/**
 * MailArchiver is an application that provides services for storing and managing e-mail messages through a Web Services SOAP interface.
 * Copyright (C) 2012  Marcio Andre Scholl Levien and Fernando Alberto Reuter Wendt and Jose Ronaldo Nogueira Fonseca Junior
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/******************************************************************************\
*
*  This product was developed by
*
*        SERVIÇO FEDERAL DE PROCESSAMENTO DE DADOS (SERPRO),
*
*  a government company established under Brazilian law (5.615/70),
*  at Department of Development of Porto Alegre.
*
\******************************************************************************/

package serpro.mailarchiver.service.web;

import java.io.IOException;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.nio.file.Files;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import javax.jdo.annotations.PersistenceAware;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;

import org.codehaus.jettison.mapped.Configuration;
import org.codehaus.jettison.mapped.MappedXMLInputFactory;
import org.codehaus.staxmate.SMInputFactory;
import org.codehaus.staxmate.in.SMHierarchicCursor;
import org.codehaus.staxmate.in.SMInputCursor;

import org.springframework.beans.factory.annotation.Autowired;

import com.ctc.wstx.stax.WstxInputFactory;

import de.schlichtherle.truezip.file.TFile;
import de.schlichtherle.truezip.nio.file.TPath;
import de.schlichtherle.truezip.fs.FsSyncException;

import serpro.mailarchiver.domain.metaarchive.Folder;
import serpro.mailarchiver.domain.metaarchive.Message;
import serpro.mailarchiver.service.BaseService;
import serpro.mailarchiver.service.find.FFolder;
import serpro.mailarchiver.service.find.FMessage;
import serpro.mailarchiver.util.Logger;
import serpro.mailarchiver.util.UserAppConfig;
import serpro.mailarchiver.util.transaction.WithReadOnlyTx;

@PersistenceAware
public class DefaultZipMessagesOperation
    extends BaseService
    implements ZipMessagesOperation
{
    private static final Logger log = Logger.getLocalLogger();

    @Autowired
    private FMessage findMessage;

    @Autowired
    private FFolder findFolder;

    @Autowired
    private UserAppConfig userAppConfig;

    @WithReadOnlyTx
    @Override
    public String apply(String zipConfig) throws ServiceFault {

        /*
         * zipConfig:
         *
         *  <zip format="zip|jar|tar|tar.gz|tgz|tar.bz2|tb2|tbz">
         *
         *      <message id="id"/>
         *
         *      <folder id="id"/>
         *      <folder id="id" recursive="true|false"/>
         *
         *  </zip>
         */

        if(zipConfig.isEmpty()) {
            ServiceFault.invalidZipConfig()
                    .setActor("zipMessages")
                    .setMessage("Zip config is null or empty.")
                    .raise();
        }

        XMLInputFactory inf = null;
        switch(zipConfig.charAt(0)) {
            case '<':
                inf = new WstxInputFactory();
                break;

            case '{':
                Configuration config = new Configuration();
                config.setIgnoreNamespaces(true);
                inf = new MappedXMLInputFactory(config);
                break;

            default:
                ServiceFault.invalidZipConfig()
                        .setActor("zipMessages")
                        .setMessage("Invalid zip config.")
                        .raise();
        }

        String guid = null;

        SMInputFactory sminf = new SMInputFactory(inf);
        StringReader strReader = new StringReader(zipConfig);

        try {
            SMHierarchicCursor cursor0 = sminf.rootElementCursor(strReader);
            cursor0.advance();
            String localName0 = cursor0.getLocalName();
            if(localName0.equalsIgnoreCase("zip")) {
                String format = "zip";
                for(int i = 0; i < cursor0.getAttrCount(); i++) {
                    String attrLocalName0 = cursor0.getAttrLocalName(i);
                    if(attrLocalName0.equalsIgnoreCase("format")) {
                        format = cursor0.getAttrValue(i);
                    }
                    else {
                        //ignore ?
                    }
                }

                if((!format.equalsIgnoreCase("zip"))
                && (!format.equalsIgnoreCase("jar"))
                && (!format.equalsIgnoreCase("tar"))
                && (!format.equalsIgnoreCase("tar.gz"))
                && (!format.equalsIgnoreCase("tgz"))
                && (!format.equalsIgnoreCase("tar.bz2"))
                && (!format.equalsIgnoreCase("tb2"))
                && (!format.equalsIgnoreCase("tbz"))) {

                    ServiceFault.unsupportedArchiveFormat()
                            .setActor("zipMessages")
                            .setMessage("Unsupported archive format.")
                            .addValue("format", format)
                            .raise();
                }

                List<Message> messages = new ArrayList<Message>();

                SMInputCursor cursor1 = cursor0.childElementCursor();
                while(cursor1.getNext() != null) {
                    String localName1 = cursor1.getLocalName();
                    if(localName1.equalsIgnoreCase("message")) {
                        String messageId = "";
                        for(int i = 0; i < cursor1.getAttrCount(); i++) {
                            String attrLocalName1 = cursor1.getAttrLocalName(i);
                            if(attrLocalName1.equalsIgnoreCase("id")) {
                                messageId = cursor1.getAttrValue(i);
                            }
                            else {
                                //ignore ?
                            }
                        }
                        addMessage(messages, messageId);
                    }
                    else if(localName1.equalsIgnoreCase("folder")) {
                        String folderId = "";
                        boolean recursive = false;
                        for(int i = 0; i < cursor1.getAttrCount(); i++) {
                            String attrLocalName1 = cursor1.getAttrLocalName(i);
                            if(attrLocalName1.equalsIgnoreCase("id")) {
                                folderId = cursor1.getAttrValue(i);
                            }
                            else if(attrLocalName1.equalsIgnoreCase("recursive")) {
                                recursive = cursor1.getAttrBooleanValue(i);
                            }
                            else {
                                //ignore ?
                            }
                        }
                        addFolder(messages, folderId, recursive);
                    }
                    else {
                        //ignore ?
                    }
                }

                Collections.sort(messages, new Comparator<Message>() {
                    @Override
                    public int compare(Message m1, Message m2) {
                        return m1.getRelativePath().compareTo(m2.getRelativePath());
                    }
                });

                try {
                    MessageDigest md = MessageDigest.getInstance("MD5");

                    md.update(format.getBytes("UTF-8"));

                    for(Message message : messages) {
                        md.update(message.getOid().getBytes("UTF-8"));
                    }

                    char[] hexDigest = new char[32];
                    int i = 0;
                    for(byte b : md.digest()) {
                        hexDigest[i++] = Character.forDigit((char)((b & 0xf0) >>> 4), 16);
                        hexDigest[i++] = Character.forDigit((char)(b & 0x0f), 16);
                    }

                    String digest = new String(hexDigest);

                    guid = digest.substring(0, 8) +
                        "-" + digest.substring(8, 12) +
                        "-" + digest.substring(12, 16) +
                        "-" + digest.substring(16, 20) +
                        "-" + digest.substring(20, 32);
                }
                catch(NoSuchAlgorithmException ex) {
                }
                catch(UnsupportedEncodingException ex) {
                }

                TPath zip = new TPath(userAppConfig.SERVER.getArchiveDir().resolve("temp").resolve("mails_" + guid + "." + format));
                if(Files.notExists(zip)) {
                    try {
                        for(Message message : messages) {
                            TFile.cp(message.getAbsolutePath().toFile(), zip.resolve(message.getRelativePath()).toFile());
                        }
                    }
                    catch(IOException ex) {
                        ServiceFault.fileSystemFailure()
                                .setActor("zipMessages")
                                .setMessage("Filesystem archive message failure.")
                                .setCause(ex)
                                .raise();
                    }
                    finally {
                        try {
                            TFile.umount(zip.toFile(), true);
                        }
                        catch(FsSyncException ex) {
                            ServiceFault.fileSystemFailure()
                                    .setActor("zipMessages")
                                    .setMessage("Archive umount failure.")
                                    .setCause(ex)
                                    .raise();
                        }
                    }
                }
            }
            else {
                //ignore ?
            }
        }
        catch(XMLStreamException ex) {
            ServiceFault.runtimeException()
                    .setActor("zipMessages")
                    .setMessage("Zip config parse exception.")
                    .setCause(ex)
                    .raise();
        }

        return guid;
    }

    private void addMessage(List<Message> messages, String messageId) throws ServiceFault {

        if(messageId.isEmpty()) {
            ServiceFault.invalidMessageId()
                    .setActor("zipMessages")
                    .setMessage("Message id is empty or null.")
                    .raise();
        }

        Message message = findMessage.byId(messageId);

        if(message == null) {
            ServiceFault.messageNotFound()
                    .setActor("zipMessages")
                    .setMessage("Message not found.")
                    .addValue("messageId", messageId)
                    .raise();
        }

        if( ! messages.contains(message)) {
            messages.add(message);
        }
    }

    private void addFolder(List<Message> messages, String folderId, boolean recursive) throws ServiceFault {

        Folder folder = findFolder.byId(folderId);

        if(folder == null) {
            ServiceFault.folderNotFound()
                    .setActor("zipMessages")
                    .setMessage("Folder not found.")
                    .addValue("folderId", folderId)
                    .raise();
        }

        addFolder(messages, folder, recursive);
    }

    private void addFolder(List<Message> messages, Folder folder, boolean recursive) {

        for(Message message : folder.getMessages()) {
            if( ! messages.contains(message)) {
                messages.add(message);
            }
        }

        if(recursive) {
            for(Folder child : folder.getChildren()) {
                addFolder(messages, child, recursive);
            }
        }
    }

}