/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-09 Wolfgang M. Meier
 *  wolfgang@exist-db.org
 *  http://exist.sourceforge.net
 *  
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *  
 *  $Id$
 */
package org.exist.xquery.functions.request;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.io.File;
import java.util.List;

import org.exist.dom.QName;
import org.exist.http.servlets.RequestWrapper;
import org.exist.xquery.*;
import org.exist.xquery.value.Base64BinaryValueType;
import org.exist.xquery.value.BinaryValueFromFile;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.JavaObjectValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;

/**
 * @author wolf
 */
public class GetUploadedFile extends BasicFunction {

    protected static final Logger logger = LogManager.getLogger(GetUploadedFile.class);
    public final static FunctionSignature signatures[] = {
        new FunctionSignature(
        new QName("get-uploaded-file-data", RequestModule.NAMESPACE_URI, RequestModule.PREFIX),
        "Retrieve the base64 encoded data where the file part of a multi-part request has been stored. "
        + "Returns the empty sequence if the request is not a multi-part request or the parameter name "
        + "does not point to a file part.",
        new SequenceType[]{
            new FunctionParameterSequenceType("upload-param-name", Type.STRING, Cardinality.EXACTLY_ONE, "The parameter name")
        },
        new FunctionReturnSequenceType(Type.BASE64_BINARY, Cardinality.ZERO_OR_MORE, "the base64 encoded data from the uploaded file"))
    };

    public GetUploadedFile(XQueryContext context, FunctionSignature signature) {
        super(context, signature);
    }

    /* (non-Javadoc)
     * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
     */
    @Override
    public Sequence eval(Sequence[] args, Sequence contextSequence)
            throws XPathException {

        final RequestModule myModule =
                (RequestModule) context.getModule(RequestModule.NAMESPACE_URI);

        // request object is read from global variable $request
        final Variable var = myModule.resolveVariable(RequestModule.REQUEST_VAR);
        if (var == null || var.getValue() == null) {
            throw new XPathException(this, ErrorCodes.XPDY0002, "No request object found in the current XQuery context.");
        }

        if (var.getValue().getItemType() != Type.JAVA_OBJECT) {
            throw new XPathException(this, ErrorCodes.XPDY0002, "Variable $request is not bound to an Java object.");
        }

        // get parameters
        final String uploadParamName = args[0].getStringValue();

        final JavaObjectValue value = (JavaObjectValue) var.getValue().itemAt(0);

        if (value.getObject() instanceof RequestWrapper) {

            final RequestWrapper request = (RequestWrapper) value.getObject();

            final List<File> files = request.getFileUploadParam(uploadParamName);
            if (files == null) {
                logger.debug("File param not found: " + uploadParamName);
                return Sequence.EMPTY_SEQUENCE;
            }


            /* InputStream is = null;
            try {
                is = new BufferedInputStream(new FileInputStream(file));
                byte buf[] = new byte[1024];
                int read = -1;
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                while ((read = is.read(buf)) != -1) {
                    baos.write(buf, 0, read);
                }

                return new Base64Binary(baos.toByteArray());

            } catch (FileNotFoundException fnfe) {
                throw new XPathException(this, fnfe.getMessage(), fnfe);

            } catch (IOException ioe) {
                throw new XPathException(this, ioe.getMessage(), ioe);

            } finally {
                if (is != null) {
                    try {
                        is.close();
                    } catch (IOException ioe) {
                        logger.warn(ioe.getMessage(), ioe);
                    }
                }
            } */

            final ValueSequence result = new ValueSequence();
            for (final File file : files) {
            	result.add(BinaryValueFromFile.getInstance(context, new Base64BinaryValueType(), file));
            }

            return result;
        } else {
            throw new XPathException(this, ErrorCodes.XPDY0002, "Variable $request is not bound to a Request object.");
        }
    }
}