// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-

const Signals = imports.signals;
const Lang = imports.lang;
const Meta = imports.gi.Meta;
const Clutter = imports.gi.Clutter;

const ShowOverviewAction = new Lang.Class({
    Name: 'ShowOverviewAction',
    Extends: Clutter.GestureAction,

    _init : function() {
        this.parent();
        this.set_n_touch_points (3);
        global.display.connect('grab-op-begin', Lang.bind(this, this.cancel));
        global.display.connect('grab-op-end', Lang.bind(this, this.cancel));
    },

    vfunc_gesture_prepare : function(action, actor) {
        return this.get_n_current_points() == this.get_n_touch_points();
    },

    _getBoundingRect : function(motion) {
        let minX, minY, maxX, maxY;

        for (let i = 0; i < this.get_n_current_points(); i++) {
            let x, y;

            if (motion == true) {
                [x, y] = this.get_motion_coords(i);
            } else {
                [x, y] = this.get_press_coords(i);
            }

            if (i == 0) {
                minX = maxX = x;
                minY = maxY = y;
            } else {
                minX = Math.min(minX, x);
                minY = Math.min(minY, y);
                maxX = Math.max(maxX, x);
                maxY = Math.max(maxY, y);
            }
        }

        return new Meta.Rectangle({ x: minX,
                                    y: minY,
                                    width: maxX - minX,
                                    height: maxY - minY });
    },

    vfunc_gesture_begin : function(action, actor) {
        this._initialRect = this._getBoundingRect(false);
        return true;
    },

    vfunc_gesture_end : function(action, actor) {
        let rect = this._getBoundingRect(true);
        let oldArea = this._initialRect.width * this._initialRect.height;
        let newArea = rect.width * rect.height;
        let areaDiff = newArea / oldArea;

        this.emit('activated', areaDiff);
    }
});
Signals.addSignalMethods(ShowOverviewAction.prototype);