Issue #71 — Backend: Admin Analytics — Revenue & Invoice Stats

[yusuftomilola]

Location: backend/src/dashboard/providers/admin-analytics.provider.ts

Description

The first set of admin analytics covers financial performance — total revenue ever, revenue this month, revenue last month, a 6-month revenue trend, and invoice summary counts. All revenue figures come from Payment records with status = SUCCESS. The 6-month trend groups payments by calendar month using DATE_TRUNC.

This is the first method on the AdminAnalyticsProvider class. Subsequent issues (#72 and #73) add more methods to the same class — contributors should coordinate to avoid merge conflicts on this file.

Acceptance Criteria

• An AdminAnalyticsProvider class is created at backend/src/dashboard/providers/admin-analytics.provider.ts with @InjectRepository decorators for Payment and Invoice
• A getRevenueStats(from?: string, to?: string) method is implemented that returns:
  • total — sum of amountKobo across all SUCCESS payments (filtered by date range if provided)
  • thisMonth — sum of amountKobo for SUCCESS payments where paidAt is in the current calendar month
  • lastMonth — sum of amountKobo for SUCCESS payments where paidAt is in the previous calendar month
  • trend — array of { month: string, totalKobo: number, totalNaira: number } for the last 6 calendar months, computed via DATE_TRUNC('month', "paidAt") grouped query, ordered oldest to newest
• A getInvoiceStats(from?: string, to?: string) method is implemented that returns:
  • total — total count of all invoices
  • paid — count of invoices with status = PAID
  • pending — count of invoices with status = PENDING
  • totalAmountKobo — sum of amountKobo across all invoices
  • totalAmountNaira — totalAmountKobo / 100
• Both methods accept optional from and to date strings and apply them as filters on the relevant timestamp column when provided
• npx tsc --noEmit passes with no errors