/*******************************************************************************
 * Copyright (c) 2014 Jeff Martin.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Contributors:
 *     Jeff Martin - initial API and implementation
 ******************************************************************************/
package cuchaz.enigma.mapping;

import java.io.IOException;
import java.io.StringReader;
import java.util.List;

import com.google.common.collect.Lists;

public class SignatureUpdater
{
	public interface ClassNameUpdater
	{
		String update( String className );
	}
	
	public static String update( String signature, ClassNameUpdater updater )
	{
		try
		{
			StringBuilder buf = new StringBuilder();
			
			// read the signature character-by-character
			StringReader reader = new StringReader( signature );
			int i = -1;
			while( ( i = reader.read() ) != -1 )
			{
				char c = (char)i;
				
				// does this character start a class name?
				if( c == 'L' )
				{
					// update the class name and add it to the buffer
					buf.append( 'L' );
					String className = readClass( reader );
					if( className == null )
					{
						throw new IllegalArgumentException( "Malformed signature: " + signature );
					}
					buf.append( updater.update( className ) );
					buf.append( ';' );
				}
				else
				{
					// copy the character into the buffer
					buf.append( c );
				}
			}
			
			return buf.toString();
		}
		catch( IOException ex )
		{
			// I'm pretty sure a StringReader will never throw one of these
			throw new Error( ex );
		}
	}
	
	private static String readClass( StringReader reader )
	throws IOException
	{
		// read all the characters in the buffer until we hit a ';'
		StringBuilder buf = new StringBuilder();
		int i = -1;
		while( ( i = reader.read() ) != -1 )
		{
			char c = (char)i;
			
			if( c == ';' )
			{
				return buf.toString();
			}
			else
			{
				buf.append( c );
			}
		}
		
		return null;
	}
	
	public static List<String> getClasses( String signature )
	{
		final List<String> classNames = Lists.newArrayList();
		update( signature, new ClassNameUpdater( )
		{
			@Override
			public String update( String className )
			{
				classNames.add( className );
				return className;
			}
		} );
		return classNames;
	}
}