# Troubleshooting Database Connection Issues

## Error: "Invalid API key"

This error occurs when your Supabase API key is missing, incorrect, or expired.

### Solution 1: Use Direct PostgreSQL Connection (RECOMMENDED)

For heavy SQL queries (which this system uses extensively), a direct PostgreSQL connection is faster and more reliable.

1. **Get your database connection string from Supabase:**
   - Go to Supabase Dashboard
   - Navigate to **Settings > Database**
   - Find **Connection String** section
   - Copy the **URI** connection string
   - It should look like: `postgresql://postgres:[password]@db.[project-ref].supabase.co:5432/postgres`

2. **Add to your `.env` file:**
   ```env
   DATABASE_URL=postgresql://postgres:your_password@db.your-project-ref.supabase.co:5432/postgres
   ```

3. **Restart your server**

The system will automatically use the direct PostgreSQL connection when `DATABASE_URL` is set, which bypasses API key issues entirely.

### Solution 2: Fix Supabase API Keys

If you prefer to use Supabase client:

1. **Get your Supabase credentials:**
   - Go to Supabase Dashboard
   - Navigate to **Settings > API**
   - Copy the following:
     - **Project URL** → `SUPABASE_URL`
     - **service_role key** (secret) → `SUPABASE_SERVICE_KEY` ⚠️ **Use this one, not anon key**

2. **Create/update `.env` file in `backend/` directory:**
   ```env
   # Supabase Configuration
   SUPABASE_URL=https://your-project-ref.supabase.co
   SUPABASE_SERVICE_KEY=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9... (your service_role key)
   
   # Optional: Direct PostgreSQL connection (recommended for heavy queries)
   DATABASE_URL=postgresql://postgres:password@db.project-ref.supabase.co:5432/postgres
   
   # Server Configuration
   PORT=3010
   NODE_ENV=development
   
   # CORS Configuration
   CORS_ORIGIN=http://localhost:5173
   ```

3. **Important Notes:**
   - ⚠️ **Use `service_role` key, NOT `anon` key** for backend operations
   - The `service_role` key has admin privileges and bypasses Row Level Security
   - Never expose the `service_role` key in frontend code
   - Keep your `.env` file in `.gitignore` (it should already be there)

4. **Restart your server:**
   ```bash
   cd backend
   npm run dev
   ```

### Solution 3: Verify Environment Variables

Check that your environment variables are being loaded:

1. **Verify `.env` file exists:**
   ```bash
   ls -la backend/.env
   ```

2. **Check if variables are loaded (add temporarily to test):**
   ```javascript
   // In backend/src/db.js, add temporarily:
   console.log('SUPABASE_URL:', process.env.SUPABASE_URL ? 'SET' : 'MISSING');
   console.log('SUPABASE_SERVICE_KEY:', process.env.SUPABASE_SERVICE_KEY ? 'SET' : 'MISSING');
   console.log('DATABASE_URL:', process.env.DATABASE_URL ? 'SET' : 'MISSING');
   ```

3. **Make sure `.env` file is in the correct location:**
   - Should be: `backend/.env`
   - NOT: `.env` (root directory)
   - NOT: `backend/src/.env`

### Common Issues

#### Issue: "Missing Supabase environment variables"
- **Cause:** `.env` file doesn't exist or variables are misspelled
- **Fix:** Create `.env` file with correct variable names (case-sensitive)

#### Issue: "Invalid API key" but key looks correct
- **Cause:** Using `anon` key instead of `service_role` key
- **Fix:** Use the `service_role` key from Supabase Dashboard > Settings > API

#### Issue: Connection works but queries fail
- **Cause:** Missing `exec_sql` RPC function in Supabase
- **Fix:** Use `DATABASE_URL` for direct PostgreSQL connection (recommended)

#### Issue: Environment variables not loading
- **Cause:** `.env` file in wrong location or `dotenv` not configured
- **Fix:** Ensure `.env` is in `backend/` directory and `dotenv.config()` is called in `db.js`

### Recommended Setup

For best performance with this trading system, use **direct PostgreSQL connection**:

```env
# Direct PostgreSQL Connection (RECOMMENDED)
DATABASE_URL=postgresql://postgres:your_password@db.your-project-ref.supabase.co:5432/postgres

# Optional: Supabase client (for simple queries)
SUPABASE_URL=https://your-project-ref.supabase.co
SUPABASE_SERVICE_KEY=your_service_role_key
```

This setup:
- ✅ Faster query execution
- ✅ No API key issues
- ✅ Direct SQL access
- ✅ Better for heavy analytical queries

### Testing Connection

After fixing your configuration, test the connection:

```bash
cd backend
npm run dev
```

You should see:
```
✅ Database connection successful (PostgreSQL direct)
```

Or:
```
✅ Database connection successful (Supabase)
```

If you still see errors, check the console output for specific error messages and refer to the troubleshooting steps above.