/**
 * Copyright 2015 DuraSpace, Inc.
 *
 * Licensed 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.fcrepo.kernel.impl.services;

import static javax.jcr.query.Query.JCR_SQL2;
import static org.fcrepo.kernel.FedoraJcrTypes.CONTENT_SIZE;
import static org.fcrepo.kernel.FedoraJcrTypes.FEDORA_BINARY;
import static org.fcrepo.kernel.FedoraJcrTypes.FEDORA_CONTAINER;
import static org.modeshape.jcr.api.JcrConstants.JCR_CONTENT;
import static org.modeshape.jcr.api.JcrConstants.JCR_DATA;
import static org.modeshape.jcr.api.JcrConstants.JCR_PATH;
import static org.modeshape.jcr.api.JcrConstants.NT_FILE;

import javax.jcr.Node;
import javax.jcr.NodeIterator;
import javax.jcr.Property;
import javax.jcr.PropertyIterator;
import javax.jcr.Repository;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.Value;
import javax.jcr.query.QueryManager;
import javax.jcr.query.QueryResult;
import javax.jcr.query.RowIterator;

import org.fcrepo.kernel.exception.RepositoryRuntimeException;
import org.springframework.stereotype.Component;

/**
 * Uncategorized helper methods
 *
 * @author awoods
 */
@Component
public abstract class ServiceHelpers {

    /**
     * Get the total size of a Node's properties
     * 
     * @param node
     * @return size in bytes
     * @throws RepositoryException
     */
    public static Long getNodePropertySize(final Node node)
        throws RepositoryException {
        Long size = 0L;
        for (final PropertyIterator i = node.getProperties(); i.hasNext();) {
            final Property p = i.nextProperty();
            if (p.isMultiple()) {
                for (final Value v : p.getValues()) {
                    size += v.getBinary().getSize();
                }
            } else {
                size += p.getBinary().getSize();
            }
        }
        return size;
    }

    /**
     * @param obj
     * @return object size in bytes
     * @throws RepositoryException
     */
    public static Long getObjectSize(final Node obj) throws RepositoryException {
        return getNodePropertySize(obj) + getObjectDSSize(obj);
    }

    /**
     * @param obj
     * @return object's datastreams' total size in bytes
     * @throws RepositoryException
     */
    private static Long getObjectDSSize(final Node obj)
        throws RepositoryException {
        Long size = 0L;
        for (final NodeIterator i = obj.getNodes(); i.hasNext();) {
            final Node node = i.nextNode();
            if (node.isNodeType(NT_FILE)) {
                size += getDatastreamSize(node);
            }
        }
        return size;
    }

    /**
     * Get the size of a datastream by calculating the size of the properties
     * and the binary properties
     * 
     * @param ds
     * @return size of the datastream's properties and binary properties
     * @throws RepositoryException
     */
    public static Long getDatastreamSize(final Node ds)
        throws RepositoryException {
        return getNodePropertySize(ds) + getContentSize(ds);
    }

    /**
     * Get the size of the JCR content binary property
     * 
     * @param ds
     * @return size of the binary content property
     * @throws RepositoryException
     */
    public static Long getContentSize(final Node ds) {
        try {
            long size = 0L;
            if (ds.hasNode(JCR_CONTENT)) {
                final Node contentNode = ds.getNode(JCR_CONTENT);

                if (contentNode.hasProperty(JCR_DATA)) {
                    size =
                            ds.getNode(JCR_CONTENT).getProperty(JCR_DATA)
                                    .getBinary().getSize();
                }
            }

            return size;

        } catch (final RepositoryException e) {
            throw new RepositoryRuntimeException(e);
        }
    }

    /**
     * @return a double of the size of the fedora:datastream binary content
     * @throws RepositoryException
     */
    public static long getRepositoryCount(final Repository repository)
        throws RepositoryException {
        final Session session = repository.login();
        try {
            final QueryManager queryManager =
                session.getWorkspace().getQueryManager();

            final String querystring =
                "SELECT [" + JCR_PATH + "] FROM ["
                        + FEDORA_CONTAINER + "]";

            final QueryResult queryResults =
                queryManager.createQuery(querystring, JCR_SQL2).execute();

            return queryResults.getRows().getSize();
        } finally {
            session.logout();
        }
    }

    /**
     * @return a double of the size of the fedora:datastream binary content
     * @throws RepositoryException
     */
    public static long getRepositorySize(final Repository repository)
        throws RepositoryException {
        final Session session = repository.login();
        try {
            long sum = 0;
            final QueryManager queryManager =
                    session.getWorkspace().getQueryManager();

            final String querystring =
                    "SELECT [" + CONTENT_SIZE + "] FROM [" +
                            FEDORA_BINARY + "]";

            final QueryResult queryResults =
                    queryManager.createQuery(querystring, JCR_SQL2).execute();

            for (final RowIterator rows = queryResults.getRows(); rows.hasNext(); ) {
                final Value value =
                        rows.nextRow().getValue(CONTENT_SIZE);
                sum += value.getLong();
            }
            return sum;
        } finally {
            session.logout();
        }
    }
}