<?php

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

namespace Twig\Node\Expression;

use Twig\Compiler;

class NameExpression extends AbstractExpression
{
    protected $specialVars = [
        '_self' => '$this',
        '_context' => '$context',
        '_charset' => '$this->env->getCharset()',
    ];

    public function __construct($name, $lineno)
    {
        parent::__construct([], ['name' => $name, 'is_defined_test' => false, 'ignore_strict_check' => false, 'always_defined' => false], $lineno);
    }

    public function compile(Compiler $compiler)
    {
        $name = $this->getAttribute('name');

        $compiler->addDebugInfo($this);

        if ($this->getAttribute('is_defined_test')) {
            if ($this->isSpecial()) {
                $compiler->repr(true);
            } else {
                $compiler
                    ->raw('(isset($context[')
                    ->string($name)
                    ->raw(']) || array_key_exists(')
                    ->string($name)
                    ->raw(', $context))');
            }
        } elseif ($this->isSpecial()) {
            $compiler->raw($this->specialVars[$name]);
        } elseif ($this->getAttribute('always_defined')) {
            $compiler
                ->raw('$context[')
                ->string($name)
                ->raw(']')
            ;
        } else {
            if (\PHP_VERSION_ID >= 70000) {
                // use PHP 7 null coalescing operator
                $compiler
                    ->raw('($context[')
                    ->string($name)
                    ->raw('] ?? ')
                ;

                if ($this->getAttribute('ignore_strict_check') || !$compiler->getEnvironment()->isStrictVariables()) {
                    $compiler->raw('null)');
                } else {
                    $compiler->raw('$this->getContext($context, ')->string($name)->raw('))');
                }
            } elseif (\PHP_VERSION_ID >= 50400) {
                // PHP 5.4 ternary operator performance was optimized
                $compiler
                    ->raw('(isset($context[')
                    ->string($name)
                    ->raw(']) ? $context[')
                    ->string($name)
                    ->raw('] : ')
                ;

                if ($this->getAttribute('ignore_strict_check') || !$compiler->getEnvironment()->isStrictVariables()) {
                    $compiler->raw('null)');
                } else {
                    $compiler->raw('$this->getContext($context, ')->string($name)->raw('))');
                }
            } else {
                $compiler
                    ->raw('$this->getContext($context, ')
                    ->string($name)
                ;

                if ($this->getAttribute('ignore_strict_check')) {
                    $compiler->raw(', true');
                }

                $compiler
                    ->raw(')')
                ;
            }
        }
    }

    public function isSpecial()
    {
        return isset($this->specialVars[$this->getAttribute('name')]);
    }

    public function isSimple()
    {
        return !$this->isSpecial() && !$this->getAttribute('is_defined_test');
    }
}

class_alias('Twig\Node\Expression\NameExpression', 'Twig_Node_Expression_Name');