/**
    *	jline - Java console input library
    *	Copyright (c) 2002, 2003, 2004, 2005, Marc Prud'hommeaux <mwp1@cornell.edu>
    *	All rights reserved.
    *
    *	Redistribution and use in source and binary forms, with or
    *	without modification, are permitted provided that the following
    *	conditions are met:
    *
   *	Redistributions of source code must retain the above copyright
   *	notice, this list of conditions and the following disclaimer.
   *
   *	Redistributions in binary form must reproduce the above copyright
   *	notice, this list of conditions and the following disclaimer
   *	in the documentation and/or other materials provided with
   *	the distribution.
   *
   *	Neither the name of JLine nor the names of its contributors
   *	may be used to endorse or promote products derived from this
   *	software without specific prior written permission.
   *
   *	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   *	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
   *	BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
   *	AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
   *	EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
   *	FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   *	OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   *	PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   *	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   *	AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   *	LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   *	IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   *	OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package jline;
  
  import java.io.*;
  import java.util.*;
  import java.text.MessageFormat;
  
  /**
   *	<p>
   *	A {@link CompletionHandler} that deals with multiple distinct completions
   *	by outputting the complete list of possibilities to the console. This
   *	mimics the behavior of the
   *	<a href="http://www.gnu.org/directory/readline.html">readline</a>
   *	library.
   *	</p>
   *
   *  @author  <a href="mailto:mwp1@cornell.edu">Marc Prud'hommeaux</a>
   */
  public class CandidateListCompletionHandler
  	implements CompletionHandler
  {
  	private static ResourceBundle loc = ResourceBundle.getBundle (
  		CandidateListCompletionHandler.class.getName ());
  
  
  	public boolean complete (final ConsoleReader reader,
  		final List candidates, final int pos)
  		throws IOException
  	{
  		CursorBuffer buf = reader.getCursorBuffer ();
  
  		// if there is only one completion, then fill in the buffer
  		if (candidates.size () == 1)
  		{
  			String value = candidates.get (0).toString ();
  
  			// fail if the only candidate is the same as the current buffer
  			if (value.equals (buf.toString ()))
  				return false;
  			setBuffer (reader, value, pos);
  			return true;
  		}
  		else if (candidates.size () > 1)
  		{
  			String value = getUnambiguousCompletions (candidates);
  			String bufString = buf.toString ();
  			setBuffer (reader, value, pos);
  
  			// if we have changed the buffer, then just return withough
  			// printing out all the subsequent candidates
  			if (bufString.length () - pos + 1 != value.length ())
  				return true;
  		}
  
  		reader.printNewline ();
  		printCandidates (reader, candidates);
  
  		// redraw the current console buffer
  		reader.drawLine ();
  
  		return true;
  	}
  
  
  	private static void setBuffer (ConsoleReader reader,
 		String value, int offset)
 		throws IOException
 	{
 		while (reader.getCursorBuffer ().cursor >= offset
 			&& reader.backspace ());
 		reader.putString (value);
 		reader.setCursorPosition (offset + value.length ());
 	}
 
 
 	/**
 	 *  Print out the candidates. If the size of the candidates
 	 *  is greated than the {@link getAutoprintThreshhold},
 	 *  they prompt with aq warning.
 	 *
 	 *  @param  candidates  the list of candidates to print
 	 */
 	private final void printCandidates (ConsoleReader reader,
 		Collection candidates)
 		throws IOException
 	{
 		Set distinct = new HashSet (candidates);
 
 		if (distinct.size () > reader.getAutoprintThreshhold ())
 		{
 			reader.printString (MessageFormat.format (
 				loc.getString ("display-candidates"),
 				new Object [] { new Integer (candidates.size ()) } ) + " ");
 
 			reader.flushConsole ();
 
 			int c;
 			
 			String noOpt = loc.getString ("display-candidates-no");
 			String yesOpt = loc.getString ("display-candidates-yes");
 
 			while ((c = reader.readCharacter (
 				new char[] { yesOpt.charAt (0), noOpt.charAt (0) })) != -1)
 			{
 				if (noOpt.startsWith (new String (new char[] {(char)c})))
 				{
 					reader.printNewline ();
 					return;
 				}
 				else if (yesOpt.startsWith (new String (new char[] {(char)c})))
 				{
 					break;
 				}
 				else
 				{
 					reader.beep ();
 				}
 			}
 		}
 
 		// copy the values and make them distinct, without otherwise
 		// affecting the ordering. Only do it if the sizes differ.
 		if (distinct.size () != candidates.size ())
 		{
 			Collection copy = new ArrayList ();
 			for (Iterator i = candidates.iterator (); i.hasNext (); )
 			{
 				Object next = i.next ();
 				if (!(copy.contains (next)))
 					copy.add (next);
 			}
 
 			candidates = copy;
 		}
 
 		reader.printColumns (candidates);
 	}
 
 
 
 
 	/**
 	 *  Returns a root that matches all the {@link String} elements
 	 *  of the specified {@link List}, or null if there are
 	 *  no commalities. For example, if the list contains
 	 *  <i>foobar</i>, <i>foobaz</i>, <i>foobuz</i>, the
 	 *  method will return <i>foob</i>.
 	 */
 	private final String getUnambiguousCompletions (final List candidates)
 	{
 		if (candidates == null || candidates.size () == 0)
 			return null;
 
 		// convert to an array for speed
 		String [] strings = (String [])candidates.toArray (
 			new String [candidates.size ()]);
 
 		String first = strings [0];
 		StringBuffer candidate = new StringBuffer ();
 		for (int i = 0; i < first.length (); i++)
 		{
 			if (startsWith (first.substring (0, i + 1), strings))
 				candidate.append (first.charAt (i));
 			else
 				break;
 		}
 
 		return candidate.toString ();
 	}
 
 
 	/**
 	 *  @return  true is all the elements of <i>candidates</i>
 	 *  			start with <i>starts</i>
 	 */
 	private final boolean startsWith (final String starts,
 		final String [] candidates)
 	{
 		for (int i = 0; i < candidates.length; i++)
 		{
 			if (!candidates [i].startsWith (starts))
 				return false;
 		}
 
 		return true;
 	}
 }