# Feature: Availability Management

## Overview
Instructors define date/time windows during which they are available for lessons. Students book from these windows.

## Data Model — `{prefix}us_availability`

| Column         | Type             | Notes                                        |
|----------------|------------------|----------------------------------------------|
| `id`           | BIGINT UNSIGNED  | Primary key                                  |
| `instructor_id`| BIGINT UNSIGNED  | WordPress user ID                            |
| `start_dt`     | DATETIME         | Slot start — stored as `Y-m-d H:i:s`        |
| `end_dt`       | DATETIME         | Slot end — stored as `Y-m-d H:i:s`          |
| `is_booked`    | TINYINT(1)       | 0 = available, 1 = booked                    |
| `created_at`   | DATETIME         | Insertion time                               |

## Admin Interface
Instructors access **My Availability** in wp-admin (`?page=us-availability`).
- Add a slot: provide start and end datetime
- Delete a slot: only allowed if `is_booked = 0`

## REST API
| Method   | Endpoint                          | Permission              |
|----------|-----------------------------------|-------------------------|
| `GET`    | `/wp-json/us-scheduler/v1/availability`       | `book_lesson`           |
| `POST`   | `/wp-json/us-scheduler/v1/availability`       | `manage_availability`   |
| `DELETE` | `/wp-json/us-scheduler/v1/availability/{id}`  | `manage_availability` + slot owner |

`GET` supports query params: `instructor_id`, `from` (datetime), `to` (datetime).

## Implementation
- Repository: `Unsupervised\Schedular\Data\AvailabilityRepository`
- Model: `Unsupervised\Schedular\Model\AvailabilitySlot`
- Admin controller: `Unsupervised\Schedular\Admin\AvailabilityController`
- REST endpoint: `Unsupervised\Schedular\Api\AvailabilityEndpoint`

## Tests
- `tests/Unit/Data/AvailabilityRepositoryTest.php`
- `tests/Unit/Model/AvailabilitySlotTest.php`