// Copyright © 2015 The CefSharp Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.

using System;
using System.Windows.Forms;

namespace CefSharp.WinForms.Internals
{
    /// <summary>
    /// ControlExtensions.
    /// </summary>
    public static class ControlExtensions
    {
        /// <summary>
        /// Executes the Action asynchronously on the UI thread, does not block execution on the calling thread.
        /// No action will be performed if the control doesn't have a valid handle or the control is Disposed/Disposing.
        /// </summary>
        /// <param name="control">the control for which the update is required</param>
        /// <param name="action">action to be performed on the control</param>
        internal static void InvokeOnUiThreadIfRequired(this Control control, Action action)
        {
            //No action
            if (control.Disposing || control.IsDisposed || !control.IsHandleCreated)
            {
                return;
            }

            if (control.InvokeRequired)
            {
                control.BeginInvoke((Action)(() =>
                {
                    //No action
                    if (control.Disposing || control.IsDisposed || !control.IsHandleCreated)
                    {
                        return;
                    }

                    action();
                }));
            }
            else
            {
                action.Invoke();
            }
        }

        /// <summary>
        /// Activates the specified control.
        /// </summary>
        /// <param name="control">The control.</param>
        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns>
        public static bool Activate(this Control control)
        {
            // Notify WinForms world that inner browser window got focus. This will trigger Leave event to previous focused control
            var containerControl = control.GetContainerControl();
            if (containerControl != null)
            {
                return containerControl.ActivateControl(control);
            }
            return false;
        }

        /// <summary>
        /// Returns whether the supplied control is the currently
        /// active control.
        /// </summary>
        /// <param name="control">the control to check</param>
        /// <returns>true if the control is the currently active control</returns>
        public static bool IsActiveControl(this Control control)
        {
            Form form = control.FindForm();
            if (form == null)
            {
                return false;
            }

            Control activeControl = form.ActiveControl;
            while (activeControl != null
                   && (activeControl is ContainerControl)
                   && !Object.ReferenceEquals(control, activeControl))
            {
                var containerControl = activeControl as ContainerControl;
                activeControl = containerControl.ActiveControl;
            }
            return Object.ReferenceEquals(control, activeControl);
        }

        /// <summary>
        /// Selects the next control.
        /// </summary>
        /// <param name="control">The control.</param>
        /// <param name="next">if set to <c>true</c> [next].</param>
        public static void SelectNextControl(this Control control, bool next)
        {
            var containerControl = control.GetContainerControl();

            while (containerControl != null)
            {
                var containerControlAsControl = containerControl as Control;
                if (containerControlAsControl == null)
                {
                    break;
                }

                var activeControl = containerControl.ActiveControl;
                if (containerControlAsControl.SelectNextControl(activeControl, next, true, true, false))
                {
                    break;
                }

                if (containerControlAsControl.Parent == null)
                {
                    break;
                }

                containerControl = containerControlAsControl.Parent.GetContainerControl();
            }
        }
    }
}