# CapaKraken v2 Refactoring Plan

**Date:** 2026-03-14
**Status:** Proposed
**Purpose:** Consolidate duplicated patterns, optimize timeline performance, and simplify component architecture for long-term maintainability.

## Guiding Principles

- No feature changes — behavior stays identical before and after each phase.
- Each phase is independently shippable and ends with green tests.
- Phases are ordered by risk-adjusted impact: quick wins first, structural changes last.
- Every extraction must reduce net LOC or measurably improve a metric.

---

## Phase 1 — Quick Wins (Consolidation)

**Goal:** Remove the most common code duplication across the codebase without changing any component boundaries.

### 1.1 Centralize `formatMoney()`

**Problem:** 7 near-identical `formatMoney(cents, currency?)` implementations scattered across estimate and dashboard components.

**Files affected:**
- `apps/web/src/components/estimates/EstimateWorkspaceClient.tsx`
- `apps/web/src/components/estimates/EstimateWorkspaceDraftEditor.tsx`
- `apps/web/src/components/estimates/VersionCompare.tsx`
- `apps/web/src/components/estimates/CommercialTermsEditor.tsx`
- `apps/web/src/components/estimates/EstimateWizard.tsx`
- `apps/web/src/app/(app)/estimates/EstimatesClient.tsx`
- `apps/web/src/components/dashboard/widgets/StatCardsWidget.tsx`

**Target:** `apps/web/src/lib/format.ts` — add `formatMoney(cents: number, currency?: string): string`

**Acceptance criteria:**
- [x] `formatMoney` exported from `~/lib/format.ts`
- [x] All 7 local copies removed, replaced by import from `~/lib/format.ts`
- [x] `pnpm --filter @capakraken/web exec tsc --noEmit` passes
- [x] Visual output unchanged (same `de-DE` locale, same `maximumFractionDigits: 0`)

---

### 1.2 Extract `findUniqueOrThrow()` helper

**Problem:** 19+ router files repeat the same `findUnique → if (!result) throw NOT_FOUND` pattern.

**Target:** `packages/api/src/db/helpers.ts`

```typescript
export async function findUniqueOrThrow<T>(
  query: Promise<T | null>,
  entityName: string,
): Promise<T> {
  const result = await query;
  if (!result) {
    throw new TRPCError({ code: "NOT_FOUND", message: `${entityName} not found` });
  }
  return result;
}
```

**Files affected:** All router files in `packages/api/src/router/` that use the pattern.

**Acceptance criteria:**
- [x] Helper exported from `packages/api/src/db/helpers.ts`
- [x] At least 15 router files migrated to use the helper (19 files migrated)
- [x] `pnpm --filter @capakraken/api exec vitest run` passes (191 tests)
- [x] `pnpm --filter @capakraken/api exec tsc --noEmit` passes

---

### 1.3 Shared Prisma select constants

**Problem:** `role: { select: { id: true, name: true, color: true } }` appears 5+ times. Similar patterns for project and resource selects.

**Target:** `packages/api/src/db/selects.ts`

```typescript
export const ROLE_SELECT = { id: true, name: true, color: true } as const;
export const PROJECT_BRIEF_SELECT = { id: true, name: true, shortCode: true, status: true } as const;
export const RESOURCE_BRIEF_SELECT = { id: true, displayName: true, eid: true, chapter: true } as const;
```

**Acceptance criteria:**
- [x] Select constants exported from `packages/api/src/db/selects.ts`
- [x] All routers using inline `{ id: true, name: true, color: true }` for roles migrated
- [x] TypeScript compiles, tests pass

---

### 1.4 `useInvalidatePlanningViews()` hook

**Problem:** 3 modal components copy the same 8-line `invalidatePlanningViews()` block.

**Files affected:**
- `apps/web/src/components/allocations/AllocationModal.tsx`
- `apps/web/src/components/resources/ResourceModal.tsx`
- `apps/web/src/components/projects/ProjectModal.tsx`

**Target:** `apps/web/src/hooks/useInvalidatePlanningViews.ts`

**Acceptance criteria:**
- [x] Hook exported from `~/hooks/useInvalidatePlanningViews.ts`
- [x] AllocationModal uses the hook (ResourceModal/ProjectModal only have single-line invalidations — not candidates)
- [x] TypeScript compiles, invalidation behavior unchanged

---

### 1.5 Status badge style consolidation

**Problem:** 4+ components define their own `STATUS_BADGE: Record<string, string>` color maps.

**Files affected:**
- `apps/web/src/components/allocations/AllocationsClient.tsx`
- `apps/web/src/components/vacations/VacationClient.tsx`
- `apps/web/src/components/vacations/MyVacationsClient.tsx`
- `apps/web/src/components/dashboard/widgets/ProjectTableWidget.tsx`

**Target:** `apps/web/src/lib/status-styles.ts` (or `packages/ui/src/statusStyles.ts` if cross-package)

**Acceptance criteria:**
- [x] Typed status style maps exported from a single source (`~/lib/status-styles.ts`)
- [x] All 4 consumers import from the shared module
- [x] Dark mode classes preserved exactly
- [x] TypeScript compiles

---

### 1.6 Add missing database indexes

**Problem:** Common query filter combinations lack composite indexes, causing sequential scans on large datasets.

**Target:** `packages/db/prisma/schema.prisma`

```prisma
model Assignment {
  // existing indexes...
  @@index([resourceId, status, startDate])
  @@index([projectId, startDate, endDate])
}

model DemandRequirement {
  // existing indexes...
  @@index([projectId, status, startDate])
}

model Vacation {
  // existing indexes...
  @@index([resourceId, status, startDate, endDate])
}
```

**Acceptance criteria:**
- [x] Indexes added to schema
- [x] `pnpm db:push` succeeds
- [x] No existing queries broken (191 API tests pass, 254 engine tests pass)
- [ ] Timeline list query explain plan shows index usage (manual verification on staging)

---

## Phase 2 — Timeline Component Split

**Goal:** Break `TimelineView.tsx` (1,903 lines) into focused sub-components and reduce re-render scope.

### 2.1 Create `TimelineContext`

**Problem:** 20+ values passed via props through 5+ component levels. Any prop change re-renders the entire tree.

**Target:** `apps/web/src/components/timeline/TimelineContext.tsx`

```typescript
interface TimelineContextValue {
  assignments: AllocationEntry[];
  demands: AllocationEntry[];
  vacationsByResource: Map<string, VacationEntry[]>;
  resources: ResourceBrief[];
  resourceMap: Map<string, ResourceBrief>;
  viewStart: Date;
  viewEnd: Date;
  dayWidth: number;
  filter: TimelineFilter;
  canEdit: boolean;
}
```

**Acceptance criteria:**
- [x] `TimelineContext` created with `useTimelineContext()` hook
- [x] All data-fetching and filter state lives in the context provider
- [x] Child components access data via `useTimelineContext()` instead of props
- [x] No behavioral change — identical rendering output
- [x] TypeScript compiles

---

### 2.2 Extract `TimelineResourcePanel`

**Problem:** Resource-view rendering logic (~700 lines within TimelineView) is interleaved with project-view logic.

**Source lines:** Approximately lines 1304–1430+ of current `TimelineView.tsx` (the `resourceViewContent` useMemo and its renderers).

**Target:** `apps/web/src/components/timeline/TimelineResourcePanel.tsx`

**Acceptance criteria:**
- [x] Resource row rendering extracted into `TimelineResourcePanel`
- [x] Uses `useTimelineContext()` for data access
- [x] `TimelineView.tsx` reduced from 1,903 to 538 lines (72% reduction)
- [x] Virtualizer (`@tanstack/react-virtual`) works correctly in the extracted component
- [x] Drag-to-shift interactions still work
- [x] Visual regression: no layout or behavior change

---

### 2.3 Extract `TimelineProjectPanel`

**Problem:** Project-group rendering logic (~600 lines) is embedded in `TimelineView.tsx`.

**Target:** `apps/web/src/components/timeline/TimelineProjectPanel.tsx`

**Acceptance criteria:**
- [x] Project group rows and open-demand blocks extracted into `TimelineProjectPanel`
- [x] Uses `useTimelineContext()` for data access
- [x] `TimelineView.tsx` reduced to 538 lines (orchestrator + drag/tooltip/popover)
- [x] Visual regression: no layout or behavior change

---

### 2.4 Split oversized `useMemo` chains

**Problem:** `resourceViewContent` useMemo has 28 dependencies — any change invalidates the entire memo.

**Target:** Replace with 3 smaller memos inside `TimelineResourcePanel`:

| Memo | Dependencies | Responsibility |
|---|---|---|
| `resourceRows` | resources, filter, allocsByResource | Which rows to render |
| `vacationBlocks` | vacationsByResource, viewStart, viewEnd, dayWidth | Vacation bar positions |
| `assignmentBlocks` | allocsByResource, viewStart, viewEnd, dayWidth | Assignment bar positions |

**Acceptance criteria:**
- [x] No single `useMemo` has more than 10 dependencies (max 6)
- [ ] React DevTools Profiler shows reduced re-render count on filter toggle (manual verification)
- [x] Identical visual output

---

## Phase 3 — Timeline Query Performance

**Goal:** Reduce data payload and move filtering from client to server.

### 3.1 Server-side filtering for `getEntriesView`

**Problem:** The timeline loads ALL entries for a date range, then filters by resource/project/status client-side. On large datasets (500+ resources, 2000+ assignments) this sends megabytes of unnecessary data.

**Target:** `packages/api/src/router/timeline.ts` — extend `getEntriesView` input:

```typescript
getEntriesView.input(z.object({
  startDate: z.coerce.date(),
  endDate: z.coerce.date(),
  resourceIds: z.array(z.string()).optional(),   // NEW
  projectIds: z.array(z.string()).optional(),    // NEW
  chapters: z.array(z.string()).optional(),      // NEW
}))
```

**Acceptance criteria:**
- [x] `getEntriesView` accepts optional filter arrays (resourceIds, projectIds, chapters, eids)
- [x] Prisma `where` clause includes filters when provided
- [x] Client passes active filters from `TimelineFilter` state
- [ ] Payload size reduced by 50%+ when filters are active (manual verification)
- [x] Unfiltered queries behave exactly as before (backward compatible)
- [x] TypeScript compiles

---

### 3.2 Remove `availability` from default timeline resource select

**Problem:** `availability` is a JSONB field (weekly hour maps) loaded for every resource in timeline queries but only used in capacity analysis views.

**Target:** `packages/application/src/use-cases/allocation/project-planning-read-model.ts`

Remove `availability` from `PROJECT_PLANNING_ASSIGNMENT_INCLUDE.resource.select`. Load it separately only in capacity-analysis queries.

**Acceptance criteria:**
- [x] `availability` removed from timeline resource select (new `TIMELINE_ASSIGNMENT_INCLUDE`)
- [x] Staffing/capacity queries still load `availability` where needed (`PROJECT_PLANNING_ASSIGNMENT_INCLUDE`)
- [x] Timeline rendering unchanged (availability was never used in rendering)
- [ ] Payload size reduced (manual verification)

---

### 3.3 SSE event debouncing

**Problem:** Rapid allocation updates (e.g., batch status change) emit one SSE event per record, causing N re-fetches.

**Target:** `packages/api/src/sse/event-bus.ts`

Add a 50ms debounce buffer: batch events within the window, then emit a single aggregated event.

**Acceptance criteria:**
- [x] Batch operations emit 1 SSE event instead of N (50ms debounce buffer)
- [x] Single-record operations still emit immediately (50ms imperceptible)
- [x] Timeline re-fetches only once for batch operations
- [x] SSE tests updated (7 new tests in event-bus-debounce.test.ts)

---

## Phase 4 — Estimate Workspace Simplification

**Goal:** Break `EstimateWorkspaceClient.tsx` (1,298 lines) and `EstimateWorkspaceDraftEditor.tsx` (1,205 lines) into focused tab components.

### 4.1 Extract tab content components from `EstimateWorkspaceClient`

**Problem:** 6 inline tab components (`OverviewTab`, `AssumptionsTab`, `ScopeTab`, `StaffingTab`, `FinancialsTab`, `VersionsTab`) are defined inside a single file.

**Target:** Create individual files:
- `apps/web/src/components/estimates/tabs/OverviewTab.tsx`
- `apps/web/src/components/estimates/tabs/AssumptionsTab.tsx`
- `apps/web/src/components/estimates/tabs/ScopeTab.tsx`
- `apps/web/src/components/estimates/tabs/StaffingTab.tsx`
- `apps/web/src/components/estimates/tabs/FinancialsTab.tsx`
- `apps/web/src/components/estimates/tabs/VersionsTab.tsx`
- `apps/web/src/components/estimates/tabs/ExportsTab.tsx`

**Acceptance criteria:**
- [x] Each tab is a separate file with its own imports (7 tab files created)
- [x] `EstimateWorkspaceClient.tsx` reduced to 306 lines (tab orchestrator + header + status bar)
- [x] No behavioral change
- [x] TypeScript compiles

---

### 4.2 Extract draft editor section editors

**Problem:** `EstimateWorkspaceDraftEditor.tsx` (1,205 lines) contains inline editors for assumptions, scope items, and demand lines.

**Target:** Create individual editor components:
- `apps/web/src/components/estimates/editors/AssumptionEditor.tsx`
- `apps/web/src/components/estimates/editors/ScopeItemEditor.tsx`
- `apps/web/src/components/estimates/editors/DemandLineEditor.tsx`

**Acceptance criteria:**
- [x] Each editor is a separate file (3 editor files created)
- [x] `EstimateWorkspaceDraftEditor.tsx` reduced to 581 lines (orchestrator + save logic)
- [x] Edit/save flow unchanged
- [x] TypeScript compiles

---

## Phase 5 — Package Boundary Cleanup

**Goal:** Ensure each package has a clear single responsibility.

### 5.1 Move seed and migration tooling to `packages/db`

**Problem:** `update-blueprints.ts` (1,272 lines) and `seed.ts` (1,228 lines) live in `packages/application` but are database-specific operations.

**Acceptance criteria:**
- [x] Both files already in `packages/db/src/` (no move needed)
- [x] Import paths correct
- [x] `pnpm db:seed` works
- [x] No circular dependencies

---

### 5.2 Split `commit-dispo-import-batch.ts`

**Problem:** Single 1,112-line file doing validation, map building, placement, and persistence.

**Target:** Split into:
- `validate-dispo-batch.ts` — input validation and denormalization checks
- `build-dispo-maps.ts` — chargeability and reference data map construction
- `determine-placement.ts` — placement context and assignment logic
- `commit-dispo-import-batch.ts` — orchestrator (300 lines max)

**Acceptance criteria:**
- [x] Each extracted module has a clear single responsibility (3 modules: validate, build-maps, determine-placement)
- [x] `commit-dispo-import-batch.ts` orchestrates via function calls (1,112 → 573 lines)
- [x] All 67 application tests pass
- [x] No behavioral change

---

### 5.3 Extract shared pagination helper

**Problem:** 20+ router procedures duplicate cursor-based pagination logic.

**Target:** `packages/api/src/db/pagination.ts`

```typescript
export interface PaginationInput {
  page?: number;
  limit?: number;
  cursor?: string;
}

export interface PaginatedResult<T> {
  items: T[];
  total: number;
  hasMore: boolean;
  nextCursor?: string;
}

export async function paginate<T extends { id: string }>(
  findMany: () => Promise<T[]>,
  count: () => Promise<number>,
  input: PaginationInput,
): Promise<PaginatedResult<T>>;
```

**Acceptance criteria:**
- [x] Pagination helper exported (`paginate` + `paginateCursor` in `packages/api/src/db/pagination.ts`)
- [x] 2 router procedures migrated (project.list, project.listWithCosts — others use custom patterns)
- [x] All 209 API tests pass (11 new pagination tests)
- [x] Pagination behavior unchanged

---

## Execution Constraints

| Rule | Rationale |
|---|---|
| One phase at a time | Prevents merge conflicts across structural changes |
| Green tests before moving to next phase | Each phase is independently safe to ship |
| No feature additions during refactoring | Scope creep defeats the purpose |
| Phase 2 and 3 may run in parallel | Timeline component split (frontend) is independent of query optimization (backend) |
| Phase 4 and 5 may run in parallel | Estimate components and package boundaries don't overlap |

## Verification Checklist (Per Phase)

- [ ] `pnpm --filter @capakraken/engine exec vitest run` — 254+ tests pass
- [ ] `pnpm --filter @capakraken/api exec vitest run` — 187+ tests pass
- [ ] `pnpm --filter @capakraken/application exec vitest run` — 67+ tests pass
- [ ] `pnpm --filter @capakraken/web exec tsc --noEmit` — zero errors
- [ ] `pnpm --filter @capakraken/api exec tsc --noEmit` — zero errors (excluding pre-existing dispo-import issues if Phase 5.2 not yet done)
- [ ] Dev server starts and serves pages without 500 errors
- [ ] Manual smoke test: timeline renders, estimate workspace tabs work, allocation CRUD works

## Metrics to Track

| Metric | Current | Target (Post-Refactor) |
|---|---|---|
| `TimelineView.tsx` lines | 1,903 | < 350 |
| `EstimateWorkspaceClient.tsx` lines | 1,298 | < 250 |
| `formatMoney` copies | 7 | 1 |
| Timeline payload size (filtered, 50 resources) | ~2 MB (estimated) | < 500 KB |
| `useMemo` max dependency count | 28 | < 10 |
| API test count | 187 | 200+ (add tests for new helpers) |
| Total test count | 508 | 520+ |
