server/src/Billing/Services/Implementations/InvoiceCreatedHandler.cs

using Bit.Core.Billing.Constants;
using Bit.Core.Services;
using Event = Stripe.Event;

namespace Bit.Billing.Services.Implementations;

public class InvoiceCreatedHandler(
    IBraintreeService braintreeService,
    ILogger<InvoiceCreatedHandler> logger,
    IStripeEventService stripeEventService,
    IProviderEventService providerEventService)
    : IInvoiceCreatedHandler
{

    /// <summary>
    /// <para>
    /// This handler processes the `invoice.created` event in <see href="https://docs.stripe.com/api/events/types#event_types-invoice.created">Stripe</see>. It has
    /// two primary responsibilities.
    /// </para>
    /// <para>
    /// 1. Checks to see if the newly created invoice belongs to a PayPal customer. If it does, and the invoice is ready to be paid, it will attempt to pay the invoice
    /// with Braintree and then let Stripe know the invoice can be marked as paid.
    /// </para>
    /// <para>
    /// 2. If the invoice is for a provider, it records a point-in-time snapshot of the invoice broken down by the provider's client organizations. This is later used in
    /// the provider invoice export.
    /// </para>
    /// </summary>
    public async Task HandleAsync(Event parsedEvent)
    {
        try
        {
            var invoice = await stripeEventService.GetInvoice(parsedEvent, true, ["customer", "parent.subscription_details.subscription"]);

            var usingPayPal = invoice.Customer.Metadata.ContainsKey("btCustomerId");

            if (usingPayPal && invoice is
                {
                    AmountDue: > 0,
                    Status: not StripeConstants.InvoiceStatus.Paid,
                    CollectionMethod: "charge_automatically",
                    BillingReason:
                    "subscription_cycle" or
                    "automatic_pending_invoice_item_invoice",
                    Parent.SubscriptionDetails.Subscription: not null
                })
            {
                await braintreeService.PayInvoice(invoice.Parent.SubscriptionDetails.Subscription, invoice);
            }
        }
        catch (Exception exception)
        {
            logger.LogError(exception, "Failed to attempt paying for invoice while handling 'invoice.created' event ({EventID})", parsedEvent.Id);
        }

        try
        {
            await providerEventService.TryRecordInvoiceLineItems(parsedEvent);
        }
        catch (Exception exception)
        {
            logger.LogError(exception, "Failed to record provider invoice line items while handling 'invoice.created' event ({EventID})", parsedEvent.Id);
        }
    }
}