# Google Calendar Integration with Service Account

## Overview
Using a Service Account to integrate Google Calendar API without OAuth user consent.

## Setup Instructions

### 1. Create Service Account in Google Cloud Console

1. Go to [Google Cloud Console](https://console.cloud.google.com/)
2. Create a new project or select existing one
3. Navigate to **IAM & Admin** → **Service Accounts**
4. Click **Create Service Account**
5. Fill in details:
   - Name: `access-hub-calendar`
   - Description: `Service account for Access Hub calendar integration`
6. Click **Create and Continue**
7. Skip granting roles (not needed for Calendar API)
8. Click **Done**

### 2. Enable Google Calendar API

1. In Google Cloud Console, go to **APIs & Services** → **Library**
2. Search for "Google Calendar API"
3. Click on it and press **Enable**

### 3. Create Service Account Key

1. Go to your service account page
2. Click on the **Keys** tab
3. Click **Add Key** → **Create New Key**
4. Select **JSON** format
5. Click **Create** - this will download a JSON file with credentials
6. **Keep this file secure** - it contains your private key

The JSON file looks like:
```json
{
  "type": "service_account",
  "project_id": "your-project-id",
  "private_key_id": "...",
  "private_key": "-----BEGIN PRIVATE KEY-----\n...",
  "client_email": "access-hub-calendar@your-project-id.iam.gserviceaccount.com",
  "client_id": "...",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://oauth2.googleapis.com/token"
}
```

### 4. Share Calendar with Service Account

1. Go to [Google Calendar](https://calendar.google.com/)
2. Find the calendar you want to use (e.g., your main calendar)
3. Click the **three dots** next to the calendar name
4. Select **Settings and sharing**
5. Scroll to **Share with specific people**
6. Click **+ Add people**
7. Enter the service account email: `access-hub-calendar@your-project-id.iam.gserviceaccount.com`
8. Set permissions to **Editor** (can make changes to events)
9. Click **Send** (ignore the email notification)

### 5. Get Calendar ID

- For your primary calendar: `your-email@gmail.com`
- For other calendars: Go to Calendar Settings → **Integrate calendar** → **Calendar ID**

## n8n Workflow Configuration

### Option A: Using Google Calendar Node

1. Add a **Google Calendar** node to your workflow
2. Select **Service Account** as authentication
3. Paste the entire Service Account JSON content
4. Select the calendar ID
5. Choose operation: **Create Event**

### Option B: Using HTTP Request Node (More Control)

```javascript
// In n8n Code node or HTTP Request node

const { GoogleToken } = require('gtoken');
const { google } = require('googleapis');

// Service account credentials
const serviceAccount = {
  type: 'service_account',
  project_id: 'your-project-id',
  private_key_id: '...',
  private_key: '-----BEGIN PRIVATE KEY-----\n...',
  client_email: 'access-hub-calendar@your-project-id.iam.gserviceaccount.com',
  client_id: '...',
};

// Create JWT client
const jwtClient = new google.auth.JWT(
  serviceAccount.client_email,
  null,
  serviceAccount.private_key,
  ['https://www.googleapis.com/auth/calendar']
);

// Authorize and create event
jwtClient.authorize(async (err, tokens) => {
  if (err) {
    console.error('JWT authorization error:', err);
    return;
  }

  const calendar = google.calendar({ version: 'v3', auth: jwtClient });

  const event = {
    summary: 'Konsultasi: ' + $json.topic + ' - ' + $json.client_name,
    start: {
      dateTime: new Date($json.date + 'T' + $json.start_time).toISOString(),
      timeZone: 'Asia/Jakarta',
    },
    end: {
      dateTime: new Date($json.date + 'T' + $json.end_time).toISOString(),
      timeZone: 'Asia/Jakarta',
    },
    description: 'Client: ' + $json.client_email + '\n\n' + $json.notes,
    attendees: [
      { email: $json.client_email },
    ],
    conferenceData: {
      createRequest: {
        requestId: $json.slot_id,
        conferenceSolutionKey: { type: 'hangoutsMeet' },
      },
    },
  };

  try {
    const result = await calendar.events.insert({
      calendarId: $json.calendar_id,
      resource: event,
      conferenceDataVersion: 1,
    });

    return {
      meet_link: result.data.hangoutLink,
      event_id: result.data.id,
    };
  } catch (error) {
    console.error('Error creating calendar event:', error);
    throw error;
  }
});
```

## Incoming Webhook Payload

Your n8n webhook at `/webhook-test/create-meet` will receive:

```json
{
  "slot_id": "uuid-of-slot",
  "date": "2025-12-25",
  "start_time": "14:00:00",
  "end_time": "15:00:00",
  "client_name": "John Doe",
  "client_email": "john@example.com",
  "topic": "Business Consulting",
  "notes": "Discuss project roadmap",
  "calendar_id": "your-calendar@gmail.com",
  "brand_name": "Your Brand",
  "test_mode": true
}
```

## Expected Response

Your n8n workflow should return:

```json
{
  "meet_link": "https://meet.google.com/abc-defg-hij",
  "event_id": "event-id-from-google-calendar"
}
```

## Security Notes

1. **Never commit the service account JSON** to version control
2. Store it securely in n8n credentials
3. Rotate the key if compromised
4. Only grant minimum necessary permissions to the service account

## Troubleshooting

### Error: 403 Forbidden
- Check if the calendar is shared with the service account email
- Verify the service account has **Editor** permissions

### Error: 401 Unauthorized
- Verify the service account JSON is correct
- Check if Calendar API is enabled in Google Cloud Console

### Error: 400 Invalid
- Check date/time format (should be ISO 8601)
- Verify calendar ID is correct
- Ensure the service account email format is correct

## Alternative: Use Google Calendar API Key (Less Secure)

If you don't want to use service accounts, you can create an API key:

1. Go to Google Cloud Console → **APIs & Services** → **Credentials**
2. Click **Create Credentials** → **API Key**
3. Restrict the key to Google Calendar API only
4. Use it with HTTP requests

However, this is **not recommended** for production as it's less secure than service accounts.