using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace ivf_tl_Operate.CustomUserControls
{
    /// <summary>
    /// M4-04-2 · 内置软键盘弹出宿主 + 绑定附加属性。
    /// <para>
    /// 用法（XAML，仅声明、不改任何业务/校验逻辑）：
    /// <code>
    ///   &lt;PasswordBox cu:SoftKeyboardHost.Mode="Password" ... /&gt;
    ///   &lt;TextBox     cu:SoftKeyboardHost.Mode="Number"   ... /&gt;
    /// </code>
    /// 输入框获焦/触控/点击时弹内置 <see cref="SoftKeyboard"/>，点「确定」「×」或点遮罩收起。
    /// 键入实时写回目标控件（TextBox.Text / PasswordBox.Password），其余 PasswordChanged/
    /// TextChanged/MouseUp 校验事件照常触发，故 tl13579 校验、参数校验语义完全不变。
    /// </para>
    /// <para>
    /// 弹出层挂在目标所属 Window 的最外层容器上：
    /// 若该 Window 暴露名为 "_mask" 的遮罩（MainWindow，与 M2-05 标定弹窗共用）则复用其遮罩背景；
    /// 否则（LoginWindow 等独立窗口）注入一层自带半透明遮罩。两种情况都不依赖具体页面。
    /// </para>
    /// </summary>
    public static class SoftKeyboardHost
    {
        /// <summary>当前已弹出的键盘宿主层（同一时刻至多一个）。</summary>
        private static KeyboardOverlay _current;

        #region 附加属性 Mode

        public static readonly DependencyProperty ModeProperty =
            DependencyProperty.RegisterAttached(
                "Mode", typeof(SoftKeyboardMode?), typeof(SoftKeyboardHost),
                new PropertyMetadata(null, OnModeChanged));

        public static void SetMode(DependencyObject element, SoftKeyboardMode? value) => element.SetValue(ModeProperty, value);
        public static SoftKeyboardMode? GetMode(DependencyObject element) => (SoftKeyboardMode?)element.GetValue(ModeProperty);

        private static void OnModeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (!(d is Control c)) return;
            // 先摘除（防重复挂载），再按需挂上。
            c.GotKeyboardFocus -= Target_TriggerOpen;
            c.PreviewMouseLeftButtonDown -= Target_PreviewMouseDown;
            c.TouchDown -= Target_TouchDown;
            if (e.NewValue is SoftKeyboardMode)
            {
                c.GotKeyboardFocus += Target_TriggerOpen;
                c.PreviewMouseLeftButtonDown += Target_PreviewMouseDown;
                c.TouchDown += Target_TouchDown;
            }
        }

        #endregion

        #region 触发弹出

        private static void Target_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            // 已为当前目标弹出则不重复；否则弹出（不抢焦点行为，仅打开键盘）。
            if (sender is Control c) Open(c);
        }

        private static void Target_TouchDown(object sender, TouchEventArgs e)
        {
            if (sender is Control c) Open(c);
        }

        private static void Target_TriggerOpen(object sender, KeyboardFocusChangedEventArgs e)
        {
            if (sender is Control c) Open(c);
        }

        #endregion

        /// <summary>
        /// 为目标输入框弹出软键盘。重复目标的弹出请求会被忽略，避免抖动。
        /// </summary>
        public static void Open(Control target)
        {
            var mode = GetMode(target);
            if (mode == null) return;

            // 同一目标已开则忽略。
            if (_current != null && ReferenceEquals(_current.Target, target)) return;
            Close(false);

            var window = Window.GetWindow(target);
            if (window == null) return;

            var overlay = new KeyboardOverlay(window, target, mode.Value);
            overlay.Closed += () =>
            {
                if (ReferenceEquals(_current, overlay)) _current = null;
            };
            _current = overlay;
            overlay.Show();
        }

        /// <summary>收起当前键盘（若有）。</summary>
        public static void Close(bool submit)
        {
            _current?.Dispose(submit);
            _current = null;
        }
    }

    /// <summary>
    /// 单次键盘弹出的宿主层：遮罩 + 浮层 + SoftKeyboard，挂在目标 Window 的根 Panel 上。
    /// </summary>
    internal sealed class KeyboardOverlay
    {
        public Control Target { get; }
        public event Action Closed;

        private readonly Window _window;
        private readonly SoftKeyboardMode _mode;
        private readonly Panel _rootPanel;     // 注入遮罩/浮层的容器（窗口根 Panel）
        private readonly UIElement _existingMask; // 复用的 _mask（MainWindow），可空
        private FrameworkElement _injectedMask;   // 自注入遮罩（无 _mask 时）
        private Grid _layer;                   // 承载键盘的浮层
        private SoftKeyboard _keyboard;
        private bool _disposed;

        public KeyboardOverlay(Window window, Control target, SoftKeyboardMode mode)
        {
            _window = window;
            Target = target;
            _mode = mode;

            _rootPanel = FindRootPanel(window);
            _existingMask = FindMask(window);
        }

        public void Show()
        {
            if (_rootPanel == null) return;

            bool mask = _mode == SoftKeyboardMode.Password;

            _keyboard = new SoftKeyboard
            {
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Bottom,
                Margin = new Thickness(0, 0, 0, 60),
                MaxWidth = 1100,
                Width = _mode == SoftKeyboardMode.Password ? 1000 : 700
            };
            _keyboard.Reset(_mode, ReadTargetText(), mask);
            _keyboard.KeyInput += OnKeyInput;
            _keyboard.RequestClose += OnRequestClose;

            // 浮层：自带一层点击可关闭的透明背景（点空白处=取消）。
            _layer = new Grid();
            var bgCatcher = new Border { Background = Brushes.Transparent };
            bgCatcher.MouseDown += (s, e) => OnRequestClose(false);
            bgCatcher.TouchDown += (s, e) => OnRequestClose(false);
            _layer.Children.Add(bgCatcher);
            _layer.Children.Add(_keyboard);

            // 背景压暗：优先复用窗口现成 _mask（与 M2-05 标定弹窗一致）；否则注入一层。
            if (_existingMask is UIElement mk)
            {
                mk.Visibility = Visibility.Visible;
            }
            else
            {
                _injectedMask = new Grid { Background = new SolidColorBrush(Color.FromArgb(204, 0, 0, 0)) };
                _rootPanel.Children.Add(_injectedMask);
            }

            _rootPanel.Children.Add(_layer);
            Panel.SetZIndex(_layer, int.MaxValue);
            if (_injectedMask != null) Panel.SetZIndex(_injectedMask, int.MaxValue - 1);
        }

        private void OnKeyInput(string text) => WriteTargetText(text);

        private void OnRequestClose(bool submit) => Dispose(submit);

        public void Dispose(bool submit)
        {
            if (_disposed) return;
            _disposed = true;

            if (_keyboard != null)
            {
                _keyboard.KeyInput -= OnKeyInput;
                _keyboard.RequestClose -= OnRequestClose;
            }
            if (_layer != null) _rootPanel?.Children.Remove(_layer);
            if (_injectedMask != null) _rootPanel?.Children.Remove(_injectedMask);
            // 复用的 _mask：仅当我们点亮过才隐藏（弹窗自身可能也用它——这里保守隐藏，
            // 因为同一时刻不会有标定弹窗与键盘并存：键盘弹出时页面处于输入态）。
            if (_existingMask is UIElement mk) mk.Visibility = Visibility.Hidden;

            Closed?.Invoke();
        }

        #region 目标读写（兼容 TextBox / PasswordBox）

        private string ReadTargetText()
        {
            switch (Target)
            {
                case PasswordBox pb: return pb.Password;
                case TextBox tb: return tb.Text;
                default: return string.Empty;
            }
        }

        private void WriteTargetText(string text)
        {
            switch (Target)
            {
                case PasswordBox pb:
                    pb.Password = text; // 触发 PasswordChanged（背景/校验钩子照常）
                    break;
                case TextBox tb:
                    tb.Text = text;     // 触发 TextChanged
                    tb.CaretIndex = tb.Text.Length;
                    break;
            }
        }

        #endregion

        #region 容器查找

        private static Panel FindRootPanel(Window w)
        {
            // 窗口内容若已是 Panel 直接用；若是 Viewbox/Border 等装饰则向下找首个 Panel；
            // 找不到则不弹（极端情况，保守）。
            DependencyObject node = w.Content as DependencyObject;
            return FindFirstPanel(node);
        }

        private static Panel FindFirstPanel(DependencyObject node)
        {
            if (node == null) return null;
            if (node is Panel p) return p;
            int count = VisualTreeHelperChildCountSafe(node);
            for (int i = 0; i < count; i++)
            {
                var child = System.Windows.Media.VisualTreeHelper.GetChild(node, i);
                var found = FindFirstPanel(child);
                if (found != null) return found;
            }
            // 逻辑树兜底（Visual 树未生成时）
            if (node is ContentControl cc && cc.Content is DependencyObject ccChild)
                return FindFirstPanel(ccChild);
            if (node is Decorator dec && dec.Child is DependencyObject decChild)
                return FindFirstPanel(decChild);
            return null;
        }

        private static int VisualTreeHelperChildCountSafe(DependencyObject node)
        {
            try { return System.Windows.Media.VisualTreeHelper.GetChildrenCount(node); }
            catch { return 0; }
        }

        /// <summary>查找窗口中名为 "_mask" 的遮罩元素（MainWindow 暴露，与标定弹窗共用）。</summary>
        private static UIElement FindMask(Window w)
        {
            return w.FindName("_mask") as UIElement;
        }

        #endregion
    }
}