/*
 * Copyright (C) 2007-2012 Argeo GmbH
 *
 * 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.argeo.jackrabbit;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.jcr.Credentials;
import javax.jcr.LoginException;
import javax.jcr.NoSuchWorkspaceException;
import javax.jcr.Node;
import javax.jcr.NodeIterator;
import javax.jcr.Repository;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.nodetype.NodeType;

import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.jackrabbit.api.JackrabbitRepository;
import org.apache.jackrabbit.commons.NamespaceHelper;
import org.apache.jackrabbit.commons.cnd.CndImporter;
import org.argeo.jcr.ArgeoJcrConstants;
import org.argeo.jcr.ArgeoJcrException;
import org.argeo.jcr.ArgeoNames;
import org.argeo.jcr.ArgeoTypes;
import org.argeo.jcr.JcrRepositoryWrapper;
import org.argeo.jcr.JcrUtils;
import org.argeo.util.security.DigestUtils;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.packageadmin.ExportedPackage;
import org.osgi.service.packageadmin.PackageAdmin;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;

/**
 * Wrapper around a Jackrabbit repository which allows to simplify configuration
 * and intercept some actions. It exposes itself as a {@link Repository}.
 */
@Deprecated
public class JackrabbitWrapper extends JcrRepositoryWrapper implements
		JackrabbitRepository, ResourceLoaderAware {
	private final static Log log = LogFactory.getLog(JackrabbitWrapper.class);
	private final static String DIGEST_ALGORITHM = "MD5";

	// local
	private ResourceLoader resourceLoader;

	// data model
	/** Node type definitions in CND format */
	private List<String> cndFiles = new ArrayList<String>();
	/**
	 * Always import CNDs. Useful during development of new data models. In
	 * production, explicit migration processes should be used.
	 */
	private Boolean forceCndImport = true;

	/** Namespaces to register: key is prefix, value namespace */
	private Map<String, String> namespaces = new HashMap<String, String>();

	private BundleContext bundleContext;

	/**
	 * Explicitly set admin credentials used in initialization. Useful for
	 * testing, in real applications authentication is rather dealt with
	 * externally
	 */
	private Credentials adminCredentials = null;

	/**
	 * Empty constructor, {@link #init()} should be called after properties have
	 * been set
	 */
	public JackrabbitWrapper() {
	}

	@Override
	public void init() {
		prepareDataModel();
	}

	/*
	 * DATA MODEL
	 */

	/**
	 * Import declared node type definitions and register namespaces. Tries to
	 * update the node definitions if they have changed. In case of failures an
	 * error will be logged but no exception will be thrown.
	 */
	protected void prepareDataModel() {
		if ((cndFiles == null || cndFiles.size() == 0)
				&& (namespaces == null || namespaces.size() == 0))
			return;

		Session session = null;
		try {
			session = login(adminCredentials);
			// register namespaces
			if (namespaces.size() > 0) {
				NamespaceHelper namespaceHelper = new NamespaceHelper(session);
				namespaceHelper.registerNamespaces(namespaces);
			}

			// load CND files from classpath or as URL
			for (String resUrl : cndFiles) {
				processCndFile(session, resUrl);
			}
		} catch (Exception e) {
			JcrUtils.discardQuietly(session);
			throw new ArgeoJcrException("Cannot import node type definitions "
					+ cndFiles, e);
		} finally {
			JcrUtils.logoutQuietly(session);
		}

	}

	protected void processCndFile(Session session, String resUrl) {
		Reader reader = null;
		try {
			// check existing data model nodes
			new NamespaceHelper(session).registerNamespace(ArgeoNames.ARGEO,
					ArgeoNames.ARGEO_NAMESPACE);
			if (!session.itemExists(ArgeoJcrConstants.DATA_MODELS_BASE_PATH))
				JcrUtils.mkdirs(session,
						ArgeoJcrConstants.DATA_MODELS_BASE_PATH);
			Node dataModels = session
					.getNode(ArgeoJcrConstants.DATA_MODELS_BASE_PATH);
			NodeIterator it = dataModels.getNodes();
			Node dataModel = null;
			while (it.hasNext()) {
				Node node = it.nextNode();
				if (node.getProperty(ArgeoNames.ARGEO_URI).getString()
						.equals(resUrl)) {
					dataModel = node;
					break;
				}
			}

			byte[] cndContent = readCndContent(resUrl);
			String newDigest = DigestUtils.digest(DIGEST_ALGORITHM, cndContent);
			Bundle bundle = findDataModelBundle(resUrl);

			String currentVersion = null;
			if (dataModel != null) {
				currentVersion = dataModel.getProperty(
						ArgeoNames.ARGEO_DATA_MODEL_VERSION).getString();
				if (dataModel.hasNode(Node.JCR_CONTENT)) {
					String oldDigest = JcrUtils.checksumFile(dataModel,
							DIGEST_ALGORITHM);
					if (oldDigest.equals(newDigest)) {
						if (log.isTraceEnabled())
							log.trace("Data model " + resUrl
									+ " hasn't changed, keeping version "
									+ currentVersion);
						return;
					}
				}
			}

			if (dataModel != null && !forceCndImport) {
				log.info("Data model "
						+ resUrl
						+ " has changed since version "
						+ currentVersion
						+ (bundle != null ? ": version " + bundle.getVersion()
								+ ", bundle " + bundle.getSymbolicName() : ""));
				return;
			}

			reader = new InputStreamReader(new ByteArrayInputStream(cndContent));
			// actually imports the CND
			try {
				CndImporter.registerNodeTypes(reader, session, true);
			} catch (Exception e) {
				log.error("Cannot import data model " + resUrl, e);
				return;
			}

			if (dataModel != null && !dataModel.isNodeType(NodeType.NT_FILE)) {
				dataModel.remove();
				dataModel = null;
			}

			// FIXME: what if argeo.cnd would not be the first called on
			// a new repo? argeo:dataModel would not be found
			String fileName = FilenameUtils.getName(resUrl);
			if (dataModel == null) {
				dataModel = dataModels.addNode(fileName, NodeType.NT_FILE);
				dataModel.addNode(Node.JCR_CONTENT, NodeType.NT_RESOURCE);
				dataModel.addMixin(ArgeoTypes.ARGEO_DATA_MODEL);
				dataModel.setProperty(ArgeoNames.ARGEO_URI, resUrl);
			} else {
				session.getWorkspace().getVersionManager()
						.checkout(dataModel.getPath());
			}
			if (bundle != null)
				dataModel.setProperty(ArgeoNames.ARGEO_DATA_MODEL_VERSION,
						bundle.getVersion().toString());
			else
				dataModel.setProperty(ArgeoNames.ARGEO_DATA_MODEL_VERSION,
						"0.0.0");
			JcrUtils.copyBytesAsFile(dataModel.getParent(), fileName,
					cndContent);
			JcrUtils.updateLastModified(dataModel);
			session.save();
			session.getWorkspace().getVersionManager()
					.checkin(dataModel.getPath());

			if (currentVersion == null)
				log.info("Data model "
						+ resUrl
						+ (bundle != null ? ", version " + bundle.getVersion()
								+ ", bundle " + bundle.getSymbolicName() : ""));
			else
				log.info("Data model "
						+ resUrl
						+ " updated from version "
						+ currentVersion
						+ (bundle != null ? ", version " + bundle.getVersion()
								+ ", bundle " + bundle.getSymbolicName() : ""));
		} catch (Exception e) {
			throw new ArgeoJcrException("Cannot process data model " + resUrl, e);
		} finally {
			IOUtils.closeQuietly(reader);
		}
	}

	protected byte[] readCndContent(String resUrl) {
		InputStream in = null;
		try {
			boolean classpath;
			// normalize URL
			if (bundleContext != null && resUrl.startsWith("classpath:")) {
				resUrl = resUrl.substring("classpath:".length());
				classpath = true;
			} else if (resUrl.indexOf(':') < 0) {
				if (!resUrl.startsWith("/")) {
					resUrl = "/" + resUrl;
					log.warn("Classpath should start with '/'");
				}
				classpath = true;
			} else {
				classpath = false;
			}

			URL url = null;
			if (classpath) {
				if (bundleContext != null) {
					Bundle currentBundle = bundleContext.getBundle();
					url = currentBundle.getResource(resUrl);
				} else {
					resUrl = "classpath:" + resUrl;
					url = null;
				}
			} else if (!resUrl.startsWith("classpath:")) {
				url = new URL(resUrl);
			}

			if (url != null) {
				in = url.openStream();
			} else if (resourceLoader != null) {
				Resource res = resourceLoader.getResource(resUrl);
				in = res.getInputStream();
				url = res.getURL();
			} else {
				throw new ArgeoJcrException("No " + resUrl + " in the classpath,"
						+ " make sure the containing" + " package is visible.");
			}

			return IOUtils.toByteArray(in);
		} catch (Exception e) {
			throw new ArgeoJcrException("Cannot read CND from " + resUrl, e);
		} finally {
			IOUtils.closeQuietly(in);
		}
	}

	/*
	 * JACKRABBIT REPOSITORY IMPLEMENTATION
	 */
	@Override
	public Session login(Credentials credentials, String workspaceName,
			Map<String, Object> attributes) throws LoginException,
			NoSuchWorkspaceException, RepositoryException {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void shutdown() {
		// TODO Auto-generated method stub

	}

	/*
	 * UTILITIES
	 */
	/** Find which OSGi bundle provided the data model resource */
	protected Bundle findDataModelBundle(String resUrl) {
		if (bundleContext == null)
			return null;

		if (resUrl.startsWith("/"))
			resUrl = resUrl.substring(1);
		String pkg = resUrl.substring(0, resUrl.lastIndexOf('/')).replace('/',
				'.');
		ServiceReference<PackageAdmin> paSr = bundleContext
				.getServiceReference(PackageAdmin.class);
		PackageAdmin packageAdmin = (PackageAdmin) bundleContext
				.getService(paSr);

		// find exported package
		ExportedPackage exportedPackage = null;
		ExportedPackage[] exportedPackages = packageAdmin
				.getExportedPackages(pkg);
		if (exportedPackages == null)
			throw new ArgeoJcrException("No exported package found for " + pkg);
		for (ExportedPackage ep : exportedPackages) {
			for (Bundle b : ep.getImportingBundles()) {
				if (b.getBundleId() == bundleContext.getBundle().getBundleId()) {
					exportedPackage = ep;
					break;
				}
			}
		}

		Bundle exportingBundle = null;
		if (exportedPackage != null) {
			exportingBundle = exportedPackage.getExportingBundle();
		} else {
			// assume this is in the same bundle
			exportingBundle = bundleContext.getBundle();
			// throw new ArgeoJcrException("No OSGi exporting package found for "
			// + resUrl);
		}
		return exportingBundle;
	}

	/*
	 * FIELDS ACCESS
	 */
	public void setNamespaces(Map<String, String> namespaces) {
		this.namespaces = namespaces;
	}

	public void setCndFiles(List<String> cndFiles) {
		this.cndFiles = cndFiles;
	}

	public void setBundleContext(BundleContext bundleContext) {
		this.bundleContext = bundleContext;
	}

	protected BundleContext getBundleContext() {
		return bundleContext;
	}

	public void setForceCndImport(Boolean forceCndUpdate) {
		this.forceCndImport = forceCndUpdate;
	}

	public void setResourceLoader(ResourceLoader resourceLoader) {
		this.resourceLoader = resourceLoader;
	}

	public void setAdminCredentials(Credentials adminCredentials) {
		this.adminCredentials = adminCredentials;
	}

}