# Bulk & Scheduled Notifications — Integration Guide

This guide documents how admin clients integrate with the Yimaru backend to send **immediate** or **scheduled** bulk notifications across four channels:

| Channel | Value | Endpoint |
|---------|-------|----------|
| SMS | `sms` | `POST /api/v1/notifications/bulk-sms` |
| Email | `email` | `POST /api/v1/notifications/bulk-email` |
| Push (FCM) | `push` | `POST /api/v1/notifications/bulk-push` |
| In-app | `in_app` | `POST /api/v1/notifications/bulk-in-app` |

Scheduled jobs are created by the same bulk endpoints when `scheduled_at` is provided. Management APIs list, inspect, and cancel pending jobs.

---

## Table of contents

1. [Architecture overview](#architecture-overview)
2. [Authentication & permissions](#authentication--permissions)
3. [Immediate vs scheduled](#immediate-vs-scheduled)
4. [Shared response envelopes](#shared-response-envelopes)
5. [Scheduled notification object](#scheduled-notification-object)
6. [Bulk SMS](#bulk-sms)
7. [Bulk email](#bulk-email)
8. [Bulk push](#bulk-push)
9. [Bulk in-app](#bulk-in-app)
10. [Scheduled job management](#scheduled-job-management)
11. [In-app real-time delivery (WebSocket)](#in-app-real-time-delivery-websocket)
12. [Recipient targeting rules](#recipient-targeting-rules)
13. [Error handling](#error-handling)
14. [Operational notes & limitations](#operational-notes--limitations)
15. [Admin UI integration checklist](#admin-ui-integration-checklist)

---

## Architecture overview

```mermaid
sequenceDiagram
    participant Admin as Admin client
    participant API as Yimaru API
    participant DB as PostgreSQL
    participant Worker as Scheduler worker
    participant Channel as SMS / Email / FCM / WS

    alt Immediate send (no scheduled_at)
        Admin->>API: POST /notifications/bulk-*
        API->>Channel: Deliver now
        API-->>Admin: 200 + sent/failed counts
    else Scheduled send (scheduled_at set)
        Admin->>API: POST /notifications/bulk-* + scheduled_at
        API->>DB: INSERT scheduled_notifications (pending)
        API-->>Admin: 201 + ScheduledNotification
        loop Every ~30s
            Worker->>DB: Claim due pending rows
            Worker->>Channel: Dispatch bulk delivery
            Worker->>DB: Mark sent or failed
        end
    end
```

- The scheduler runs **in-process** on each API instance (30-second poll).
- Row claiming uses `FOR UPDATE SKIP LOCKED` so multiple API replicas can run safely.
- There is **no separate “create scheduled job” endpoint** — scheduling is done via `scheduled_at` on the bulk send endpoints.

---

## Authentication & permissions

All bulk and scheduled-management endpoints require:

```http
Authorization: Bearer <access_token>
Content-Type: application/json
```

(Push and email use `multipart/form-data`; see below.)

### Required RBAC permissions

| Action | Permission key |
|--------|----------------|
| Bulk SMS | `notifications.bulk_sms` |
| Bulk email | `notifications.bulk_email` |
| Bulk push | `notifications.bulk_push` |
| Bulk in-app | `notifications.bulk_in_app` |
| List scheduled jobs | `notifications_scheduled.list` |
| Get scheduled job | `notifications_scheduled.get` |
| Cancel scheduled job | `notifications_scheduled.cancel` |

Team members with the **ADMIN** role bundle receive these permissions after RBAC seeding. Ensure migration `000083` has been applied for `in_app` scheduled channel support.

---

## Immediate vs scheduled

| `scheduled_at` | Behavior | HTTP status |
|----------------|----------|-------------|
| **Omitted or empty** | Send immediately | `200 OK` |
| **Present, RFC3339, future** | Create scheduled job | `201 Created` |
| **Present, past** | Rejected | `400 Bad Request` |
| **Invalid format** | Rejected | `400 Bad Request` |

**Format:** RFC3339 UTC recommended, e.g. `2026-06-15T09:00:00Z`

---

## Shared response envelopes

### Success (`domain.Response`)

```json
{
  "message": "Human-readable summary",
  "data": { },
  "success": true,
  "status_code": 200,
  "metadata": null
}
```

### Error (`domain.ErrorResponse`)

```json
{
  "message": "Short error title",
  "error": "Optional detail string"
}
```

### Immediate send `data` shape (SMS, email, in-app)

```json
{
  "total_recipients": 150,
  "sent": 148,
  "failed": 2
}
```

### Immediate push `data` shape

```json
{
  "target_users": 150,
  "sent": 200,
  "failed": 5,
  "image": "https://api.example.com/files/notification_images/abc.jpg"
}
```

> Push `sent`/`failed` count **device tokens**, not users. One user may have multiple devices.

---

## Scheduled notification object

Returned when scheduling (`201`) and from management GET endpoints.

```json
{
  "id": 42,
  "channel": "sms",
  "title": "Optional subject / headline",
  "message": "Body text",
  "html": "Optional HTML (email only)",
  "scheduled_at": "2026-06-15T09:00:00.000Z",
  "status": "pending",
  "target_user_ids": [1, 2, 3],
  "target_role": "STUDENT",
  "target_raw": { "phones": ["+251911000000"] },
  "attempt_count": 0,
  "last_error": "",
  "processing_started_at": null,
  "sent_at": null,
  "cancelled_at": null,
  "created_by": 7,
  "created_at": "2026-06-10T12:00:00.000Z",
  "updated_at": "2026-06-10T12:00:00.000Z"
}
```

### `channel` values

| Value | Description |
|-------|-------------|
| `sms` | AfroMessage SMS |
| `email` | Resend / messenger email |
| `push` | Firebase Cloud Messaging |
| `in_app` | DB notification + WebSocket broadcast |

### `status` lifecycle

| Status | Meaning |
|--------|---------|
| `pending` | Waiting for `scheduled_at` |
| `processing` | Claimed by worker, dispatch in progress |
| `sent` | Dispatch completed (at least one recipient succeeded) |
| `failed` | All deliveries failed or unsupported channel |
| `cancelled` | Cancelled via API before send |

### `target_raw` structure

Used when recipients cannot be expressed only via `target_user_ids` / `target_role`:

```json
{
  "phones": ["+251911000000", "+251922000000"],
  "emails": ["user@example.com"],
  "type": "system_alert",
  "level": "info"
}
```

| Field | Used by |
|-------|---------|
| `phones` | Scheduled SMS with direct phone numbers |
| `emails` | Scheduled email with direct addresses |
| `type`, `level` | Scheduled in-app metadata (defaults: `system_alert`, `info`) |

---

## Bulk SMS

### Endpoint

```
POST /api/v1/notifications/bulk-sms
Content-Type: application/json
Permission: notifications.bulk_sms
```

### Request body

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `message` | string | **Yes** | SMS body |
| `user_ids` | int64[] | No* | Platform user IDs (resolved to `phone_number`) |
| `role` | string | No* | All users with this platform role |
| `phone_numbers` | string[] | No* | Direct E.164 or local numbers |
| `scheduled_at` | string | No | RFC3339; omit for immediate send |

\* At least one of `user_ids`, `role`, or `phone_numbers` is required.

### Example — immediate

```http
POST /api/v1/notifications/bulk-sms
Authorization: Bearer <token>
Content-Type: application/json

{
  "message": "Your subscription expires tomorrow.",
  "role": "STUDENT"
}
```

### Example — scheduled

```json
{
  "message": "Reminder: class starts at 9 AM.",
  "user_ids": [10, 11, 12],
  "scheduled_at": "2026-06-15T08:00:00Z"
}
```

### Example — scheduled with direct phones

```json
{
  "message": "Welcome to Yimaru!",
  "phone_numbers": ["+251911000000"],
  "scheduled_at": "2026-06-15T09:00:00Z"
}
```

### Success responses

**Immediate (`200`):**

```json
{
  "message": "Bulk SMS sent",
  "success": true,
  "status_code": 200,
  "data": {
    "total_recipients": 3,
    "sent": 3,
    "failed": 0
  }
}
```

**Scheduled (`201`):**

```json
{
  "message": "SMS scheduled",
  "success": true,
  "status_code": 201,
  "data": { /* ScheduledNotification */ }
}
```

---

## Bulk email

### Endpoint

```
POST /api/v1/notifications/bulk-email
Content-Type: multipart/form-data
Permission: notifications.bulk_email
```

### Form fields

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `subject` | string | **Yes** | Email subject (stored as `title` when scheduled) |
| `message` | string | No** | Plain-text body |
| `html` | string | No** | HTML body |
| `user_ids` | string | No* | JSON array string, e.g. `[1,2,3]` |
| `role` | string | No* | Platform role filter |
| `emails` | string | No* | JSON array string, e.g. `["a@b.com"]` |
| `scheduled_at` | string | No | RFC3339 |
| `file` | file | No | Attachment (immediate send only) |

\* At least one of `user_ids`, `role`, or `emails` is required.

\** At least one of `message` or `html` is required.

### Example — immediate (cURL)

```bash
curl -X POST "https://api.example.com/api/v1/notifications/bulk-email" \
  -H "Authorization: Bearer <token>" \
  -F "subject=New course available" \
  -F "html=<p>Check out our new module!</p>" \
  -F "role=STUDENT" \
  -F "file=@banner.png"
```

### Example — scheduled (cURL)

```bash
curl -X POST "https://api.example.com/api/v1/notifications/bulk-email" \
  -H "Authorization: Bearer <token>" \
  -F "subject=Weekly digest" \
  -F "message=Here is your weekly summary." \
  -F "emails=[\"admin@example.com\",\"user@example.com\"]" \
  -F "scheduled_at=2026-06-15T09:00:00Z"
```

> **Note:** Attachments are **not** stored for scheduled emails. Upload and send immediately if an attachment is required.

### Success responses

**Immediate (`200`):**

```json
{
  "message": "Bulk email sent",
  "success": true,
  "status_code": 200,
  "data": {
    "total_recipients": 50,
    "sent": 49,
    "failed": 1
  }
}
```

**Scheduled (`201`):**

```json
{
  "message": "Email scheduled",
  "success": true,
  "status_code": 201,
  "data": {
    "id": 43,
    "channel": "email",
    "title": "Weekly digest",
    "message": "Here is your weekly summary.",
    "html": "",
    "scheduled_at": "2026-06-15T09:00:00.000Z",
    "status": "pending",
    "target_raw": { "emails": ["admin@example.com", "user@example.com"] },
    "created_by": 7
  }
}
```

---

## Bulk push

### Endpoint

```
POST /api/v1/notifications/bulk-push
Content-Type: multipart/form-data
Permission: notifications.bulk_push
```

Requires **FCM** credentials (`FCM_SERVICE_ACCOUNT_KEY`) on the server.

### Form fields

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `title` | string | **Yes** | Notification title |
| `message` | string | **Yes** | Notification body |
| `user_ids` | string | No* | JSON array string, e.g. `[1,2,3]` |
| `role` | string | No* | Platform role filter |
| `scheduled_at` | string | No | RFC3339 |
| `file` | file | No | Image (immediate send only) |

\* At least one of `user_ids` or `role` is required.

### Example — immediate

```bash
curl -X POST "https://api.example.com/api/v1/notifications/bulk-push" \
  -H "Authorization: Bearer <token>" \
  -F "title=Practice reminder" \
  -F "message=Complete today's practice." \
  -F "user_ids=[1,2,3]" \
  -F "file=@thumb.jpg"
```

### Example — scheduled

```bash
curl -X POST "https://api.example.com/api/v1/notifications/bulk-push" \
  -H "Authorization: Bearer <token>" \
  -F "title=Exam tomorrow" \
  -F "message=Don't forget to review Unit 3." \
  -F "role=STUDENT" \
  -F "scheduled_at=2026-06-14T18:00:00Z"
```

> **Note:** Push images are **not** preserved when scheduling. Use immediate send for image pushes.

### Success responses

**Immediate (`200`):**

```json
{
  "message": "Bulk push notification sent",
  "success": true,
  "status_code": 200,
  "data": {
    "target_users": 3,
    "sent": 4,
    "failed": 0,
    "image": "https://api.example.com/files/notification_images/abc.jpg"
  }
}
```

**Scheduled (`201`):**

```json
{
  "message": "Push notification scheduled",
  "success": true,
  "status_code": 201,
  "data": { /* ScheduledNotification, channel: "push" */ }
}
```

---

## Bulk in-app

In-app notifications are persisted in the `notifications` table and pushed to connected clients via WebSocket (`CREATED_NOTIFICATION` event). Users without an active socket still see them on next `GET /api/v1/notifications`.

### Endpoint

```
POST /api/v1/notifications/bulk-in-app
Content-Type: application/json
Permission: notifications.bulk_in_app
```

### Request body

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `title` | string | **Yes** | Headline (`payload.headline`) |
| `message` | string | **Yes** | Body (`payload.message`) |
| `user_ids` | int64[] | No* | Target user IDs |
| `role` | string | No* | All users with platform role |
| `scheduled_at` | string | No | RFC3339 |
| `type` | string | No | Notification type (default `system_alert`) |
| `level` | string | No | `info`, `warning`, `error`, `success` (default `info`) |

\* At least one of `user_ids` or `role` is required.

### Notification `type` values (common)

| Value | Use case |
|-------|----------|
| `system_alert` | Admin broadcasts (default) |
| `subscription_expiring` | Billing reminders |
| `course_completed` | Learning milestones |
| `payment_verified` | Payment events |

### Example — immediate

```json
{
  "title": "Maintenance tonight",
  "message": "The app will be unavailable 11 PM–1 AM UTC.",
  "role": "STUDENT"
}
```

### Example — scheduled

```json
{
  "title": "New practice unlocked",
  "message": "Unit 4 practice is now available.",
  "user_ids": [100, 101, 102],
  "type": "system_alert",
  "level": "info",
  "scheduled_at": "2026-06-16T07:00:00Z"
}
```

### Success responses

**Immediate (`200`):**

```json
{
  "message": "Bulk in-app notification sent",
  "success": true,
  "status_code": 200,
  "data": {
    "total_recipients": 3,
    "sent": 3,
    "failed": 0
  }
}
```

**Scheduled (`201`):**

```json
{
  "message": "In-app notification scheduled",
  "success": true,
  "status_code": 201,
  "data": {
    "id": 44,
    "channel": "in_app",
    "title": "New practice unlocked",
    "message": "Unit 4 practice is now available.",
    "scheduled_at": "2026-06-16T07:00:00.000Z",
    "status": "pending",
    "target_user_ids": [100, 101, 102],
    "target_raw": { "type": "system_alert", "level": "info" }
  }
}
```

---

## Scheduled job management

### List scheduled notifications

```
GET /api/v1/notifications/scheduled
Permission: notifications_scheduled.list
```

#### Query parameters

| Param | Type | Default | Description |
|-------|------|---------|-------------|
| `status` | string | — | `pending`, `processing`, `sent`, `failed`, `cancelled` |
| `channel` | string | — | `sms`, `email`, `push`, `in_app` |
| `after` | RFC3339 | — | `scheduled_at >= after` |
| `before` | RFC3339 | — | `scheduled_at <= before` |
| `limit` | int | 20 | Page size |
| `page` | int | 1 | Page number (1-based) |

#### Example

```http
GET /api/v1/notifications/scheduled?channel=in_app&status=pending&page=1&limit=20
Authorization: Bearer <token>
```

#### Response

```json
{
  "scheduled_notifications": [ /* ScheduledNotification[] */ ],
  "total_count": 42,
  "limit": 20,
  "page": 1
}
```

### Get one scheduled notification

```
GET /api/v1/notifications/scheduled/:id
Permission: notifications_scheduled.get
```

#### Response (`200`)

```json
{
  "message": "Scheduled notification retrieved",
  "success": true,
  "status_code": 200,
  "data": { /* ScheduledNotification */ }
}
```

### Cancel scheduled notification

```
POST /api/v1/notifications/scheduled/:id/cancel
Permission: notifications_scheduled.cancel
```

Only jobs with status `pending` or `processing` can be cancelled.

#### Response (`200`)

```json
{
  "message": "Scheduled notification cancelled",
  "success": true,
  "status_code": 200,
  "data": {
    "id": 42,
    "status": "cancelled",
    "cancelled_at": "2026-06-10T14:30:00.000Z"
  }
}
```

---

## In-app real-time delivery (WebSocket)

Mobile/web clients should connect to receive in-app notifications instantly.

### Connect

```
GET /api/v1/ws/connect?token=<access_token>
Permission: notifications.ws_connect (validated via query token)
```

Auth uses the **JWT access token in query string** (not `Authorization` header).

### Broadcast payload

When an in-app notification is created, connected clients receive:

```json
{
  "type": "CREATED_NOTIFICATION",
  "recipient_id": 123,
  "payload": {
    "id": "notif-uuid",
    "recipient_id": 123,
    "type": "system_alert",
    "level": "info",
    "delivery_channel": "in_app",
    "payload": {
      "headline": "Title",
      "message": "Body"
    },
    "is_read": false,
    "timestamp": "2026-06-10T12:00:00.000Z"
  }
}
```

### Polling fallback

```
GET /api/v1/notifications?limit=20&offset=0
Permission: notifications.list_mine
```

```
GET /api/v1/notifications/unread
Permission: notifications.count_unread
```

---

## Recipient targeting rules

### Platform roles (`role` field)

Valid platform `users.role` values:

| Role | Value |
|------|-------|
| Student | `STUDENT` |
| Open learner | `OPEN_LEARNER` |
| Instructor | `INSTRUCTOR` |
| Admin | `ADMIN` |
| Super admin | `SUPER_ADMIN` |
| Support | `SUPPORT` |

When `role` is set without `user_ids`, the API loads **all users** matching that role.

### Combining targets

| Channel | `user_ids` | `role` | Direct (`phones` / `emails`) |
|---------|------------|--------|------------------------------|
| SMS | ✓ | ✓ | `phone_numbers` |
| Email | ✓ | ✓ | `emails` (form field) |
| Push | ✓ | ✓ | — |
| In-app | ✓ | ✓ | — |

For immediate SMS/email, all sources are **unioned** (deduplicated). Scheduled jobs store the targeting fields as-is and resolve at dispatch time.

---

## Error handling

### Common `400` errors

| Message | Cause |
|---------|-------|
| `Message is required` | Empty SMS/in-app body |
| `Title is required` | Empty push/in-app title |
| `No recipients specified` | Missing all targeting fields |
| `No target users found` | Role/user_ids resolved to zero users |
| `Invalid scheduled_at format` | Not RFC3339 |
| `scheduled_at must be in the future` | Past timestamp |
| `Invalid user_ids format` | Push/email: not a JSON array string |

### Common `401` / `403`

| Situation | Result |
|-----------|--------|
| Missing/invalid Bearer token | `401` |
| Missing RBAC permission | `403` |

### Common `500`

| Situation | Result |
|-----------|--------|
| FCM not configured (push) | Push send fails |
| AfroMessage / Resend misconfigured | SMS/email failures |
| DB error creating scheduled row | Schedule request fails |

### Partial delivery

For immediate sends, the API returns `sent` and `failed` counts. The HTTP status is still `200` if the request was processed.

For scheduled jobs, if **at least one** recipient succeeds, status becomes `sent`. If **all** fail, status becomes `failed` and `last_error` is set.

---

## Operational notes & limitations

| Topic | Detail |
|-------|--------|
| Scheduler interval | ~30 seconds (not exact-to-the-second) |
| Scheduled push images | Not supported — image upload only on immediate push |
| Scheduled email attachments | Not supported — attachments only on immediate send |
| Scheduled job retry | No automatic retry; failed jobs stay `failed` |
| Edit / reschedule | Not supported — cancel and create a new job |
| Multi-instance | Safe via DB row locking |
| SMS provider | AfroMessage |
| Email provider | Resend (messenger service) |
| Push provider | Firebase Cloud Messaging |
| History records | Immediate SMS/email/push call `RecordNotification` for known `user_ids`; scheduled SMS/email/push do **not** write per-user history rows. In-app always creates notification rows (immediate and scheduled). |
| Migration | `000083` required for `in_app` scheduled channel |

---

## Admin UI integration checklist

### Compose screen (per channel)

- [ ] Title/subject + message fields (channel-specific)
- [ ] Recipient picker: user multi-select, role dropdown, and/or direct phones/emails
- [ ] Toggle: **Send now** vs **Schedule**
- [ ] Date/time picker → serialize as RFC3339 UTC (`scheduled_at`)
- [ ] Optional: image upload (push immediate only), email attachment (immediate only)
- [ ] Optional: in-app `type` and `level` selectors

### After submit

- [ ] Immediate: show `sent` / `failed` / `total_recipients` from `data`
- [ ] Scheduled: show returned `id`, `scheduled_at`, `status` — link to job detail view

### Scheduled jobs list

- [ ] Call `GET /notifications/scheduled` with filters (`status`, `channel`, date range)
- [ ] Paginate with `page` + `limit`
- [ ] Show status badges: pending → processing → sent / failed / cancelled
- [ ] Cancel button → `POST /notifications/scheduled/:id/cancel` for `pending`/`processing`

### Learner app (in-app only)

- [ ] WebSocket connect on login with `?token=`
- [ ] Handle `CREATED_NOTIFICATION` events
- [ ] Fallback poll `GET /notifications` and `GET /notifications/unread`

---

## Quick reference — all endpoints

| Method | Path | Purpose |
|--------|------|---------|
| `POST` | `/api/v1/notifications/bulk-sms` | Bulk / schedule SMS |
| `POST` | `/api/v1/notifications/bulk-email` | Bulk / schedule email |
| `POST` | `/api/v1/notifications/bulk-push` | Bulk / schedule push |
| `POST` | `/api/v1/notifications/bulk-in-app` | Bulk / schedule in-app |
| `GET` | `/api/v1/notifications/scheduled` | List scheduled jobs |
| `GET` | `/api/v1/notifications/scheduled/:id` | Get scheduled job |
| `POST` | `/api/v1/notifications/scheduled/:id/cancel` | Cancel scheduled job |
| `GET` | `/api/v1/ws/connect?token=` | In-app WebSocket |
| `GET` | `/api/v1/notifications` | User notification inbox |