using System.Runtime.InteropServices;
using System.Windows.Automation.Peers;
using System.Windows.Automation.Provider;
using System.Windows.Input;

using Melskin.Assists;

namespace Melskin.Controls;

/// <summary>
/// MelWindow 类继承自 WPF 的 Window 类，用于创建具有特定样式和功能的窗口。
/// 该类通过设置默认样式资源引用来自定义窗口外观，并提供属性来控制窗口的行为和内容布局。
/// </summary>
public class MelWindow : Window
{
    private const string VbMinimizeButtonName = "minimizeButton";
    private const string VbMaximizeRestoreButtonName = "maximizeRestoreButton";
    /// <summary>
    /// 用于在XAML模板中标识关闭按钮的名称。
    /// 此常量字符串值为 "closeButton"，用于在窗口样式应用时通过GetTemplateChild方法查找对应的关闭按钮控件。
    /// </summary>
    private const string VbCloseButtonName = "closeButton";
    /// <summary>
    /// 
    /// </summary>
    public MelWindow()
    {
        SetResourceReference(StyleProperty, typeof(MelWindow)); //设置默认的样式资源引用
    }

    #region 自定义标题栏按钮行为

    /// <inheritdoc />
    protected override void OnSourceInitialized(EventArgs e)
    {
        base.OnSourceInitialized(e);
        var helper = new WindowInteropHelper(this);
        var hwndSource = HwndSource.FromHwnd(helper.Handle);
        hwndSource?.AddHook(HwndSourceHook);
    }

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool TrackMouseEvent(ref TRACKMOUSEEVENT lpEventTrack);

    /// <summary>
    /// 跟踪鼠标事件的结构体。
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public struct TRACKMOUSEEVENT
    {
        /// <summary>
        /// 结构体大小
        /// </summary>
        public int cbSize;
        /// <summary>
        /// 控制跟踪行为的标志
        /// </summary>
        public uint dwFlags;
        /// <summary>
        /// 要为其跟踪鼠标事件的窗口句柄
        /// </summary>
        public IntPtr hwndTrack;
        /// <summary>
        /// 可选的悬停时间（毫秒）
        /// </summary>
        public uint dwHoverTime;
        /// <summary>
        /// 初始化 TRACKMOUSEEVENT 结构体的新实例。
        /// </summary>
        /// <param name="dwFlags">A combination of flags that specify the services requested. The value should correspond to the TME_*
        /// constants defined by the Windows API.</param>
        /// <param name="hwndTrack">窗口句柄</param>
        public TRACKMOUSEEVENT(uint dwFlags, IntPtr hwndTrack)
        {
            this.cbSize = Marshal.SizeOf(typeof(TRACKMOUSEEVENT));
            this.dwFlags = dwFlags;
            this.hwndTrack = hwndTrack;
            this.dwHoverTime = 0;
        }
    }

    private const int WM_NCHITTEST = 0x0084;
    private const int WM_NCMOUSEMOVE = 0x00A0;
    private const int WM_NCMOUSELEAVE = 0x02A2;
    private const int WM_NCLBUTTONDOWN = 0x00A1;
    private const int WM_NCLBUTTONUP = 0x00A2;
    private const int HTMAXBUTTON = 9;
    private const uint TME_LEAVE = 0x00000002;
    private const uint TME_NONCLIENT = 0x00000010;

    #endregion

    private bool isMouseOverMaximizeButton = false;
    private bool isMaximizeButtonPressed = false;

    private IntPtr HwndSourceHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        switch (msg)
        {
            case WM_NCHITTEST:
                if (IsMouseOverMaximizeButton(lParam))
                {
                    handled = true;
                    return new IntPtr(HTMAXBUTTON);
                }
                else if (isMouseOverMaximizeButton || isMaximizeButtonPressed)
                {
                    // 如果鼠标移出按钮区域，重置状态
                    isMouseOverMaximizeButton = false;
                    isMaximizeButtonPressed = false;
                    UpdateMaximizeButtonVisualState();
                }
                break;

            case WM_NCMOUSEMOVE:
                bool isCurrentlyOver = IsMouseOverMaximizeButton(lParam);
                if (isCurrentlyOver != isMouseOverMaximizeButton)
                {
                    isMouseOverMaximizeButton = isCurrentlyOver;
                    UpdateMaximizeButtonVisualState();

                    if (isMouseOverMaximizeButton)
                    {
                        var tme = new TRACKMOUSEEVENT(TME_LEAVE | TME_NONCLIENT, hwnd);
                        TrackMouseEvent(ref tme);
                    }
                }
                break;

            case WM_NCMOUSELEAVE:
                isMouseOverMaximizeButton = false;
                isMaximizeButtonPressed = false;
                UpdateMaximizeButtonVisualState();
                break;

            case WM_NCLBUTTONDOWN:
                if (isMouseOverMaximizeButton)
                {
                    isMaximizeButtonPressed = true;
                    UpdateMaximizeButtonVisualState();
                    handled = true;
                }
                break;

            case WM_NCLBUTTONUP:
                if (isMaximizeButtonPressed)
                {
                    isMaximizeButtonPressed = false;
                    UpdateMaximizeButtonVisualState();

                    if (isMouseOverMaximizeButton)
                    {
                        maximizeRestoreButton?.RaiseEvent(new RoutedEventArgs(Button.ClickEvent));
                    }
                    handled = true;
                }
                break;
        }

        return IntPtr.Zero;
    }

    private bool IsMouseOverMaximizeButton(IntPtr lParam)
    {
        var x = (short)(lParam.ToInt32() & 0xFFFF);
        var y = (short)(lParam.ToInt32() >> 16);
        var mousePos = new Point(x, y);

        var windowPos = this.PointFromScreen(mousePos);

        if (maximizeRestoreButton is Visual maximizeButtonVisual)
        {
            var bounds = VisualTreeHelper.GetDescendantBounds(maximizeButtonVisual);
            var buttonTransform = maximizeButtonVisual.TransformToAncestor(this);
            var buttonRect = buttonTransform.TransformBounds(bounds);

            return buttonRect.Contains(windowPos);
        }

        return false;
    }

    private void UpdateMaximizeButtonVisualState()
    {
        string stateName;
        if (isMaximizeButtonPressed && isMouseOverMaximizeButton)
        {
            stateName = "Pressed";
        }
        else if (isMouseOverMaximizeButton)
        {
            stateName = "MouseOver";
        }
        else
        {
            stateName = "Normal";
        }
        //VisualStateManager.GoToState(maximizeRestoreButton, stateName, true);
        maximizeRestoreButton?.Background = stateName switch
        {
            "Pressed" =>
                //VisualStateManager.GoToState(maximizeRestoreButton, "Pressed", true);
                new SolidColorBrush((Color)ColorConverter.ConvertFromString("#33000000")),
            "MouseOver" =>
                //VisualStateManager.GoToState(maximizeRestoreButton, "MouseOver", true);
                new SolidColorBrush((Color)ColorConverter.ConvertFromString("#1A000000")),
            "Normal" => Brushes.Transparent,
                //VisualStateManager.GoToState(maximizeRestoreButton, "Normal", true);
            _ => maximizeRestoreButton?.Background
        };
    }

    #region Window Control Methods

    private void TitleBar_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        if (e.ClickCount == 2)
        {
            ToggleWindowState();
        }
        else
        {
            this.DragMove();
        }
    }

    private void maximizeRestoreButton_Click(object sender, RoutedEventArgs e)
    {
        ToggleWindowState();
    }

    private void ToggleWindowState()
    {
        this.WindowState = (this.WindowState == WindowState.Normal) ? WindowState.Maximized : WindowState.Normal;
    }

    private void CloseButton_Click(object sender, RoutedEventArgs e)
    {
        this.Close();
    }

    #endregion
    static MelWindow()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(MelWindow), new FrameworkPropertyMetadata(typeof(MelWindow)));
    }
    /// <summary>
    /// 如果窗口不活动，请让窗口的内容淡出。
    /// 默认值为真（已启用）。
    /// </summary>
    public static readonly DependencyProperty FadeContentIfInactiveProperty = DependencyProperty.Register(
            nameof(FadeContentIfInactive), typeof(bool), typeof(MelWindow), new FrameworkPropertyMetadata(true));

    /// <summary>
    /// 如果窗口不活动，请让窗口的内容淡出。
    /// 默认值为真（已启用）。
    /// </summary>
    public bool FadeContentIfInactive
    {
        get => (bool)GetValue(FadeContentIfInactiveProperty);

        set => SetValue(FadeContentIfInactiveProperty, value);
    }

    /// <summary>
    /// 标题栏左侧内容模板
    /// </summary>
    public object TitleBarLeftContent
    {
        get => (object)GetValue(TitleBarLeftContentProperty);
        set => SetValue(TitleBarLeftContentProperty, value);
    }

    /// <summary>
    /// 用于定义窗口左侧内容区域的数据模板。
    /// 此依赖属性允许开发者自定义左侧内容的布局和显示方式，通过设置不同的DataTemplate来改变该区域的内容呈现形式。
    /// </summary>
    public static readonly DependencyProperty TitleBarLeftContentProperty =
        DependencyProperty.Register(nameof(TitleBarLeftContent), typeof(object), typeof(MelWindow));
    /// <summary>
    /// 标题栏右侧内容模板
    /// </summary>
    public object TitleBarRightContent
    {
        get => (object)GetValue(TitleBarRightContentProperty);
        set => SetValue(TitleBarRightContentProperty, value);
    }

    /// <summary>
    /// 用于定义窗口右侧内容区域的数据模板。
    /// 此依赖属性允许开发者自定义右侧内容的布局和显示方式，通过设置不同的DataTemplate来改变该区域的内容呈现形式。
    /// </summary>
    public static readonly DependencyProperty TitleBarRightContentProperty =
        DependencyProperty.Register(nameof(TitleBarRightContent), typeof(object), typeof(MelWindow));
    private Button? minimizeButton;
    private Button? maximizeRestoreButton;
    private Button? closeButton;

    /// <inheritdoc />
    public override void OnApplyTemplate()
    {
        if (minimizeButton != null)
        {
            minimizeButton.Click -= MinimizeButtonClickHandler;
        }

        minimizeButton = GetTemplateChild(VbMinimizeButtonName) as Button;

        if (minimizeButton != null)
        {
            minimizeButton.Click += MinimizeButtonClickHandler;
        }

        if (maximizeRestoreButton != null)
        {
            maximizeRestoreButton.Click -= MaximizeRestoreButtonClickHandler;
        }

        maximizeRestoreButton = GetTemplateChild(VbMaximizeRestoreButtonName) as Button;

        if (maximizeRestoreButton != null)
        {
            maximizeRestoreButton.Click += MaximizeRestoreButtonClickHandler;
        }

        if (closeButton != null)
        {
            closeButton.Click -= CloseButtonClickHandler;
        }

        closeButton = GetTemplateChild(VbCloseButtonName) as Button;

        if (closeButton != null)
        {
            closeButton.Click += CloseButtonClickHandler;
        }

        base.OnApplyTemplate();
    }

    private void CloseButtonClickHandler(object sender, RoutedEventArgs args)
    {
        Close();
    }

    private void MaximizeRestoreButtonClickHandler(object sender, RoutedEventArgs args)
    {
        WindowState = (WindowState == WindowState.Normal) ? WindowState.Maximized : WindowState.Normal;
    }

    private void MinimizeButtonClickHandler(object sender, RoutedEventArgs args)
    {
        WindowState = WindowState.Minimized;
    }
}