/*
 * Copyright 2012, 2013 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.agent.cli.impl;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Semaphore;

import org.osgi.framework.BundleContext;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.ServiceReference;

import com.redhat.thermostat.agent.cli.impl.db.StorageAlreadyRunningException;
import com.redhat.thermostat.agent.cli.impl.db.StorageCommand;
import com.redhat.thermostat.agent.cli.impl.locale.LocaleResources;
import com.redhat.thermostat.common.ActionEvent;
import com.redhat.thermostat.common.ActionListener;
import com.redhat.thermostat.common.Launcher;
import com.redhat.thermostat.common.cli.AbstractCommand;
import com.redhat.thermostat.common.cli.CommandContext;
import com.redhat.thermostat.common.cli.CommandException;
import com.redhat.thermostat.common.tools.ApplicationState;
import com.redhat.thermostat.shared.locale.Translate;

/**
 * Simple service that allows starting Agent and DB Backend
 * in a single step.
 */
public class ServiceCommand extends AbstractCommand implements ActionListener<ApplicationState> {
    
    private static final Translate<LocaleResources> translator = LocaleResources.createLocalizer();

    private List<ActionListener<ApplicationState>> listeners;
    private Semaphore agentBarrier = new Semaphore(0);
    private BundleContext context;
    private Launcher launcher;
    private boolean storageFailed = false;

    public ServiceCommand(BundleContext context) {
        this.context = context;
        listeners = new ArrayList<>();
        listeners.add(this);
    }

    @Override
    public void run(CommandContext ctx) throws CommandException {
        ServiceReference launcherRef = context.getServiceReference(Launcher.class);
        if (launcherRef == null) {
            throw new CommandException(translator.localize(LocaleResources.LAUNCHER_UNAVAILABLE));
        }
        launcher = (Launcher) context.getService(launcherRef);
        String[] storageStartArgs = new String[] { "storage", "--start" };
        launcher.run(storageStartArgs, listeners, false);
        agentBarrier.acquireUninterruptibly();
        
        if (storageFailed) {
            storageFailed = false;
            context.ungetService(launcherRef);
            throw new CommandException(translator.localize(LocaleResources.SERVICE_FAILED_TO_START_DB));
        }
        
        String[] storageStopArgs = new String[] { "storage", "--stop" };
        launcher.run(storageStopArgs, false);
        
        context.ungetService(launcherRef);
    }

    @Override
    public void actionPerformed(ActionEvent<ApplicationState> actionEvent) {
        if (actionEvent.getSource() instanceof StorageCommand) {
            StorageCommand storage = (StorageCommand) actionEvent.getSource();
            // Implementation detail: there is a single StorageCommand instance registered
            // as an OSGi service.  We remove ourselves as listener so that we don't get
            // notified in the case that the command is invoked by some other means later.
            storage.getNotifier().removeActionListener(this);
            switch (actionEvent.getActionId()) {
            case START:
                String dbUrl = storage.getConfiguration().getDBConnectionString();
                String[] agentArgs =  new String[] {"agent", "-d", dbUrl};
                System.err.println(translator.localize(LocaleResources.STARTING_AGENT).getContents());
                launcher.run(agentArgs, false);
                break;
            case FAIL:
                storageFailed = true;
                Object payload = actionEvent.getPayload();
                if (payload instanceof StorageAlreadyRunningException) {
                    System.err.println(translator.localize(LocaleResources.STORAGE_ALREADY_RUNNING).getContents());
                }
                break;
            }
            agentBarrier.release();
        }
    }

    @Override
    public boolean isStorageRequired() {
        return false;
    }

}