# PLAN: Shift Scheduling System

Enable dynamic shift assignment and scheduling directly from the Shift Calendar matrix.

## 1. Context & Objectives
The user wants to manage employee schedules from `hr/shifts/calendar`.
- "Assigning" a shift creates or updates an `AttendanceRecord` as a scheduling placeholder.
- Supports bulk assignment across a **date range**.
- Includes a **Rest Day** toggle.
- Allows choosing from **Active Shifts**.

## 2. Technical Strategy
### Backend
- **Endpoint**: Implement `POST /hr/shifts/assign` in `ShiftController`.
- **Logic**: Use `CarbonPeriod` to iterate through dates and `updateOrCreate` on `AttendanceRecord`.

### Frontend
- **Enhancement**: Convert matrix cells into clickable triggers.
- **Component**: Integrate `CrudFormModal` for the scheduling form.
- **Data**: The `calendar` view must now provide a list of all active `available_shifts` for the dropdown.

## 3. Task Breakdown

### Phase 1: Backend Scaffolding
- [ ] Add `all_shifts` to the data returned by `ShiftController@calendar`.
- [ ] Implement `assignShift` method:
    - Validate: `employee_id`, `start_date`, `end_date`, `shift_id`, `is_rest_day`.
    - Iteration logic for date ranges.
    - `AttendanceRecord::updateOrCreate` implementation.

### Phase 2: Frontend Interactivity
- [ ] Add Modal state transitions to `resources/js/pages/hr/shifts/calendar.tsx`.
- [ ] Implement `handleCellClick` to pre-populate the assignment form.
- [ ] Add `cursor-pointer` and hover styles to the grid badges.

### Phase 3: Scheduling Modal
- [ ] Configure `CrudFormModal` with:
    - Date Range (Start/End).
    - Shift Switcher (Dropdown).
    - Rest Day Toggle.
- [ ] Implement `handleFormSubmit` and handle validation errors.

### Phase 4: Verification
- [ ] Test assigning a shift to a 7-day range.
- [ ] Test marking a day as a Rest Day and verify it shows as `RD`.
- [ ] Verify that assigned shifts appear in the grid after a successful update.

## 4. Agent Assignments
| Agent | Task |
|-------|------|
| Backend Specialist | Range assignment logic & Controller updates |
| Frontend Specialist | Calendar modal & Range selection UI |
| Quality Assurance | Gap verification between attendance & shifts |