MemberPress: Generate Invoice Numbers for Zero Amount Transactions

/**

 * MemberPress - Generate Invoice Numbers for Zero Amount Transactions

 * 

 * Creates invoice numbers for transactions with zero amounts to maintain

 * accounting consistency.

 */

function mepr_create_invoice_number( $event ) {

    // Fetch MemberPress options

    $mepr_options = MeprOptions::fetch();

    // Get the transaction data from the event

    $transaction = $event->get_data();

    // Check if the transaction amount is negative

    if( $transaction->amount < 0 ) {

        return; // Exit the function if the amount is negative

    }

    // Check if the transaction already has an invoice number

    if( MePdfInvoiceNumber::find_invoice_num_by_txn_id( $transaction->id ) ) {

        return; // Exit the function if an invoice number already exists

    }

    // Get the next available invoice number

    $invoice_no = absint( MePdfInvoiceNumber::next_invoice_num() );

    // Check if the invoice number is valid

    if( $invoice_no <= 0 ) {

        return; // Exit the function if the invoice number is invalid

    }

    // Create a new invoice number object and assign the values

    $invoice_number = new MePdfInvoiceNumber();

    $invoice_number->invoice_number = absint( $invoice_no );

    $invoice_number->transaction_id = absint( $transaction->id );

    // Store the invoice number

    $invoice_number->store();

}

// Add the action to trigger the function when a transaction is completed

add_action( 'mepr-event-transaction-completed', 'mepr_create_invoice_number' );