using System.ComponentModel;

namespace System.Windows.Forms
{
    // In WinForms, ContextMenuStrip must be a descendant of ToolStripDropDown.
    // However in WPF these two classes use different approaches (Popup vs ContextMenu).
    // That's why we use IPopupWrapper which supplies correct implementation.
    public partial class ToolStripDropDown : ToolStrip
    {
        private IPopupWrapper popup;
        private bool isOpened;
        private int closedTicks;

        internal IPopupWrapper Popup => popup ??= InitPopup();

        public new bool Visible => isOpened || (Environment.TickCount - closedTicks) < 300;

        public event CancelEventHandler Opening;
        public event EventHandler Opened;
        public event ToolStripDropDownClosedEventHandler Closed;

        protected virtual void OnOpening(CancelEventArgs e) => Opening?.Invoke(this, e);

        protected virtual void OnOpened(EventArgs e) => Opened?.Invoke(this, e);

        protected virtual void OnClosed(ToolStripDropDownClosedEventArgs e) => Closed?.Invoke(this, e);

        internal virtual IPopupWrapper CreatePopup() => new PopupWrapper(this);
        
        private IPopupWrapper InitPopup()
        {
            var popup = CreatePopup();
            popup.Opened += (s, e) =>
            {
                OnOpened(e);
                isOpened = true;
            };
            popup.Closed += (s, e) =>
            {
                OnClosed(new ToolStripDropDownClosedEventArgs(ToolStripDropDownCloseReason.ItemClicked));
                isOpened = false;
                closedTicks = Environment.TickCount;
            };
            return popup;
        }

        private void OpenPopup()
        {
            if (isOpened)
            {
                Close();
                return;
            }

            Popup.FixupDpi();

            var args = new CancelEventArgs();
            OnOpening(args);
            if (!args.Cancel)
                Popup.IsOpen = true;
        }

        public void Show(int x, int y)
        {
            Popup.Placement = Windows.Controls.Primitives.PlacementMode.Absolute;
            Popup.HorizontalOffset = x / DpiScale;
            Popup.VerticalOffset = y / DpiScale;
            OpenPopup();
        }

        public void Show(System.Drawing.Point screenLocation) => Show(screenLocation.X, screenLocation.Y);

        public void Show(Control control, int x, int y)
        {
            x = (int)(x / control.DpiScale);
            y = (int)(y / control.DpiScale);
            Popup.Placement = Windows.Controls.Primitives.PlacementMode.Relative;
            Popup.PlacementTarget = control.control;
            Popup.HorizontalOffset = control.control.FlowDirection == FlowDirection.RightToLeft ? control.Width / control.DpiScale - x : x;
            Popup.VerticalOffset = y;
            OpenPopup();
        }

        public void Show(Control control, System.Drawing.Point position) => Show(control, position.X, position.Y);

        internal void Show(Control control)
        {
            Popup.Placement = Windows.Controls.Primitives.PlacementMode.Bottom;
            Popup.PlacementTarget = control.control;
            OpenPopup();
        }

        public void Close()
        {
            // do not close not-yet-opened popup. Case: DataColumnDropDown control
            if (isOpened)
            {
                Popup.IsOpen = false;
                isOpened = false;
            }
        }

        // TODO? reason param
        public void Close(ToolStripDropDownCloseReason reason) => Close();

        internal override void AddChild(Control child) => Popup.AddChild(child);

        internal override void RemoveChild(Control child) => Popup.RemoveChild(child);

        internal override void SetChildIndex(Control child, int index) => Popup.SetChildIndex(child, index);
    }
}