using System;
using System.Runtime.InteropServices;
using Avalonia.Controls;
using Avalonia.Controls.Primitives;
using Avalonia.Input;
using Avalonia.Markup.Xaml;
using ReactiveUI.Avalonia;
using Microsoft.Extensions.Logging;
using AuroraDesk.Presentation.ViewModels;
using AuroraDesk.Presentation.Views.Dialogs;
using ReactiveUI;
using System.Reactive.Disposables;
using System.Threading.Tasks;

namespace AuroraDesk.Presentation.Views;

/// <summary>
/// 主窗口
/// </summary>
public partial class MainWindow : ReactiveWindow<MainWindowViewModel>, IActivatableView
{
    private readonly ILogger<MainWindow>? _logger;
    private bool _isClosingConfirmed = false;
    private bool _isDragging = false;
    private Avalonia.PixelPoint _dragStartScreenPoint;
    private Avalonia.PixelPoint _dragStartWindowPosition;
    private Avalonia.Point _lastWindowPoint;

    /// <summary>
    /// 无参构造函数，用于 XAML 设计器
    /// </summary>
    public MainWindow()
    {
        InitializeComponent();
        SetupWindowControls();
    }

    /// <summary>
    /// 构造函数，接受依赖注入的 ViewModel
    /// </summary>
    /// <param name="viewModel">主窗口的 ViewModel</param>
    /// <param name="logger">日志记录器</param>
    public MainWindow(MainWindowViewModel viewModel, ILogger<MainWindow>? logger = null)
    {
        ArgumentNullException.ThrowIfNull(viewModel);

        _logger = logger;
        InitializeComponent();
        ViewModel = viewModel;
        SetupWindowControls();
        
        _logger?.LogInformation("MainWindow 已创建，ViewModel 已设置");
        
        // 处理窗口关闭事件，显示确认框
        this.Closing += OnWindowClosing;
        
        // 使用 WhenActivated 管理订阅
        this.WhenActivated(disposables =>
        {
            // 注册关闭确认对话框 Interaction Handler
            if (ViewModel != null)
            {
                disposables.Add(
                    ViewModel.CloseConfirmInteraction
                        .RegisterHandler(async interaction =>
                        {
                            var dialog = new CloseConfirmDialog(interaction.Input);
                            
                            // 在 Linux 上，确保窗口在显示前已准备好
                            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
                            {
                                // 先准备好窗口，但不显示
                                dialog.ShowActivated = false;
                                dialog.Opacity = 0;
                                
                                // 等待窗口初始化完成
                                await System.Threading.Tasks.Task.Delay(10);
                                
                                // 触发布局，确保内容已渲染
                                dialog.InvalidateMeasure();
                                dialog.InvalidateArrange();
                                
                                // 等待布局和渲染完成
                                await System.Threading.Tasks.Task.Delay(50);
                                
                                // 设置透明度为1，准备显示
                                dialog.Opacity = 1;
                                dialog.ShowActivated = true;
                            }
                            
                            var result = await dialog.ShowDialog<bool>(this);
                            interaction.SetOutput(result);
                        }));
            }
        });
    }

    private void InitializeComponent()
    {
        AvaloniaXamlLoader.Load(this);
    }

    /// <summary>
    /// 设置窗口控制按钮事件
    /// </summary>
    private void SetupWindowControls()
    {
        // 设置左侧导航栏拖动功能
        var leftNavigationBar = this.FindControl<Border>("LeftNavigationBar");
        if (leftNavigationBar != null)
        {
            leftNavigationBar.PointerPressed += OnLeftNavigationBarPointerPressed;
        }
        
        // Linux 平台需要在窗口级别处理鼠标移动和释放事件
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
        {
            this.PointerMoved += OnWindowPointerMoved;
            this.PointerReleased += OnWindowPointerReleased;
        }

        // 最小化按钮
        var minimizeButton = this.FindControl<Button>("MinimizeButton");
        if (minimizeButton != null)
        {
            minimizeButton.Click += (sender, e) => WindowState = WindowState.Minimized;
        }

        // 最大化/还原按钮
        var maximizeButton = this.FindControl<Button>("MaximizeButton");
        if (maximizeButton != null)
        {
            maximizeButton.Click += (sender, e) =>
            {
                if (WindowState == WindowState.Maximized)
                {
                    WindowState = WindowState.Normal;
                    ToolTip.SetTip(maximizeButton, "最大化");
                }
                else
                {
                    WindowState = WindowState.Maximized;
                    ToolTip.SetTip(maximizeButton, "还原");
                }
            };
        }

        // 关闭按钮 - 显示确认框而不是直接关闭
        var closeButton = this.FindControl<Button>("CloseButton");
        if (closeButton != null)
        {
            if (ViewModel != null)
            {
                // 关闭按钮点击时显示确认框
                closeButton.Click += async (sender, e) =>
                {
                    var confirmed = await ViewModel.RequestCloseConfirmAsync();
                    if (confirmed)
                    {
                        // 设置标志，表示用户已确认关闭
                        _isClosingConfirmed = true;
                        Close();
                    }
                };
            }
            else
            {
                // 设计器模式或无 ViewModel 时，直接关闭（用于设计器预览）
                closeButton.Click += (sender, e) => Close();
            }
        }
    }

    /// <summary>
    /// 处理左侧导航栏鼠标按下事件，实现窗口拖动
    /// </summary>
    private void OnLeftNavigationBarPointerPressed(object? sender, PointerPressedEventArgs e)
    {
        if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
        {
            // Linux 平台需要手动实现拖动
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            {
                _isDragging = true;
                // 记录按下时的窗口位置和鼠标屏幕坐标
                var pointerPoint = e.GetCurrentPoint(this);
                var windowPoint = pointerPoint.Position;
                // 计算鼠标的屏幕坐标：窗口位置 + 鼠标在窗口内的位置
                _dragStartScreenPoint = new Avalonia.PixelPoint(
                    Position.X + (int)Math.Round(windowPoint.X),
                    Position.Y + (int)Math.Round(windowPoint.Y));
                _dragStartWindowPosition = Position;
                _lastWindowPoint = windowPoint;
                // 捕获指针到窗口，确保拖动流畅
                pointerPoint.Pointer.Capture(this);
                e.Handled = true;
            }
            else
            {
                // Windows 和其他平台使用系统方法
                BeginMoveDrag(e);
            }
        }
    }
    
    /// <summary>
    /// 处理窗口鼠标移动事件（仅 Linux 平台）
    /// </summary>
    private void OnWindowPointerMoved(object? sender, PointerEventArgs e)
    {
        if (_isDragging && e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
        {
            // 获取当前鼠标在窗口内的位置
            var currentPoint = e.GetCurrentPoint(this);
            var currentWindowPoint = currentPoint.Position;
            
            // 计算鼠标在窗口内的移动量（相对于上次记录的位置）
            var deltaWindowX = currentWindowPoint.X - _lastWindowPoint.X;
            var deltaWindowY = currentWindowPoint.Y - _lastWindowPoint.Y;
            
            // 只有当鼠标在窗口内实际移动了超过0.5像素时才更新
            if (Math.Abs(deltaWindowX) > 0.5 || Math.Abs(deltaWindowY) > 0.5)
            {
                // 根据鼠标在窗口内的移动量更新窗口位置
                var newX = Position.X + (int)Math.Round(deltaWindowX);
                var newY = Position.Y + (int)Math.Round(deltaWindowY);
                var newPosition = new Avalonia.PixelPoint(newX, newY);
                
                // 更新窗口位置
                Position = newPosition;
                
                // 更新记录的上次鼠标位置
                _lastWindowPoint = currentWindowPoint;
            }
            
            e.Handled = true;
        }
    }
    
    /// <summary>
    /// 处理窗口鼠标释放事件（仅 Linux 平台）
    /// </summary>
    private void OnWindowPointerReleased(object? sender, PointerReleasedEventArgs e)
    {
        if (_isDragging)
        {
            _isDragging = false;
            // 释放指针捕获
            var pointerPoint = e.GetCurrentPoint(this);
            pointerPoint.Pointer.Capture(null);
            e.Handled = true;
        }
    }
    
    /// <summary>
    /// 处理窗口关闭事件，显示确认框
    /// </summary>
    private async void OnWindowClosing(object? sender, WindowClosingEventArgs e)
    {
        // 如果用户已经通过关闭按钮确认关闭，直接允许关闭
        if (_isClosingConfirmed)
        {
            return;
        }
        
        if (ViewModel != null)
        {
            // 取消默认关闭行为
            e.Cancel = true;
            
            // 显示确认框
            var confirmed = await ViewModel.RequestCloseConfirmAsync();
            if (confirmed)
            {
                // 用户确认关闭，设置标志并允许窗口关闭
                _isClosingConfirmed = true;
                e.Cancel = false;
                // 不需要手动调用 Close()，系统会自动关闭窗口
            }
            // 如果用户取消，e.Cancel = true 已设置，窗口不会关闭
        }
        // 如果没有 ViewModel（设计器模式），允许直接关闭
    }
}