/*
    * Copyright (c) 2002-2012, the original author or authors.
    *
    * This software is distributable under the BSD license. See the terms of the
    * BSD license in the documentation provided with this software.
    *
    * http://www.opensource.org/licenses/bsd-license.php
    */
   package jline.console.internal;
   
  import jline.console.ConsoleReader;
   
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.SequenceInputStream;
  import java.util.Enumeration;
  
  // FIXME: Clean up API and move to jline.console.runner package
  
  /**
   * An {@link InputStream} implementation that wraps a {@link ConsoleReader}.
   * It is useful for setting up the {@link System#in} for a generic console.
   *
   * @author <a href="mailto:mwp1@cornell.edu">Marc Prud'hommeaux</a>
   * @since 2.7
   */
  class ConsoleReaderInputStream
      extends SequenceInputStream
  {
      private static InputStream systemIn = System.in;
   
      public static void setIn() throws IOException {
          setIn(new ConsoleReader());
      }
   
      public static void setIn(final ConsoleReader reader) {
          System.setIn(new ConsoleReaderInputStream(reader));
      }
   
      /**
       * Restore the original {@link System#in} input stream.
       */
      public static void restoreIn() {
          System.setIn(systemIn);
      }
   
      public ConsoleReaderInputStream(final ConsoleReader reader) {
          super(new ConsoleEnumeration(reader));
      }
   
      private static class ConsoleEnumeration
          implements Enumeration
      {
          private final ConsoleReader reader;
          private ConsoleLineInputStream next = null;
          private ConsoleLineInputStream prev = null;
   
          public ConsoleEnumeration(final ConsoleReader reader) {
              this.reader = reader;
          }
   
          public Object nextElement() {
              if (next != null) {
                  InputStream n = next;
                  prev = next;
                  next = null;
   
                  return n;
              }
   
              return new ConsoleLineInputStream(reader);
          }
   
          public boolean hasMoreElements() {
              // the last line was null
              if ((prev != null) && (prev.wasNull == true)) {
                  return false;
              }
   
              if (next == null) {
                  next = (ConsoleLineInputStream) nextElement();
              }
   
              return next != null;
          }
      }
   
      private static class ConsoleLineInputStream
          extends InputStream
      {
          private final ConsoleReader reader;
          private String line = null;
          private int index = 0;
          private boolean eol = false;
          protected boolean wasNull = false;
   
          public ConsoleLineInputStream(final ConsoleReader reader) {
              this.reader = reader;
          }
  
         public int read() throws IOException {
             if (eol) {
                 return -1;
             }
  
             if (line == null) {
                 line = reader.readLine();
             }
  
             if (line == null) {
                 wasNull = true;
                 return -1;
             }
  
             if (index >= line.length()) {
                 eol = true;
                 return '\n'; // lines are ended with a newline
             }
  
             return line.charAt(index++);
         }
     }
 }