/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.tika.parser.microsoft;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import org.apache.poi.hmef.Attachment;
import org.apache.poi.hmef.HMEFMessage;
import org.apache.poi.hmef.attribute.MAPIAttribute;
import org.apache.poi.hmef.attribute.MAPIRtfAttribute;
import org.apache.poi.hsmf.datatypes.MAPIProperty;
import org.apache.tika.exception.TikaException;
import org.apache.tika.extractor.EmbeddedDocumentExtractor;
import org.apache.tika.extractor.EmbeddedDocumentUtil;
import org.apache.tika.io.TikaInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.metadata.TikaCoreProperties;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.AbstractParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.sax.EmbeddedContentHandler;
import org.apache.tika.sax.XHTMLContentHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

/**
 * A POI-powered Tika Parser for TNEF (Transport Neutral
 * Encoding Format) messages, aka winmail.dat
 */
public class TNEFParser extends AbstractParser {
    private static final long serialVersionUID = 4611820730372823452L;

    private static final Set<MediaType> SUPPORTED_TYPES =
            Collections.unmodifiableSet(new HashSet<MediaType>(Arrays.asList(
                    MediaType.application("vnd.ms-tnef"),
                    MediaType.application("ms-tnef"),
                    MediaType.application("x-tnef")
            )));

    public Set<MediaType> getSupportedTypes(ParseContext context) {
        return SUPPORTED_TYPES;
    }

    /**
     * Extracts properties and text from an MS Document input stream
     */
    public void parse(
            InputStream stream, ContentHandler handler,
            Metadata metadata, ParseContext context)
            throws IOException, SAXException, TikaException {

        // We work by recursing, so get the appropriate bits
        EmbeddedDocumentExtractor embeddedExtractor =
                EmbeddedDocumentUtil.getEmbeddedDocumentExtractor(context);

        // Ask POI to process the file for us
        HMEFMessage msg = new HMEFMessage(stream);

        // Set the message subject if known
        String subject = msg.getSubject();
        if (subject != null && subject.length() > 0) {
            metadata.set(TikaCoreProperties.TITLE, subject);
            metadata.set(TikaCoreProperties.SUBJECT, subject);
        }
        XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
        xhtml.startDocument();
        // Recurse into the message body RTF
        MAPIAttribute attr = msg.getMessageMAPIAttribute(MAPIProperty.RTF_COMPRESSED);
        if (attr != null && attr instanceof MAPIRtfAttribute) {
            MAPIRtfAttribute rtf = (MAPIRtfAttribute) attr;
            handleEmbedded(
                    "message.rtf", "application/rtf",
                    rtf.getData(),
                    embeddedExtractor, xhtml
            );
        }

        // Recurse into each attachment in turn
        for (Attachment attachment : msg.getAttachments()) {
            String name = attachment.getLongFilename();
            if (name == null || name.length() == 0) {
                name = attachment.getFilename();
            }
            if (name == null || name.length() == 0) {
                String ext = attachment.getExtension();
                if (ext != null) {
                    name = "unknown" + ext;
                }
            }
            handleEmbedded(
                    name, null, attachment.getContents(),
                    embeddedExtractor, xhtml
            );
        }
        xhtml.endDocument();
    }

    private void handleEmbedded(String name, String type, byte[] contents,
                                EmbeddedDocumentExtractor embeddedExtractor, ContentHandler handler)
            throws IOException, SAXException, TikaException {
        Metadata metadata = new Metadata();
        if (name != null)
            metadata.set(TikaCoreProperties.RESOURCE_NAME_KEY, name);
        if (type != null)
            metadata.set(Metadata.CONTENT_TYPE, type);

        if (embeddedExtractor.shouldParseEmbedded(metadata)) {
            embeddedExtractor.parseEmbedded(
                    TikaInputStream.get(contents),
                    new EmbeddedContentHandler(handler),
                    metadata, false);
        }
    }
}
