/*
 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */
package javax.xml.catalog;

import java.io.StringReader;
import java.util.Iterator;
import org.xml.sax.InputSource;

/**
 * A SAX EntityResolver/JAXP URIResolver that uses catalogs.
 *
 * <p>
 * This class implements both a SAX EntityResolver and a JAXP URIResolver.
 *
 *
 * @since 9
 */
final class CatalogResolverImpl implements CatalogResolver {
    Catalog catalog;

    /**
     * Construct an instance of the CatalogResolver from a Catalog.
     *
     * @param catalog A Catalog.
     */
    public CatalogResolverImpl(Catalog catalog) {
        this.catalog = catalog;
    }

    @Override
    public InputSource resolveEntity(String publicId, String systemId) {
        //Normalize publicId and systemId
        systemId = Normalizer.normalizeURI(Util.getNotNullOrEmpty(systemId));
        publicId = Normalizer.normalizePublicId(Normalizer.decodeURN(Util.getNotNullOrEmpty(publicId)));

        //check whether systemId is an urn
        if (systemId != null && systemId.startsWith("urn:publicid:")) {
            systemId = Normalizer.decodeURN(systemId);
            if (publicId != null && !publicId.equals(systemId)) {
                systemId = null;
            } else {
                publicId = systemId;
                systemId = null;
            }
        }

        CatalogImpl c = (CatalogImpl)catalog;
        String resolvedSystemId = resolve(c, publicId, systemId);

        if (resolvedSystemId != null) {
            return new InputSource(resolvedSystemId);
        }

        GroupEntry.ResolveType resolveType = ((CatalogImpl) catalog).getResolve();
        switch (resolveType) {
            case IGNORE:
                return new InputSource(new StringReader(""));
            case STRICT:
                CatalogMessages.reportError(CatalogMessages.ERR_NO_MATCH,
                        new Object[]{publicId, systemId});
        }

        //no action, allow the parser to continue
        return null;
    }

    /**
     * Resolves the publicId or systemId using public or system entries in the catalog.
     *
     * The resolution follows the following rules determined by the prefer setting:
     *
     * prefer "system": attempts to resolve with a system entry;
     *                  attempts to resolve with a public entry when only
     *                  publicId is specified.
     *
     * prefer "public": attempts to resolve with a system entry;
     *                  attempts to resolve with a public entry if no matching
     *                  system entry is found.
     * @param catalog the catalog
     * @param publicId the publicId
     * @param systemId the systemId
     * @return the resolved systemId if a match is found, null otherwise
     */
    String resolve(CatalogImpl catalog, String publicId, String systemId) {
        String resolvedSystemId = null;

        //search the current catalog
        catalog.reset();
        if (systemId != null) {
            /*
               If a system identifier is specified, it is used no matter how
            prefer is set.
            */
            resolvedSystemId = catalog.matchSystem(systemId);
        }

        if (resolvedSystemId == null && publicId != null) {
            resolvedSystemId = catalog.matchPublic(publicId);
        }

        //mark the catalog as having been searched before trying alternatives
        catalog.markAsSearched();

        //search alternative catalogs
        if (resolvedSystemId == null) {
            Iterator<Catalog> iter = catalog.catalogs().iterator();
            while (iter.hasNext()) {
                resolvedSystemId = resolve((CatalogImpl)iter.next(), publicId, systemId);
                if (resolvedSystemId != null) {
                    break;
                }

            }
        }

        return resolvedSystemId;
    }
}