/*
 * 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.karaf.deployer.kar;

import org.apache.felix.fileinstall.ArtifactInstaller;
import org.apache.karaf.features.Feature;
import org.apache.karaf.features.FeaturesService;
import org.apache.karaf.features.Repository;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.Enumeration;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

public class KarArtifactInstaller implements ArtifactInstaller {

    public static final String FEATURES_CLASSIFIER = "features";
	private final Logger logger = LoggerFactory.getLogger(KarArtifactInstaller.class);

	private static final String KAR_SUFFIX = ".kar";
	private static final String ZIP_SUFFIX = ".zip";

    private String base = "./";
	private String localRepoPath = "./target/local-repo";

	private String timestampPath;

	private DocumentBuilderFactory dbf;

	private FeaturesService featuresService;

	public void init() {
		dbf = DocumentBuilderFactory.newInstance();
		dbf.setNamespaceAware(true);

		timestampPath = localRepoPath + File.separator + ".timestamps";
		if (new File(timestampPath).mkdirs()) {
			logger.warn("Unable to create directory for Karaf Archive timestamps. Results may vary...");
		}

        logger.info("Karaf archives will be extracted to {}", localRepoPath);
		logger.info("Timestamps for Karaf archives will be extracted to {}", timestampPath);
	}

	public void destroy() {
		logger.info("Karaf archive installer destroyed.");
	}


	public void install(File file) throws Exception {
		// Check to see if this file has already been extracted. For example, on restart of Karaf,
		// we don't necessarily want to re-extract all the Karaf Archives!
		//
		if (alreadyExtracted(file)) {
			logger.info("Ignoring '{}'; timestamp indicates it's already been deployed.", file);
			return;
		}

        logger.info("Installing KAR file {}", file);

		ZipFile zipFile = new ZipFile(file);

        List<URI> featuresRepositoriesInKar = new ArrayList<URI>();

        Enumeration<ZipEntry> entries = (Enumeration<ZipEntry>) zipFile.entries();
		while (entries.hasMoreElements()) {
			ZipEntry entry = entries.nextElement();

            String repoEntryName = getRepoEntryName(entry);

			if (repoEntryName != null) {
                File extract = extract(zipFile, entry, repoEntryName, localRepoPath);
                if (isFeaturesRepository(extract)) {
                    addToFeaturesRepositories(extract.toURI());
                    featuresRepositoriesInKar.add(extract.toURI());
                }
			}
            if (entry.getName().startsWith("resource")) {
                String resourceEntryName = entry.getName().substring("resource/".length());
                extract(zipFile, entry, resourceEntryName, base);
            }
		}

        installFeatures(featuresRepositoriesInKar);

		zipFile.close();

		updateTimestamp(file);
	}

    private void installFeatures(List<URI> featuresRepositories) {
        for (Repository repository : featuresService.listRepositories()) {
            for (URI karFeatureRepoUri : featuresRepositories) {
                if (repository.getURI().equals(karFeatureRepoUri)) {
                    try {
                        for (Feature feature : repository.getFeatures()) {
                            try {
                                featuresService.installFeature(feature, EnumSet.noneOf(FeaturesService.Option.class));
                            } catch (Exception e) {
                                logger.warn("Unable to install Kar feature {}", feature.getName() + "/" + feature.getVersion(), e);
                            }
                        }
                    } catch (Exception e) {
                        logger.warn("Can't get features for KAR {}", karFeatureRepoUri, e);
                    }
                }
            }
        }
    }

    private File extract(ZipFile zipFile, ZipEntry entry, String repoEntryName, String base) throws IOException {
        File extract;
        if (entry.isDirectory()) {
            extract = new File(base + File.separator + repoEntryName);
            logger.debug("Creating directory '{}'", extract.getName());
            extract.mkdirs();
        } else {
            extract = new File(base + File.separator + repoEntryName);
            extract.getParentFile().mkdirs();

            InputStream in = zipFile.getInputStream(entry);
            FileOutputStream out = new FileOutputStream(extract);

            byte[] buffer = new byte[8192];
            int count = in.read(buffer);
            int totalBytes = 0;
            while (count >= 0) {
                out.write(buffer, 0, count);
                totalBytes += count;
                count = in.read(buffer);
            }

            logger.debug("Extracted {} bytes to {}", totalBytes, extract);

            in.close();
            out.flush();
            out.close();
        }
        return extract;
    }

    private String getRepoEntryName(ZipEntry entry) {
        String entryName = entry.getName();
        if (entryName.startsWith("repository")) {
            return entryName.substring("repository/".length());
        }
        if (entryName.startsWith("META-INF") || entryName.startsWith("resources")) {
            return null;

        }
        return entryName;
    }

    public void uninstall(File file) throws Exception {
        File timestamp = getArchiveTimestampFile(file);
        if (timestamp.exists()) {
            logger.debug("Removing the timestamp file");
            timestamp.delete();
        }
		logger.warn("Karaf archive '{}' has been removed; however, its feature URLs have not been deregistered, and its bundles are still available in '{}'.", file, localRepoPath);
	}

	public void update(File file) throws Exception {
		logger.warn("Karaf archive '{}' has been updated; redeploying.", file);
		install(file);
	}

	protected void updateTimestamp(File karafArchive) throws Exception {
		File timestamp = getArchiveTimestampFile(karafArchive);

		if (timestamp.exists()) {
            logger.debug("Deleting old timestamp file '{}'", timestamp);

			if (!timestamp.delete()) {
				throw new Exception("Unable to delete archive timestamp '" + timestamp + "'");
			}
		}

		logger.debug("Creating timestamp file '{}'", timestamp);
		timestamp.createNewFile();
	}

	protected boolean alreadyExtracted(File karafArchive) {
		File timestamp = getArchiveTimestampFile(karafArchive);
		if (timestamp.exists()) {
			return timestamp.lastModified() >= karafArchive.lastModified();
		}
		return false;
	}

	protected File getArchiveTimestampFile(File karafArchive) {
        File timestampDir = new File(new File(localRepoPath), ".timestamps");
        if (!timestampDir.exists()) {
            timestampDir.mkdirs();
        }
		return new File(timestampDir, karafArchive.getName());
	}

	protected boolean isFeaturesRepository(File artifact)  {
        try {
			if (artifact.isFile() && artifact.getName().endsWith(".xml")) {
			    Document doc = parse(artifact);
			    String name = doc.getDocumentElement().getLocalName();
			    String uri  = doc.getDocumentElement().getNamespaceURI();
			    if ("features".equals(name) && (uri == null || "".equals(uri) || uri.startsWith("http://karaf.apache.org/xmlns/features/v"))) {
			        return true;
			    }
			}
		} catch (Exception e) {
            logger.debug("File '{}' is not a features file.", artifact.getName(), e);
		}
		return false;
	}

    protected Document parse(File artifact) throws Exception {
        DocumentBuilder db = dbf.newDocumentBuilder();
        db.setErrorHandler(new ErrorHandler() {
            public void warning(SAXParseException exception) throws SAXException {
            }
            public void error(SAXParseException exception) throws SAXException {
            }
            public void fatalError(SAXParseException exception) throws SAXException {
                throw exception;
            }
        });
        return db.parse(artifact);
    }

	private void addToFeaturesRepositories(URI uri)  {
        // URI mvnUri = pathToMvnUri(path);
		try {
            featuresService.removeRepository(uri);
			featuresService.addRepository(uri);
            logger.info("Added feature repository '{}'.", uri);
		} catch (Exception e) {
			logger.warn("Unable to add repository '{}'", uri, e);
		}
	}

    static URI pathToMvnUri(String path) {
        String[] bits = path.split("/");
        String classifier = FEATURES_CLASSIFIER;
        String artifactType = "xml";
        String version = bits[bits.length - 2];
        String artifactId = bits[bits.length - 3];
        StringBuilder buf = new StringBuilder("mvn:");
        for (int i = 0; i < bits.length - 3; i++) {
            buf.append(bits[i]);
            if (i < bits.length - 4) {
                buf.append(".");
            }
        }
        buf.append("/").append(artifactId).append("/").append(version).append("/").append(artifactType).append("/").append(classifier);
        URI mvnUri = URI.create(buf.toString());
        return mvnUri;
    }

    public boolean canHandle(File file) {
		// If the file ends with .kar, then we can handle it!
		//
		if (file.isFile() && file.getName().endsWith(KAR_SUFFIX)) {
			logger.info("Found a .kar file to deploy.");
			return true;
		}
		// Otherwise, check to see if it's a zip file containing a META-INF/KARAF.MF manifest.
		//
		else if (file.isFile() && file.getName().endsWith(ZIP_SUFFIX)) {
			logger.debug("Found a .zip file to deploy; checking contents to see if it's a Karaf archive.");
			try {
				if (new ZipFile(file).getEntry("META-INF/KARAF.MF") != null) {
					logger.info("Found a Karaf archive with .zip prefix; will deploy.");
					return true;
				}
			} catch (Exception e) {
				logger.warn("Problem extracting zip file '{}'; ignoring.", file.getName(), e);
			}
		}

		return false;
	}

	public boolean deleteLocalRepository() {
		return deleteDirectory(new File(localRepoPath));
	}

	private boolean deleteDirectory(File path) {
		if (path.exists()) {
			File[] files = path.listFiles();
			for (int i = 0; i < files.length; i++) {
				if (files[i].isDirectory()) {
					deleteDirectory(files[i]);
				} else {
					files[i].delete();
				}
			}
		}
		return (path.delete());
	}

    public void setBasePath(String base) {
        this.base = base;
    }

    public void setLocalRepoPath(String localRepoPath) {
		this.localRepoPath = localRepoPath;
	}

	public void setFeaturesService(FeaturesService featuresService) {
		this.featuresService = featuresService;
	}

}