/*
 * Copyright 2006-2019 DLR, Germany
 * 
 * SPDX-License-Identifier: EPL-1.0
 * 
 * http://www.rcenvironment.de/
 */

package de.rcenvironment.core.component.registration.internal;

import java.util.Dictionary;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleEvent;
import org.osgi.framework.BundleException;
import org.osgi.framework.BundleListener;

import de.rcenvironment.core.component.api.ComponentConstants;
import de.rcenvironment.core.component.execution.api.Component;
import de.rcenvironment.core.configuration.CommandLineArguments;
import de.rcenvironment.core.utils.common.StringUtils;

/**
 * {@link BundleListener} to recognize when new {@link Bundle}s providing a {@link Component} are installed in oder to start this
 * {@link Bundle} and thus enforce the registration of the containing component.
 * 
 * @author Doreen Seider
 */
public class ComponentBundleListener implements BundleListener {

    /** The logger for this class. */
    private static final Log LOGGER = LogFactory.getLog(ComponentBundleListener.class);

    @Override
    public void bundleChanged(BundleEvent event) {
        if (event.getType() == BundleEvent.INSTALLED) {
            ComponentBundleListener.handleBundle(event.getBundle());
        }
    }

    /**
     * Checks the given {@link Bundle} if it provides a {@link Component} and declare that in its Manifest and starts it if it does.
     * 
     * @param bundle The given bundle to check and possibly to start.
     */
    public static void handleBundle(Bundle bundle) {
        if (!CommandLineArguments.isDoNotStartComponentsRequested()) {
            Dictionary<String, String> headers = bundle.getHeaders();
            String componentEntry = headers.get(ComponentConstants.MANIFEST_ENTRY_RCE_COMPONENT);
            if (componentEntry != null && Boolean.valueOf(componentEntry)) {
                if (bundle.getState() == Bundle.RESOLVED) {
                    try {
                        bundle.start();
                    } catch (BundleException e) {
                        LOGGER.error(StringUtils.format("Failed to start bundle '%s' that provides a workflow component",
                            bundle.getSymbolicName()), e);
                    }
                }
            }
        }
    }
}
