# Firebase Notification Implementation Summary

## What Was Added

This implementation adds Firebase Cloud Messaging (FCM) push notification support to allow collection agents to send notifications to admins.

## Files Created/Modified

### New Files Created

1. **`utils/firebase.js`**
   - Firebase Admin SDK utility functions
   - Functions for sending notifications to single/multiple devices
   - Function for sending notifications to all company admins

2. **`add_fcm_token_to_staff.sql`**
   - SQL script to add `fcm_token` column to `staff` table

3. **`FIREBASE_SETUP.md`**
   - Complete setup guide for Firebase notifications
   - Configuration instructions
   - Troubleshooting tips

4. **`NOTIFICATION_API_EXAMPLES.md`**
   - API usage examples
   - Integration examples for mobile apps
   - Error handling guide

5. **`FIREBASE_IMPLEMENTATION_SUMMARY.md`** (this file)
   - Overview of implementation

### Files Modified

1. **`models/Staff.js`**
   - Added `fcm_token` field to store Firebase Cloud Messaging tokens

2. **`controllers/CollectionAgentController.js`**
   - Added `sendNotificationToAdmins()` method
   - Allows agents to send notifications to all admins in their company

3. **`controllers/AdminController.js`**
   - Added `registerFCMToken()` method
   - Added `removeFCMToken()` method
   - Allows admins to register/remove their FCM tokens

4. **`routes/auth.js`**
   - Added route: `POST /admin/register_fcm_token`
   - Added route: `POST /admin/remove_fcm_token`
   - Added route: `POST /send_notification_to_admins`

5. **`package.json`**
   - Added `firebase-admin` dependency (already installed)

## Database Changes Required

Run the SQL script to add the `fcm_token` column:

```bash
mysql -u root -p xesstech_dayloan < add_fcm_token_to_staff.sql
```

Or manually:

```sql
ALTER TABLE `staff` 
ADD COLUMN `fcm_token` VARCHAR(500) NULL AFTER `token_expires`;

CREATE INDEX `idx_staff_fcm_token` ON `staff` (`fcm_token`);
```

## Firebase Configuration Required

**Important:** The Firebase client SDK configuration you provided is for client-side use. For server-side notifications, you need Firebase Admin SDK with a service account key.

### Steps to Configure:

1. Go to [Firebase Console](https://console.firebase.google.com/)
2. Select your project: `finlms-f8227`
3. Go to **Project Settings** > **Service Accounts**
4. Click **Generate New Private Key**
5. Save the JSON file as: `config/firebase-service-account.json`

The Firebase utility will automatically use this file if it exists.

## API Endpoints

### Admin Endpoints

1. **Register FCM Token**
   - `POST /admin/register_fcm_token`
   - Requires admin authentication
   - Body: `{ "fcm_token": "..." }`

2. **Remove FCM Token**
   - `POST /admin/remove_fcm_token`
   - Requires admin authentication

### Agent Endpoints

1. **Send Notification to Admins**
   - `POST /send_notification_to_admins`
   - Requires agent authentication
   - Body: `{ "title": "...", "body": "...", "data": {...} }`
   - Sends notification to all admins in the agent's company

## Usage Flow

1. **Admin Side:**
   - Admin logs into mobile app
   - Mobile app gets FCM token from Firebase
   - Mobile app calls `POST /admin/register_fcm_token` with the token
   - Admin is now ready to receive notifications

2. **Agent Side:**
   - Agent performs an action (e.g., collects payment)
   - Agent calls `POST /send_notification_to_admins` with notification details
   - All admins in the same company receive the push notification

3. **Notification Delivery:**
   - Firebase sends notification to all registered admin devices
   - Admins receive notification on their mobile devices
   - Mobile app can handle notification and navigate to relevant screen

## Key Features

- ✅ Agents can send notifications to all admins in their company
- ✅ Admins can register/update their FCM tokens
- ✅ Support for custom notification data payload
- ✅ Automatic handling of invalid/expired tokens
- ✅ Batch sending to multiple admins
- ✅ Comprehensive error handling

## Next Steps

1. **Run Database Migration:**
   ```bash
   mysql -u root -p xesstech_dayloan < add_fcm_token_to_staff.sql
   ```

2. **Configure Firebase Admin SDK:**
   - Download service account JSON from Firebase Console
   - Place it at: `config/firebase-service-account.json`

3. **Update Mobile App:**
   - Integrate FCM token registration after admin login
   - Handle incoming notifications
   - Update token on refresh

4. **Test the Integration:**
   - Register admin FCM token via API
   - Send test notification from agent
   - Verify notification is received on admin device

## Notes

- The notification system sends to all admins in the same company as the agent
- If an admin doesn't have an FCM token, they won't receive notifications
- Invalid tokens are automatically handled by Firebase
- All notification data values are converted to strings (FCM requirement)
- The implementation supports both Android and iOS platforms

## Support

For detailed setup instructions, see `FIREBASE_SETUP.md`
For API usage examples, see `NOTIFICATION_API_EXAMPLES.md`