10;
            filterBar.Add(filterLabel);


            _showRefIncreasedToggle = CreateFilterToggle("引用增加", true);
            _showRefIncreasedToggle.RegisterValueChangedCallback(evt => RefreshFilteredList());
            filterBar.Add(_showRefIncreasedToggle);

            _showRefDecreasedToggle = CreateFilterToggle("引用减少", true);
            _showRefDecreasedToggle.RegisterValueChangedCallback(evt => RefreshFilteredList());
            filterBar.Add(_showRefDecreasedToggle);

            _showUnchangedToggle = CreateFilterToggle("无变化", false);
            _showUnchangedToggle.RegisterValueChangedCallback(evt => RefreshFilteredList());
            filterBar.Add(_showUnchangedToggle);

            // 列表头部
            var headerBar = new VisualElement();
            headerBar.style.flexDirection = FlexDirection.Row;
            headerBar.style.height = 22;
            headerBar.style.backgroundColor = new Color(0.3f, 0.3f, 0.3f);
            _root.Add(headerBar);

            AddHeaderLabel(headerBar, "差异类型", 100);
            AddHeaderLabel(headerBar, "包裹名", 120);
            AddHeaderLabel(headerBar, "资源路径", 0, true); // 自动填充剩余宽度
            AddHeaderLabel(headerBar, "一级引用", 100);
            AddHeaderLabel(headerBar, "一级变化", 80);
            AddHeaderLabel(headerBar, "二级引用", 100);
            AddHeaderLabel(headerBar, "二级变化", 80);

            // 差异列表
            _diffListView = new ListView();
            _diffListView.style.flexGrow = 1f;
            _diffListView.makeItem = MakeDiffListViewItem;
            _diffListView.bindItem = BindDiffListViewItem;
            _diffListView.itemsSource = _filteredDiffInfos;
#if UNITY_2021_2_OR_NEWER
            _diffListView.fixedItemHeight = 22;
#else
            _diffListView.itemHeight = 22;
#endif
            _root.Add(_diffListView);
        }

        private void AddHeaderLabel(VisualElement parent, string text, float width, bool flexGrow = false)
        {
            var label = new Label(text);
            label.style.unityTextAlign = TextAnchor.MiddleLeft;
            if (flexGrow)
            {
                label.style.flexGrow = 1f;
                label.style.minWidth = 200;
            }
            else
            {
                label.style.width = width;
            }
            label.style.unityFontStyleAndWeight = FontStyle.Bold;
            label.style.paddingLeft = 3;
            parent.Add(label);
        }
        
        private Toggle CreateFilterToggle(string label, bool defaultValue)
        {
            var toggle = new Toggle();
            toggle.value = defaultValue;
            toggle.style.marginRight = 5;
            
            // 创建标签并设置样式
            var labelElement = new Label(label);
            labelElement.style.marginLeft = 2;
            labelElement.style.marginRight = 10;
            toggle.Add(labelElement);
            
            return toggle;
        }

        /// <summary>
        /// 设置对比的两帧数据
        /// </summary>
        public void SetCompareFrames(DebugReport report1, DebugReport report2)
        {
            _report1 = report1;
            _report2 = report2;

            if (report1 != null)
                _frame1Label.text = $"Frame A: {report1.FrameCount}";
            else
                _frame1Label.text = "Frame A: 未选择";

            if (report2 != null)
                _frame2Label.text = $"Frame B: {report2.FrameCount}";
            else
                _frame2Label.text = "Frame B: 未选择";

            ComputeDiff();
            RefreshFilteredList();
        }

        /// <summary>
        /// 设置搜索关键字
        /// </summary>
        public void SetSearchKeyWord(string searchKeyWord)
        {
            _searchKeyWord = searchKeyWord;
            RefreshFilteredList();
        }

        /// <summary>
        /// 计算差异
        /// </summary>
        private void ComputeDiff()
        {
            _allDiffInfos.Clear();

            if (_report1 == null || _report2 == null)
            {
                UpdateSummary();
                return;
            }

            // 收集两帧的所有Provider信息
            var providers1 = new Dictionary<string, DebugProviderInfo>();
            var providers2 = new Dictionary<string, DebugProviderInfo>();

            foreach (var packageData in _report1.PackageDatas)
            {
                foreach (var providerInfo in packageData.ProviderInfos)
                {
                    var key = $"{packageData.PackageName}|{providerInfo.AssetPath}";
                    providerInfo.PackageName = packageData.PackageName;
                    providers1[key] = providerInfo;
                }
            }

            foreach (var packageData in _report2.PackageDatas)
            {
                foreach (var providerInfo in packageData.ProviderInfos)
                {
                    var key = $"{packageData.PackageName}|{providerInfo.AssetPath}";
                    providerInfo.PackageName = packageData.PackageName;
                    providers2[key] = providerInfo;
                }
            }

            // 找出新增的（在report2中有，在report1中没有）- 归类为引用增加
            foreach (var kvp in providers2)
            {
                if (!providers1.ContainsKey(kvp.Key))
                {
                    _allDiffInfos.Add(new DiffProviderInfo
                    {
                        Type = DiffType.RefIncreased,
                        ProviderInfo = kvp.Value,
                        OldProviderInfo = null,
                        RefCountDelta = kvp.Value.RefCount,
                        SecondaryRefCountDelta = kvp.Value.SecondaryRefCount
                    });
                }
            }

            // 找出移除的（在report1中有，在report2中没有）- 归类为引用减少
            foreach (var kvp in providers1)
            {
                if (!providers2.ContainsKey(kvp.Key))
                {
                    _allDiffInfos.Add(new DiffProviderInfo
                    {
                        Type = DiffType.RefDecreased,
                        ProviderInfo = kvp.Value,
                        OldProviderInfo = null,
                        RefCountDelta = -kvp.Value.RefCount,
                        SecondaryRefCountDelta = -kvp.Value.SecondaryRefCount
                    });
                }
            }

            // 找出修改的和未变化的
            foreach (var kvp in providers1)
            {
                if (providers2.TryGetValue(kvp.Key, out var provider2))
                {
                    var provider1 = kvp.Value;
                    int refCountDelta = provider2.RefCount - provider1.RefCount;
                    int secondaryRefCountDelta = provider2.SecondaryRefCount - provider1.SecondaryRefCount;

                    // 判断差异类型：一级或二级引用计数有任一增加则为增加，有任一减少则为减少
                    DiffType diffType;
                    if (refCountDelta > 0 || secondaryRefCountDelta > 0)
                        diffType = DiffType.RefIncreased;
                    else if (refCountDelta < 0 || secondaryRefCountDelta < 0)
                        diffType = DiffType.RefDecreased;
                    else
                        diffType = DiffType.Unchanged;

                    _allDiffInfos.Add(new DiffProviderInfo
                    {
                        Type = diffType,
                        ProviderInfo = provider2,
                        OldProviderInfo = provider1,
                        RefCountDelta = refCountDelta,
                        SecondaryRefCountDelta = secondaryRefCountDelta
                    });
                }
            }

            // 排序：按差异类型排序，同类型按资源路径排序
            _allDiffInfos.Sort((a, b) =>
            {
                int typeCompare = a.Type.CompareTo(b.Type);
                if (typeCompare != 0) return typeCompare;
                return string.CompareOrdinal(a.ProviderInfo.AssetPath, b.ProviderInfo.AssetPath);
            });

            UpdateSummary();
        }

        /// <summary>
        /// 更新统计信息
        /// </summary>
        private void UpdateSummary()
        {
            int refIncreasedCount = _allDiffInfos.Count(d => d.Type == DiffType.RefIncreased);
            int refDecreasedCount = _allDiffInfos.Count(d => d.Type == DiffType.RefDecreased);
            int unchangedCount = _allDiffInfos.Count(d => d.Type == DiffType.Unchanged);

            _summaryLabel.text = $"统计: 引用↑ {refIncreasedCount} | 引用↓ {refDecreasedCount} | 无变化 {unchangedCount}";
        }

        /// <summary>
        /// 刷新过滤后的列表
        /// </summary>
        private void RefreshFilteredList()
        {
            _filteredDiffInfos.Clear();

            foreach (var diffInfo in _allDiffInfos)
            {
                // 类型过滤
                if (diffInfo.Type == DiffType.RefIncreased && !_showRefIncreasedToggle.value) continue;
                if (diffInfo.Type == DiffType.RefDecreased && !_showRefDecreasedToggle.value) continue;
                if (diffInfo.Type == DiffType.Unchanged && !_showUnchangedToggle.value) continue;

                // 关键字过滤
                if (!string.IsNullOrEmpty(_searchKeyWord))
                {
                    if (!diffInfo.ProviderInfo.AssetPath.Contains(_searchKeyWord))
                        continue;
                }

                _filteredDiffInfos.Add(diffInfo);
            }

            _diffListView.itemsSource = _filteredDiffInfos;
            _diffListView.Rebuild();
        }

        /// <summary>
        /// 清空页面
        /// </summary>
        public void ClearView()
        {
            _report1 = null;
            _report2 = null;
            _allDiffInfos.Clear();
            _filteredDiffInfos.Clear();
            _frame1Label.text = "Frame A: 未选择";
            _frame2Label.text = "Frame B: 未选择";
            _summaryLabel.text = "";
            _diffListView.Rebuild();
        }

        /// <summary>
        /// 挂接到父类页面上
        /// </summary>
        public void AttachParent(VisualElement parent)
        {
            parent.Add(_root);
        }

        /// <summary>
        /// 从父类页面脱离开
        /// </summary>
        public void DetachParent()
        {
            _root.RemoveFromHierarchy();
        }

        // 列表项相关
        private VisualElement MakeDiffListViewItem()
        {
            VisualElement element = new VisualElement();
            element.style.flexDirection = FlexDirection.Row;

            // 差异类型
            AddItemLabel(element, "Label0", 100);
            // 包裹名
            AddItemLabel(element, "Label1", 120);
            // 资源路径 - 自动填充剩余宽度
            AddItemLabel(element, "Label2", 0, true);
            // 一级引用计数
            AddItemLabel(element, "Label3", 100);
            // 一级引用变化
            AddItemLabel(element, "Label4", 80);
            // 二级引用计数
            AddItemLabel(element, "Label5", 100);
            // 二级引用变化
            AddItemLabel(element, "Label6", 80);

            return element;
        }

        private void AddItemLabel(VisualElement parent, string name, float width, bool flexGrow = false)
        {
            var label = new Label();
            label.name = name;
            label.style.unityTextAlign = TextAnchor.MiddleLeft;
            label.style.marginLeft = 3f;
            if (flexGrow)
            {
                label.style.flexGrow = 1f;
                label.style.minWidth = 200;
            }
            else
            {
                label.style.width = width;
            }
            parent.Add(label);
        }

        private void BindDiffListViewItem(VisualElement element, int index)
        {
            var diffInfo = _filteredDiffInfos[index];
            var providerInfo = diffInfo.ProviderInfo;

            // 差异类型
            var label0 = element.Q<Label>("Label0");
            label0.text = diffInfo.GetDiffTypeString();
            label0.style.color = diffInfo.GetDiffColor();

            // 包裹名
            var label1 = element.Q<Label>("Label1");
            label1.text = providerInfo.PackageName;

            // 资源路径
            var label2 = element.Q<Label>("Label2");
            label2.text = providerInfo.AssetPath;

            // 一级引用计数
            var label3 = element.Q<Label>("Label3");
            if (diffInfo.RefCountDelta != 0 && diffInfo.OldProviderInfo != null)
            {
                label3.text = $"{diffInfo.OldProviderInfo.RefCount} -> {providerInfo.RefCount}";
            }
            else
            {
                label3.text = providerInfo.RefCount.ToString();
            }

            // 一级引用变化
            var label4 = element.Q<Label>("Label4");
            if (diffInfo.RefCountDelta > 0)
            {
                label4.text = $"+{diffInfo.RefCountDelta}";
                label4.style.color = new Color(0.3f, 0.8f, 0.3f);
            }
            else if (diffInfo.RefCountDelta < 0)
            {
                label4.text = diffInfo.RefCountDelta.ToString();
                label4.style.color = new Color(0.9f, 0.3f, 0.3f);
            }
            else
            {
                label4.text = "0";
                label4.style.color = Color.gray;
            }
            
            // 二级引用计数
            var label5 = element.Q<Label>("Label5");
            if (diffInfo.SecondaryRefCountDelta != 0 && diffInfo.OldProviderInfo != null)
            {
                label5.text = $"{diffInfo.OldProviderInfo.SecondaryRefCount} -> {providerInfo.SecondaryRefCount}";
            }
            else
            {
                label5.text = providerInfo.SecondaryRefCount.ToString();
            }

            // 二级引用变化
            var label6 = element.Q<Label>("Label6");
            if (diffInfo.SecondaryRefCountDelta > 0)
            {
                label6.text = $"+{diffInfo.SecondaryRefCountDelta}";
                label6.style.color = new Color(0.3f, 0.8f, 0.3f);
            }
            else if (diffInfo.SecondaryRefCountDelta < 0)
            {
                label6.text = diffInfo.SecondaryRefCountDelta.ToString();
                label6.style.color = new Color(0.9f, 0.3f, 0.3f);
            }
            else
            {
                label6.text = "0";
                label6.style.color = Color.gray;
            }
        }
    }
}
#endif