/*
    * FQAN.java
    *
    * Created on September 10, 2004, 12:14 PM
    */
   
   package gov.bnl.gums;
   
   import java.util.StringTokenizer;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /*** Represent a VOMS extended proxy credential as defined in
   * http://edg-wp2.web.cern.ch/edg-wp2/security/voms/edg-voms-credential.pdf.
   * <p>
   * A Fully Qualified Attribute Name consists of a VO, a group, a role and
   * a capability. Only the VO is mandatory. The syntax is
   * /VO[/group[/subgroup(s)]][/Role=role][/Capability=cap].
   * <p>
   * The class will always check that every modification matches the regex
   * /[\w-\.]+(/[\w-\.]+)*(/Role=[\w-\.]+)?(/Capability=[\w-\.]+)?
   * which fully defines all the characters allowed. This differs slightly from
   * the one contained in the specification, as it cointained some small errors.
   * It matches the description of the syntax of the document.
   *
   * @author  Gabriele Carcassi
   */
  public class FQAN {
      
      private String fqan;
      private String vo;
      private String group;
      private String role;
      private String capability;
      
      // Compiling this huge pattern requires time...
      // Let's do it once.
      private static Pattern fqanPattern = Pattern.compile("/[//w-//.]+(/[//w-//.]+)*(/Role=[//w-//.]+)?(/Capability=[//w-//.]+)?");
      
      /***
       * Creates a FQAN based on String representation. If the parsing fails, it will
       * throw an exception.
       * @param fqan A VOMS FQAN (i.e. "/atlas/production/Role=Leader")
       */
      public FQAN(String fqan) {
          setFqan(fqan);
          parseFqan(fqan);
          generateFqan();
      }
      
      /*** Creates a FQAN based on the different pieces of information.
       * 
       * @param vo The VO name, which cannot be null (i.e. "atlas")
       * @param group A group path, including subgroups (i.e. "/production")
       * @param role The role (i.e. "Leader")
       * @param capability A capability (i.e. "capability"). Note capabilities are
       * being deprecated in VOMS.
       */
      public FQAN(String vo, String group, String role, String capability) {
          if (vo == null)
              throw new IllegalArgumentException("The vo for a FQAN can't be null");
          setVo(vo);
          setGroup(group);
          setRole(role);
          setCapability(capability);
          generateFqan();
      }
      
      /*** A full String representation of the FQAN.
       * 
       * @return The Fully Qualified Attribute name String representation (i.e. "/atlas/production/Role=Leader")
       */
      public String getFqan() {
          return this.fqan;
      }
  
      private void setFqan(String fqan) {
          this.fqan = fqan;
      }
  
      /*** Returns the VO corresponding to the FQAN.
       * 
       * @return The VO name (i.e. "atlas")
       */
      public String getVo() {
          return this.vo;
      }
      
      private void setVo(String vo) {
          if ((vo != null) && (!vo.matches("[//w-//.]+"))) {
              throw new IllegalArgumentException("The vo '" + vo + "' is malformed");
          }
          this.vo = vo;
      }
      
      /*** The path which includes the groups and subgroups within the FQAN.
       * 
       * @return The group path (i.e. "/production")
       */
     public String getGroup() {
         return this.group;
     }
     
     private void setGroup(String group) {
         if ((group != null) && (!group.matches("(/[//w-//.]+)+"))) {
             throw new IllegalArgumentException("The group '" + group + "' is malformed");
         }
         this.group = group;
     }
     
     /*** The role used within the FQAN.
      * 
      * @return The role or null if no role was specified
      */
     public String getRole() {
         return this.role;
     }
     
     private void setRole(String role) {
         if ((role != null) && (!role.matches("[//w-//.]+"))) {
             throw new IllegalArgumentException("The role '" + role + "' is malformed");
         }
         this.role = role;
         if ("NULL".equalsIgnoreCase(role)) {
             this.role = null;
         }
     }
     
     /***
      *  The capability used within the FQAN.
      * @return The capability or null if none was specified.
      */
     public String getCapability() {
         return this.capability;
     }
     
     private void setCapability(String capability) {
         if ((capability != null) && (!capability.matches("[//w-//.]+"))) {
             throw new IllegalArgumentException("The capability '" + capability + "' is malformed");
         }
         this.capability = capability;
         if ("NULL".equalsIgnoreCase(capability)) {
             this.capability = null;
         }
     }
     
     private void parseFqan(String fqan) {
         // Matches to the specification.
         Matcher m = fqanPattern.matcher(fqan);
         if (!m.matches())
             throw new IllegalArgumentException("FQAN '" + fqan + "' is malformed (syntax: /VO[/group[/subgroup(s)]][/Role=role][/Capability=cap])");
         
         StringTokenizer stk = new StringTokenizer(fqan, "/");
         vo = stk.nextToken();
         if (!stk.hasMoreTokens()) {
             group = null;
             role = null;
             capability = null;
             return;
         }
         String tempGroup = "";
         String token = stk.nextToken();
         while ((!token.startsWith("Role=") && !token.startsWith("Capability="))) {
             tempGroup = tempGroup + "/" + token;
             group = tempGroup;
             if (!stk.hasMoreTokens()) {
                 role = null;
                 capability = null;
                 return;
             }
             token =  stk.nextToken();
         }
         if (token.startsWith("Role=")) {
             setRole(token.substring(5));
             if (!stk.hasMoreTokens()) {
                 capability = null;
                 return;
             }
             token = stk.nextToken();
         }
         if (token.startsWith("Capability=")) {
             setCapability(token.substring(11));
         }
     }
     
     private void generateFqan() {
         if (vo == null) {
             fqan = null;
             return;
         }
         StringBuffer bf = new StringBuffer();
         bf.append('/');
         bf.append(vo);
         if (group != null)
             bf.append(group);
         if (role != null) {
             bf.append("/Role=");
             bf.append(role);
         }
         if (capability != null) {
             bf.append("/Capability=");
             bf.append(capability);
         }
         fqan = bf.toString();
     }
     
     /*** Returns the full string representation of the FQAN.
      * 
      * @return The full FQAN (i.e. "/atlas/production/Role=Leader")
      */
     public String toString() {
         return fqan;
     }
     
     /*** A hashcode generated from the string representation.
      * 
      * @return A hashcode.
      */
     public int hashCode() {
         if (fqan == null) return 0;
         return fqan.hashCode();
     }
     
     /*** FQANs are equals to each other if their vo, group, role and capability
      * are the same.
      * 
      * @param obj Another object.
      * @return True if the object was a FQAN with equal information. False otherwise.
      */
     public boolean equals(Object obj) {
         if (obj == null) return false;
         FQAN fqan2 = (FQAN) obj;
         return (fqan2.fqan == null) ? fqan == null : fqan2.fqan.equals(fqan);
     }
     
 }