# Notification System

**Status:** ✅ Implemented | Extensible notification system with Discord, ntfy, and Pushover support

## Overview
Sends notifications for audiobook request events (pending approval, approved, available, error) to configured backends. Non-blocking, atomic per-backend failure handling. Proper notification timing for all request flows including interactive search.

## Key Details
- **Backends:** Apprise (API), Discord (webhooks), ntfy (API), Pushover (API)
- **Events:** request_pending_approval, request_approved, request_available, request_error
- **Encryption:** AES-256-GCM for sensitive config (webhook URLs, API keys, notification URLs)
- **Delivery:** Async via Bull job queue (priority 5)
- **Failure Handling:** Non-blocking, Promise.allSettled (one backend fails, others succeed)

## Database Schema

```prisma
model NotificationBackend {
  id        String   @id @default(uuid())
  type      String   // 'apprise' | 'discord' | 'ntfy' | 'pushover'
  name      String   // User-friendly label
  config    Json     // Encrypted sensitive values
  events    Json     // Array of subscribed events
  enabled   Boolean  @default(true)
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}
```

## Event Types

| Event | Trigger | Notification Sent When |
|-------|---------|------------------------|
| request_pending_approval | User creates request | Request needs admin approval |
| request_approved | Admin approves OR auto-approval | Request approved (manual or auto) |
| request_available | Plex/ABS scan completes | Audiobook available in library |
| request_error | Download/import fails | Request failed at any stage |

## Notification Triggers

**Request Creation (POST /api/requests)**
- Automatic search, approval needed: `status === 'awaiting_approval'` → request_pending_approval
- Automatic search, auto-approved: `status === 'pending'` → request_approved
- Interactive search: NO notification yet (deferred until torrent selection)

**BookDate Swipe (POST /api/bookdate/swipe)**
- Right swipe, approval needed: `status === 'awaiting_approval'` → request_pending_approval
- Right swipe, auto-approved: `status === 'pending'` → request_approved

**Request with Pre-Selected Torrent (POST /api/audiobooks/request-with-torrent)**
- Approval needed: `status === 'awaiting_approval'` → request_pending_approval
- Auto-approved: `status === 'downloading'` → request_approved

**Torrent Selection for Existing Request (POST /api/requests/[id]/select-torrent)**
- Approval needed: `status === 'awaiting_approval'` → request_pending_approval
- Auto-approved: `status === 'downloading'` → request_approved

**Admin Approval (POST /api/admin/requests/[id]/approve)**
- Approve (with or without pre-selected torrent): After job triggered → request_approved
- Deny: No notification

**Request Available (processors: scan-plex, plex-recently-added)**
- After `status: 'available'` update → request_available
- Includes user info in query (plexUsername)

**Request Error (processors: monitor-download, organize-files)**
- After `status: 'failed'` or `status: 'warn'` update → request_error
- Includes error message in payload

## Configuration Encryption

**Encrypted Values:**
- Apprise: `urls`, `authToken`
- Discord: `webhookUrl`
- ntfy: `accessToken`
- Pushover: `userKey`, `appToken`

**Pattern:** `iv:authTag:encryptedData` (base64)

**Masking:** Sensitive values returned as `••••••••` in API responses

**Preservation:** Masked values preserved on update (if value === '••••••••', use existing encrypted value)

## Message Formatting

**Apprise (JSON via Apprise API):**
- Type: info (pending), success (approved/available), failure (error)
- Modes: Stateless (send URLs directly) or Stateful (use persistent configKey, optional tag filter)
- Endpoint: `{serverUrl}/notify/` (stateless) or `{serverUrl}/notify/{configKey}` (stateful)
- Auth: Optional Bearer token via `authToken` config field
- Format: Event title + book details + user + error (if applicable)

**Discord (Rich Embeds):**
- Color-coded by event (yellow=pending, green=approved, blue=available, red=error)
- Fields: Title, Author, Requested By, Error (if applicable)
- Footer: Request ID
- Timestamp: Event time

**ntfy (JSON with Tags):**
- Tags: mailbox_with_mail, white_check_mark, tada, x (rendered as emojis by ntfy)
- Priority: Default (3) for pending/approved, High (4) for available/error
- Format: Event title + book details + user + error (if applicable)
- Auth: Optional Bearer token via `accessToken` config field
- Server: Configurable `serverUrl` (default: https://ntfy.sh)

**Pushover (Plain Text with Emojis):**
- Emojis: 📬 📬 🎉 ❌
- Priority: Normal (0) for pending/approved, High (1) for available/error
- Format: Event title + book details + user + error (if applicable)

## API Endpoints

**GET /api/admin/notifications**
- Returns all backends (sensitive values masked)

**POST /api/admin/notifications**
- Create backend (encrypts sensitive values)
- Body: `{type, name, config, events, enabled}`

**GET /api/admin/notifications/[id]**
- Get single backend (sensitive values masked)

**PUT /api/admin/notifications/[id]**
- Update backend (preserves masked values, encrypts new values)

**DELETE /api/admin/notifications/[id]**
- Delete backend

**POST /api/admin/notifications/test**
- Test notification (synchronous, not via job queue)
- Body: `{type, config}` (plaintext for testing)
- Sends test payload: "The Hitchhiker's Guide to the Galaxy" by Douglas Adams

## UI Components

**NotificationsTab (src/app/admin/settings/tabs/NotificationsTab)**
- Type selector cards (Discord: indigo "D", Pushover: blue "P")
- Configured backends grid (3 columns)
- Backend cards: type icon, name, enabled status, event count, edit/delete actions
- Modal: type-specific forms, event checkboxes, enable toggle, test button

**Modal Features:**
- Type-first selection (user clicks "Add Discord" or "Add Pushover")
- Password inputs for sensitive values
- Event subscription checkboxes (4 events, default: available + error)
- Test button (sends synchronous test notification)
- Save button (validates and creates/updates backend)

## Job Queue Integration

**Job Type:** `send_notification` (priority 5, concurrency 5)

**Payload:**
```typescript
{
  jobId?: string,
  event: string,
  requestId: string,
  title: string,
  author: string,
  userName: string,
  message?: string,
  timestamp: Date
}
```

**Processor:** `src/lib/processors/send-notification.processor.ts`
- Calls NotificationService.sendNotification()
- Non-blocking error handling (logs but doesn't throw)

**Queue Method:** `addNotificationJob(event, requestId, title, author, userName, message?)`

## Architecture

**Provider Pattern:** `INotificationProvider` interface + registry (matches `IAuthProvider` pattern)

```
src/lib/services/notification/
  INotificationProvider.ts          # Interface + shared types
  notification.service.ts           # Core service with registry
  index.ts                          # Re-exports
  providers/
    apprise.provider.ts             # Apprise API (100+ services)
    discord.provider.ts             # Discord webhook
    ntfy.provider.ts                # ntfy API
    pushover.provider.ts            # Pushover API
```

**Registry:** Module-level `Map<string, INotificationProvider>` with `registerProvider()` / `getProvider()`

**INotificationProvider interface:**
- `type: string` — provider identifier (registry key)
- `sensitiveFields: string[]` — fields needing encryption/masking
- `metadata: ProviderMetadata` — self-describing UI/validation metadata
- `send(config, payload): Promise<void>` — receives decrypted config

**ProviderMetadata:** `{ type, displayName, description, iconLabel, iconColor, configFields[] }`
**ProviderConfigField:** `{ name, label, type, required, placeholder?, defaultValue?, options? }`

**Helper functions:**
- `getRegisteredProviderTypes(): string[]` — all registered type keys
- `getAllProviderMetadata(): ProviderMetadata[]` — metadata for all providers

**API Endpoint:** `GET /api/admin/notifications/providers` — returns all provider metadata (admin-only)

## Extensibility

**Adding New Backend (2 steps):**
1. Create `providers/email.provider.ts` implementing `INotificationProvider`:
   - Set `type = 'email'`, `sensitiveFields = ['smtpPassword']`
   - Set `metadata` with displayName, description, iconLabel, iconColor, configFields
   - Implement `send()` with email-specific logic
2. Register in `notification.service.ts`: `registerProvider(new EmailProvider())` + re-export from `index.ts`

No UI changes, no API route changes, no Zod schema changes needed — the UI renders dynamically from provider metadata.

**Adding New Event (e.g., download_complete):**
1. Add 'download_complete' to NotificationEvent enum
2. Add to event labels in UI
3. Add trigger point in processor
4. Add message formatting in Discord/Pushover formatters

## Tech Stack
- Bull (job queue)
- Node.js crypto (AES-256-GCM encryption)
- Apprise API, Discord webhooks, ntfy API, Pushover API
- React (UI), Tailwind CSS (styling)

## Related
- [Job Queue System](jobs.md)
- [Config Encryption](config.md)
- [Settings Pages](../../settings-pages.md)