/*
Copyright (c) 2011 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 {

/////////////////////////////////////////////////////////////////////////    
/// Globally binds key stroke to given ID's. When one of the bound 
/// strokes is invoked, a signal with the according ID is emitted.
/////////////////////////////////////////////////////////////////////////

public class BindingManager : GLib.Object {

    /////////////////////////////////////////////////////////////////////
    /// Called when a stored binding is invoked. The according ID is
    /// passed as argument.
    /////////////////////////////////////////////////////////////////////

    public signal void on_press(string id);
    
    /////////////////////////////////////////////////////////////////////
    /// A list storing bindings, which are invoked even if Gnome-Pie
    /// doesn't have the current focus
    /////////////////////////////////////////////////////////////////////
    
    private Gee.List<Keybinding> bindings = new Gee.ArrayList<Keybinding>();

    /////////////////////////////////////////////////////////////////////
    /// Ignored modifier masks, used to grab all keys even if these locks
    /// are active.
    /////////////////////////////////////////////////////////////////////
    
    private static uint[] lock_modifiers = {
        0,
        Gdk.ModifierType.MOD2_MASK,
        Gdk.ModifierType.LOCK_MASK,
        Gdk.ModifierType.MOD5_MASK,
        Gdk.ModifierType.MOD2_MASK|Gdk.ModifierType.LOCK_MASK,
        Gdk.ModifierType.MOD2_MASK|Gdk.ModifierType.MOD5_MASK,
        Gdk.ModifierType.LOCK_MASK|Gdk.ModifierType.MOD5_MASK,
        Gdk.ModifierType.MOD2_MASK|Gdk.ModifierType.LOCK_MASK|Gdk.ModifierType.MOD5_MASK
    };
 
    /////////////////////////////////////////////////////////////////////
    /// Helper class to store keybinding
    /////////////////////////////////////////////////////////////////////
    
    private class Keybinding {
    
        public Keybinding(string accelerator, int keycode, Gdk.ModifierType modifiers, string id) {
            this.accelerator = accelerator;
            this.keycode = keycode;
            this.modifiers = modifiers;
            this.id = id;
        }
 
        public string accelerator { get; set; }
        public int keycode { get; set; }
        public Gdk.ModifierType modifiers { get; set; }
        public string id { get; set; }
    }
 
    /////////////////////////////////////////////////////////////////////
    /// C'tor adds the event filter to the root window.
    /////////////////////////////////////////////////////////////////////
    
    public BindingManager() {
        // init filter to retrieve X.Events
        Gdk.Window rootwin = Gdk.get_default_root_window();
        if(rootwin != null) {
            rootwin.add_filter(event_filter);
        }
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Binds the ID to the given accelerator.
    /////////////////////////////////////////////////////////////////////
     
    public void bind(string accelerator, string id) {
        uint keysym;
        Gdk.ModifierType modifiers;
        Gtk.accelerator_parse(accelerator, out keysym, out modifiers);
        
        if (keysym == 0) {
            warning("Invalid keystroke: " + accelerator);
            return;
        }
 
        Gdk.Window rootwin = Gdk.get_default_root_window();
        X.Display display = Gdk.x11_drawable_get_xdisplay(rootwin);
        X.ID xid = Gdk.x11_drawable_get_xid(rootwin);
        int keycode = display.keysym_to_keycode(keysym);
 
        if(keycode != 0) {
            Gdk.error_trap_push();
 
            foreach(uint lock_modifier in lock_modifiers) {
                display.grab_key(keycode, modifiers|lock_modifier, xid, false, X.GrabMode.Async, X.GrabMode.Async);
            }
 
            Gdk.flush();
 
            Keybinding binding = new Keybinding(accelerator, keycode, modifiers, id);
            bindings.add(binding);
        }
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Unbinds the accelerator of the given ID.
    /////////////////////////////////////////////////////////////////////
 
    public void unbind(string id) {
        Gdk.Window rootwin = Gdk.get_default_root_window();
        X.Display display = Gdk.x11_drawable_get_xdisplay(rootwin);
        X.ID xid = Gdk.x11_drawable_get_xid(rootwin);
        Gee.List<Keybinding> remove_bindings = new Gee.ArrayList<Keybinding>();
        foreach(var binding in bindings) {
            if(id == binding.id) {
                foreach(uint lock_modifier in lock_modifiers) {
                    display.ungrab_key(binding.keycode, binding.modifiers, xid);
                }
                remove_bindings.add(binding);
            }
        }

        bindings.remove_all(remove_bindings);
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Returns a human readable accelerator for the given ID.
    /////////////////////////////////////////////////////////////////////
    
    public string get_accelerator_label_of(string id) {
        string accelerator = this.get_accelerator_of(id);
        
        if (accelerator == "")
            return _("Not bound");
        
        uint key = 0;
        Gdk.ModifierType mods;
        Gtk.accelerator_parse(accelerator, out key, out mods);
        return Gtk.accelerator_get_label(key, mods);
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Returns the accelerator to which the given ID is bound.
    /////////////////////////////////////////////////////////////////////
    
    public string get_accelerator_of(string id) {
        foreach (var binding in bindings) {
            if (binding.id == id) {
                return binding.accelerator;
            }
        }
        
        return "";
    }

    /////////////////////////////////////////////////////////////////////
    /// Event filter method needed to fetch X.Events
    /////////////////////////////////////////////////////////////////////
    
    private Gdk.FilterReturn event_filter(Gdk.XEvent gdk_xevent, Gdk.Event gdk_event) {
        Gdk.FilterReturn filter_return = Gdk.FilterReturn.CONTINUE;
 
        void* pointer = &gdk_xevent;
        X.Event* xevent = (X.Event*) pointer;
 
        if(xevent->type == X.EventType.KeyPress) {
            foreach(var binding in bindings) {
                // remove NumLock, CapsLock and ScrollLock from key state
                uint event_mods = xevent.xkey.state & ~ (lock_modifiers[7]);
                if(xevent->xkey.keycode == binding.keycode && event_mods == binding.modifiers) {
                    on_press(binding.id);
                }
            }
         } 
 
        return filter_return;
    }
}

}