package org.activityinfo.ui.client.local.capability;

/*
 * #%L
 * ActivityInfo Server
 * %%
 * Copyright (C) 2009 - 2013 UNICEF
 * %%
 * 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/gpl-3.0.html>.
 * #L%
 */

import com.google.gwt.core.client.GWT;
import com.google.gwt.gears.client.Factory;
import com.google.gwt.user.client.rpc.AsyncCallback;
import org.activityinfo.legacy.shared.Log;

/**
 * Utilities for Gears-based offline capability profiles.
 */
public abstract class GearsCapabilityProfile extends LocalCapabilityProfile {

    protected final boolean isGearsInstalled() {
        return Factory.getInstance() != null;
    }

    @Override
    public final boolean isOfflineModeSupported() {
        return isGearsInstalled();
    }

    @Override
    public final void acquirePermission(AsyncCallback<Void> callback) {
        Log.trace("GearsCapabilityProfile: acquiring permissions...");
        try {
            if (!isGearsInstalled()) {
                callback.onFailure(new UnsupportedOperationException("Gears is not installed"));
            } else if (acquirePermissions()) {
                callback.onSuccess(null);
            } else {
                callback.onFailure(new PermissionRefusedException());
            }
        } catch (Exception e) {
            callback.onFailure(e);
        }
    }

    @Override
    public final boolean hasPermission() {
        if (!isGearsInstalled()) {
            throw new UnsupportedOperationException("Gears is not installed");
        }
        return Factory.getInstance().hasPermission();
    }

    private boolean acquirePermissions() {
        return Factory.getInstance().getPermission("ActivityInfo", GWT.getModuleBaseURL() + "desktopicons/64x64.png");
    }
}