using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;
using WinForms = System.Windows.Forms;

namespace DrillTools
{
    /// <summary>
    /// 拖放帮助类
    /// </summary>
    public static class DragDropHelper
    {
        private static System.Windows.Point _startPoint;
        private static bool _isDragging;
        private static DragToolTipWindow? _dragToolTipWindow;
        private static Window? _ownerWindow;
        private static System.Windows.Shapes.Rectangle? _insertionIndicator;
        private static int _insertionIndex = -1;
        private static DateTime? _lastUpdateTime;

        /// <summary>
        /// 启用 ListView 的拖放功能
        /// </summary>
        /// <typeparam name="T">数据项类型</typeparam>
        /// <param name="listView">ListView 控件</param>
        /// <param name="insertionIndicator">插入位置指示器</param>
        public static void EnableDragDrop<T>(System.Windows.Controls.ListView listView, System.Windows.Shapes.Rectangle insertionIndicator) where T : class
        {
            _insertionIndicator = insertionIndicator;
            _ownerWindow = Window.GetWindow(listView);
            
            listView.PreviewMouseLeftButtonDown += (sender, e) =>
            {
                _startPoint = e.GetPosition(null);
                _isDragging = false;
            };

            listView.PreviewMouseMove += (sender, e) =>
            {
                if (e.LeftButton == MouseButtonState.Pressed && !_isDragging)
                {
                    System.Windows.Point position = e.GetPosition(null);
                    if (Math.Abs(position.X - _startPoint.X) > SystemParameters.MinimumHorizontalDragDistance ||
                        Math.Abs(position.Y - _startPoint.Y) > SystemParameters.MinimumVerticalDragDistance)
                    {
                        _isDragging = true;
                        var listViewItem = FindAncestor<System.Windows.Controls.ListViewItem>((DependencyObject)e.OriginalSource);
                        if (listViewItem != null)
                        {
                            var item = listView.ItemContainerGenerator.ItemFromContainer(listViewItem) as T;
                            if (item != null)
                            {
                                // 获取屏幕坐标
                                var screenPosition = listView.PointToScreen(e.GetPosition(listView));
                                
                                // 创建并显示拖动提示
                                CreateDragToolTip(item, screenPosition);
                                
                                // 使用 QueryContinueDrag 事件来更新位置
                                System.Windows.QueryContinueDragEventHandler queryContinueHandler = null;
                                queryContinueHandler = (sender, e) =>
                                {
                                    if (_dragToolTipWindow != null)
                                    {
                                        // 获取当前鼠标位置
                                        var currentPos = WinForms.Control.MousePosition;
                                        _dragToolTipWindow.UpdatePosition(new System.Windows.Point(currentPos.X, currentPos.Y));
                                    }
                                    
                                    // 如果拖放结束，移除事件处理
                                    if (e.Action == System.Windows.DragAction.Drop || e.Action == System.Windows.DragAction.Cancel)
                                    {
                                        DragDrop.RemoveQueryContinueDragHandler(listView, queryContinueHandler);
                                    }
                                };
                                
                                DragDrop.AddQueryContinueDragHandler(listView, queryContinueHandler);
                                
                                System.Windows.DataObject data = new System.Windows.DataObject(typeof(T), item);
                                DragDrop.DoDragDrop(listViewItem, data, System.Windows.DragDropEffects.Move);
                                
                                // 清理拖动提示
                                CleanupDragToolTip();
                            }
                        }
                    }
                }
            };

            listView.DragOver += (sender, e) =>
            {
                if (e.Data.GetDataPresent(typeof(T)))
                {
                    e.Effects = System.Windows.DragDropEffects.Move;
                    
                    // 更新插入位置指示器
                    UpdateInsertionIndicator(listView, e.GetPosition(listView));
                }
                else
                {
                    e.Effects = System.Windows.DragDropEffects.None;
                }
                e.Handled = true;
            };
            
            listView.DragLeave += (sender, e) =>
            {
                HideInsertionIndicator();
            };
            
            listView.Drop += (sender, e) =>
            {
                try
                {
                    // 隐藏插入指示器
                    HideInsertionIndicator();
                    
                    Debug.WriteLine($"[DragDrop] Drop事件触发 - OriginalSource类型: {e.OriginalSource?.GetType().Name}");
                    Debug.WriteLine($"[DragDrop] Drop位置: ({e.GetPosition(listView).X}, {e.GetPosition(listView).Y})");

                    if (e.Data.GetDataPresent(typeof(T)))
                    {
                        var droppedItem = e.Data.GetData(typeof(T)) as T;
                        if (droppedItem != null)
                        {
                            Debug.WriteLine($"[DragDrop] 拖放项: {droppedItem}");

                            // 检查是否是机台码刀具，如果是则不允许移动
                            if (droppedItem is ToolItem toolItem && toolItem.ToolType == ToolType.MachineCode)
                            {
                                Debug.WriteLine("[DragDrop] 机台码刀具不允许移动");
                                System.Windows.MessageBox.Show("机台码刀具不允许移动位置", "提示", MessageBoxButton.OK, MessageBoxImage.Information);
                                _isDragging = false;
                                return;
                            }

                            var targetItem = FindAncestor<System.Windows.Controls.ListViewItem>((DependencyObject)e.OriginalSource);
                            string ss = targetItem == null ? "NULL" : "找到";
                            Debug.WriteLine($"[DragDrop] 目标ListViewItem: {ss}");

                            if (targetItem == null)
                            {
                                Debug.WriteLine("[DragDrop] 警告: 目标项为空，可能是拖放到列表外部");
                                _isDragging = false;
                                return;
                            }

                            var targetIndex = listView.ItemContainerGenerator.IndexFromContainer(targetItem);
                            Debug.WriteLine($"[DragDrop] 目标索引: {targetIndex}");

                            var sourceIndex = listView.Items.IndexOf(droppedItem);
                            Debug.WriteLine($"[DragDrop] 源索引: {sourceIndex}");

                            // 检查目标位置是否是机台码刀具
                            var viewModel = listView.DataContext as MainWindowViewModel;
                            if (viewModel != null && viewModel.Tools.Count > targetIndex)
                            {
                                var targetTool = viewModel.Tools[targetIndex];
                                if (targetTool.ToolType == ToolType.MachineCode)
                                {
                                    Debug.WriteLine("[DragDrop] 不能移动到机台码刀具位置");
                                    System.Windows.MessageBox.Show("不能移动到机台码刀具位置", "提示", MessageBoxButton.OK, MessageBoxImage.Information);
                                    _isDragging = false;
                                    return;
                                }
                            }

                            if (sourceIndex != -1 && targetIndex != -1 && sourceIndex != targetIndex)
                            {
                                viewModel?.ReorderTools(sourceIndex, targetIndex);
                                Debug.WriteLine($"[DragDrop] 重新排序完成: {sourceIndex} -> {targetIndex}");
                            }
                            else
                            {
                                Debug.WriteLine($"[DragDrop] 跳过重新排序 - 源索引: {sourceIndex}, 目标索引: {targetIndex}");
                            }
                        }
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"[DragDrop] 异常: {ex.GetType().Name} - {ex.Message}");
                    Debug.WriteLine($"[DragDrop] 堆栈跟踪: {ex.StackTrace}");
                    System.Windows.MessageBox.Show($"拖放操作发生错误: {ex.Message}", "错误", MessageBoxButton.OK, MessageBoxImage.Error);
                }
                finally
                {
                    _isDragging = false;
                }
            };
        }

        /// <summary>
        /// 查找指定类型的父元素
        /// </summary>
        /// <typeparam name="T">父元素类型</typeparam>
        /// <param name="current">当前元素</param>
        /// <returns>找到的父元素，如果未找到则返回 null</returns>
        private static T? FindAncestor<T>(DependencyObject current) where T : DependencyObject
        {
            Debug.WriteLine($"[FindAncestor] 开始查找类型 {typeof(T).Name}，起始元素类型: {current?.GetType().Name ?? "NULL"}");
            int depth = 0;

            while (current != null)
            {
                Debug.WriteLine($"[FindAncestor] 深度 {depth}: 当前类型 {current.GetType().Name}");

                if (current is T ancestor)
                {
                    Debug.WriteLine($"[FindAncestor] 找到匹配的祖先类型 {typeof(T).Name}");
                    return ancestor;
                }

                current = VisualTreeHelper.GetParent(current);
                depth++;

                if (depth > 10) // 防止无限循环
                {
                    Debug.WriteLine("[FindAncestor] 警告: 搜索深度超过10层，停止搜索");
                    break;
                }
            }

            Debug.WriteLine($"[FindAncestor] 未找到类型 {typeof(T).Name} 的祖先");
            return null;
        }
        
        /// <summary>
        /// 处理主窗口鼠标移动事件，更新拖动提示位置
        /// </summary>
        private static void OnOwnerWindowMouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (_dragToolTipWindow != null && _isDragging)
            {
                // 获取屏幕坐标
                var windowPosition = e.GetPosition(_ownerWindow);
                var screenPosition = _ownerWindow.PointToScreen(windowPosition);
                _dragToolTipWindow.UpdatePosition(screenPosition);
            }
        }
        
        /// <summary>
        /// 创建拖动提示窗口
        /// </summary>
        private static void CreateDragToolTip<T>(T item, System.Windows.Point position) where T : class
        {
            if (item is ToolItem toolItem && _ownerWindow != null)
            {
                _dragToolTipWindow = new DragToolTipWindow();
                _dragToolTipWindow.SetToolInfo(toolItem);
                _dragToolTipWindow.UpdatePosition(position);
                // 不设置 Owner，这样窗口可以独立定位
                _dragToolTipWindow.Show();
            }
        }
        
        /// <summary>
        /// 清理拖动提示窗口
        /// </summary>
        private static void CleanupDragToolTip()
        {
            if (_dragToolTipWindow != null)
            {
                _dragToolTipWindow.Close();
                _dragToolTipWindow = null;
            }
            
            if (_ownerWindow != null)
            {
                _ownerWindow.MouseMove -= OnOwnerWindowMouseMove;
            }
        }
        
        /// <summary>
        /// 更新插入位置指示器
        /// </summary>
        private static void UpdateInsertionIndicator(System.Windows.Controls.ListView listView, System.Windows.Point position)
        {
            if (_insertionIndicator == null) return;
            
            // 使用节流机制，避免过于频繁的更新
            if (_lastUpdateTime != null && DateTime.Now - _lastUpdateTime < TimeSpan.FromMilliseconds(16))
                return;
                
            _lastUpdateTime = DateTime.Now;
            
            try
            {
                // 使用 VisualTreeHelper 找到鼠标下的元素
                var element = listView.InputHitTest(position) as DependencyObject;
                var listViewItem = FindAncestor<System.Windows.Controls.ListViewItem>(element);
                
                if (listViewItem != null)
                {
                    var index = listView.ItemContainerGenerator.IndexFromContainer(listViewItem);
                    var itemBounds = listViewItem.TransformToAncestor(listView)
                                                 .TransformBounds(new Rect(0, 0, listViewItem.ActualWidth, listViewItem.ActualHeight));
                    
                    // 判断是在上半部分还是下半部分
                    bool insertAfter = position.Y > itemBounds.Top + itemBounds.Height / 2;
                    int targetIndex = insertAfter ? index + 1 : index;
                    
                    if (targetIndex != _insertionIndex)
                    {
                        _insertionIndex = targetIndex;
                        
                        // 更新指示器位置
                        _insertionIndicator.Visibility = Visibility.Visible;
                        
                        // 计算指示器位置
                        double indicatorTop = insertAfter ? itemBounds.Bottom : itemBounds.Top;
                        
                        // 使用 VerticalAlignment 和 Margin 结合来定位指示器
                        _insertionIndicator.VerticalAlignment = VerticalAlignment.Top;
                        _insertionIndicator.Margin = new Thickness(0, indicatorTop, 0, 0);
                    }
                }
                else
                {
                    // 如果没有找到目标项，检查是否在列表末尾
                    if (position.Y > listView.ActualHeight - 20)
                    {
                        _insertionIndex = listView.Items.Count;
                        // 在列表末尾显示指示器
                        _insertionIndicator.Visibility = Visibility.Visible;
                        _insertionIndicator.VerticalAlignment = VerticalAlignment.Top;
                        _insertionIndicator.Margin = new Thickness(0, listView.ActualHeight - 2, 0, 0);
                    }
                    else
                    {
                        HideInsertionIndicator();
                    }
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine($"[DragDrop] 更新插入指示器时发生错误: {ex.Message}");
                HideInsertionIndicator();
            }
        }
        
        /// <summary>
        /// 隐藏插入位置指示器
        /// </summary>
        private static void HideInsertionIndicator()
        {
            if (_insertionIndicator != null)
            {
                _insertionIndicator.Visibility = Visibility.Collapsed;
            }
            _insertionIndex = -1;
        }
    }
}