---
phase: 02-subscriber-and-billing-core
plan: "01"
subsystem: database
tags: [prisma, postgresql, accounting, double-entry, chart-of-accounts, multi-tenancy]

# Dependency graph
requires:
  - phase: 01-foundation
    provides: Tenant model, User model, createTenant(), withTenantContext(), withPermission() HOF

provides:
  - Account Prisma model with tenant scoping, code/name/accountType/normalBalance/parentId
  - AccountingPeriod Prisma model with year/month/status/closedAt/closedById
  - ISP_CHART_OF_ACCOUNTS: 28-account definition covering all 5 accounting types
  - seedChartOfAccounts(tx, tenantId): auto-provisions COA inside Prisma transaction
  - createTenant() now provisions full COA atomically with tenant+user creation
  - closePeriod, getOpenPeriod, isDateInClosedPeriod functions
  - GET /api/accounting/accounts — list COA for authenticated tenant
  - GET /api/accounting/periods — list accounting periods
  - POST /api/accounting/periods/[id]/close — close a period

affects:
  - 02-02-journal-entry-service (posts to Account records created here; enforces closed periods)
  - 02-03-invoice-billing (uses Subscription Revenue 4010, Accounts Receivable 1100)
  - 02-04-payment-collection (uses Cash accounts 1010/1020, credits AR)
  - All future phases that touch financial data

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "COA auto-provisioning in Prisma $transaction — atomic tenant+user+COA creation"
    - "Zero mutable balance fields — all balances derived from journal entry sums"
    - "On-demand period creation via getOpenPeriod() — periods created at first use"
    - "TxClient pattern — seed functions accept transaction client, not full PrismaClient"
    - "withTenantContext() extended with account and accountingPeriod query blocks"

key-files:
  created:
    - prisma/migrations/20260304144656_add_accounting_models/migration.sql
    - src/lib/accounting/chart-of-accounts.ts
    - src/lib/accounting/accounting-period.ts
    - src/lib/accounting/seed-coa.ts
    - src/app/api/accounting/accounts/route.ts
    - src/app/api/accounting/periods/route.ts
    - src/app/api/accounting/periods/[id]/close/route.ts
    - src/lib/__tests__/accounting-coa.test.ts
  modified:
    - prisma/schema.prisma
    - src/lib/prisma-tenant.ts
    - src/lib/tenant.ts

key-decisions:
  - "28 accounts in ISP COA — 5 parent headers (1000/2000/3000/4000/5000) + 23 leaf accounts"
  - "Subscriber Credits (1150) is contra-asset with CREDIT normal balance — reduces AR"
  - "seedChartOfAccounts receives Prisma tx client (not full PrismaClient) — works inside $transaction"
  - "Periods created on-demand via getOpenPeriod() — not pre-seeded at tenant creation"
  - "closedPeriods back-reference added on User model for Prisma relation integrity"
  - "close route uses closure pattern (withPermission wrapping inside POST fn) for param access"

patterns-established:
  - "Accounting isolation: zero mutable balance fields — enforced at model level (no balanceColumn exists)"
  - "COA seeding: ISP_CHART_OF_ACCOUNTS array ordered parents-before-children for correct parentId resolution"

# Metrics
duration: 7min
completed: 2026-03-04
---

# Phase 2 Plan 01: Chart of Accounts and Accounting Period Management Summary

**ISP double-entry COA (28 accounts, all 5 types) auto-provisioned atomically on tenant signup, with period open/close management — zero mutable balance fields anywhere**

## Performance

- **Duration:** 7 min
- **Started:** 2026-03-04T14:44:47Z
- **Completed:** 2026-03-04T14:51:56Z
- **Tasks:** 2
- **Files modified:** 11

## Accomplishments

- Account and AccountingPeriod Prisma models added with full tenant scoping (RLS-ready indexes, @@unique per tenant)
- 28-account ISP Chart of Accounts (1000-5000 ranges) with correct normal balances across all 5 types
- Every new tenant signup atomically provisions a complete COA inside the existing $transaction
- Accounting period close logic (closePeriod, getOpenPeriod, isDateInClosedPeriod) ready for journal entry enforcement in 02-02
- 28 new tests (121 total) covering COA definition purity, seeding correctness, period management, and createTenant integration

## Task Commits

Each task was committed atomically:

1. **Task 1: Account and AccountingPeriod Prisma models + COA definition** - `7c0caf5` (feat)
2. **Task 2: COA auto-provisioning on tenant signup + API routes + tests** - `a53ee9c` (feat)

## Files Created/Modified

- `prisma/schema.prisma` - Added AccountType/NormalBalance/PeriodStatus enums, Account model, AccountingPeriod model with User.closedPeriods back-reference
- `prisma/migrations/20260304144656_add_accounting_models/migration.sql` - Migration creating account and accounting_period tables
- `src/lib/accounting/chart-of-accounts.ts` - ISP_CHART_OF_ACCOUNTS (28 accounts), AccountType and NormalBalance TypeScript types
- `src/lib/accounting/accounting-period.ts` - getOpenPeriod, closePeriod, isDateInClosedPeriod functions
- `src/lib/accounting/seed-coa.ts` - seedChartOfAccounts(tx, tenantId) — resolves parentCode to parentId during seeding
- `src/lib/prisma-tenant.ts` - Added "account" and "accountingPeriod" to TENANT_SCOPED_MODELS; full query extension blocks for both models
- `src/lib/tenant.ts` - createTenant() now calls seedChartOfAccounts(tx, tenant.id) inside the existing $transaction
- `src/app/api/accounting/accounts/route.ts` - GET /api/accounting/accounts (read:Account permission)
- `src/app/api/accounting/periods/route.ts` - GET /api/accounting/periods (read:Account permission)
- `src/app/api/accounting/periods/[id]/close/route.ts` - POST /api/accounting/periods/[id]/close (manage:Account permission)
- `src/lib/__tests__/accounting-coa.test.ts` - 28 integration and unit tests

## Decisions Made

- **28 accounts with parent headers:** 5 category headers (1000, 2000, 3000, 4000, 5000) plus 23 leaf accounts — provides hierarchical COA structure for reporting
- **Contra-asset 1150:** Subscriber Credits has CREDIT normal balance despite being ASSET type — correctly models overpayments that reduce the AR balance
- **TxClient via `any` cast in tests:** Prisma transaction client types don't align perfectly with interface extraction; using `any` in test is safe (the actual seedChartOfAccounts function is typed correctly via PrismaClient.$transaction parameter inference)
- **Close route uses closure pattern:** `withPermission` HOF doesn't support route params directly — POST function closes over `params` from Next.js route context before invoking the HOF
- **On-demand period creation:** Periods are created on first use (getOpenPeriod), not pre-seeded — avoids creating 12 periods per tenant on signup for months that may never have entries

## Deviations from Plan

None — plan executed exactly as written.

## Issues Encountered

None.

## User Setup Required

None — no external service configuration required.

## Next Phase Readiness

- Account and AccountingPeriod models in database — ready for journal entry posting (02-02)
- All 28 standard ISP accounts provisioned for every new tenant — journal entries can reference accounts by code
- closedPeriods enforcement hook ready — 02-02 JournalEntryService calls isDateInClosedPeriod before posting
- CASL "Account" subject already defined in casl/types.ts — permissions are operational
- withPermission("manage", "Account") guards period close endpoint — aligns with ADMIN-only restriction

---
*Phase: 02-subscriber-and-billing-core*
*Completed: 2026-03-04*