# Analysis: Admin Configuration for Model Selection per Batch

## Executive Summary

This document analyzes how to add a feature that allows admins to configure which AI model to use for each batch during QR verification. Currently, the system uses a default model for all batches when `feature_comparison_threshold > 0.01`.

## Current State

### 1. Batch Model (`CodeBatch`)
- Location: `api/products/models.py:162`
- Key field: `feature_comparison_threshold` (FloatField, default=0.0)
  - When `> 0.01`, triggers v5 QR verification
  - When `<= 0.01`, skips v5 QR verification

### 2. QR Verification Flow
- Location: `api/products/views.py:665-680`
- Method: `QrVerifyView.do_v5_qr_verify()`
- Current behavior:
  - Makes POST request to `https://themblem.com/api/v5/qr_verify`
  - Sends image files only
  - **Does NOT specify a model parameter**
  - Server uses default model: `best_model_ep82_pos98.94_neg96.13_20250720_222102.pt`

### 3. V5 QR Verify Server
- Location: `emblem5/ai/server.py:83-114`
- Endpoint: `/api/v5/qr_verify`
- Model selection:
  - Accepts `model` parameter from form data: `fd.get('model', default_model)`
  - Default model defined in `emblem5/ai/common.py:42`
  - Models are downloaded from OSS bucket `emblem-models` if not cached locally

### 4. Admin UI
- Location: `web/src/views/code-batch.vue`
- Current editable fields include `feature_comparison_threshold`
- Uses `GenericManager` component for CRUD operations

## Requirements

1. **Database**: Add a field to `CodeBatch` to store the model identifier
2. **API**: Pass the model parameter to v5 QR verify endpoint when specified
3. **UI**: Allow admins to configure the model per batch
4. **Backward Compatibility**: Existing batches should continue using default model if not configured

## Design Approach

### Option 1: Simple Model Name Field (Recommended)
- Add `verification_model` field to `CodeBatch` (CharField, nullable)
- Store model filename (e.g., `best_model_ep82_pos98.94_neg96.13_20250720_222102.pt`)
- Pass to v5 endpoint when `feature_comparison_threshold > 0.01` and model is set
- **Pros**: Simple, minimal changes, flexible
- **Cons**: No validation of model existence, manual entry required

### Option 2: Model Reference with Validation
- Add `verification_model` field + create `VerificationModel` table
- Store available models in database
- Validate model exists before allowing selection
- **Pros**: Better validation, can track model metadata
- **Cons**: More complex, requires model management UI

### Option 3: Use GlobalConfig for Model List
- Store available models in `GlobalConfig`
- Add `verification_model` field to `CodeBatch`
- Validate against GlobalConfig list
- **Pros**: Reuses existing config system, simple validation
- **Cons**: Still requires manual model management

**Recommendation**: Option 1 for minimal changes, with future enhancement to Option 3 if needed.

## Implementation Plan

### Phase 1: Database Changes

1. **Create Migration**
   - Add `verification_model` field to `CodeBatch` model
   - Type: `CharField(max_length=255, null=True, blank=True)`
   - Verbose name: "验证模型名称（可选，留空使用默认模型）"
   - Default: `None` (uses server default)

2. **Update Model**
   ```python
   # api/products/models.py
   class CodeBatch(models.Model):
       # ... existing fields ...
       verification_model = models.CharField(
           max_length=255, 
           null=True, 
           blank=True,
           verbose_name="验证模型名称（可选，留空使用默认模型）"
       )
   ```

### Phase 2: API Changes

1. **Update `do_v5_qr_verify()` method**
   - Location: `api/products/views.py:668`
   - Accept `model_name` parameter
   - Pass `model` in form data if provided
   - Fallback to default (current behavior) if not provided

2. **Update `QrVerifyView.post()` method**
   - Location: `api/products/views.py:722`
   - Get model from `sc.batch.verification_model`
   - Pass to `do_v5_qr_verify()` when calling

3. **Code Changes**
   ```python
   def do_v5_qr_verify(self, imgs, messages, model_name=None):
       files = {}
       for i, img in enumerate(imgs):
           files[f'frame_{i}_{img[1]}'] = img[0]
       
       data = {}
       if model_name:
           data['model'] = model_name
       
       resp = requests.post(
           "https://themblem.com/api/v5/qr_verify",
           files=files,
           data=data,  # Add model parameter if specified
       )
       # ... rest of method ...
   
   # In post() method:
   if sc.batch.feature_comparison_threshold > 0.01:
       model_name = sc.batch.verification_model if hasattr(sc.batch, 'verification_model') else None
       self.do_v5_qr_verify(imgs, messages, model_name=model_name)
   ```

### Phase 3: UI Changes

1. **Update Vue Component**
   - Location: `web/src/views/code-batch.vue`
   - Add `verification_model` to `editable_fields` array
   - Add to `visible_fields` array (optional, for display)

2. **Optional: Model Selection Helper**
   - Could add a dropdown/autocomplete if model list is available
   - For now, text input is sufficient (admins know model names)

### Phase 4: Testing

1. **Unit Tests**
   - Test `do_v5_qr_verify()` with and without model parameter
   - Test backward compatibility (null model uses default)

2. **Integration Tests**
   - Test QR verification with custom model
   - Test QR verification without model (default behavior)
   - Test with `feature_comparison_threshold = 0` (should skip)

3. **Manual Testing**
   - Create batch with custom model
   - Verify model is passed to v5 endpoint
   - Verify default model used when field is empty

## Database Schema Change

```python
# Migration file: api/products/migrations/XXXX_add_verification_model_to_codebatch.py

from django.db import migrations, models

class Migration(migrations.Migration):
    dependencies = [
        ('products', 'XXXX_previous_migration'),
    ]

    operations = [
        migrations.AddField(
            model_name='codebatch',
            name='verification_model',
            field=models.CharField(
                max_length=255,
                blank=True,
                null=True,
                verbose_name='验证模型名称（可选，留空使用默认模型）'
            ),
        ),
    ]
```

## API Changes Summary

### Modified Endpoints
- **None** (internal method change only)

### New Behavior
- `QrVerifyView.do_v5_qr_verify()` now accepts optional `model_name` parameter
- When `CodeBatch.verification_model` is set, it's passed to v5 endpoint
- When `CodeBatch.verification_model` is null/empty, server uses default model

## UI Changes Summary

### Modified Views
- `web/src/views/code-batch.vue`
  - Add `verification_model` to editable fields
  - Optional: Add to visible fields for display

### User Experience
- Admin can edit batch and set `verification_model` field
- Field is optional - leaving empty uses default model
- Text input allows entering model filename directly

## Backward Compatibility

✅ **Fully Compatible**
- Existing batches have `verification_model = None`
- When `None`, v5 endpoint uses default model (current behavior)
- No breaking changes to existing functionality

## Future Enhancements

1. **Model Management UI**
   - List available models from OSS bucket
   - Show model metadata (accuracy, date, etc.)
   - Auto-complete model selection

2. **Model Validation**
   - Check if model exists before saving
   - Show warning if model not found

3. **Model Versioning**
   - Track model versions per batch
   - Allow rollback to previous models

4. **A/B Testing**
   - Support multiple models per batch
   - Compare model performance

## Files to Modify

1. `api/products/models.py` - Add `verification_model` field
2. `api/products/views.py` - Update `do_v5_qr_verify()` and `QrVerifyView.post()`
3. `web/src/views/code-batch.vue` - Add field to editable fields
4. Create migration file in `api/products/migrations/`

## Estimated Effort

- **Database Migration**: 15 minutes
- **Backend Changes**: 30 minutes
- **Frontend Changes**: 15 minutes
- **Testing**: 1 hour
- **Total**: ~2 hours

## Risks and Considerations

1. **Model Availability**: No validation that model exists in OSS bucket
   - **Mitigation**: Server will return error if model not found, which is acceptable

2. **Model Naming**: Admins must know exact model filename
   - **Mitigation**: Document model names, or add helper UI later

3. **Default Model Changes**: If default model changes in server, batches without explicit model will use new default
   - **Mitigation**: This is expected behavior, but could be documented

4. **Performance**: No performance impact expected
   - Model download is cached on server side

## Conclusion

This feature can be implemented with minimal changes following Option 1 (Simple Model Name Field). The implementation is backward compatible and allows admins to configure models per batch while maintaining default behavior for existing batches.