package com.atlassian.plugin.osgi.util;
   
   import aQute.lib.osgi.Clazz;
   import aQute.libg.header.OSGiHeader;
   import com.atlassian.plugin.osgi.factory.OsgiPlugin;
   import com.atlassian.plugin.osgi.hostcomponents.HostComponentRegistration;
   import com.atlassian.plugin.util.ClassLoaderUtils;
   import com.atlassian.plugin.util.ClassUtils;
   import com.atlassian.plugin.osgi.util.ClassBinaryScanner.InputStreamResource;
  import com.atlassian.plugin.osgi.util.ClassBinaryScanner.ScanResult;
  import com.google.common.base.Predicate;
  import com.google.common.collect.ImmutableMap;
  import com.google.common.collect.ImmutableSet;
  import com.google.common.collect.Sets;
  import org.osgi.framework.Bundle;
  import org.osgi.framework.Constants;
  import org.osgi.framework.Version;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.jar.Manifest;
  
  /**
   * Utilities to help create OSGi headers
   */
  public class OsgiHeaderUtil
  {
      static Logger log = LoggerFactory.getLogger(OsgiHeaderUtil.class);
      private static final String EMPTY_OSGI_VERSION = Version.emptyVersion.toString();
  
      /**
       * Finds all referred packages for host component registrations by scanning their declared interfaces' bytecode.
       * Packages starting with "java." are ignored.
       *
       * @param registrations A list of host component registrations
       * @return The set of referred packages.
       * @throws IOException If there are any problems scanning bytecode
       * @since 2.7.0
       */
      public static Set<String> findReferredPackageNames(List<HostComponentRegistration> registrations) throws IOException
      {
          return findReferredPackagesInternal(registrations);
      }
  
      /**
       * Finds all referred packages for host component registrations by scanning their declared interfaces' bytecode.
       *
       * @param registrations A list of host component registrations
       * @return The referred package map ( package-> version ).
       * @throws IOException If there are any problems scanning bytecode
       * @since 2.7.0
       */
      public static Map<String, String> findReferredPackageVersions(List<HostComponentRegistration> registrations, Map<String, String> packageVersions) throws IOException
      {
          Set<String> referredPackages = findReferredPackagesInternal(registrations);
          return matchPackageVersions(referredPackages, packageVersions);
      }
  
      /**
       * Finds all referred packages for host component registrations by scanning their declared interfaces' bytecode.
       *
       * @param registrations A list of host component registrations
       * @return The referred packages in a format compatible with an OSGi header
       * @throws IOException If there are any problems scanning bytecode
       * @since 2.4.0
       * @deprecated Since 2.7.0, use {@link #findReferredPackageNames(java.util.List)} instead.
       */
      @Deprecated
      public static String findReferredPackages(List<HostComponentRegistration> registrations) throws IOException
      {
          return findReferredPackages(registrations, Collections.<String, String>emptyMap());
      }
  
      /**
       * Finds all referred packages for host component registrations by scanning their declared interfaces' bytecode.
       *
       * @param registrations A list of host component registrations
       * @return The referred packages in a format compatible with an OSGi header
       * @throws IOException If there are any problems scanning bytecode
       * @deprecated Since 2.7.0, use {@link #findReferredPackageVersions(java.util.List, java.util.Map)} instead.
       */
      @Deprecated
      public static String findReferredPackages(List<HostComponentRegistration> registrations, Map<String, String> packageVersions) throws IOException
      {
          StringBuffer sb = new StringBuffer();
          Set<String> referredPackages = new HashSet<String>();
          Set<String> referredClasses = new HashSet<String>();
          if (registrations == null)
          {
             sb.append(",");
         }
         else
         {
             for (HostComponentRegistration reg : registrations)
             {
                 Set<Class> classesToScan = new HashSet<Class>();
 
                 // Make sure we scan all extended interfaces as well
                 for (Class inf : reg.getMainInterfaceClasses())
                     ClassUtils.findAllTypes(inf, classesToScan);
 
                 for (Class inf : classesToScan)
                 {
                     String clsName = inf.getName().replace('.','/')+".class";
                     crawlReferenceTree(clsName, referredClasses, referredPackages, 1);
                 }
             }
             for (String pkg : referredPackages)
             {
                 String version = packageVersions.get(pkg);
                 sb.append(pkg);
                 if (version != null) {
                     try {
                         Version.parseVersion(version);
                         sb.append(";version=").append(version);
                     } catch (IllegalArgumentException ex) {
                         log.info("Unable to parse version: "+version);
                     }
                 }
                 sb.append(",");
             }
         }
         return sb.toString();
     }
 
     static Map<String, String> matchPackageVersions(Set<String> packageNames, Map<String, String> packageVersions)
     {
         Map<String, String> output = new HashMap<String, String>();
 
         for (String pkg : packageNames)
         {
             String version = packageVersions.get(pkg);
 
             String effectiveKey = pkg;
             String effectiveValue = EMPTY_OSGI_VERSION;
 
             if (version != null)
             {
                 try
                 {
                     Version.parseVersion(version);
                     effectiveValue = version;
                 }
                 catch (IllegalArgumentException ex)
                 {
                     log.info("Unable to parse version: "+version);
                 }
             }
             output.put(effectiveKey, effectiveValue);
         }
 
         return ImmutableMap.copyOf(output);
     }
 
     static Set<String> findReferredPackagesInternal(List<HostComponentRegistration> registrations) throws IOException
     {
         final Set<String> referredPackages = new HashSet<String>();
         final Set<String> referredClasses = new HashSet<String>();
 
         if (registrations != null)
         {
             for (HostComponentRegistration reg : registrations)
             {
                 Set<Class> classesToScan = new HashSet<Class>();
 
                 // Make sure we scan all extended interfaces as well
                 for (Class inf : reg.getMainInterfaceClasses())
                 {
                     ClassUtils.findAllTypes(inf, classesToScan);
                 }
 
                 for (Class inf : classesToScan)
                 {
                     String clsName = inf.getName().replace('.','/')+".class";
                     crawlReferenceTree(clsName, referredClasses, referredPackages, 1);
                 }
             }
         }
 
         return ImmutableSet.copyOf(referredPackages);
     }
 
     /**
      * Helps filter "java." packages.
      */
     private static final Predicate<String> JAVA_PACKAGE_FILTER = new Predicate<String>()
     {
         public boolean apply(String pkg)
         {
             return !pkg.startsWith("java.");
         }
     };
 
     /**
      * Helps filter class entries under "java." packages.
      */
     private static final Predicate<String> JAVA_CLASS_FILTER = new Predicate<String>()
     {
         public boolean apply(String classEntry)
         {
             return !classEntry.startsWith("java/");
         }
     };
 
     /**
      * This will crawl the class interfaces to the desired level.
      *
      * @param className name of the class.
      * @param scannedClasses set of classes that have been scanned.
      * @param packageImports set of imports that have been found.
      * @param level depth of scan (recursion).
      * @throws IOException error loading a class.
      */
     static void crawlReferenceTree(String className, Set<String> scannedClasses, Set<String> packageImports, int level) throws IOException
     {
         if (level <= 0)
         {
             return;
         }
 
         if (className.startsWith("java/"))
             return;
 
         if (scannedClasses.contains(className))
             return;
         else
             scannedClasses.add(className);
 
         if (log.isDebugEnabled())
             log.debug("Crawling "+className);
 
         InputStreamResource classBinaryResource = null;
         try
         {
             // look for the class binary by asking class loader.
             InputStream in = ClassLoaderUtils.getResourceAsStream(className, OsgiHeaderUtil.class);
             if (in == null)
             {
                 log.error("Cannot find class: [" + className + "]");
                 return;
             }
 
             // read the class binary and scan it.
             classBinaryResource = new InputStreamResource(in);
             final ScanResult scanResult = ClassBinaryScanner.scanClassBinary(new Clazz(className, classBinaryResource));
 
             // remember all the imported packages. ignore java packages.
             packageImports.addAll(Sets.filter(scanResult.getReferredPackages(), JAVA_PACKAGE_FILTER));
 
             // crawl
             Set<String> referredClasses = Sets.filter(scanResult.getReferredClasses(), JAVA_CLASS_FILTER);
             for (String ref : referredClasses)
             {
                 crawlReferenceTree(ref + ".class", scannedClasses, packageImports, level-1);
             }
         }
         finally
         {
             if (classBinaryResource != null)
             {
                 classBinaryResource.close();
             }
         }
     }
 
 
     /**
      * Parses an OSGi header line into a map structure
      *
      * @param header The header line
      * @return A map with the key the entry value and the value a map of attributes
      * @since 2.2.0
      */
     public static Map<String,Map<String,String>> parseHeader(String header)
     {
         return OSGiHeader.parseHeader(header);
     }
 
     /**
      * Builds the header string from a map
      * @param values The header values
      * @return A string, suitable for inclusion into an OSGI header string
      * @since 2.6
      */
     public static String buildHeader(Map<String,Map<String,String>> values)
     {
         StringBuilder header = new StringBuilder();
         for (Iterator<Map.Entry<String,Map<String,String>>> i = values.entrySet().iterator(); i.hasNext(); )
         {
             Map.Entry<String,Map<String,String>> entry = i.next();
             buildHeader(entry.getKey(), entry.getValue(), header);
             if (i.hasNext())
             {
                 header.append(",");
             }
         }
         return header.toString();
     }
 
     /**
      * Builds the header string from a map
      * @param key The header value
      * @param attrs The map of attributes
      * @return A string, suitable for inclusion into an OSGI header string
      * @since 2.2.0
      */
     public static String buildHeader(String key, Map<String,String> attrs)
     {
         StringBuilder fullPkg = new StringBuilder();
         buildHeader(key, attrs, fullPkg);
         return fullPkg.toString();
     }
 
     /**
      * Builds the header string from a map
      * @since 2.6
      */
     private static void buildHeader(String key, Map<String,String> attrs, StringBuilder builder)
     {
         builder.append(key);
         if (attrs != null && !attrs.isEmpty())
         {
             for (Map.Entry<String,String> entry : attrs.entrySet())
             {
                 builder.append(";");
                 builder.append(entry.getKey());
                 builder.append("=\"");
                 builder.append(entry.getValue());
                 builder.append("\"");
             }
         }
     }
 
     /**
      * Gets the plugin key from the bundle
      *
      * WARNING: shamelessly copied at {@link com.atlassian.plugin.osgi.bridge.PluginBundleUtils}, which can't use
      * this class due to creating a cyclic build dependency.  Ensure these two implementations are in sync.
      *
      * This method shouldn't be used directly.  Instead consider consuming the {@link com.atlassian.plugin.osgi.bridge.external.PluginRetrievalService}.
      *
      * @param bundle The plugin bundle
      * @return The plugin key, cannot be null
      * @since 2.2.0
      */
     public static String getPluginKey(Bundle bundle)
     {
         return getPluginKey(
                 bundle.getSymbolicName(),
                 bundle.getHeaders().get(OsgiPlugin.ATLASSIAN_PLUGIN_KEY),
                 bundle.getHeaders().get(Constants.BUNDLE_VERSION)
         );
     }
 
     /**
      * Gets the plugin key from the jar manifest
      *
      * @param mf The plugin jar manifest
      * @return The plugin key, cannot be null
      * @since 2.2.0
      */
     public static String getPluginKey(Manifest mf)
     {
         return getPluginKey(
                 mf.getMainAttributes().getValue(Constants.BUNDLE_SYMBOLICNAME),
                 mf.getMainAttributes().getValue(OsgiPlugin.ATLASSIAN_PLUGIN_KEY),
                 mf.getMainAttributes().getValue(Constants.BUNDLE_VERSION)
         );
     }
 
     private static String getPluginKey(Object bundleName, Object atlKey, Object version)
     {
         Object key = atlKey;
         if (key == null)
         {
             key = bundleName + "-" + version;
         }
 
         return key.toString();
     }
 
     /**
      * Generate package version string such as "com.abc;version=1.2,com.atlassian".
      * The output can be used for import or export.
      *
      * @param packages map of packagename->version.
      */
     public static String generatePackageVersionString(Map<String, String> packages)
     {
         if (packages == null || packages.size()==0)
         {
             return "";
         }
 
         final StringBuilder sb = new StringBuilder();
 
         // add deterministism to string generation.
         List<String> packageNames = new ArrayList<String>(packages.keySet());
         Collections.sort(packageNames);
 
         for(String packageName:packageNames)
         {
             sb.append(",");
             sb.append(packageName);
 
             String version = packages.get(packageName);
 
             // we can drop the version component if it's empty for a slight performance gain.
             if (version != null && !version.equals(EMPTY_OSGI_VERSION))
             {
                 sb.append(";version=").append(version);
             }
         }
 
         // delete the initial ",".
         sb.delete(0, 1);
 
         return sb.toString();
     }
 
 }