/* gnu.classpath.tools.taglets.AuthorTaglet
   Copyright (C) 2001 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */

package gnu.classpath.tools.taglets;

import java.util.Map;

import java.util.regex.Pattern;
import java.util.regex.Matcher;

import com.sun.tools.doclets.Taglet;

import com.sun.javadoc.Tag;

/**
 *  The default Taglet which handles Author information.
 *
 *  @author Julian Scheid (julian@sektor37.de)
 */
public class AuthorTaglet implements Taglet {
   
   /**
    *  Enum class which denotes whether and how to replace email
    *  addresses in author tags.
    */
   public static class EmailReplacement {
      private EmailReplacement() {}

      /**
       *  Specifies that email addresses should not be replaced.
       */
      public static final EmailReplacement NO_REPLACEMENT = new EmailReplacement();

      /**
       *  Specifies that author tag text matching "Real Name
       *  (user@domain.tld)" is converted to "&lt;a
       *  href="mailto:user@domain.tld"&gt;Real Name&lt;/a&gt;.
       */
      public static final EmailReplacement MAILTO_NAME = new EmailReplacement();

      /**
       *  Specifies that author tag text matching "Real Name
       *  (user@domain.tld)" is converted to "Real Name (&lt;a
       *  href="mailto:user@domain.tld"&gt;user@domain.tld&lt;/a&gt;).
       */
      public static final EmailReplacement NAME_MAILTO_ADDRESS = new EmailReplacement();

      /**
       *  Specifies that author tag text matching "Real Name
       *  (user@domain.tld)" is converted to "Real Name (user AT
       *  domain DOT tld)", where the "AT" and "DOT" replacement are
       *  specified by AuthorTaglet.emailAtReplacement and
       *  AuthorTaglet.emailDotReplacement.
       */
      public static final EmailReplacement NAME_MANGLED_ADDRESS = new EmailReplacement();      
   }

   private static EmailReplacement emailReplacementType = EmailReplacement.NO_REPLACEMENT;
   private static String atReplacement = " <b>at</b> ";
   private static String dotReplacement = " <b>dot</b> ";

   private static final String NAME = "author";
   private static final String SINGLE_HEADER = "Author:";
   private static final String MULTI_HEADER = "Authors:";

   private static boolean enabled = true;
   
   /**
    *  Matches <code>.</code> (dot).
    */
   private static final Pattern dotPattern = Pattern.compile("[.]");

   /**
    *  Matches <code>@</code> (at sign).
    */
   private static final Pattern atPattern = Pattern.compile("[@]");

   /**
    *  Matches <code>Real Name (user@domain.tld)</code>.
    */
   private static final Pattern authorEmailPattern
     = Pattern.compile("^"
                       + "\\s*" // optional whitespace
                       + "(" // group #1 start (real name)
                       + "(?:[^\t\r\n ]|\\()+" // first name
                       + "(?:\\s+(?:[^\t\r\n ]|\\()+)*" // additional names
                       + ")" // group #1 end
                       + "\\s*" // optional whitespace                    
                       + "[(<]" // opening paren
                       + "\\s*" // optional whitespace                       
                       + "(" // group #2 start (email address)
                       + "(" // group #3 start (email user)
                       + "[A-z0-9_\\-\\.]+" // username
                       + ")" // group #3 end
                       + "[@]" // at sign
                       + "[A-z0-9_\\-]+(?:[.][A-z0-9_\\-]+)+[A-z]" // domain
                       + ")" // group #2 end
                       + "\\s*" // optional whitespace
                       + "(?:\\)|>)" // closing paren
                       + "$");
    
   public String getName() {
      return NAME;
   }
    
   public boolean inField() {
      return true;
   }

   public boolean inConstructor() {
      return true;
   }
    
   public boolean inMethod() {
      return true;
   }
   
   public boolean inOverview() {
      return true;
   }

   public boolean inPackage() {
      return true;
   }

   public boolean inType() {
      return true;
   }
    
   public boolean isInlineTag() {
      return false;
   }    

   public static void register(Map tagletMap) {
      AuthorTaglet authorTaglet = new AuthorTaglet();
      tagletMap.put(authorTaglet.getName(), authorTaglet);
   }

   public String toString(Tag tag) {
      if (enabled) {
         return toString(new Tag[] { tag });
      }
      else {
         return null;
      }
   }

   public String toString(Tag[] tags) {
      if (!enabled || tags.length == 0) {
         return null;
      }
      else {
         boolean haveValidTag = false;
         for (int i = 0; i < tags.length && !haveValidTag; ++i) {
            if (tags[i].text().length() > 0) {
               haveValidTag = true;
            }
         }
         
         if (haveValidTag) {
            StringBuffer result = new StringBuffer();
            result.append("<dl class=\"tag list\">");
            result.append("<dt class=\"tag section header\"><b>");
            if (tags.length == 1) {
               result.append(SINGLE_HEADER);
            }
            else {
               result.append(MULTI_HEADER);
            }
            result.append("</b></dt>");
            for (int i = 0; i < tags.length; i++) {
               result.append("<dd class=\"tag item\">");
               result.append(replaceEmail(tags[i].text()));
               result.append("</dd>");
            }
            result.append("</dl>");
            return result.toString();
         }
         else {
            return null;
         }
      }
   }   

   /**
    *  Reformat the tag text according to {@link #emailReplacementType}.
    */
   private String replaceEmail(String text) {

      if (EmailReplacement.NO_REPLACEMENT == emailReplacementType) {
         return text;
      }
      else {
         Matcher matcher = authorEmailPattern.matcher(text);
         if (matcher.matches()) {
            String realName = matcher.group(1);
            String emailAddress = matcher.group(2);
            if (EmailReplacement.MAILTO_NAME == emailReplacementType) {         
               return "<a href=\"mailto:" + emailAddress + "\">" + realName + "</a>";
            }
            else if (EmailReplacement.NAME_MAILTO_ADDRESS == emailReplacementType) {
               return realName + " (<a href=\"mailto:" + emailAddress + "\">" + emailAddress + "</a>)";
            }
            else if (EmailReplacement.NAME_MANGLED_ADDRESS == emailReplacementType) {
               Matcher dotMatcher = dotPattern.matcher(emailAddress);
               Matcher atMatcher = atPattern.matcher(dotMatcher.replaceAll(dotReplacement));
               String mangledAddress = atMatcher.replaceAll(atReplacement);
               return realName + " (" + mangledAddress + ")";
            }
            else {
               // this shouldn't happen
               return text;
            }
         }
         else {
            return text;
         }
      }
   }

   /**
    *  Set the email replacement type.
    */
   public static void setEmailReplacementType(EmailReplacement emailReplacementType)
   {
      if (null == emailReplacementType) {
         throw new NullPointerException();
      }
      AuthorTaglet.emailReplacementType = emailReplacementType;
   }

   /**
    *  Set the HTML text by which the <code>@</code> (at sign) in email
    *  addresses should be replaced if the email replacement type is
    *  <code>NAME_MANGLED_ADDRESS</code>.
    */
   public static void setAtReplacement(String atReplacement)
   {
      AuthorTaglet.atReplacement = atReplacement;
   }

   /**
    *  Set the HTML text by which the <code>.</code> (dot) in email
    *  addresses should be replaced if the email replacement type is
    *  <code>NAME_MANGLED_ADDRESS</code>.
    */
   public static void setDotReplacement(String dotReplacement)
   {
      AuthorTaglet.dotReplacement = dotReplacement;
   }

   /**
    *  Enables/disables this taglet.
    */
   public static void setTagletEnabled(boolean enabled)
   {
      AuthorTaglet.enabled = enabled;
   }
}
