# Milestone 2 Completion Note

## Project

Open Solar Payments: Open-Source Bitcoin Payment Rails for Solar Access in Emerging Markets

## Milestone

Bitcoin/Lightning checkout: implement invoice creation and checkout flow.

## Status

Working scaffold complete.

## Implemented Deliverables

- Lightning-style invoice generation through a provider adapter
- Checkout payment state
- Payment expiry handling
- Payment confirmation flow through webhook processing
- Basic receipt generation
- Idempotent duplicate webhook handling
- Runnable demo and test script

## Current Provider

The current provider is `MockLightningProvider`. It is intentionally used for Milestone 2 so the payment lifecycle can be verified without live BTCPay Server credentials.

The next implementation step is to add a `BTCPayProvider` adapter behind the same interface:

```text
createInvoice(paymentRequest)
getInvoiceStatus(providerInvoiceId)
parseWebhook(payload, headers)
verifyWebhook(event)
```

## Grant-Ready Claim

The project can now say:

> Milestone 2 has a working checkout scaffold. It creates Bitcoin/Lightning payment requests and invoices, tracks checkout state, handles invoice expiry, processes payment confirmation, and generates a basic receipt. The provider interface is ready for BTCPay Server integration.

## Remaining To Make It Production-Ready

- Add real BTCPay Server adapter
- Add persistent database storage
- Add authenticated customer/admin routes
- Add signed webhook verification
- Add Suntecorb UI integration
- Add workorder settlement linkage for Milestone 3