/*
 * Copyright 2012-2014 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat 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 2, or (at your
 * option) any later version.
 *
 * Thermostat 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 Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.common.cli;

import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.Objects;

import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;

/**
 * Handles registration and un-registration of {@link Command}s.
 */
public class CommandRegistryImpl implements CommandRegistry {

    private BundleContext context;
    private Map<String, ServiceRegistration<?>> regMapping;

    public CommandRegistryImpl(BundleContext ctx) {
        context = ctx;
        regMapping = new HashMap<>();
    }

    @Override
    public synchronized void registerCommand(String name, Command cmd) {
        Objects.requireNonNull(name);
        Objects.requireNonNull(cmd);

        Hashtable<String,String> props = new Hashtable<>();
        props.put(Command.NAME, name);
        ServiceRegistration<?> registration = context.registerService(Command.class.getName(), cmd, props);
        regMapping.put(name, registration);
    }

    @Override
    public synchronized void unregisterCommand(String name) {
        Objects.requireNonNull(name);
        ServiceRegistration reg = regMapping.remove(name);
        if (reg != null) {
             reg.unregister();
         }
     }

    @Override
    public synchronized void unregisterCommands() {
        for (ServiceRegistration<?> reg : regMapping.values()) {
            reg.unregister();
        }
        regMapping.clear();
    }

}