/////////////////////////////////////////////////////////////////////////
// Copyright (c) 2011-2016 by Simon Schneegans
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or (at
// your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
/////////////////////////////////////////////////////////////////////////

namespace GnomePie {

/////////////////////////////////////////////////////////////////////////
/// Some helper methods which focus the input on a given Gtk.Window.
/////////////////////////////////////////////////////////////////////////

public class FocusGrabber : GLib.Object {

    /////////////////////////////////////////////////////////////////////
    /// Utilities for grabbing focus.
    /// Code roughly from Gnome-Do/Synapse.
    /////////////////////////////////////////////////////////////////////

    public static void grab(Gdk.Window window, bool keyboard = true, bool pointer = true, bool owner_events = true) {
        if (keyboard || pointer) {
            window.raise();
            window.focus(Gdk.CURRENT_TIME);

            if (!try_grab_window(window, keyboard, pointer, owner_events)) {
                int i = 0;
                Timeout.add(100, () => {
                    if (++i >= 100) return false;
                    return !try_grab_window(window, keyboard, pointer, owner_events);
                });
            }
        }
    }

    /////////////////////////////////////////////////////////////////////
    /// Code roughly from Gnome-Do/Synapse.
    /////////////////////////////////////////////////////////////////////

    public static void ungrab(bool keyboard = true, bool pointer = true) {
        var display = Gdk.Display.get_default();
        var manager = display.get_device_manager();

        GLib.List<weak Gdk.Device?> list = manager.list_devices(Gdk.DeviceType.MASTER);

        foreach(var device in list) {
            if ((device.input_source == Gdk.InputSource.KEYBOARD && keyboard)
             || (device.input_source != Gdk.InputSource.KEYBOARD && pointer))

                device.ungrab(Gdk.CURRENT_TIME);
        }
    }

    /////////////////////////////////////////////////////////////////////
    /// Code roughly from Gnome-Do/Synapse.
    /////////////////////////////////////////////////////////////////////

    private static bool try_grab_window(Gdk.Window window, bool keyboard, bool pointer, bool owner_events) {
        var display = Gdk.Display.get_default();
        var manager = display.get_device_manager();

        bool grabbed_all = true;

        GLib.List<weak Gdk.Device?> list = manager.list_devices(Gdk.DeviceType.MASTER);

        foreach(var device in list) {
            if ((device.input_source == Gdk.InputSource.KEYBOARD && keyboard)
             || (device.input_source != Gdk.InputSource.KEYBOARD && pointer)) {

                var status = device.grab(window, Gdk.GrabOwnership.APPLICATION, owner_events,
                                         Gdk.EventMask.ALL_EVENTS_MASK, null, Gdk.CURRENT_TIME);

                if (status != Gdk.GrabStatus.SUCCESS)
                    grabbed_all = false;
            }
        }

        if (grabbed_all)
            return true;

        ungrab(keyboard, pointer);

        return false;
    }
}

}