package com.atlassian.plugin.spring.scanner.core;
   
   import com.atlassian.plugin.spring.scanner.annotation.Profile;
   import javassist.bytecode.ClassFile;
   import org.slf4j.Logger;
   
   import java.io.BufferedInputStream;
   import java.io.DataInputStream;
   import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeMap;
  import java.util.TreeSet;
  
  import static java.util.Collections.emptySet;
  
  /**
   * This little guy can help find the package-info.java of a given class file and cache what profiles are in play and
   * also what profiles are in a given class file.
   */
  class ProfileFinder {
      private static final String PACKAGE_INFO = "package-info";
      private final Set<URL> buildPath;
      private final Logger log;
      private final JavassistHelper javassistHelper;
      private final Map<String, Set<String>> mapOfPackagesToProfiles = new TreeMap<String, Set<String>>();
  
      public ProfileFinder(final Set<URL> buildPath, final Logger log) {
          this.buildPath = buildPath;
          this.log = log;
          this.javassistHelper = new JavassistHelper();
      }
  
      boolean isPackageClass(ClassFile classFile) {
          return classFile.getName().endsWith("." + PACKAGE_INFO);
      }
  
      /**
       * Called to get the Profiles that apply to this class file
       *
       * @param classFile the class file in question
       * @return a set of applicable profiles
       */
      Set<String> getProfiles(ClassFile classFile) {
          String classFileName = classFile.getName();
          if (log.isDebugEnabled()) {
              log.debug(String.format("Checking for profile annotations on %s", classFileName));
          }
  
          if (isPackageClass(classFile)) {
              recordPackageClassProfileAnnotations(classFile);
              return emptySet();
          } else {
              Set<String> packageInfoProfileAnnotations = getPackageInfoProfileAnnotations(classFile);
              Set<String> classSpecificProfiles = findProfiles(classFile);
              //
              // if we have specific @Profile annotations on the class then they override the package level ones
              if (!classSpecificProfiles.isEmpty()) {
                  return classSpecificProfiles;
              }
              return packageInfoProfileAnnotations;
          }
      }
  
      /**
       * Records in the cache just the package info class file profiles
       *
       * @param packageInfoClassFile should only be a package-info.class
       */
      private void recordPackageClassProfileAnnotations(final ClassFile packageInfoClassFile) {
          String packageName = getClassPackageAsFileName(packageInfoClassFile);
          Set<String> profiles = mapOfPackagesToProfiles.get(packageName);
          //
          // it possible that we have seen a package class member BEFORE we have seen the package-info class
          // and hence the other paths will have recorded the package-info profile information already
          //
          if (profiles == null) {
              mapOfPackagesToProfiles.put(packageName, findProfiles(packageInfoClassFile));
          }
      }
  
      private Set<String> getPackageInfoProfileAnnotations(final ClassFile classFile) {
          //
          // we need to look to see if we have seen this package before
          String packageName = getClassPackageAsFileName(classFile);
          Set<String> profiles = mapOfPackagesToProfiles.get(packageName);
          if (profiles != null) {
              return profiles;
          }
          //
          // ok we haven't see the package-info class yet.  So we do a preemptive lookup
  
          ClassFile packageInfoClassFile = loadPackageInfoClass(packageName);
         if (packageInfoClassFile != null) {
             recordPackageClassProfileAnnotations(packageInfoClassFile);
         } else {
             //
             // ok we have no package-info class so record that for posterity
             mapOfPackagesToProfiles.put(packageName, emptySet());
         }
         //
         // now lookup again cause it is now recorded
         return mapOfPackagesToProfiles.get(packageName);
     }
 
     private ClassFile loadPackageInfoClass(final String packageName) {
         for (URL url : buildPath) {
             try {
                 File parentFile = new File(url.toURI());
                 File packageInfoFile = new File(parentFile, packageName + "/" + "package-info.class");
                 if (!packageInfoFile.exists()) {
                     continue;
                 }
 
                 try (InputStream inputStream = new FileInputStream(packageInfoFile)) {
                     DataInputStream dis = new DataInputStream(new BufferedInputStream(inputStream));
                     return new ClassFile(dis);
                 } catch (IOException e) {
                     log.error(String.format("Could not create class file from %s", packageInfoFile), e);
                 }
             } catch (URISyntaxException e) {
                 log.error(String.format("Unable to load package-info file %s from %s", packageName, url));
             }
         }
         return null;
     }
 
     private Set<String> findProfiles(final ClassFile classFile) {
         List<String> classAnnotationNames = javassistHelper.getClassAnnotationNames(classFile);
         Set<String> profiles = new TreeSet<String>();
         for (String annotationType : classAnnotationNames) {
             if (Profile.class.getCanonicalName().equals(annotationType)) {
                 Set<String> profileValues = javassistHelper.getAnnotationMemberSet(classFile, annotationType, "value");
                 profiles.addAll(profileValues);
             }
             //
             // we have support for Spring 3.1 profile in a preemptive attempt that MAYBE one day we might get there :)
             if ("org.springframework.context.annotation.Profile".equals(annotationType)) {
                 Set<String> profileValues = javassistHelper.getAnnotationMemberSet(classFile, annotationType, "value");
                 profiles.addAll(profileValues);
             }
         }
         return profiles;
     }
 
     private String getClassPackageAsFileName(final ClassFile classFile) {
         String fileName = classFile.getName();
         int lastDot = fileName.lastIndexOf('.');
         if (lastDot == -1) {
             return fileName;
         }
         String packageName = fileName.substring(0, lastDot);
         return packageName.replace('.', '/');
     }
 }