/********************************************************************************
 * Copyright (c) 2019 TypeFox and others.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the Eclipse
 * Public License v. 2.0 are satisfied: GNU General Public License, version 2
 * with the GNU Classpath Exception which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 ********************************************************************************/

import { injectable } from "inversify";
import { Point } from "sprotty-protocol/lib/utils/geometry";
import { SModelElementImpl } from "../../base/model/smodel";
import { isBoundsAware } from "../bounds/model";

/**
 * A snapper helps to align nodes and routing handles.
 */
export interface ISnapper {
    /**
     * @retruns the closest snapped position that for the `element` located at `position`
     */
    snap(position: Point, element: SModelElementImpl): Point
}

/**
 * A simple snapper that snaps the center of nodes and routing points to a grid.
 */
@injectable()
export class CenterGridSnapper implements ISnapper {

    get gridX() {
        return 10;
    }

    get gridY() {
        return 10;
    }

    snap(position: Point, element: SModelElementImpl): Point {
        if (element && isBoundsAware(element))
            return {
                x: Math.round((position.x + 0.5 * element.bounds.width) / this.gridX) * this.gridX - 0.5 * element.bounds.width,
                y: Math.round((position.y + 0.5 * element.bounds.height) / this.gridY) * this.gridY - 0.5 * element.bounds.height
            };
        else
            return {
                x: Math.round(position.x / this.gridX) * this.gridX,
                y: Math.round(position.y / this.gridY) * this.gridY
            };
    }
}