/*
 * 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.sling.distribution.packaging.impl;

import static org.apache.sling.distribution.util.impl.DigestUtils.openDigestOutputStream;
import static org.apache.sling.distribution.util.impl.DigestUtils.readDigestMessage;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.DigestOutputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NavigableMap;
import java.util.UUID;

import javax.jcr.RepositoryException;

import org.apache.commons.io.IOUtils;
import org.apache.sling.api.resource.PersistenceException;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceUtil;
import org.apache.sling.distribution.DistributionRequest;
import org.apache.sling.distribution.common.DistributionException;
import org.apache.sling.distribution.packaging.DistributionPackage;
import org.apache.sling.distribution.serialization.DistributionContentSerializer;
import org.apache.sling.distribution.serialization.DistributionExportFilter;
import org.apache.sling.distribution.serialization.DistributionExportOptions;
import org.apache.sling.distribution.serialization.impl.vlt.VltUtils;
import org.apache.sling.distribution.util.impl.FileBackedMemoryOutputStream;
import org.apache.sling.distribution.util.impl.FileBackedMemoryOutputStream.MemoryUnit;
import org.jetbrains.annotations.NotNull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class ResourceDistributionPackageBuilder extends AbstractDistributionPackageBuilder {
    private static final String PREFIX_PATH = "/var/sling/distribution/packages/";

    private final Logger log = LoggerFactory.getLogger(getClass());
    private final String packagesPath;
    private final File tempDirectory;
    private final DistributionContentSerializer distributionContentSerializer;
    private final int fileThreshold;
    private final MemoryUnit memoryUnit;
    private final boolean useOffHeapMemory;
    private final String digestAlgorithm;
    private final NavigableMap<String, List<String>> nodeFilters;
    private final NavigableMap<String, List<String>> propertyFilters;

    public ResourceDistributionPackageBuilder(String type,
                                              DistributionContentSerializer distributionContentSerializer,
                                              String tempFilesFolder,
                                              int fileThreshold,
                                              MemoryUnit memoryUnit,
                                              boolean useOffHeapMemory,
                                              String digestAlgorithm, String[] nodeFilters,
                                              String[] propertyFilters) {
        super(type);
        this.distributionContentSerializer = distributionContentSerializer;
        this.nodeFilters = VltUtils.parseFilters(nodeFilters);
        this.propertyFilters = VltUtils.parseFilters(propertyFilters);
        this.packagesPath = PREFIX_PATH + type + "/data";
        this.tempDirectory = VltUtils.getTempFolder(tempFilesFolder);
        this.fileThreshold = fileThreshold;
        this.memoryUnit = memoryUnit;
        this.useOffHeapMemory = useOffHeapMemory;
        this.digestAlgorithm = digestAlgorithm;
    }

    @Override
    protected DistributionPackage createPackageForAdd(@NotNull ResourceResolver resourceResolver, @NotNull DistributionRequest request) throws DistributionException {
        DistributionPackage distributionPackage;

        try {
            FileBackedMemoryOutputStream outputStream = null;
            DigestOutputStream digestStream = null;
            String digestMessage = null;

            try {
                outputStream = new FileBackedMemoryOutputStream(fileThreshold, memoryUnit, useOffHeapMemory, tempDirectory, "distrpck-create-", "." + getType());
                if (digestAlgorithm != null) {
                    digestStream = openDigestOutputStream(outputStream, digestAlgorithm);
                    export(resourceResolver, request, digestStream);
                } else {
                    export(resourceResolver, request, outputStream);
                }
                outputStream.flush();

                if (digestAlgorithm != null) {
                    digestMessage = readDigestMessage(digestStream);
                }
            } finally {
                IOUtils.closeQuietly(outputStream);
                IOUtils.closeQuietly(digestStream);
            }

            Resource packagesRoot = DistributionPackageUtils.getPackagesRoot(resourceResolver, packagesPath);

            InputStream inputStream = null;
            Resource packageResource = null;

            try {
                inputStream = outputStream.openWrittenDataInputStream();

                packageResource = uploadStream(resourceResolver, packagesRoot, inputStream, outputStream.size());
            } finally {
                IOUtils.closeQuietly(inputStream);
                outputStream.clean();
            }

            distributionPackage = new ResourceDistributionPackage(packageResource, getType(), resourceResolver, digestAlgorithm, digestMessage);
        } catch (IOException e) {
            throw new DistributionException(e);
        }

        return distributionPackage;
    }

    private void export(@NotNull ResourceResolver resourceResolver, @NotNull final DistributionRequest request, OutputStream outputStream) throws DistributionException {
        final DistributionExportFilter filter = distributionContentSerializer.isRequestFiltering() ? null : DistributionExportFilter.createFilter(request, nodeFilters, propertyFilters);
        DistributionExportOptions distributionExportOptions = new DistributionExportOptions(request, filter);
        distributionContentSerializer.exportToStream(resourceResolver, distributionExportOptions, outputStream);
    }

    @Override
    protected DistributionPackage readPackageInternal(@NotNull ResourceResolver resourceResolver, @NotNull InputStream inputStream)
            throws DistributionException {
        try {
            Resource packagesRoot = DistributionPackageUtils.getPackagesRoot(resourceResolver, packagesPath);

            Resource packageResource = uploadStream(resourceResolver, packagesRoot, inputStream, -1);
            return new ResourceDistributionPackage(packageResource, getType(), resourceResolver, null, null);
        } catch (PersistenceException e) {
            throw new DistributionException(e);
        }
    }

    @Override
    protected boolean installPackageInternal(@NotNull ResourceResolver resourceResolver, @NotNull InputStream inputStream)
            throws DistributionException {
        try {
            distributionContentSerializer.importFromStream(resourceResolver, inputStream);
            return true;
        } finally {
            IOUtils.closeQuietly(inputStream);
        }
    }

    @Override
    protected DistributionPackage getPackageInternal(@NotNull ResourceResolver resourceResolver, @NotNull String id) {
        try {
            Resource packagesRoot = DistributionPackageUtils.getPackagesRoot(resourceResolver, packagesPath);
            Resource packageResource = packagesRoot.getChild(id);
            if (packageResource == null) {
                return null;
            } else {
                return new ResourceDistributionPackage(packageResource, getType(), resourceResolver, null, null);
            }
        } catch (PersistenceException e) {
            return null;
        }
    }


    private Resource uploadStream(ResourceResolver resourceResolver, Resource parent, InputStream stream, long size) throws PersistenceException {

        String name;
        log.debug("uploading stream");
        if (size == -1) {
            // stable id
            Map<String, Object> info = new HashMap<String, Object>();
            DistributionPackageUtils.readInfo(stream, info);
            log.debug("read header {}", info);
            Object remoteId = info.get(DistributionPackageUtils.PROPERTY_REMOTE_PACKAGE_ID);
            if (remoteId != null) {
                name = remoteId.toString();
                if (name.contains("/")) {
                    name = name.substring(name.lastIndexOf('/') + 1);
                }
                log.debug("preserving remote id {}", name);
            } else {
                name = "dstrpck-" + System.currentTimeMillis() + "-" + UUID.randomUUID().toString();
                log.debug("generating a new id {}", name);
            }
        } else {
            name = "dstrpck-" + System.currentTimeMillis() + "-" + UUID.randomUUID().toString();
        }

        Map<String, Object> props = new HashMap<String, Object>();
        props.put(ResourceResolver.PROPERTY_RESOURCE_TYPE, "sling:Folder");
        props.put("type", getType());

        if (size != -1) {
            props.put("size", size);
        }

        Resource r = resourceResolver.getResource(parent, name);
        if (r != null) {
            resourceResolver.delete(r);
        } else {
            // check parent is there at least
            Resource parentResource = ResourceUtil.getOrCreateResource(resourceResolver, parent.getPath(), "nt:unstructured",
                    "nt:unstructured", true);
            log.debug("created parent {}", parentResource.getPath());
        }

        Resource resource = resourceResolver.create(parent, name, props);
        try {
            DistributionPackageUtils.uploadStream(resource, stream);
        } catch (RepositoryException e) {
            throw new PersistenceException("cannot upload stream", e);
        }

        resourceResolver.commit();

        return resource;
    }

    @NotNull
    public Iterator<ResourceDistributionPackage> getPackages(@NotNull ResourceResolver resourceResolver)
            throws DistributionException {
        try {
            Resource packagesRoot = DistributionPackageUtils.getPackagesRoot(resourceResolver, packagesPath);
            return new ResourceDistributionPackageIterator(packagesRoot, resourceResolver, getType());
        } catch (PersistenceException e) {
            throw new DistributionException("Failed to get the package list", e);
        }
    }

    private static final class ResourceDistributionPackageIterator implements Iterator<ResourceDistributionPackage> {

        final Iterator<Resource> packages;

        final ResourceResolver resourceResolver;

        final String type;

        private ResourceDistributionPackageIterator(@NotNull Resource packagesRoot, @NotNull ResourceResolver resourceResolver,
                                            @NotNull String type) {
            this.packages = packagesRoot.listChildren();
            this.resourceResolver = resourceResolver;
            this.type = type;
        }

        @Override
        public boolean hasNext() {
            return packages.hasNext();
        }

        @Override
        public ResourceDistributionPackage next() {
            Resource packageResource = packages.next();
            return new ResourceDistributionPackage(packageResource, type, resourceResolver, null, null);
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("remove");
        }
    }
}