/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.xml.internal.org.jvnet.mimepull;

import java.io.File;

import java.io.InputStream;

import java.nio.ByteBuffer;

import java.util.List;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 * Represents an attachment part in a MIME message. MIME message parsing is done

 * lazily using a pull parser, so the part may not have all the data. {@link #read}

 * and {@link #readOnce} may trigger the actual parsing the message. In fact,

 * parsing of an attachment part may be triggered by calling {@link #read} methods

 * on some other attachment parts. All this happens behind the scenes so the

 * application developer need not worry about these details.

 *

 * @author Jitendra Kotamraju, Martin Grebac

 */

public class MIMEPart {

    private static final Logger LOGGER = Logger.getLogger(MIMEPart.class.getName());

    private volatile InternetHeaders headers;

    private volatile String contentId;

    private String contentType;

    private String contentTransferEncoding;

    volatile boolean parsed;    // part is parsed or not

    final MIMEMessage msg;

    private final DataHead dataHead;

    MIMEPart(MIMEMessage msg) {

        this.msg = msg;

        this.dataHead = new DataHead(this);

    }

    MIMEPart(MIMEMessage msg, String contentId) {

        this(msg);

        this.contentId = contentId;

    }

    /**

     * Can get the attachment part's content multiple times. That means

     * the full content needs to be there in memory or on the file system.

     * Calling this method would trigger parsing for the part's data. So

     * do not call this unless it is required(otherwise, just wrap MIMEPart

     * into a object that returns InputStream for e.g DataHandler)

     *

     * @return data for the part's content

     */

    public InputStream read() {

        InputStream is = null;

        try {

            is = MimeUtility.decode(dataHead.read(), contentTransferEncoding);

        } catch (DecodingException ex) { //ignore

            if (LOGGER.isLoggable(Level.WARNING)) {

                LOGGER.log(Level.WARNING, null, ex);

            }

        }

        return is;

    }

    /**

     * Cleans up any resources that are held by this part (for e.g. deletes

     * the temp file that is used to serve this part's content). After

     * calling this, one shouldn't call {@link #read()} or {@link #readOnce()}

     */

    public void close() {

        dataHead.close();

    }

    /**

     * Can get the attachment part's content only once. The content

     * will be lost after the method. Content data is not be stored

     * on the file system or is not kept in the memory for the

     * following case:

     *   - Attachement parts contents are accessed sequentially

     *

     * In general, take advantage of this when the data is used only

     * once.

     *

     * @return data for the part's content

     */

    public InputStream readOnce() {

        InputStream is = null;

        try {

            is = MimeUtility.decode(dataHead.readOnce(), contentTransferEncoding);

        } catch (DecodingException ex) { //ignore

            if (LOGGER.isLoggable(Level.WARNING)) {

                LOGGER.log(Level.WARNING, null, ex);

            }

        }

        return is;

    }

    public void moveTo(File f) {

        dataHead.moveTo(f);

    }

    /**

     * Returns Content-ID MIME header for this attachment part

     *

     * @return Content-ID of the part

     */

    public String getContentId() {

        if (contentId == null) {

            getHeaders();

        }

        return contentId;

    }

    /**

     * Returns Content-Transfer-Encoding MIME header for this attachment part

     *

     * @return Content-Transfer-Encoding of the part

     */

    public String getContentTransferEncoding() {

        if (contentTransferEncoding == null) {

            getHeaders();

        }

        return contentTransferEncoding;

    }

    /**

     * Returns Content-Type MIME header for this attachment part

     *

     * @return Content-Type of the part

     */

    public String getContentType() {

        if (contentType == null) {

            getHeaders();

        }

        return contentType;

    }

    private void getHeaders() {

        // Trigger parsing for the part headers

        while(headers == null) {

            if (!msg.makeProgress()) {

                if (headers == null) {

                    throw new IllegalStateException("Internal Error. Didn't get Headers even after complete parsing.");

                }

            }

        }

    }

    /**

     * Return all the values for the specified header.

     * Returns <code>null</code> if no headers with the

     * specified name exist.

     *

     * @param   name header name

     * @return  list of header values, or null if none

     */

    public List<String> getHeader(String name) {

        getHeaders();

        assert headers != null;

        return headers.getHeader(name);

    }

    /**

     * Return all the headers

     *

     * @return list of Header objects

     */

    public List<? extends Header> getAllHeaders() {

        getHeaders();

        assert headers != null;

        return headers.getAllHeaders();

    }

    /**

     * Callback to set headers

     *

     * @param headers MIME headers for the part

     */

    void setHeaders(InternetHeaders headers) {

        this.headers = headers;

        List<String> ct = getHeader("Content-Type");

        this.contentType = (ct == null) ? "application/octet-stream" : ct.get(0);

        List<String> cte = getHeader("Content-Transfer-Encoding");

        this.contentTransferEncoding = (cte == null) ? "binary" : cte.get(0);

    }

    /**

     * Callback to notify that there is a partial content for the part

     *

     * @param buf content data for the part

     */

    void addBody(ByteBuffer buf) {

        dataHead.addBody(buf);

    }

    /**

     * Callback to indicate that parsing is done for this part

     * (no more update events for this part)

     */

    void doneParsing() {

        parsed = true;

        dataHead.doneParsing();

    }

    /**

     * Callback to set Content-ID for this part

     * @param cid Content-ID of the part

     */

    void setContentId(String cid) {

        this.contentId = cid;

    }

    /**

     * Callback to set Content-Transfer-Encoding for this part

     * @param cte Content-Transfer-Encoding of the part

     */

    void setContentTransferEncoding(String cte) {

        this.contentTransferEncoding = cte;

    }

    @Override

    public String toString() {

        return "Part="+contentId+":"+contentTransferEncoding;

    }

}