<?php

declare(strict_types=1);

namespace App\Cfnpp\Expression\Token;

use App\Cfnpp\Expression\Token;
use App\Cfnpp\Expression\TokenUnary;
use App\Cfnpp\Expression\ICloudformationNative;

/**
 * Basic operators that take one parameter.
 *
 * @author Adam Pippin <hello@adampippin.ca>
 */
class OperatorUnary extends TokenUnary implements ICloudformationNative
{
	/**
	 * List of valid operators.
	 * @var string[]
	 */
	public const OPERATORS = [
		'not'
	];

	/**
	 * The operator this instance represents.
	 * @var string
	 */
	protected $operator;

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

	/**
	 * Get the operator this instance represents.
	 *
	 * @return string
	 */
	public function getOperator()
	{
		return $this->operator;
	}

	public static function isToken(string $stream): bool
	{
		foreach (static::OPERATORS as $operator)
		{
			if (strlen($stream) >= strlen($operator) &&
				substr($stream, 0, strlen($operator)) == $operator)
			{
				return true;
			}
		}
		return false;
	}

	public static function getToken(string &$stream): Token
	{
		foreach (static::OPERATORS as $operator)
		{
			if (strlen($stream) >= strlen($operator) &&
				substr($stream, 0, strlen($operator)) == $operator)
			{
				$operator = substr($stream, 0, strlen($operator));
				$stream = substr($stream, strlen($operator));
				return new OperatorUnary($operator);
			}
		}
		throw new \Exception('Could not parse OperatorUnary');
	}

	/**
	 * Execute the operator.
	 *
	 * Suppressing accesses to arguments since this is guaranteed valid
	 * unless there are bugs in Expression.
	 * @suppress PhanTypeArraySuspiciousNullable
	 * @param  ?\App\Util\GraphNode[]                $arguments
	 * @return \App\Util\GraphNode|Token|scalar|null
	 */
	public function execute(?array $arguments = null)
	{
		$value = $arguments[0]->getValue();
		switch ($this->getOperator())
		{
			case 'not':
				return is_scalar($value) ? !$value : null;
			default:
				throw new \Exception('Missing implementation for unary operator: '.$this->getOperator());
		}
	}

	/**
	 * Convert this token into a CloudFormation intrinsic.
	 *
	 * Suppressing accesses to arguments since this is guaranteed valid
	 * unless there are bugs in Expression.
	 * @suppress PhanTypeArraySuspiciousNullable
	 * @param  ?\App\Util\GraphNode[] $arguments
	 * @return mixed[]
	 */
	public function toCloudformation(?array $arguments = null): array
	{
		$value = $arguments[0]->getValue();
		switch ($this->getOperator())
		{
			case 'not':
				return ['Fn::Not' => [$value]];
			default:
				throw new \Exception('Missing implementation for unary operator: '.$this->getOperator());
		}
	}
}