rosavox/lib/alveolata/auth/policy.php

<?php

namespace alveolata\auth;

// require_once(DIR_ALVEOLATA . '/definitions.php');
require_once(DIR_ALVEOLATA . '/list/functions.php');
require_once(DIR_ALVEOLATA . '/string/functions.php');
require_once(DIR_ALVEOLATA . '/session/session.php');



/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class class_exception_policyreport extends \Exception
{
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
		$messages
	)
	{
		parent::__construct(
			' | '.join($messages)
		);
	}
	
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
abstract class class_policy
{
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
	)
	{
	}
	
	
	/**
	 * @param record<session_id:string> $environment
	 * @return list<string>
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	abstract public function check(
		array $environment
	) : array
	;
	
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class class_policy_none extends class_policy
{
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
	)
	{
		parent::__construct();
	}
	
	
	/**
	 * @implementation
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function check(
		array $environment
	) : array
	{
		return [];
	}
	
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class class_policy_conjunction extends class_policy
{
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
		array $subpolicies
	)
	{
		parent::__construct();
		$this->subpolicies = $subpolicies;
	}
	
	
	/**
	 * @implementation
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function check(
		array $environment
	) : array
	{
		return (
			\alveolata\list_\reduce(
				\alveolata\list_\map(
					$this->subpolicies,
					function ($policy) use ($environment) {
						return $policy->check($environment);
					}
				),
				[],
				function ($x, $y) {return \alveolata\list_\concat($x, $y);}
			)
		);
	}
	
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class class_policy_disjunction extends class_policy
{
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
		array $subpolicies
	)
	{
		parent::__construct();
		$this->subpolicies = $subpolicies;
	}
	
	
	/**
	 * @implementation
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function check(
		array $environment
	) : array
	{
		$some = \alveolata\list_\some(
			$this->subpolicies,
			function ($policy) use ($environment) {
				return $policy->check($environment);
			}
		);
		return ($some ? [] : ['all alternatives failed']);
	}
	
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class class_policy_logged_in extends class_policy
{
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
	)
	{
		parent::__construct();
	}
	
	
	/**
	 * @implementation
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function check(
		array $environment
	) : array
	{
		if (! array_key_exists('session_id', $environment)) {
			return ['session id not set'];
		}
		else {
			if (! \alveolata\session\has($environment['session_id'])) {
				return ['no session present'];
			}
			else {
				return [];
			}
		}
	}
	
}


/**
 * @param record<kind:string,parameters:map<strin,any>>
 * @return class_policy
 * @author Christian Fraß <frass@greenscale.de>
 */
function make(
	array $description
) : class_policy
{
	switch ($description['kind']) {
		default: {
			throw (
				new \Exception(
					\alveolata\string\coin('unhandled policy kind "{{kind}}"', ['kind' => $description['kind']])
				)
			);
			break;
		}
		case 'none': {
			return (
				new class_policy_none(
				)
			);
			break;
		}
		case 'logged_in': {
			return (
				new class_policy_logged_in(
				)
			);
			break;
		}
		case 'conjunction': {
			return (
				new class_policy_conjunction(
					\helper\list_\map(
						$description['parameters']['sub'] ?? [],
						function ($description_) {
							return make($description_);
						}
					)
				)
			);
			break;
		}
		case 'disjunction': {
			return (
				new class_policy_disjunction(
					\helper\list_\map(
						$description['parameters']['sub'] ?? [],
						function ($description_) {
							return make($description_);
						}
					)
				)
			);
			break;
		}
	}
}


/**
 * @param class_policy $policy
 * @param function<void,type_result> $function
 * @param record<session_id:string> $environment
 * @return type_result
 * @throw \Exception if the policy check fails
 * @author Christian Fraß <frass@greenscale.de>
 */
function wrap/*<type_result>*/(
	class_policy $policy,
	array $environment,
	\Closure $function
)/* : type_result*/
{
	$messages = $policy->check($environment);
	if (count($messages) === 0) {
		$result = $function();
		return $result;
	}
	else {
		throw (new class_exception_policyreport($messages));
	}
}