package com.atlassian.plugin.osgi.factory.transform.model;
   
   import com.atlassian.plugin.osgi.util.OsgiHeaderUtil;
   import com.google.common.collect.ImmutableMap;
   
   import java.util.LinkedHashMap;
   import java.util.Map;
   
   import static com.google.common.collect.Maps.transformValues;
  
  /**
   * Encapsulates the package exports from the system bundle
   *
   * @since 2.2.0
   */
  public class SystemExports {
      private final Map<String, Map<String, String>> exports;
  
      public static final SystemExports NONE = new SystemExports("");
  
      /**
       * Constructs an instance by parsing the exports line from the manifest
       *
       * @param exportsLine The Export-Package header value
       */
      public SystemExports(String exportsLine) {
          if (exportsLine == null) {
              exportsLine = "";
          }
  
          this.exports = internAttributeKeys(OsgiHeaderUtil.parseHeader(exportsLine));
      }
  
      /**
       * OSGi manifest header keys come from a very small set of possible strings, and are ripe for interning. The other
       * strings in this map are less suitable for interning, and so are left alone.
       */
      private static Map<String, Map<String, String>> internAttributeKeys(final Map<String, Map<String, String>> map) {
          return transformValues(map, SystemExports::internKeys);
      }
  
      private static Map<String, String> internKeys(final Map<String, String> innerMap) {
          // Guava doesn't offer a "transformKeys" method, so we do it the old-fashioned way
          final ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
          for (Map.Entry<String, String> entry : innerMap.entrySet()) {
              builder.put(
                      entry.getKey().intern(),  // this here's the manifest header key
                      entry.getValue()
              );
          }
  
          return builder.build();
      }
  
      /**
       * Constructs a package export, taking into account any attributes on the system export, including the version.
       * The version is handled special, in that is added as an exact match, i.e. [1.0,1.0].
       *
       * @param pkg The java package
       * @return The full export line to use for a host component import
       */
      public String getFullExport(String pkg) {
          if (exports.containsKey(pkg)) {
              Map<String, String> attrs = new LinkedHashMap<>(exports.get(pkg));
              if (attrs.containsKey("version")) {
                  final String version = attrs.get("version");
                  attrs.put("version", "[" + version + "," + version + "]");
              }
              return OsgiHeaderUtil.buildHeader(pkg, attrs);
          }
          return pkg;
      }
  
      /**
       * @param pkg The package to check
       * @return True if the package is being exported, false otherwise
       */
      public boolean isExported(String pkg) {
          return exports.containsKey(pkg);
      }
  }