<?php

declare(strict_types=1);

namespace App\Cfnpp\Expression\Token;

use App\Cfnpp\Expression\Token;
use App\Cfnpp\Expression\TokenLiteral;

/**
 * Reference to a variable.
 *
 * @author Adam Pippin <hello@adampippin.ca>
 */
class Variable extends TokenLiteral
{
	/**
	 * Name of the variable.
	 * @var string
	 */
	protected $name;

	/**
	 * New variable reference.
	 *
	 * @param string $name
	 */
	public function __construct(string $name)
	{
		$this->name = $name;
	}

	/**
	 * Get the name of the variable.
	 *
	 * @return string
	 */
	public function getName(): string
	{
		return $this->name;
	}

	public static function isToken(string $stream): bool
	{
		return (bool)preg_match('/^[A-Za-z]$/', $stream[0]);
	}

	public static function getToken(string &$stream): Token
	{
		$buffer = '';
		$buffer = $stream[0];
		for ($i = 1; $i < strlen($stream); $i++)
		{
			if (preg_match('/^[A-Za-z0-9]$/', $stream[$i]))
			{
				$buffer .= $stream[$i];
			}
			else
			{
				break;
			}
		}

		$stream = substr($stream, strlen($buffer));

		return new Variable($buffer);
	}

	/**
	 * Not valid. Variable replacement should be handled by the expression parser.
	 *
	 * @param  ?\App\Util\GraphNode[]                $arguments
	 * @throws \Exception                            if called
	 * @return \App\Util\GraphNode|Token|scalar|null
	 */
	public function execute(?array $arguments = null)
	{
		throw new \Exception('Unreplaced variable');
	}
}