# Hugging Face Spaces Setup Guide

## Quick Setup

1. **Create a new Space** on Hugging Face with:
   - SDK: Docker
   - Hardware: CPU basic (or GPU if you need faster processing)

2. **Environment Variables/Secrets**:
   Add these to your Space's settings > Variables and Secrets:
   
   ```
   NEBIUS_API_KEY=your_nebius_api_key
   MODAL_TOKEN_ID=your_modal_token_id
   MODAL_TOKEN_SECRET=your_modal_token_secret
   GITHUB_TOKEN=your_github_token
   ```

3. **Upload Control** (Optional):
   - By default, uploads are **enabled** in Spaces
   - To disable uploads, add: `DISABLE_UPLOADS=true`

## Storage in Hugging Face Spaces

### Persistent vs Temporary Storage

Hugging Face Spaces provide:
- **Temporary storage**: `/tmp` directory (used by this app)
  - ✅ Survives app restarts
  - ✅ Suitable for uploads and database
  - ❌ Not persistent across Space rebuilds
  - ❌ Limited size (~10GB)

### How This App Handles Storage

The app automatically detects Hugging Face Spaces and:

1. **Database**: Stored in `/tmp/knowledgebridge.db`
2. **Uploads**: Stored in `/tmp/uploads/`
3. **Vector Indexes**: Stored in `/tmp/` via Modal

### Adding Persistent Storage (Advanced)

For truly persistent storage, you have these options:

#### Option 1: External Database
```bash
# Add to your Space environment
DATABASE_URL=postgresql://user:pass@host:port/db
```

#### Option 2: Cloud Storage
```bash
# Add to your Space environment  
AWS_ACCESS_KEY_ID=your_key
AWS_SECRET_ACCESS_KEY=your_secret
S3_BUCKET=your_bucket
```

#### Option 3: Hugging Face Hub (Git LFS)
For large files, use Git LFS:
```bash
git lfs track "*.pdf" "*.db"
git add .gitattributes
```

## Troubleshooting

### "File uploads disabled" Error

If you see this error, check:

1. **Environment Detection**: Look for this log message:
   ```
   🔍 Environment check: { NODE_ENV: 'production', DISABLE_UPLOADS: undefined, isHuggingFaceSpace: true, hasWritableStorage: true, isDocumentUploadEnabled: true }
   ```

2. **Force Enable**: Add this environment variable:
   ```
   ENABLE_UPLOADS=true
   ```

3. **Check Logs**: Look for these success messages:
   ```
   ✅ Created uploads directory: /tmp/uploads
   ✅ Upload directory is writable: /tmp/uploads  
   ✅ Document uploads enabled - full functionality available
   ```

### Vector Search Issues

If vector search shows "disabled":

1. **Check Modal Integration**: Ensure Modal tokens are set
2. **Check Logs**: Look for Modal API connectivity
3. **Fallback**: The app will use text search if vector search fails

### Performance Optimization

For better performance in Spaces:

1. **Use GPU Hardware**: For faster AI processing
2. **Enable Caching**: Vector indexes are cached in `/tmp`
3. **Batch Operations**: Upload multiple files at once

## Environment Detection

The app detects Hugging Face Spaces using these environment variables:
- `SPACE_ID`
- `HF_SPACE_ID` 
- `HUGGINGFACE_SPACE_ID`
- `HF_TOKEN`

When detected, uploads are automatically enabled regardless of other settings.

## Monitoring

Check your Space logs for these indicators:

### ✅ Successful Setup
```
✅ Document uploads enabled - full functionality available
✅ Created uploads directory: /tmp/uploads
🔍 Environment check: { isHuggingFaceSpace: true, isDocumentUploadEnabled: true }
```

### ❌ Issues
```
❌ Failed to create or write to uploads directory
ℹ️ Document uploads disabled - using fallback routes
🔍 Environment check: { isDocumentUploadEnabled: false }
```

## Support

If you encounter issues:

1. Check the Space logs for error messages
2. Verify environment variables are set correctly  
3. Test with a small PDF file first
4. Check the app health endpoint: `/api/health`