////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2015 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
////////////////////////////////////////////////////////////////////////////////
package edu.cmu.cs.vbc.prog.checkstyle.checks.naming;

import edu.cmu.cs.varex.annotation.VConditional;
import edu.cmu.cs.vbc.prog.checkstyle.api.DetailAST;
import edu.cmu.cs.vbc.prog.checkstyle.api.ScopeUtils;
import edu.cmu.cs.vbc.prog.checkstyle.api.TokenTypes;
import edu.cmu.cs.vbc.prog.checkstyle.api.Utils;

import java.util.regex.Pattern;

/**
 * <p>
 * Checks that local, non-final variable names conform to a format specified
 * by the format property. A catch parameter is considered to be
 * a local variable. The format is a
 * {@link java.util.regex.Pattern regular expression}
 * and defaults to
 * <strong>^[a-z][a-zA-Z0-9]*$</strong>.
 * </p>
 * <p>
 * An example of how to configure the check is:
 * </p>
 * <pre>
 * &lt;module name="LocalVariableName"/&gt;
 * </pre>
 * <p>
 * An example of how to configure the check for names that begin with a lower
 * case letter, followed by letters, digits, and underscores is:
 * </p>
 * <pre>
 * &lt;module name="LocalVariableName"&gt;
 *    &lt;property name="format" value="^[a-z](_?[a-zA-Z0-9]+)*$"/&gt;
 * &lt;/module&gt;
 * </pre>
 * <p>
 * An example of one character variable name in
 * initialization expression(like "i") in FOR loop:
 * </p>
 * <pre>
 * for(int i = 1; i &lt; 10; i++) {}
 * </pre>
 * <p>
 * An example of how to configure the check to allow one char variable name in
 * <a href="http://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
 * initialization expressions</a> in FOR loop:
 * </p>
 * <pre>
 * &lt;module name="LocalVariableName"&gt;
 *    &lt;property name="allowOneCharVarInForLoop" value="true"/&gt;
 * &lt;/module&gt;
 * </pre>
 * <p>
 *
 * @author Rick Giles
 * @author maxvetrenko
 * @version 1.0
 */
public class LocalVariableNameCheck
    extends AbstractNameCheck
{
	@VConditional
	private static boolean LocalVariableName = true;
	
	@Override
	public boolean isEnabled() {
		return LocalVariableName;
	}
	
    /**
     * Allow one character name for initialization expression in FOR loop.
     */
	@VConditional
    private final static boolean LocalVariableNameallowOneCharVarInForLoop = true;

    /** Regexp for one-char loop variables. */
    private static Pattern sSingleChar = Utils.getPattern("^[a-z]$");

    /** Creates a new <code>LocalVariableNameCheck</code> instance. */
    public LocalVariableNameCheck()
    {
        super("^[a-z][a-zA-Z0-9]*$");
    }

    public final void setAllowOneCharVarInForLoop(boolean allow)
    {
//        LocalVariableNameallowOneCharVarInForLoop = allow;
    }

    @Override
    public int[] getDefaultTokens()
    {
        return new int[] {
            TokenTypes.VARIABLE_DEF,
            TokenTypes.PARAMETER_DEF,
        };
    }

    @Override
    public int[] getAcceptableTokens()
    {
        return new int[] {
            TokenTypes.VARIABLE_DEF,
            TokenTypes.PARAMETER_DEF,
        };
    }

    @Override
    protected final boolean mustCheckName(DetailAST ast)
    {
        final DetailAST modifiersAST =
            ast.findFirstToken(TokenTypes.MODIFIERS);
        final boolean isFinal = (modifiersAST != null)
            && modifiersAST.branchContains(TokenTypes.FINAL);
        if (LocalVariableNameallowOneCharVarInForLoop && isForLoopVariable(ast)) {
            final String variableName =
                    ast.findFirstToken(TokenTypes.IDENT).getText();
            return !sSingleChar.matcher(variableName).find();
        }
        return (!isFinal && ScopeUtils.isLocalVariableDef(ast));
    }

    /**
     * Checks if a variable is the loop's one.
     * @param variableDef variable definition.
     * @return true if a variable is the loop's one.
     */
    private boolean isForLoopVariable(DetailAST variableDef)
    {
        final int parentType = variableDef.getParent().getType();
        return  parentType == TokenTypes.FOR_INIT
                || parentType == TokenTypes.FOR_EACH_CLAUSE;
    }
}
