/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This 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 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.portal.mop.management.operations;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.exoplatform.portal.config.DataStorage;
import org.exoplatform.portal.config.model.Page;
import org.exoplatform.portal.config.model.PageNavigation;
import org.exoplatform.portal.config.model.PortalConfig;
import org.exoplatform.portal.mop.SiteKey;
import org.exoplatform.portal.mop.description.DescriptionService;
import org.exoplatform.portal.mop.importer.ImportMode;
import org.exoplatform.portal.mop.management.exportimport.NavigationExportTask;
import org.exoplatform.portal.mop.management.exportimport.NavigationImportTask;
import org.exoplatform.portal.mop.management.exportimport.PageExportTask;
import org.exoplatform.portal.mop.management.exportimport.PageImportTask;
import org.exoplatform.portal.mop.management.exportimport.SiteLayoutExportTask;
import org.exoplatform.portal.mop.management.exportimport.SiteLayoutImportTask;
import org.exoplatform.portal.mop.navigation.NavigationService;
import org.exoplatform.portal.mop.page.PageService;
import org.exoplatform.portal.pom.config.POMSession;
import org.exoplatform.portal.pom.config.POMSessionManager;
import org.gatein.common.logging.Logger;
import org.gatein.common.logging.LoggerFactory;
import org.gatein.management.api.ContentType;
import org.gatein.management.api.binding.Marshaller;
import org.gatein.management.api.exceptions.OperationException;
import org.gatein.management.api.exceptions.ResourceNotFoundException;
import org.gatein.management.api.operation.OperationAttachment;
import org.gatein.management.api.operation.OperationContext;
import org.gatein.management.api.operation.OperationHandler;
import org.gatein.management.api.operation.ResultHandler;
import org.gatein.management.api.operation.model.NoResultModel;
import org.gatein.mop.api.workspace.Site;
import org.gatein.mop.api.workspace.Workspace;

/**
 * @author <a href="mailto:nscavell@redhat.com">Nick Scavelli</a>
 * @version $Revision$
 */
public class MopImportResource implements OperationHandler {
    private static final Logger log = LoggerFactory.getLogger(MopImportResource.class);

    // TODO: Would like to see the step operations be handled by mgmt core.

    // TODO: Clean this up when we have time
    @Override
    public void execute(final OperationContext operationContext, ResultHandler resultHandler) throws ResourceNotFoundException,
            OperationException {
        final String operationName = operationContext.getOperationName();

        OperationAttachment attachment = operationContext.getAttachment(true);
        if (attachment == null)
            throw new OperationException(operationContext.getOperationName(), "No attachment available for MOP import.");

        InputStream inputStream = attachment.getStream();
        if (inputStream == null)
            throw new OperationException(operationContext.getOperationName(), "No data stream available for import.");

        final POMSessionManager mgr = operationContext.getRuntimeContext().getRuntimeComponent(POMSessionManager.class);
        POMSession session = mgr.getSession();
        if (session == null)
            throw new OperationException(operationName, "MOP session was null");

        Workspace workspace = session.getWorkspace();
        if (workspace == null)
            throw new OperationException(operationName, "MOP workspace was null");

        DataStorage dataStorage = operationContext.getRuntimeContext().getRuntimeComponent(DataStorage.class);
        if (dataStorage == null)
            throw new OperationException(operationName, "DataStorage was null");

        PageService pageService = operationContext.getRuntimeContext().getRuntimeComponent(PageService.class);
        if (pageService == null)
            throw new OperationException(operationName, "PageService was null");

        NavigationService navigationService = operationContext.getRuntimeContext().getRuntimeComponent(NavigationService.class);
        if (navigationService == null)
            throw new OperationException(operationName, "Navigation service was null");

        DescriptionService descriptionService = operationContext.getRuntimeContext().getRuntimeComponent(
                DescriptionService.class);
        if (descriptionService == null)
            throw new OperationException(operationName, "Description service was null");

        String mode = operationContext.getAttributes().getValue("importMode");
        if (mode == null || "".equals(mode))
            mode = "merge";

        ImportMode importMode;
        try {
            importMode = ImportMode.valueOf(mode.trim().toUpperCase());
        } catch (Exception e) {
            throw new OperationException(operationName, "Unknown importMode " + mode);
        }

        Map<SiteKey, MopImport> importMap = new HashMap<SiteKey, MopImport>();
        final NonCloseableZipInputStream zis = new NonCloseableZipInputStream(inputStream);
        ZipEntry entry;
        boolean empty = false;
        try {
            log.info("Preparing data for import.");
            while ((entry = zis.getNextEntry()) != null) {
                // Skip directories
                if (entry.isDirectory())
                    continue;
                // Skip empty entries (this allows empty zip files to not cause exceptions).
                empty = entry.getName().equals("");
                if (empty)
                    continue;

                // Parse zip entry
                String[] parts = parseEntry(entry);
                SiteKey siteKey = Utils.siteKey(parts[0], parts[1]);
                String file = parts[2];

                MopImport mopImport = importMap.get(siteKey);
                if (mopImport == null) {
                    mopImport = new MopImport();
                    importMap.put(siteKey, mopImport);
                }

                if (SiteLayoutExportTask.FILES.contains(file)) {
                    // Unmarshal site layout data
                    Marshaller<PortalConfig> marshaller = operationContext.getBindingProvider().getMarshaller(
                            PortalConfig.class, ContentType.XML);
                    PortalConfig portalConfig = marshaller.unmarshal(zis);
                    portalConfig.setType(siteKey.getTypeName());
                    if (!portalConfig.getName().equals(siteKey.getName())) {
                        throw new OperationException(operationName,
                                "Name of site does not match that of the zip entry site name.");
                    }

                    // Add import task to run later
                    mopImport.siteTask = new SiteLayoutImportTask(portalConfig, siteKey, dataStorage);
                } else if (file.equals(PageExportTask.FILE)) {
                    // Unmarshal page data
                    Marshaller<Page.PageSet> marshaller = operationContext.getBindingProvider().getMarshaller(
                            Page.PageSet.class, ContentType.XML);
                    Page.PageSet pages = marshaller.unmarshal(zis);
                    for (Page page : pages.getPages()) {
                        page.setOwnerType(siteKey.getTypeName());
                        page.setOwnerId(siteKey.getName());
                    }

                    // Obtain the site from the session when it's needed.
                    MOPSiteProvider siteProvider = new MOPSiteProvider() {
                        @Override
                        public Site getSite(SiteKey siteKey) {
                            return mgr.getSession().getWorkspace()
                                    .getSite(Utils.getObjectType(siteKey.getType()), siteKey.getName());
                        }
                    };
                    // Add import task to run later.
                    mopImport.pageTask = new PageImportTask(pages, siteKey, dataStorage, pageService, siteProvider);
                } else if (file.equals(NavigationExportTask.FILE)) {
                    // Unmarshal navigation data
                    Marshaller<PageNavigation> marshaller = operationContext.getBindingProvider().getMarshaller(
                            PageNavigation.class, ContentType.XML);
                    PageNavigation navigation = marshaller.unmarshal(zis);
                    navigation.setOwnerType(siteKey.getTypeName());
                    navigation.setOwnerId(siteKey.getName());

                    // Add import task to run later
                    mopImport.navigationTask = new NavigationImportTask(navigation, siteKey, navigationService,
                            descriptionService, dataStorage);
                }
            }

            resultHandler.completed(NoResultModel.INSTANCE);
        } catch (Throwable t) {
            throw new OperationException(operationContext.getOperationName(), "Exception reading data for import.", t);
        } finally {
            try {
                zis.reallyClose();
            } catch (IOException e) {
                log.warn("Exception closing underlying data stream from import.");
            }
        }

        if (empty) {
            log.info("Nothing to import, zip file empty.");
            return;
        }

        // Perform import
        Map<SiteKey, MopImport> importsRan = new HashMap<SiteKey, MopImport>();
        try {
            log.info("Performing import using importMode '" + mode + "'");
            for (Map.Entry<SiteKey, MopImport> mopImportEntry : importMap.entrySet()) {
                SiteKey siteKey = mopImportEntry.getKey();
                MopImport mopImport = mopImportEntry.getValue();
                MopImport ran = new MopImport();

                if (importsRan.containsKey(siteKey)) {
                    throw new IllegalStateException("Multiple site imports for same operation.");
                }
                importsRan.put(siteKey, ran);

                log.debug("Importing data for site " + siteKey);

                // Site layout import
                if (mopImport.siteTask != null) {
                    log.debug("Importing site layout data.");
                    ran.siteTask = mopImport.siteTask;
                    mopImport.siteTask.importData(importMode);
                }

                // Page import
                if (mopImport.pageTask != null) {
                    log.debug("Importing page data.");
                    ran.pageTask = mopImport.pageTask;
                    mopImport.pageTask.importData(importMode);
                }

                // Navigation import
                if (mopImport.navigationTask != null) {
                    log.debug("Importing navigation data.");
                    ran.navigationTask = mopImport.navigationTask;
                    mopImport.navigationTask.importData(importMode);
                }
            }
            log.info("Import successful !");
        } catch (Throwable t) {
            boolean rollbackSuccess = true;
            log.error("Exception importing data.", t);
            log.info("Attempting to rollback data modified by import.");
            for (Map.Entry<SiteKey, MopImport> mopImportEntry : importsRan.entrySet()) {
                SiteKey siteKey = mopImportEntry.getKey();
                MopImport mopImport = mopImportEntry.getValue();

                log.debug("Rolling back imported data for site " + siteKey);
                if (mopImport.navigationTask != null) {
                    log.debug("Rolling back navigation modified during import...");
                    try {
                        mopImport.navigationTask.rollback();
                    } catch (Throwable t1) // Continue rolling back even though there are exceptions.
                    {
                        rollbackSuccess = false;
                        log.error("Error rolling back navigation data for site " + siteKey, t1);
                    }
                }
                if (mopImport.pageTask != null) {
                    log.debug("Rolling back pages modified during import...");
                    try {
                        mopImport.pageTask.rollback();
                    } catch (Throwable t1) // Continue rolling back even though there are exceptions.
                    {
                        rollbackSuccess = false;
                        log.error("Error rolling back page data for site " + siteKey, t1);
                    }
                }
                if (mopImport.siteTask != null) {
                    log.debug("Rolling back site layout modified during import...");
                    try {
                        mopImport.siteTask.rollback();
                    } catch (Throwable t1) // Continue rolling back even though there are exceptions.
                    {
                        rollbackSuccess = false;
                        log.error("Error rolling back site layout for site " + siteKey, t1);
                    }
                }
            }

            String message = (rollbackSuccess) ? "Error during import. Tasks successfully rolled back. Portal should be back to consistent state."
                    : "Error during import. Errors in rollback as well. Portal may be in an inconsistent state.";

            throw new OperationException(operationName, message, t);
        } finally {
            importMap.clear();
            importsRan.clear();
        }
    }

    private static String[] parseEntry(ZipEntry entry) throws IOException {
        String name = entry.getName();
        if (isSiteLayoutEntry(name) || name.endsWith(PageExportTask.FILE) || name.endsWith(NavigationExportTask.FILE)) {
            String[] parts = new String[3];
            parts[0] = name.substring(0, name.indexOf("/"));
            parts[1] = name.substring(parts[0].length() + 1, name.lastIndexOf("/"));
            parts[2] = name.substring(name.lastIndexOf("/") + 1);
            return parts;
        } else {
            throw new IOException("Unknown entry " + name + " in zip file.");
        }
    }

    private static boolean isSiteLayoutEntry(String zipEntryName) {
        for (String file : SiteLayoutExportTask.FILES) {
            if (zipEntryName.endsWith(file))
                return true;
        }

        return false;
    }

    // Bug in SUN's JDK XMLStreamReader implementation closes the underlying stream when
    // it finishes reading an XML document. This is no good when we are using a ZipInputStream.
    // See http://bugs.sun.com/view_bug.do?bug_id=6539065 for more information.
    private static class NonCloseableZipInputStream extends ZipInputStream {
        private NonCloseableZipInputStream(InputStream inputStream) {
            super(inputStream);
        }

        @Override
        public void close() throws IOException {
        }

        private void reallyClose() throws IOException {
            super.close();
        }
    }

    private static class MopImport {
        private SiteLayoutImportTask siteTask;
        private PageImportTask pageTask;
        private NavigationImportTask navigationTask;
    }
}
