////////////////////////////////////////////////////////////////////////////////
// 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.coding;

import edu.cmu.cs.varex.annotation.VConditional;
import edu.cmu.cs.vbc.prog.checkstyle.api.DetailAST;
import edu.cmu.cs.vbc.prog.checkstyle.api.TokenTypes;
import edu.cmu.cs.vbc.prog.checkstyle.checks.CheckUtils;

/**
 * Restricts nested if-else blocks to a specified depth (default = 1).
 *
 * @author <a href="mailto:simon@redhillconsulting.com.au">Simon Harris</a>
 */
public final class NestedIfDepthCheck extends AbstractNestedDepthCheck
{
	@VConditional
	private static boolean NestedIfDepth = true;
	
	@Override
	public boolean isEnabled() {
		return NestedIfDepth;
	}
    /**
     * A key is pointing to the warning message text in "messages.properties"
     * file.
     */
    public static final String MSG_KEY = "nested.if.depth";

    /** default allowed nesting depth. */
    private static final int DEFAULT_MAX = 1;

    /** Creates new check instance with default allowed nesting depth. */
    public NestedIfDepthCheck()
    {
        super(DEFAULT_MAX);
    }

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

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

    @Override
    public void visitToken(DetailAST ast)
    {
        switch (ast.getType()) {
            case TokenTypes.LITERAL_IF:
                visitLiteralIf(ast);
                break;
            default:
                throw new IllegalStateException(ast.toString());
        }
    }

    @Override
    public void leaveToken(DetailAST ast)
    {
        switch (ast.getType()) {
            case TokenTypes.LITERAL_IF:
                leaveLiteralIf(ast);
                break;
            default:
                throw new IllegalStateException(ast.toString());
        }
    }

    /**
     * Increases current nesting depth.
     * @param literalIf node for if.
     */
    private void visitLiteralIf(DetailAST literalIf)
    {
        if (!CheckUtils.isElseIf(literalIf)) {
            nestIn(literalIf, MSG_KEY);
        }
    }

    /**
     * Decreases current nesting depth.
     * @param literalIf node for if.
     */
    private void leaveLiteralIf(DetailAST literalIf)
    {
        if (!CheckUtils.isElseIf(literalIf)) {
            nestOut();
        }
    }
}
