class ExecutionState

class ExecutionState implements ExecutionStateInterface {
    use DataFetcherTrait;
    use GlobalContextRepositoryTrait;
    use TypedDataTrait;
    
    /**
     * Globally keeps the ids of rules blocked due to recursion prevention.
     *
     * @var array
     *
     * @todo Implement recursion prevention from D7.
     * @todo Move this out of Context namespace?
     * @see https://www.drupal.org/project/rules/issues/2677094
     */
    protected static $blocked = [];
    
    /**
     * The known variables.
     *
     * @var \Drupal\Core\TypedData\TypedDataInterface[]
     */
    protected $variables = [];
    
    /**
     * Holds variables for auto-saving later.
     *
     * @var array
     */
    protected $saveLater = [];
    
    /**
     * Variable for saving currently blocked configs for serialization.
     *
     * @var array
     */
    protected $currentlyBlocked;
    
    /**
     * Creates the object.
     *
     * @param \Drupal\Core\TypedData\TypedDataInterface[] $variables
     *   (optional) Variables to initialize this state with.
     *
     * @return static
     */
    public static function create(array $variables = []) {
        return new static($variables);
    }
    
    /**
     * Constructs the object.
     *
     * @param \Drupal\Core\TypedData\TypedDataInterface[] $variables
     *   (optional) Variables to initialize this state with.
     */
    protected function __construct(array $variables) {
        $this->variables = $variables;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setVariable($name, ContextDefinitionInterface $definition, $value) {
        $data = $this->getTypedDataManager()
            ->create($definition->getDataDefinition(), $value);
        $this->setVariableData($name, $data);
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setVariableData($name, TypedDataInterface $data) {
        $this->variables[$name] = $data;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getVariable($name) {
        if (!$this->hasVariable($name)) {
            // @todo This crashes site in certain circumstances - for example if
            // you're reacting on a "Drupal is initializing" event ... Need to handle
            // a problem here gracefully - maybe disable the rule that caused the
            // problem?
            throw new EvaluationException("Unable to get variable '{$name}'; it is not defined.");
        }
        return $this->variables[$name];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getVariableValue($name) {
        return $this->getVariable($name)
            ->getValue();
    }
    
    /**
     * {@inheritdoc}
     */
    public function hasVariable($name) {
        if (!array_key_exists($name, $this->variables)) {
            // If there is no such variable, lazy-add global context variables. That
            // way we can save time fetching global context if it is not needed.
            if (!($name[0] === '@' && strpos($name, ':') !== FALSE)) {
                return FALSE;
            }
            $contexts = $this->getGlobalContextRepository()
                ->getRuntimeContexts([
                $name,
            ]);
            if (!array_key_exists($name, $contexts)) {
                return FALSE;
            }
            $this->setVariableData($name, $contexts[$name]->getContextData());
        }
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function removeVariable($name) {
        if (array_key_exists($name, $this->variables)) {
            unset($this->variables[$name]);
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function fetchDataByPropertyPath($property_path, $langcode = NULL) {
        try {
            // Support global context names as variable name by ignoring points in
            // the service name; e.g. @user.current_user_context:current_user.name.
            if ($property_path[0] == '@') {
                [
                    $service,
                    $property_path,
                ] = explode(':', $property_path, 2);
            }
            $parts = explode('.', $property_path);
            $var_name = array_shift($parts);
            if (isset($service)) {
                $var_name = $service . ':' . $var_name;
            }
            return $this->getDataFetcher()
                ->fetchDataBySubPaths($this->getVariable($var_name), $parts, $langcode);
        } catch (InvalidArgumentException $e) {
            // Pass on the original exception in the exception trace.
            throw new EvaluationException($e->getMessage(), 0, $e);
        } catch (MissingDataException $e) {
            // Pass on the original exception in the exception trace.
            throw new EvaluationException($e->getMessage(), 0, $e);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function saveChangesLater($selector) {
        $this->saveLater[$selector] = TRUE;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAutoSaveSelectors() {
        return array_keys($this->saveLater);
    }
    
    /**
     * {@inheritdoc}
     */
    public function autoSave() {
        // Make changes permanent.
        foreach ($this->saveLater as $selector => $flag) {
            $typed_data = $this->fetchDataByPropertyPath($selector);
            // Things that can be saved must have a save() method, right?
            // Saving is always done at the root of the typed data tree, for example
            // on the entity level.
            $typed_data->getRoot()
                ->getValue()
                ->save();
        }
        return $this;
    }

}