<?php

/**
 * this class is used when we want to publish a request to the AdminIn broker.  The class wraps all of the 
 * RabbitMQ initialization and communication work so you don't have to.  Especially useful for unit testing.
 * 
 * 
 * @author  mike@givingassistant.org
 * @version 1.0
 * 
 * HISTORY:
 * ========
 * 06-15-17     mks     original coding
 * 07-07-17     mks     CORE-463: updated for async logging (appserver posting log events to admin server)
 * 07-31-18     mks     CORE-774:  PHP7.2 exception handling
 * 01-29-20     mks     DB-144: PHP7.4 support
 * 10-15-20     mks     DB-168: renamed, supports all namaste work queues (adminBrokerIn and sBroker)
 *
 */

use PhpAmqpLib\Channel\AMQPChannel;
use PhpAmqpLib\Exception\AMQPRuntimeException;
use PhpAmqpLib\Exception\AMQPTimeoutException;
use PhpAmqpLib\Message\AMQPMessage;

class gacWorkQueueClient
{
    private object $rabbitConnection;  // actually contains AMQPStreamConnection type but the API declares object|null
    private ?AMQPChannel $rabbitChannel = null;
    private ?string $rabbitCallbackQueue;
    private ?string $rabbitResponse;
    private string $rabbitCorrelationID;
    private string $queueName;

    public bool $status;

    /**
     * __construct() -- public method
     *
     * this is the constructor for the class.  it requests an admin resource from the resource manager and declares
     * a client-side connection to the service.
     *
     * there is an optional input parameter -- $_fw (from-where) that inserts a string into the queue label allowing
     * easy identification of the requesting source.
     *
     * the method returns no values.  It only sets the class' status member variable, a Boolean, on success or fail,
     * accordingly.
     *
     *
     * @author  mike@givingassistant.org
     * @version 1.0
     *
     *
     * @param $_fw - "from where" - tweaks queue label to identify request origin
     * @param $_which - which fire-n-forget broker queue to attache to (default is adminIn)
     *
     *
     * HISTORY:
     * ========
     * 06-15-17     mks     original coding
     * 05-31-18     mks     CORE-1011: update for new XML broker services configuration
     * 05-31-18     mks     CORE-1011: update for new XML broker services configuration
     * 09-19-19     mks     DB-136: improved exception handling
     * 10-02-20     mks     DB-168: support for (new) session broker (also fire-n-forget), removed callback method
     *
     */
    public function __construct(string $_fw = __METHOD__ . AT . __LINE__, string $_which = BROKER_QUEUE_AI)
    {
        register_shutdown_function(array($this, STRING_DESTRUCTOR));
        $this->status = false;

        switch ($_which) {
            case BROKER_QUEUE_AI :
                $resource = RESOURCE_ADMIN;
                $queue = BROKER_QUEUE_AI;
                $labelClient = 'gacAdminInClient<';
            break;
            case BROKER_QUEUE_S :
                $resource = RESOURCE_TERCERO;
                $queue = BROKER_QUEUE_S;
                $labelClient = 'gacSessionClient<';
            break;
            default :
                consoleLog('cACI: ', CON_ERROR, ERROR_CONFIG_RESOURCE_404 . $_which);
                return;
            break;
        }

        $this->queueName = gasConfig::$settings[CONFIG_BROKER_SERVICES][CONFIG_BROKER_QUEUE_TAG] . $queue;
        try {
            $this->rabbitConnection = gasResourceManager::fetchResource($resource);
            if (is_null($this->rabbitConnection)) return;
            $this->rabbitChannel = $this->rabbitConnection->channel();
            $label = uniqid($labelClient . $_fw . '>:');
            list($this->rabbitCallbackQueue, ,) = $this->rabbitChannel->queue_declare($label . uniqid(), false, false, false, true);
            $this->rabbitChannel->basic_consume($this->rabbitCallbackQueue, '', false, true, false, false);
            $this->rabbitResponse = null;
            $this->status = true;
        } catch (AMQPRuntimeException | AMQPTimeoutException | Throwable | TypeError $t) {
            $hdr = basename(__METHOD__) . AT . __LINE__ . COLON;
            @handleExceptionMessaging($hdr, $t->getMessage(), $foo, true);
        }
    }


    /**
     * call() -- public method
     *
     * This method is invoked outside of the class and is the entry point for publishing a message request to the
     * AdminIn broker.  It creates a new AMQP message and publishes it to the queue (defined in the constructor),
     * and then exits, returning a true message indicating that the messages was successfully published.
     *
     * Since the AdminIN broker is a fire-n-forget broker, there are no return messages to block-and-wait on.
     *
     * If an exception is raised by this class, then a false value will be returned.
     *
     * NOTE: the true/false return values are not, in any way, a reflection of the processing success/failure on the
     * remote service.  The general RoT is that if we can publish the request, then we can only assume that the request
     * was successfully consumed and processed.
     *
     * @author  mike@givingassistant.org
     * @version 1.0
     *
     * @param $_data
     * @return bool
     *
     * HISTORY:
     * ========
     * 06-15-17     mks     original coding
     * 08-17-17     mks     CORE-500: returning a boolean that actually indicates if we successfully published the event
     * 09-19-19     mks     DB-136: refactored exception handling, fixed the AMQPMessage create call
     * 10-20-20     mks     DB-168: better exception handling, removed channel close b/c autodelete is on
     *
     */
    public function call($_data): bool
    {
        $this->rabbitResponse = null;
        $this->rabbitCorrelationID = uniqid();
        $success = false;

        try {
            $rabbitMessage = new AMQPMessage((string)$_data);
            $this->rabbitChannel->basic_publish($rabbitMessage, '', $this->queueName);
            $success = true;
        } catch (AMQPTimeoutException | AMQPRuntimeException | Throwable $e) {
            $hdr = basename(__METHOD__) . AT . __LINE__ . COLON;
            @handleExceptionMessaging($hdr, $e->getMessage(), $foo, true);
        }
        return ($success);
    }


    public function __destruct()
    {
        // As of PHP 5.3.10 destructors are not run on shutdown caused by fatal errors.
        //
        // destructor is registered shut-down function in constructor -- so any recovery
        // efforts should go in this method.
        try {
            if (!is_null($this->rabbitChannel)) {
                $this->rabbitChannel->close();
                $this->rabbitConnection->close();
            }
        } catch (AMQPRuntimeException | AMQPTimeoutException | Throwable | TypeError $t) {
            $hdr = basename(__METHOD__) . AT . __LINE__ . COLON;
            @handleExceptionMessaging($hdr, $t->getMessage(), $foo, true);
        }
    }
}