<?php

namespace DoctrineExtensions\Query\Mysql;

use Doctrine\ORM\Query\AST\Functions\FunctionNode;
use Doctrine\ORM\Query\Lexer;

/**
 * @author Andrew Mackrodt <andrew@ajmm.org>
 */
class NullIf extends FunctionNode
{
    private $expr1;

    private $expr2;

    public function parse(\Doctrine\ORM\Query\Parser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $this->expr1 = $parser->ArithmeticExpression();
        $parser->match(Lexer::T_COMMA);
        $this->expr2 = $parser->ArithmeticExpression();
        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }

    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
    {
        return sprintf(
            'NULLIF(%s, %s)',
            $sqlWalker->walkArithmeticPrimary($this->expr1),
            $sqlWalker->walkArithmeticPrimary($this->expr2)
        );
    }
}