---
phase: 02-backend-refactor
plan: "02"
subsystem: http-handlers
tags: [server-struct, dependency-injection, store-interface, test-isolation, in-memory-sqlite, refactor]

# Dependency graph
requires:
  - phase: 02-01
    provides: Store interface (9 methods), SQLiteStore, RunMigrations
provides:
  - Server struct with Store field and webhookSecret field
  - NewServer constructor wiring Store and secret
  - All 6 handlers converted to *Server methods calling s.store.X()
  - NewTestServer / NewTestServerWithSecret helpers for isolated per-test databases
  - main.go wiring: sql.Open -> RunMigrations -> NewSQLiteStore -> NewServer -> routes
affects:
  - 03-postgresql (PostgreSQLStore will implement same Store interface; Server struct accepts any Store)

# Tech tracking
tech-stack:
  added: []
  patterns:
    - Server struct pattern - all handler dependencies injected via constructor, no package-level globals
    - export_test.go internal helpers (TestUpsertEvent, TestGetUpdatesMap) - access unexported fields without exposing Store accessor
    - Per-test in-memory SQLite database via NewTestServer() - eliminates shared state between tests
    - NewTestServerWithSecret for auth-enabled test scenarios

key-files:
  created: []
  modified:
    - pkg/diunwebhook/diunwebhook.go
    - pkg/diunwebhook/export_test.go
    - pkg/diunwebhook/diunwebhook_test.go
    - cmd/diunwebhook/main.go

key-decisions:
  - "Option B for test store access: internal helpers in export_test.go (TestUpsertEvent, TestGetUpdatesMap) instead of exported Store() accessor - keeps store field unexported"
  - "t.Errorf used inside goroutines in TestConcurrentUpdateEvent (t.Fatalf is not safe from non-test goroutines)"
  - "_ modernc.org/sqlite blank import moved from diunwebhook.go to main.go and migrate.go - driver registration happens where needed"

patterns-established:
  - "Server struct: HTTP handlers as methods on *Server, all deps injected at construction"
  - "NewTestServer pattern: each test creates its own in-memory SQLite DB via RunMigrations + NewSQLiteStore + NewServer"
  - "export_test.go internal methods: (s *Server) TestUpsertEvent / TestGetUpdatesMap access s.store without exporting Store field"

requirements-completed: [REFAC-01, REFAC-02, REFAC-03]

# Metrics
duration: 3min
completed: "2026-03-23"
---

# Phase 02 Plan 02: Server Struct Refactor and Test Isolation Summary

**Server struct with Store injection, globals removed, all 6 handlers as *Server methods calling s.store.X(), per-test in-memory databases via NewTestServer**

## Performance

- **Duration:** ~3 min
- **Started:** 2026-03-23T21:02:53Z
- **Completed:** 2026-03-23T21:05:09Z
- **Tasks:** 2
- **Files modified:** 4

## Accomplishments

- Removed all package-level globals (db, mu, webhookSecret) from diunwebhook.go
- Removed InitDB, SetWebhookSecret, UpdateEvent, GetUpdates functions (replaced by Store and Server)
- Added Server struct with store Store and webhookSecret string fields
- Added NewServer(store Store, webhookSecret string) *Server constructor
- Converted all 6 handler functions to *Server methods using s.store.X() for all persistence
- Rewrote export_test.go: NewTestServer, NewTestServerWithSecret, TestUpsertEvent, TestGetUpdatesMap helpers
- Rewrote diunwebhook_test.go: every test creates its own isolated in-memory database (no shared global state)
- Updated main.go: sql.Open -> RunMigrations -> NewSQLiteStore -> NewServer -> route registration
- All 35 tests pass against the new Server/Store architecture

## Task Commits

Each task was committed atomically:

1. **Task 1: Convert diunwebhook.go to Server struct and update main.go** - `78543d7` (feat)
2. **Task 2: Rewrite export_test.go and update all tests for Server/Store** - `e35b4f8` (test)

## Files Created/Modified

- `pkg/diunwebhook/diunwebhook.go` - Server struct, NewServer constructor, all 6 handlers as *Server methods; globals and standalone functions removed
- `pkg/diunwebhook/export_test.go` - NewTestServer, NewTestServerWithSecret, (s *Server) TestUpsertEvent, TestGetUpdates, TestGetUpdatesMap
- `pkg/diunwebhook/diunwebhook_test.go` - All 35 tests rewritten to use NewTestServer per-test; no shared state; no TestMain
- `cmd/diunwebhook/main.go` - Full replacement: sql.Open -> RunMigrations -> NewSQLiteStore -> NewServer -> route registration with srv.XHandler

## Decisions Made

- Test store access via internal helper methods in export_test.go (Option B) — avoids exposing Store field publicly while still letting tests call UpsertEvent/GetUpdates
- t.Errorf used inside goroutine in TestConcurrentUpdateEvent — t.Fatalf is not safe from non-test goroutines (pre-existing issue resolved)
- _ "modernc.org/sqlite" blank import moved to main.go (and already in migrate.go) — driver registered where *sql.DB is opened

## Deviations from Plan

None - plan executed exactly as written.

## Known Stubs

None.

## Self-Check: PASSED

- pkg/diunwebhook/diunwebhook.go: FOUND
- pkg/diunwebhook/export_test.go: FOUND
- pkg/diunwebhook/diunwebhook_test.go: FOUND
- cmd/diunwebhook/main.go: FOUND
- Commit 78543d7: FOUND
- Commit e35b4f8: FOUND
- All 35 tests pass: VERIFIED (go test -v -count=1 ./pkg/diunwebhook/)

## Next Phase Readiness

- Server struct accepts any Store implementation — PostgreSQL store can be introduced in Phase 3 without touching handlers
- RunMigrations called in main.go before store creation — Phase 3 just needs to add a postgres migration variant
- Per-test isolation via NewTestServer is the established pattern — Phase 3 tests can follow the same approach
- All acceptance criteria verified: no globals, no SQL in handlers, s.store.X() pattern throughout, main.go wiring complete

---
*Phase: 02-backend-refactor*
*Completed: 2026-03-23*