QualPay Checkout payment gateway

add_action( 'woocommerce_init', function() {

	// Payment Gateway Class
	class WC_Gateway_QualPayCheckout extends WC_Payment_Gateway {

		// Constructor
		function __construct() {
			$this->endpoint = 'https://api.qualpay.com';
			$this->has_fields = false;
			$this->id = 'qualpaycheckout';
			$this->method_title = 'QualPay Checkout';
			$this->method_description = 'Implements QualPay Checkout Pay Page';
			$this->init_form_fields();
			$this->init_settings();
			$this->title = $this->get_option( 'title' );
			add_action(
				'woocommerce_update_options_payment_gateways_' . $this->id,
				[ $this, 'process_admin_options' ]
			);
		}

		// Settings Fields
		function init_form_fields() {
			$this->form_fields = array(
				'enabled' => array(
					'title' => __( 'Enable/Disable', 'woocommerce' ),
					'type' => 'checkbox',
					'label' => 'Enable QualPay Checkout',
					'default' => 'yes',
				),
				'testmode' => array(
					'title' => __( 'Test mode', 'woocommerce' ),
					'type' => 'checkbox',
					'label' => 'Enable test mode',
					'default' => 'yes',
				),
				'title' => array(
					'title' => __( 'Title', 'woocommerce' ),
					'type' => 'text',
				),
				'api_key' => array(
					'title' => 'QualPay API Key',
					'type' => 'text',
				),
				'checkout_id' => array(
					'title' => 'QualPay Checkout ID',
					'type' => 'number',
				),
				'currency_code' => array(
					'title' => 'QualPay Currency Code',
					'type' => 'number',
				),
				'profile_id' => array(
					'title' => 'QualPay Profile ID',
					'type' => 'number',
				),
			);
		}

		// WooCommerce Order Submitted
		function process_payment( $order_id ) {

			// Get Customer And Order
			$customer = WC()->session->get( 'customer' );
			$order = new WC_Order( $order_id );

			// Set Payent Pending Status
			$order->update_status( 'pending', __( 'Awaiting payment', 'woocommerce' ) );

			// Build Checkout Request
			$request = ( object ) [
				'amt_tran' => ( float ) $order->get_total(),
				'tran_currency' => ( string ) $this->settings['currency_code'],
				'purchase_id' => 'WC-' . $order_id,
				'profile_id' => ( string ) $this->settings['profile_id'],
				'merch_ref_num' => 'WC-' . $order_id,
				'customer_first_name' => $customer['first_name'],
				'customer_last_name' => $customer['last_name'],
				'customer_firm_name' => $customer['company'],
				'customer_email' => $customer['email'],
				'billing_addr1' => $customer['address_1'],
				'billing_addr2' => $customer['address_2'],
				'billing_state' => $customer['state'],
				'billing_city' => $customer['city'],
				'billing_zip' => $customer['postcode'],
				'moto_ecomm_ind' => '7',
				'preferences' => ( object ) [
					'success_url' => $this->get_return_url( $order ),
					'failure_url' => $order->get_checkout_payment_url(),
					'allow_partial_payments' => false,
					'allow_save_card' => false,
					'allow_ach_payment' => false,
					'email_receipt' => false,
					'request_type' => 'sale',
					'expire_in_secs' => 10000,
				],
				'checkout_profile_id' => $this->settings['checkout_id'],
			];
			$args = [
				'headers' => [
					'Authorization:Basic' => base64_encode( $this->settings['api_key'] . ':' ),
					'Content-Type' => 'application/json; charset=utf-8',
				],
				'data_format' => 'body',
				'body' => json_encode( $request )
			];

			// Send Checkout Request
			if( $this->settings['testmode'] == 'yes' ) {
				$this->endpoint = str_replace( 'api', 'api-test', $this->endpoint );
			}
			$url = $this->endpoint . '/platform/checkout';
			$response = wp_remote_post( $url, $args );

			// Parse Response
			$response = isset( $response['body'] ) ? json_decode( $response['body'] ) : $response;
			$message = isset( $response->message ) ? $response->message : $response;
			$data = isset( $response->data ) ? $response->data : '';
			$checkout_link = isset( $data->checkout_link ) ? $data->checkout_link : '';
			$checkout_id = isset( $data->checkout_id ) ? $data->checkout_id : '';

			// Handle Checkout Error
			if( ! $checkout_link ) {
				$message = sprintf(
					'Problem with QualPay Checkout: %s',
					print_r( $message, true )
				);
				$order->update_status( 'failed', $message );
				wc_add_notice( print_r( $message, true ), 'error' );
				return;
			}

			// Handle Checkout Success
			$order->add_order_note( 'Redirected to QP Checkout ID ' . $checkout_id );
			return [ 'result' => 'success', 'redirect' => $checkout_link ];
		}
	}
} );

// Add Gateway To WooCommerce
add_filter( 'woocommerce_payment_gateways', function( $methods ) {
	$methods[] = 'WC_Gateway_QualPayCheckout'; 
	return $methods;
} );

// Handle Double Querystring Bug
add_action( 'template_redirect', function() {
	$order_key = isset( $_GET['key'] ) ? esc_attr( $_GET['key'] ) : '';
	$rcode = isset( $_GET['rcode'] ) ? esc_attr( $_GET['rcode'] ) : '';
	if( strchr( $order_key, '?' ) ) {
		global $wp;
		$order_id = absint( $wp->query_vars['order-received'] );
		if( ! $order_id ) {
			$order_id = absint( $wp->query_vars['order-pay'] );
		}
		if( ! $order_id ) { return; }
		$order = new WC_Order( $order_id );
		if( is_wp_error( $order ) || ! $order ) { return; }
		$order_key = substr( $order_key, 0, strpos( $order_key, '?' ) );
		$redirect = empty( $_GET['pay_for_order'] )
			? $order->get_checkout_order_received_url() . '&rcode=' . $rcode
			: $order->get_checkout_payment_url() . '&rcode=' . $rcode;
		exit( wp_redirect( $redirect ) );
	}
} );

// Handle Payment Errors
add_action( 'template_redirect', function() {
	$rcode = isset( $_GET['rcode'] ) ? esc_attr( $_GET['rcode'] ) : '';
	if( $rcode == '000' || ! $rcode ) { return; }
	$rcodes = [
		'000' => 'Success',
		'005' => 'Simulation',
		100 => 'Bad request',
		101 => 'Invalid credentials',
		102 => 'Invalid pg_id',
		103 => 'Missing cardholder data',
		104 => 'Invalid transaction amount',
		105 => 'Missing auth_code',
		106 => 'Invalid AVS (Address Verification Service) data',
		107 => 'Invalid expiration date',
		108 => 'Invalid card number',
		109 => 'Field length validation failed',
		110 => 'Dynamic DBA not allowed',
		111 => 'Credits not allowed',
		112 => 'Invalid customer data',
		113 => 'Declined due to merchant risk settings',
		114 => 'Invalid currency code',
		115 => 'Invalid surcharge data',
		116 => 'Invalid email address',
		117 => 'Email address is required',
		118 => 'Invalid merchant logo URL',
		119 => 'Invalid ACH payment',
		401 => 'Void failed',
		402 => 'Refund failed',
		403 => 'Capture failed',
		404 => 'Batch close failed',
		405 => 'Tokenization failed',
		998 => 'Timeout',
		999 => 'Internal error',
	];
	if( empty( $rcodes[$rcode] ) ) {
		$rcodes[$rcode] = 'Missing error descriptor';
	}
	$error_message = sprintf(
		'QualPay Checkout error code %s: %s', $rcode, $rcodes[$rcode]
	);

	// Set Woo Order Status And Note
	$order_id = get_query_var( 'order-pay' );
	if( intval( $order_id ) ) {
		$order = new WC_Order( $order_id );
		if( ! is_wp_error( $order ) && $order ) {
			$order->update_status( 'failed' );
			$order->add_order_note( $error_message );
		}
	}

	// Set Woo Notice
	if( function_exists( 'wc_add_notice' ) ) {
		$message = sprintf(
			'
				Please try again.
				<a href="mailto:%s">Let us know if the problem persists.</a>
			',
			get_bloginfo( 'admin_email' )
		);
		wc_add_notice( $error_message . $message, 'error' );
	}
} );

// Handle Successful Payments
add_action( 'woocommerce_thankyou_qualpaycheckout', function( $order_id ) {

	// Get Order
	$order = new WC_Order( $order_id );
	if( is_wp_error( $order ) || ! $order ) { return; }

	// Security Check
	$order_key = isset( $_GET['key'] ) ? esc_attr( $_GET['key'] ) : '';
	if( $order_key != $order->get_order_key() ) { return; }

	// Return Code Check
	$rcode = isset( $_GET['rcode'] ) ? esc_attr( $_GET['rcode'] ) : '';
	if( $rcode != '000' ) { return; }

	// Empty The Cart
	global $woocommerce;
	$woocommerce->cart->empty_cart();

	// Set Order Note
	$order->add_order_note( 'QualPay Checkout payment success.' );

	// Mark Order Paid
	$order->payment_complete();
} );