Sprout settings

functions.php

add_filter( 'si_discount_after_taxes', '__return_false', 1);

function process_ninja_form_and_create_invoice( $entry = array() ) {
    
    $fields = $entry['fields_by_key'];

    $address = array(
        'street' => $fields['address_1530704017856']['value'],
        'city' => $fields['city_1530704053248']['value'],
        'zone' => '',
        'postal_code' => $fields['postal_code_1530704039567']['value'],
        'country' => 'Sweden',
    );
    $args = array(
        'company_name' => $fields['nf_field_foretag']['value'], // required
        'website' => '', // optional
        'address' => $address, // optional
        'user_id' => '' // optional
    );
    $client_id = SI_Client::new_client( $args );

    $data = array(
        'subject' => $fields['reference_numb_1532682390724']['value'] . ' - ' . $fields['nf_field_foretag']['value'] . ' (' . $fields['nf_field_org_numb']['value'] . ')', // title
        'user_id' => '', // user id that created the invoice
        'invoice_id' => $fields['reference_numb_1532682390724']['value'], // Invoice #/ID
        'estimate_id' => '', // Associated Estimate ID (post_id)
        'client_id' => $client_id,  // Associated Client ID (post_id)
        'project_id' => '', // Associated Project ID (post_id)
        'status' => 'pending', // temp, publish, future, partial, complete, write-off
        'deposit' => (float) 0, // deposit amount

        // Setting this doesn't affect the total at all
        'total' => '', // invoice total

        'po_number' => '', // PO number   
        'discount' => 20, // discount
        'tax' => (float) 25, // Tax
        'tax2' => (float) 0, // Tax 2
        'notes' => '', // Notes
        'terms' => '', // Terms
        'issue_date' => time(), // Issue Date (timestamp)
        'due_date' => $fields['invoice_due_date_1534002818312']['value'], // Due Date (timestamp)
        'expiration_date' => 0, // Expiration date (timestamp)
        'line_items' => array( // example of two line items
            array(
                'type' => 'service',
                'rate' => 350,
                'qty' => 1,
                'tax' => '',
                'total' => 350,
                'desc' => $fields['language_1530703794562']['value'],
            )
        ), // associated array of line items
    );
    $invoice_id = SI_Invoice::create_invoice( $data );
    
}
add_action( 'ninja_forms_after_submission', 'process_ninja_form_and_create_invoice', 10, 2 );