/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 * http://www.dspace.org/license/
 */

package org.dspace.rdf.storage;

import org.apache.log4j.Logger;
import org.dspace.content.DSpaceObject;
import org.dspace.core.Constants;
import org.dspace.core.Context;
import org.dspace.identifier.DOI;
import org.dspace.identifier.IdentifierException;

import java.sql.SQLException;

/**
 *
 * @author pbecker
 */
public class DOIURIGenerator
implements URIGenerator
{
    private static final Logger log = Logger.getLogger(DOIURIGenerator.class);

    /*
     * Currently (August 31 2014, in preparation of DSpace 5.0) DSpace supports DOIs for items only. This fallback
     * will be used to generate an URI, whenever no DOI was found that could be used to.
     */
    protected final static URIGenerator fallback = new LocalURIGenerator();
    
    @Override
    public String generateIdentifier(Context context, int type, int id, String handle, String[] identifiers) throws SQLException {
        if (type != Constants.SITE
                && type != Constants.COMMUNITY
                && type != Constants.COLLECTION
                && type != Constants.ITEM)
        {
            return null;
        }

        String doi = null;
        for (String identifier : identifiers)
        {
            try
            {
                doi = DOI.DOIToExternalForm(identifier);
            } catch (IdentifierException ex) {
                // identifier is not a DOI: no problem, keep on looking.
            }
        }
        if (doi != null) {
            return doi;
        } else {
            log.info("Didn't find a DOI for " + Constants.typeText[type] + ", id " + Integer.toString(id)
                    + ", will use fallback URIGenerator.");
            return fallback.generateIdentifier(context, type, id, handle, identifiers);
        }
    }

    public String generateIdentifier(Context context, DSpaceObject dso)
            throws SQLException
    {
        return generateIdentifier(context, dso.getType(), dso.getID(), dso.getHandle(), dso.getIdentifiers(context));
    }
    
}