/*
    * Copyright 2002,2004 The Apache Software Foundation.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.jelly.tags.fmt;
  
  import org.apache.commons.jelly.JellyTagException;
  import org.apache.commons.jelly.XMLOutput;
  import org.apache.commons.jelly.Tag;
  import org.apache.commons.jelly.TagSupport;
  import org.apache.commons.jelly.expression.Expression;
  
  import org.xml.sax.SAXException;
  
  import java.text.MessageFormat;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.ResourceBundle;
  import java.util.MissingResourceException;
  
  /***
   * Support for tag handlers for <message>, the lookup up
   * localized message tag in JSTL.
   * @author <a href="mailto:willievu@yahoo.com">Willie Vu</a>
   * @version 1.1
   *
   * @task decide how to implement setResponseLocale
   */
  public class MessageTag extends TagSupport {
  
      private static final String UNDEFINED_KEY = "???";
  
      private Expression key;
      private Expression bundle;
  
      private LocalizationContext locCtxt;
  
      private String var;
  
      private String scope;
  
      private List params;
  
      /*** Creates a new instance of MessageTag */
      public MessageTag() {
          params = new ArrayList();
      }
  
      /***
       * Adds an argument (for parametric replacement) to this tag's message.
       */
      public void addParam(Object arg) {
          params.add(arg);
      }
  
      public void doTag(XMLOutput output) throws JellyTagException {
  
          Object keyInput = null;
          if (this.key != null) {
              keyInput = this.key.evaluate(context);
              // process <param> sub tags
              invokeBody(output);
          }
          else {
              // get key from body
              keyInput = getBodyText();
          }
  
  
          if ((keyInput == null) || keyInput.equals("")) {
              try {
                  output.write("??????");
              } catch (SAXException e) {
                  throw new JellyTagException(e);
              }
              return;
          }
  
          Object bundleInput = null;
          if (this.bundle != null) {
              bundleInput = this.bundle.evaluate(context);
          }
          if (bundleInput != null && bundleInput instanceof LocalizationContext) {
              locCtxt = (LocalizationContext) bundleInput;
          }
  
          String prefix = null;
          if (locCtxt == null) {
             Tag t = findAncestorWithClass(this, BundleTag.class);
             if (t != null) {
                 // use resource bundle from parent <bundle> tag
                 BundleTag parent = (BundleTag) t;
                 locCtxt = parent.getLocalizationContext();
                 prefix = parent.getPrefixAsString();
             } else {
                 locCtxt = BundleTag.getLocalizationContext(context);
             }
         } else {
             // localization context taken from 'bundle' attribute
             if (locCtxt.getLocale() != null) {
                 // TODO
                 // SetLocaleSupport.setResponseLocale(pageContext,
                 // locCtxt.getLocale());
             }
         }
 
         String message = UNDEFINED_KEY + keyInput + UNDEFINED_KEY;
         if (locCtxt != null) {
             ResourceBundle bundle = locCtxt.getResourceBundle();
             if (bundle != null) {
                 try {
                     // prepend 'prefix' attribute from parent bundle
                     if (prefix != null) {
                         keyInput = prefix + keyInput;
                     }
                     message = bundle.getString(keyInput.toString());
                     // Perform parametric replacement if required
                     if (!params.isEmpty()) {
                         Object[] messageArgs = params.toArray();
                         MessageFormat formatter = new MessageFormat("");
                         if (locCtxt.getLocale() != null) {
                             formatter.setLocale(locCtxt.getLocale());
                         }
                         formatter.applyPattern(message);
                         message = formatter.format(messageArgs);
                     }
                 } catch (MissingResourceException mre) {
                     message = UNDEFINED_KEY + keyInput + UNDEFINED_KEY;
                 }
             }
         }
 
 
         if (scope != null) {
             if (var != null) {
                 context.setVariable(var, scope, message);
             }
             else {
                 throw new JellyTagException( "If 'scope' is specified, 'var' must be defined for this tag" );
             }
         }
         else {
             if (var != null) {
                 context.setVariable(var, message);
             }
             else {
                 // write the message
                 try {
                     output.write(message);
                 } catch (SAXException e) {
                     throw new JellyTagException(e);
                 }
             }
         }
     }
 
     /*** Setter for property key.
      * @param key New value of property key.
      *
      */
     public void setKey(Expression key) {
         this.key = key;
     }
 
     /*** Setter for property bundle.
      * @param bundle New value of property bundle.
      *
      */
     public void setBundle(Expression bundle) {
         this.bundle = bundle;
     }
 
     /*** Setter for property var.
      * @param var New value of property var.
      *
      */
     public void setVar(String var) {
         this.var = var;
     }
 
     /*** Setter for property scope.
      * @param scope New value of property scope.
      *
      */
     public void setScope(String scope) {
         this.scope = scope;
     }
 
 }