/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.accumulo.core.conf;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.Map.Entry;
  import java.util.TreeMap;
  
  import org.apache.log4j.Logger;
  
  public class DefaultConfiguration extends AccumuloConfiguration {
    private static DefaultConfiguration instance = null;
    private static Logger log = Logger.getLogger(DefaultConfiguration.class);
    
    synchronized public static DefaultConfiguration getInstance() {
      if (instance == null) {
        instance = new DefaultConfiguration();
        ConfigSanityCheck.validate(instance);
      }
      return instance;
    }
    
    @Override
    public String get(Property property) {
      return property.getDefaultValue();
    }
    
    @Override
    public Iterator<Entry<String,String>> iterator() {
      TreeMap<String,String> entries = new TreeMap<String,String>();
      for (Property prop : Property.values())
        if (!prop.isExperimental() && !prop.getType().equals(PropertyType.PREFIX))
          entries.put(prop.getKey(), prop.getDefaultValue());
      
      return entries.entrySet().iterator();
    }
    
    private static void generateDocumentation(PrintStream doc) {
      // read static content from resources and output
      InputStream data = DefaultConfiguration.class.getClassLoader().getResourceAsStream("config.html");
      if (data != null) {
        byte[] buffer = new byte[1024];
        int n;
        try {
          while ((n = data.read(buffer)) > 0)
            doc.print(new String(buffer, 0, n));
        } catch (IOException e) {
          e.printStackTrace();
          return;
        } finally {
      	  try { 
      		  data.close();
      	  } catch (IOException ex) {
      		  log .error(ex, ex);
      	  }
        }
      }
      doc.println();
      
      ArrayList<Property> prefixes = new ArrayList<Property>();
      TreeMap<String,Property> sortedProps = new TreeMap<String,Property>();
      for (Property prop : Property.values()) {
        if (prop.isExperimental())
          continue;
  
        if (prop.getType().equals(PropertyType.PREFIX))
          prefixes.add(prop);
        else
          sortedProps.put(prop.getKey(), prop);
      }
      
      doc.println("  <p>Jump to: ");
      String delimiter = "";
      for (Property prefix : prefixes) {
        if (prefix.isExperimental())
          continue;
  
        doc.print(delimiter + "<a href='#" + prefix.name() + "'>" + prefix.getKey() + "*</a>");
        delimiter = "&nbsp;|&nbsp;";
      }
      doc.println("  </p>");
     
     doc.println("  <table>");
     for (Property prefix : prefixes) {
       
       if (prefix.isExperimental())
         continue;
 
       doc.println("   <tr><td colspan='5'><a name='" + prefix.name() + "' class='large'>" + prefix.getKey() + "*</a></td></tr>");
       doc.println("   <tr><td colspan='5'><i>" + prefix.getDescription() + "</i></td></tr>");
       if (!prefix.equals(Property.TABLE_CONSTRAINT_PREFIX) && !prefix.equals(Property.TABLE_ITERATOR_PREFIX)
           && !prefix.equals(Property.TABLE_LOCALITY_GROUP_PREFIX))
         doc.println("   <tr><th>Property</th><th>Type</th><th>Zookeeper Mutable</th><th>Default Value</th><th>Description</th></tr>");
       
       boolean highlight = true;
       for (Property prop : sortedProps.values()) {
         if (prop.isExperimental())
           continue;
 
         if (prop.getKey().startsWith(prefix.getKey())) {
           doc.println("   <tr " + (highlight ? "class='highlight'" : "") + ">");
           highlight = !highlight;
           doc.println("    <td>" + prop.getKey() + "</td>");
           doc.println("    <td><b><a href='#" + prop.getType().name() + "'>" + prop.getType().toString().replaceAll(" ", "&nbsp;") + "</a></b></td>");
           String zoo = "no";
           if (Property.isValidZooPropertyKey(prop.getKey())) {
             zoo = "yes";
             if (Property.isFixedZooPropertyKey(prop)) {
               zoo = "yes but requires restart of the " + prop.getKey().split("[.]")[0];
             }
           }
           doc.println("    <td>" + zoo + "</td>");
           doc.println("    <td><pre>" + (prop.getDefaultValue().isEmpty() ? "&nbsp;" : prop.getDefaultValue().replaceAll(" ", "&nbsp;")) + "</pre></td>");
           doc.println("    <td>" + prop.getDescription() + "</td>");
           doc.println("   </tr>");
         }
       }
     }
     doc.println("  </table>");
     
     doc.println("  <h1>Property Type Descriptions</h1>");
     doc.println("  <table>");
     doc.println("   <tr><th>Property Type</th><th>Description</th></tr>");
     boolean highlight = true;
     for (PropertyType type : PropertyType.values()) {
       if (type.equals(PropertyType.PREFIX))
         continue;
       doc.println("   <tr " + (highlight ? "class='highlight'" : "") + ">");
       highlight = !highlight;
       doc.println("     <td><h3><a name='" + type.name() + "'>" + type + "</a></td>");
       doc.println("     <td>" + type.getFormatDescription() + "</td>");
       doc.println("    </tr>");
     }
     doc.println("  </table>");
     doc.println(" </body>");
     doc.println("</html>");
     doc.close();
   }
   
   /*
    * Generate documentation for conf/accumulo-site.xml file usage
    */
   public static void main(String[] args) {
     if (args.length == 1 && args[0].equals("--generate-doc"))
       generateDocumentation(System.out);
   }
 }