<?php
/*
 * Copyright (C) 2017 Champs Libres Cooperative <info@champs-libres.coop>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
namespace Chill\MainBundle\Doctrine\DQL;

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

/**
 * Return an aggregation of values in a json representation, as a string.
 * 
 * Internally, this function use the postgresql `jsonb_agg` function. Using
 * json allow to aggregate data from different types without have to cast them.
 *
 * @author Julien Fastré <julien.fastre@champs-libres.coop>
 */
class JsonAggregate extends FunctionNode
{
    private $expr;
    
    public function getSql(SqlWalker $sqlWalker)
    {
        return sprintf('jsonb_agg(%s)', $this->expr->dispatch($sqlWalker));
    }

    public function parse(Parser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $this->expr = $parser->StringPrimary();
        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }
}