/*******************************************************************************
 * 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.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;

import javassist.bytecode.Descriptor;

public class NameValidator
{
	private static final Pattern IdentifierPattern;
	private static final Pattern ClassPattern;
	private static final List<String> ReservedWords = Arrays.asList(
		"abstract", "continue", "for", "new", "switch",
		"assert", "default", "goto", "package", "synchronized",
		"boolean", "do", "if", "private", "this",
		"break", "double", "implements", "protected", "throw",
		"byte", "else", "import", "public", "throws",
		"case", "enum", "instanceof", "return", "transient",
		"catch", "extends", "int", "short", "try",
		"char", "final", "interface", "static", "void",
		"class", "finally", "long", "strictfp", "volatile",
		"const", "float", "native", "super", "while"
	);
	
	static
	{
		// java allows all kinds of weird characters...
		StringBuilder startChars = new StringBuilder();
		StringBuilder partChars = new StringBuilder();
		for( int i = Character.MIN_CODE_POINT; i <= Character.MAX_CODE_POINT; i++ )
		{
			if( Character.isJavaIdentifierStart( i ) )
			{
				startChars.appendCodePoint( i );
			}
			if( Character.isJavaIdentifierPart( i ) )
			{
				partChars.appendCodePoint( i );
			}
		}
		
		String identifierRegex = "[A-Za-z_<][A-Za-z0-9_>]*";
		IdentifierPattern = Pattern.compile( identifierRegex );
		ClassPattern = Pattern.compile( String.format( "^(%s(\\.|/))*(%s)$", identifierRegex, identifierRegex ) );
	}
	
	public static String validateClassName( String name )
	{
		if( name == null || !ClassPattern.matcher( name ).matches() || ReservedWords.contains( name ) )
		{
			throw new IllegalNameException( name, "This doesn't look like a legal class name" );
		}
		if( new ClassEntry( name ).getPackageName() == null )
		{
			throw new IllegalNameException( name, "Classes must be in a package" );
		}
		return Descriptor.toJvmName( name );
	}
	
	public static String validateFieldName( String name )
	{
		if( name == null || !IdentifierPattern.matcher( name ).matches() || ReservedWords.contains( name ) )
		{
			throw new IllegalNameException( name, "This doesn't look like a legal identifier" );
		}
		return name;
	}
	
	public static String validateMethodName( String name )
	{
		return validateFieldName( name );
	}
	
	public static String validateArgumentName( String name )
	{
		return validateFieldName( name );
	}
}