<?php

declare(strict_types=1);

namespace App\Cfnpp\Expression\Token;

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

/**
 * A boolean literal (true/false).
 *
 * @author Adam Pippin <hello@adampippin.ca>
 */
class BooleanLiteral extends TokenLiteral
{
	/**
	 * Value of this literal.
	 * @var bool
	 */
	protected $value;

	/**
	 * New boolean literal.
	 *
	 * @param bool $value
	 */
	public function __construct(bool $value)
	{
		$this->value = $value;
	}

	/**
	 * Get the value of this literal.
	 *
	 * @return bool
	 */
	public function getValue(): bool
	{
		return $this->value;
	}

	public static function isToken(string $stream): bool
	{
		return
			(strlen($stream) >= 4 && strtolower(substr($stream, 0, 4)) == 'true') ||
			(strlen($stream) >= 5 && strtolower(substr($stream, 0, 5)) == 'false');
	}

	public static function getToken(string &$stream): Token
	{
		if (strlen($stream) >= 4 && strtolower(substr($stream, 0, 4)) == 'true')
		{
			$stream = substr($stream, 4);
			return new BooleanLiteral(true);
		}
		elseif (strlen($stream) >= 5 && strtolower(substr($stream, 0, 5)) == 'false')
		{
			$stream = substr($stream, 5);
			return new BooleanLiteral(false);
		}
		throw new \Exception('Unparseable boolean');
	}

	/**
	 * Get the value of this token.
	 *
	 * @param  ?\App\Util\GraphNode[]                $arguments
	 * @return \App\Util\GraphNode|Token|scalar|null
	 */
	public function execute(?array $arguments = null)
	{
		return $this->getValue();
	}
}