<?php

/*
 * This file is part of Twig.
 *
 * (c) Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Twig\Node\Expression\Binary;

use Twig\Compiler;
use Twig\Node\EmptyNode;
use Twig\Node\Expression\AbstractExpression;
use Twig\Node\Expression\BlockReferenceExpression;
use Twig\Node\Expression\OperatorEscapeInterface;
use Twig\Node\Expression\Test\DefinedTest;
use Twig\Node\Expression\Test\NullTest;
use Twig\Node\Expression\Unary\NotUnary;
use Twig\Node\Node;
use Twig\TwigTest;

final class NullCoalesceBinary extends AbstractBinary implements OperatorEscapeInterface
{
    /**
     * @param AbstractExpression $left
     * @param AbstractExpression $right
     */
    public function __construct(Node $left, Node $right, int $lineno)
    {
        parent::__construct($left, $right, $lineno);

        $test = new DefinedTest(clone $left, new TwigTest('defined'), new EmptyNode(), $left->getTemplateLine());
        // for "block()", we don't need the null test as the return value is always a string
        if (!$left instanceof BlockReferenceExpression) {
            $test = new AndBinary(
                $test,
                new NotUnary(new NullTest($left, new TwigTest('null'), new EmptyNode(), $left->getTemplateLine()), $left->getTemplateLine()),
                $left->getTemplateLine(),
            );
        }

        $left->setAttribute('always_defined', true);
        $this->setNode('test', $test);
    }

    public function compile(Compiler $compiler): void
    {
        $compiler
            ->raw('((')
            ->subcompile($this->getNode('test'))
            ->raw(') ? (')
            ->subcompile($this->getNode('left'))
            ->raw(') : (')
            ->subcompile($this->getNode('right'))
            ->raw('))')
        ;
    }

    public function operator(Compiler $compiler): Compiler
    {
        return $compiler->raw('??');
    }

    public function getOperandNamesToEscape(): array
    {
        return ['left', 'right'];
    }
}