/*
 * 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.tuscany.maven.bundle.plugin;

import static org.osgi.framework.Constants.BUNDLE_CLASSPATH;
import static org.osgi.framework.Constants.BUNDLE_MANIFESTVERSION;
import static org.osgi.framework.Constants.BUNDLE_NAME;
import static org.osgi.framework.Constants.BUNDLE_SYMBOLICNAME;
import static org.osgi.framework.Constants.BUNDLE_VERSION;
import static org.osgi.framework.Constants.DYNAMICIMPORT_PACKAGE;
import static org.osgi.framework.Constants.EXPORT_PACKAGE;
import static org.osgi.framework.Constants.IMPORT_PACKAGE;

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.logging.Logger;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.maven.artifact.versioning.ArtifactVersion;
import org.osgi.framework.Version;

/**
 * Common functions used by the plugin.
 *
 * @version $Rev$ $Date$
 */
final class BundleUtil {
    private final static Logger logger = Logger.getLogger(BundleUtil.class.getName());
    /**
     * Returns the name of a bundle, or null if the given file is not a bundle.
     *  
     * @param file
     * @return
     * @throws IOException
     */
    static String getBundleSymbolicName(File file) throws IOException {
        if (!file.exists()) {
            return null;
        }
        String bundleName = null;
        if (file.isDirectory()) {
            File mf = new File(file, "META-INF/MANIFEST.MF");
            if (mf.isFile()) {
                Manifest manifest = new Manifest(new FileInputStream(mf));
                bundleName = manifest.getMainAttributes().getValue(BUNDLE_SYMBOLICNAME);
            }
        } else {
            JarFile jar = new JarFile(file, false);
            Manifest manifest = jar.getManifest();
            if (manifest != null){
            	bundleName = manifest.getMainAttributes().getValue(BUNDLE_SYMBOLICNAME);
            }
            jar.close();
        }
        if (bundleName == null) {
            return bundleName;
        }
        int sc = bundleName.indexOf(';');
        if (sc != -1) {
            bundleName = bundleName.substring(0, sc);
        }
        return bundleName;
    }

    /**
     * Generate a Bundle manifest for a set of JAR files.
     * 
     * @param jarFiles
     * @param name
     * @param symbolicName
     * @param version
     * @param dir 
     * @return
     * @throws IllegalStateException
     */
    static Manifest libraryManifest(Set<File> jarFiles, String name, String symbolicName, String version, String dir)
    throws IllegalStateException {
    	return libraryManifest(jarFiles, name, symbolicName, version, dir, null);
    }
    /**
     * Generate a Bundle manifest for a set of JAR files.
     * 
     * @param jarFiles
     * @param name
     * @param symbolicName
     * @param version
     * @param dir 
     * @param buddyPolicy 
     * @return
     * @throws IllegalStateException
     */
    static Manifest libraryManifest(Set<File> jarFiles, String name, String symbolicName, String version, String dir, String buddyPolicy)
        throws IllegalStateException {
        try {

            // List exported packages and bundle classpath entries
            StringBuffer classpath = new StringBuffer();
            Set<String> exportedPackages = new HashSet<String>();
            for (File jarFile : jarFiles) {
                addPackages(jarFile, exportedPackages, version);
                if (dir != null) {
                    classpath.append(dir).append("/");
                } 
                classpath.append(jarFile.getName());
                classpath.append(",");
            }

            // Generate export-package and import-package declarations
            StringBuffer exports = new StringBuffer();
            StringBuffer imports = new StringBuffer();
            Set<String> pkgs = new HashSet<String>();
            for (String export : exportedPackages) {
                String packageName = packageName(export);
                if (!pkgs.contains(packageName)) {
                    // Add corresponding import declaration
//                    imports.append(export);
//                    imports.append(',');
                    pkgs.add(packageName);
                    exports.append(export);
                    exports.append(',');
                } else {
                    logger.warning("Duplicate package skipped: " + export);
                }
            }
 
            // Create a manifest
            Manifest manifest = new Manifest();
            Attributes attributes = manifest.getMainAttributes();
            attributes.putValue("Manifest-Version", "1.0");
            attributes.putValue(BUNDLE_MANIFESTVERSION, "2");
            attributes.putValue(BUNDLE_SYMBOLICNAME, symbolicName);
            attributes.putValue(BUNDLE_NAME, name);
            attributes.putValue(BUNDLE_VERSION, version);
            attributes.putValue(DYNAMICIMPORT_PACKAGE, "*");
            if (buddyPolicy != null && buddyPolicy.length() > 0){
            	attributes.putValue("Eclipse-BuddyPolicy", buddyPolicy);
            }
            if (exports.length() > 1) {
                attributes.putValue(EXPORT_PACKAGE, exports.substring(0, exports.length() - 1));
            }
            if (imports.length() > 1) {
                attributes.putValue(IMPORT_PACKAGE, imports.substring(0, imports.length() - 1));
            }
            if (classpath.length() > 1) {
                attributes.putValue(BUNDLE_CLASSPATH, classpath.substring(0, classpath.length() - 1));
            }

            return manifest;
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Write a bundle manifest.
     * 
     * @param manifest
     * @param out
     * @throws IOException
     */
    static void write(Manifest manifest, OutputStream out) throws IOException {
        DataOutputStream dos = new DataOutputStream(out);
        Attributes attributes = manifest.getMainAttributes();
        write(attributes, "Manifest-Version", dos);
        write(attributes, BUNDLE_MANIFESTVERSION, dos);
        write(attributes, BUNDLE_SYMBOLICNAME, dos);
        write(attributes, BUNDLE_NAME, dos);
        write(attributes, BUNDLE_VERSION, dos);
        write(attributes, DYNAMICIMPORT_PACKAGE, dos);
        write(attributes, BUNDLE_CLASSPATH, dos);
        write(attributes, IMPORT_PACKAGE, dos);
        write(attributes, EXPORT_PACKAGE, dos);
        write(attributes, "Eclipse-BuddyPolicy", dos);
        dos.flush();
    }

    /**
     * Add packages to be exported out of a JAR file.
     * 
     * @param jarFile
     * @param packages
     * @throws IOException
     */
    private static void addPackages(File jarFile, Set<String> packages, String version) throws IOException {
        if (getBundleSymbolicName(jarFile) == null) {
            String ver = ";version=" + version;
            addAllPackages(jarFile, packages, ver);
        } else {
            addExportedPackages(jarFile, packages);
        }
    }

    /**
     * Write manifest attributes.
     * 
     * @param attributes
     * @param key
     * @param dos
     * @throws IOException
     */
    private static void write(Attributes attributes, String key, DataOutputStream dos) throws IOException {
        String value = attributes.getValue(key);
        if (value == null) {
            return;
        }
        StringBuffer line = new StringBuffer();
        line.append(key);
        line.append(": ");
        line.append(new String(value.getBytes("UTF8")));
        line.append("\r\n");
        int l = line.length();
        if (l > 72) {
            for (int i = 70; i < l - 2;) {
                line.insert(i, "\r\n ");
                i += 72;
                l += 3;
            }
        }
        dos.writeBytes(line.toString());
    }

    /**
     * Strip an OSGi export, only retain the package name and version.
     * 
     * @param export
     * @return
     */
    private static String stripExport(String export) {
        int sc = export.indexOf(';');
        if (sc == -1) {
            return export;
        }
        String base = export.substring(0, sc);
        int v = export.indexOf("version=");
        if (v != -1) {
            sc = export.indexOf(';', v + 1);
            if (sc != -1) {
                return base + ";" + export.substring(v, sc);
            } else {
                return base + ";" + export.substring(v);
            }
        } else {
            return base;
        }
    }

    /**
     * Add all the packages out of a JAR.
     * 
     * @param jarFile
     * @param packages
     * @param version
     * @throws IOException
     */
    private static void addAllPackages(File jarFile, Set<String> packages, String version) throws IOException {
        ZipInputStream is = new ZipInputStream(new FileInputStream(jarFile));
        ZipEntry entry;
        while ((entry = is.getNextEntry()) != null) {
            String entryName = entry.getName();
            if (!entry.isDirectory() && entryName != null
                && entryName.length() > 0
                && !entryName.startsWith(".")
                && entryName.endsWith(".class") // Exclude resources from Export-Package
                && entryName.lastIndexOf("/") > 0
                && Character.isJavaIdentifierStart(entryName.charAt(0))) {
                String pkg = entryName.substring(0, entryName.lastIndexOf("/")).replace('/', '.');
                if (!pkg.endsWith(".enum")) {
                    packages.add(pkg + version);
                }
            }
        }
        is.close();
    }

    /**
     * Returns the name of the exported package in the given export.
     * @param export
     * @return
     */
    private static String packageName(String export) {
        int sc = export.indexOf(';');
        if (sc != -1) {
            export = export.substring(0, sc);
        }
        return export;
    }

    /**
     * Add the packages exported by a bundle.
     *  
     * @param file
     * @param packages
     * @return
     * @throws IOException
     */
    private static void addExportedPackages(File file, Set<String> packages) throws IOException {
        if (!file.exists()) {
            return;
        }

        // Read the export-package declaration and get a list of the packages available in a JAR
        Set<String> existingPackages = null;
        String exports = null;
        if (file.isDirectory()) {
            File mf = new File(file, "META-INF/MANIFEST.MF");
            if (mf.isFile()) {
                Manifest manifest = new Manifest(new FileInputStream(mf));
                exports = manifest.getMainAttributes().getValue(EXPORT_PACKAGE);
            }
        } else {
            JarFile jar = new JarFile(file, false);
            Manifest manifest = jar.getManifest();
            exports = manifest.getMainAttributes().getValue(EXPORT_PACKAGE);
            jar.close();
            existingPackages = new HashSet<String>();
            addAllPackages(file, existingPackages, "");
        }
        if (exports == null) {
            return;
        }

        // Parse the export-package declaration, and extract the individual packages
        StringBuffer buffer = new StringBuffer();
        boolean q = false;
        for (int i = 0, n = exports.length(); i < n; i++) {
            char c = exports.charAt(i);
            if (c == '\"') {
                q = !q;
            }
            if (!q) {
                if (c == ',') {

                    // Add the exported package to the set, after making sure it really exists in
                    // the JAR
                    String export = buffer.toString();
                    if (existingPackages == null || existingPackages.contains(packageName(export))) {
                        packages.add(stripExport(export));
                    }
                    buffer = new StringBuffer();
                    continue;
                }
            }
            buffer.append(c);
        }
        if (buffer.length() != 0) {

            // Add the exported package to the set, after making sure it really exists in
            // the JAR
            String export = buffer.toString();
            if (existingPackages == null || existingPackages.contains(packageName(export))) {
                packages.add(stripExport(export));
            }
        }
    }

    /**
     * Convert the maven version into OSGi version 
     * @param mavenVersion
     * @return
     */
    static String osgiVersion(String mavenVersion) {
        ArtifactVersion ver = new OSGIArtifactVersion(mavenVersion);
        String qualifer = ver.getQualifier();
        if (qualifer != null) {
            StringBuffer buf = new StringBuffer(qualifer);
            for (int i = 0; i < buf.length(); i++) {
                char c = buf.charAt(i);
                if (Character.isLetterOrDigit(c) || c == '-' || c == '_') {
                    // Keep as-is
                } else {
                    buf.setCharAt(i, '_');
                }
            }
            qualifer = buf.toString();
        }
        Version osgiVersion =
            new Version(ver.getMajorVersion(), ver.getMinorVersion(), ver.getIncrementalVersion(), qualifer);
        String version = osgiVersion.toString();
        return version;
    }

}