// CacheResource_p.java
// -----------------------
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
//$LastChangedDate$
//$LastChangedRevision$
//$LastChangedBy$
//
// This program 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 of the License, or
// (at your option) any later version.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

import net.yacy.cora.document.id.DigestURL;
import net.yacy.cora.federate.yacy.CacheStrategy;
import net.yacy.cora.protocol.ClientIdentification;
import net.yacy.cora.protocol.RequestHeader;
import net.yacy.cora.protocol.ResponseHeader;
import net.yacy.cora.util.ConcurrentLog;
import net.yacy.crawler.data.Cache;
import net.yacy.crawler.retrieval.Response;
import net.yacy.document.ImageParser;
import net.yacy.search.Switchboard;
import net.yacy.server.serverObjects;
import net.yacy.server.serverSwitch;
import net.yacy.server.servletProperties;

public class CacheResource_p {

    public static Object respond(final RequestHeader header, final serverObjects post, final serverSwitch env) {
        Switchboard sb = (Switchboard) env;
        final servletProperties prop = new servletProperties();
        prop.put("resource", new byte[0]);

        if (post == null) return prop;

        boolean load = post.getBoolean("load");
        final String u = post.get("url", "");
        DigestURL url;
        try {
            url = new DigestURL(u);
        } catch (final MalformedURLException e) {
            ConcurrentLog.logException(e);
            return prop;
        }

        byte[] resource = Cache.getContent(url.hash());
        ResponseHeader responseHeader = null;
        if (resource == null) {
            if (load) {
                try {
                    final Response response = sb.loader.load(sb.loader.request(url, false, true), CacheStrategy.NOCACHE, Integer.MAX_VALUE, null, ClientIdentification.yacyInternetCrawlerAgent);
                    responseHeader = response.getResponseHeader();
                    resource = response.getContent();
                } catch (IOException e) {
                    return prop;
                }
            } else return prop;
        }

        // check request type
        if (header.get("EXT", "html").equals("png")) {
            // a png was requested
            return ImageParser.parse(u, resource);
        }
        // get response header and set mime type
        if (responseHeader == null) {
            responseHeader = Cache.getResponseHeader(url.hash());
        }

        // because for display a servlet html variable is use
        // which is internally processed using utf-8, we need to convert encoding of cached resource
        final String charsetName = responseHeader.getCharacterEncoding();
        if (charsetName != null && !charsetName.equalsIgnoreCase(StandardCharsets.UTF_8.name())) {
        	Charset decoderCharset;
        	/* Specified charset might be incorrect or not supported */
        	if(Charset.isSupported(charsetName)) {
        		decoderCharset = Charset.forName(charsetName);
        	} else {
        		decoderCharset = StandardCharsets.UTF_8;
        	}
            CharBuffer cb = decoderCharset.decode(ByteBuffer.wrap(resource));
            ByteBuffer x = StandardCharsets.UTF_16.encode(cb); // encode to a default java string (which uses utf-16 and is handled correct for servlet content)
            prop.put("resource", x.asCharBuffer().toString());

        } else {
            prop.put("resource", resource);
        }

        // add resource   
        return prop;
    }
}