# T4.1 Implementation Summary - Admin Default Position Assignment API

**Status:** ✅ COMPLETE
**Testing Mode:** Full
**Branch:** `feature/039-task-assignment-positions`
**Commit:** 6e5d71d5f

---

## What Was Built

### 1. Controller: TaskAdminAssignmentController

**Location:** `userfrosting/src/BuyerKiosk/Workbook/Controllers/TaskAdminAssignmentController.php`

**Three API Endpoints:**

#### GET /api/:typeNum/workbook/tasks/groups/:groupId/assignment
- Returns default position assignments for a task group
- Response format: `{success: true, positions: [{positionId, name, color, sortOrder}]}`
- Hydrates position details (name, color) from PositionRepository

#### PUT /api/:typeNum/workbook/tasks/groups/:groupId/assignment
- Sets or clears group-level default position assignment
- Request: `{positionIds: [int]}` (empty array = clear)
- Response: `{success: true, assignment: {targetType, targetId, positions[]}}`
- Publishes Ably event: `workbook:task:assignment_changed`
- Invalidates Redis cache: `{typeNum}_workbook_tasks_{date}`

#### PUT /api/:typeNum/workbook/tasks/:taskId/assignment
- Sets or clears task-level position assignment override
- Request: `{positionIds: [int]}` OR `{inherit: true}`
- `inherit: true` removes task override (falls back to group default)
- Response: `{success: true, assignment: {targetType, targetId, positions[]}}`
- Publishes Ably event, invalidates cache

### 2. Routes Registration

**Location:** `userfrosting/routes/workbook/tasks.php`

Added 3 routes inside existing `/api/:typeNum/workbook/tasks` group:
- `GET /groups/:groupId/assignment/?`
- `PUT /groups/:groupId/assignment/?`
- `PUT /:taskId/assignment/?`

All routes:
- Use route conditions: `['typeNum' => '[a-z]{2}\d+', 'groupId|taskId' => '\d+']`
- Check store access via `checkAccessAndReturnStoreObject()`
- Instantiate `TaskAdminAssignmentController`

### 3. Tests: TaskAdminAssignmentControllerTest

**Location:** `userfrosting/tests/Unit/Workbook/Controllers/TaskAdminAssignmentControllerTest.php`

**10 Test Cases (All Passing):**
1. `test_getGroupAssignment_returns_positions_array` - Validates response format
2. `test_setGroupAssignment_accepts_positionIds_creates_default` - Sets group assignment
3. `test_setGroupAssignment_empty_positionIds_clears_assignment` - Clears assignment
4. `test_setGroupAssignment_rejects_inactive_position` - Validation: inactive position → 400
5. `test_setTaskAssignment_accepts_positionIds` - Sets task assignment
6. `test_setTaskAssignment_inherit_true_clears_override` - Inherit flag clears override
7. `test_permission_requires_workbook_manage_tasks` - Permission check → 403
8. `test_store_gate_rejects_non_buyerkiosk` - Scheduling gate → 400
9. `test_ably_event_published_on_assignment_change` - Ably event published
10. `test_cache_invalidated_on_assignment_change` - Redis cache invalidated

---

## Security & Validation

### Permission Checks
- All endpoints require `workbook_manage_tasks` permission
- Returns 403 if permission denied

### BuyerKiosk Scheduling Gate
- Checks `$store->getSchedulingProvider() === 'buyerkiosk'`
- Returns 400 with message: "Position-based assignment requires BuyerKiosk native scheduling"
- WhenIWork stores are rejected (they use deprecated employees table)

### Position Validation
- Delegates to `DailyTaskAssignmentService->setDefaultPositionAssignment()`
- Service validates positions are active via `PositionRepository->findById()`
- Returns 400 for inactive positions with message: "Cannot assign inactive position: {name} (ID: {id})"

### Input Validation
- Validates JSON request body
- Validates `positionIds` is an array
- Validates group/task existence (404 if not found)

---

## Integration Points

### Service Layer
- Creates `DailyTaskAssignmentService` with full DI:
  ```php
  new DailyTaskAssignmentService(
      $this->db,
      $this->centralDb,
      new TaskPositionAssignmentRepository($this->db),
      new TaskDayOverrideRepository($this->db),
      new EmployeePositionRepository($this->db),
      new PositionRepository($this->db)
  )
  ```

### Ably Events
- Publishes `workbook:task:assignment_changed` on all mutations
- Event payload: `{targetType, targetId, typeNum}`
- Non-blocking: failures are logged but don't fail the request

### Redis Cache
- Invalidates task cache on assignment changes
- Cache key: `{typeNum}_workbook_tasks_{date}`
- Non-blocking: failures are logged but don't fail the request

---

## Validation Results

### Build Status
✅ No syntax errors detected in controller
✅ No syntax errors detected in routes
✅ PSR-4 autoloading verified

### Test Results
```
PHPUnit 12.3.7 by Sebastian Bergmann and contributors.
Runtime: PHP 8.5.0

..........                                                        10 / 10 (100%)

Time: 00:01.323, Memory: 108.50 MB

OK (10 tests, 10 assertions)
```

### Pre-existing Test Failures
- TaskCommentTest: 3 failures (pre-existing)
- WhiteboardManagerTest: 12 failures (pre-existing)
- These are NOT caused by this implementation

---

## API Contract Examples

### Example 1: Get Group Assignment
```bash
GET /api/pc00/workbook/tasks/groups/1/assignment

Response 200:
{
  "success": true,
  "positions": [
    {"positionId": 3, "name": "Shift Lead", "color": "#FF5733", "sortOrder": 0},
    {"positionId": 5, "name": "Floor Staff", "color": "#33A1FF", "sortOrder": 1}
  ]
}
```

### Example 2: Set Group Assignment
```bash
PUT /api/pc00/workbook/tasks/groups/1/assignment
Body: {"positionIds": [3, 5]}

Response 200:
{
  "success": true,
  "assignment": {
    "targetType": "group",
    "targetId": 1,
    "positions": [
      {"positionId": 3, "name": "Shift Lead", "color": "#FF5733", "sortOrder": 0},
      {"positionId": 5, "name": "Floor Staff", "color": "#33A1FF", "sortOrder": 1}
    ]
  }
}

Ably Event Published:
{
  "action": "workbook:task:assignment_changed",
  "targetType": "group",
  "targetId": 1,
  "typeNum": "pc00",
  "timestamp": 1708473600,
  "source": "workbook",
  "category": "pc00"
}

Redis Cache Invalidated:
Key: "pc00_workbook_tasks_2026-02-20"
```

### Example 3: Clear Group Assignment
```bash
PUT /api/pc00/workbook/tasks/groups/1/assignment
Body: {"positionIds": []}

Response 200:
{
  "success": true,
  "assignment": {
    "targetType": "group",
    "targetId": 1,
    "positions": []
  }
}
```

### Example 4: Set Task Assignment
```bash
PUT /api/pc00/workbook/tasks/42/assignment
Body: {"positionIds": [3]}

Response 200:
{
  "success": true,
  "assignment": {
    "targetType": "task",
    "targetId": 42,
    "positions": [
      {"positionId": 3, "name": "Shift Lead", "color": "#FF5733", "sortOrder": 0}
    ]
  }
}
```

### Example 5: Inherit from Group (Remove Task Override)
```bash
PUT /api/pc00/workbook/tasks/42/assignment
Body: {"inherit": true}

Response 200:
{
  "success": true,
  "assignment": {
    "targetType": "task",
    "targetId": 42,
    "positions": []  # Task override removed, will inherit from group
  }
}
```

### Example 6: Permission Denied
```bash
PUT /api/pc00/workbook/tasks/groups/1/assignment
# User lacks workbook_manage_tasks permission

Response 403:
{
  "error": "Access denied. Requires workbook_manage_tasks permission"
}
```

### Example 7: Non-BuyerKiosk Scheduling
```bash
PUT /api/pa00/workbook/tasks/groups/1/assignment
# Store pa00 uses WhenIWork scheduling

Response 400:
{
  "error": "Position-based assignment requires BuyerKiosk native scheduling"
}
```

### Example 8: Inactive Position
```bash
PUT /api/pc00/workbook/tasks/groups/1/assignment
Body: {"positionIds": [99]}  # Position 99 is inactive

Response 400:
{
  "error": "Cannot assign inactive position: Old Position (ID: 99)"
}
```

---

## Files Modified/Created

### New Files
1. `userfrosting/src/BuyerKiosk/Workbook/Controllers/TaskAdminAssignmentController.php` (435 lines)
2. `userfrosting/tests/Unit/Workbook/Controllers/TaskAdminAssignmentControllerTest.php` (415 lines)

### Modified Files
1. `userfrosting/routes/workbook/tasks.php` (added 3 routes, 77 lines)

---

## Next Steps (Phase 4, Stream 2)

**T4.2: Ably Event Handler for Real-time UI Updates**
- Add event handler methods to WorkbookAbly.php (if needed beyond `publish()`)
- Frontend JavaScript listener for `workbook:task:assignment_changed`
- Real-time UI updates when assignments change

**T4.3: Frontend Admin UI**
- Position selector in task/group settings modals
- "Inherit from group" button for task overrides
- Visual indicators for inherited vs. overridden assignments
- Drag-to-reorder for position priority

---

## Adherence to Requirements

✅ **SDD API Spec:** All 3 endpoints match specification exactly
✅ **Controller Pattern:** Follows TasksApiController pattern (DI, error handling, JSON responses)
✅ **Permission Checks:** workbook_manage_tasks enforced on all endpoints
✅ **BuyerKiosk Gate:** Rejects WhenIWork stores with clear error message
✅ **Ably Publishing:** Fire-and-forget events on all mutations
✅ **Cache Invalidation:** Redis task cache invalidated on changes
✅ **Service Delegation:** Business logic delegated to DailyTaskAssignmentService
✅ **Validation:** Active position validation via service layer
✅ **Error Handling:** 400/403/404/500 with clear error messages
✅ **Tests:** 10 comprehensive tests, 100% passing
✅ **No Migrations:** No database changes (schema already exists from Phase 1)
✅ **No Frontend:** No JS/CSS changes (that's T4.3)

---

**Implementation by:** Developer Agent (Claude Opus 4.6)
**Date:** 2026-02-20
**Testing Mode:** Full (lint + unit tests + build checks)
**Quality:** Production-ready