# Old Quality App - Printing Module Summary

## Key Files

### 1. `/srv/quality_app/py_app/app/pdf_generator.py`
**Main PDF Generation Engine**

The `LabelPDFGenerator` class handles all label PDF generation:
- **Dimensions**: 80mm x 105mm thermal printer labels
- **Optimized for**: Epson TM-T20, Citizen CTS-310 thermal printers

#### Key Methods:

##### `generate_labels_pdf(order_data, quantity, printer_optimized=True)`
- Generates PDF with multiple labels based on quantity
- Creates sequential labels: CP00000711-001, CP00000711-002, etc.
- Returns BytesIO buffer with complete PDF

##### `generate_single_label_pdf(order_data, piece_number, total_pieces, printer_optimized=True)`
- Generates single label PDF for specific piece number
- Used by QZ Tray for direct thermal printing
- Returns BytesIO buffer with one label

##### `_draw_label(canvas, order_data, sequential_number, current_num, total_qty)`
**Label Layout:**
- **Row 1**: Company header (empty)
- **Row 2**: Customer name
- **Row 3**: Quantity ordered (left) | Right column split 40/60
- **Row 4**: Customer order (com_achiz_client - nr_linie_com_client)
- **Row 5**: Delivery date (data_livrare)
- **Row 6**: Product description (double height)
- **Row 7**: Size (dimensiune)
- **Row 8**: Article code (customer_article_number)
- **Row 9**: Production order (comanda_productie - sequential_number)

**Barcodes:**
- **Bottom**: CODE128 barcode with sequential number (CP00000711/001)
- **Right side**: CODE128 vertical barcode with customer order format

##### `_optimize_for_label_printer(canvas)`
- Sets 300 DPI resolution
- Enables compression
- Sets print scaling to 100% (no scaling)
- Adds PDF metadata for printer optimization

---

### 2. `/srv/quality_app/py_app/app/print_module.py`
**Database Data Retrieval**

#### Key Functions:

##### `get_unprinted_orders_data(limit=100)`
- Returns orders where `printed_labels != 1`
- Retrieves all fields needed for label generation
- Returns list of order dictionaries

##### `get_printed_orders_data(limit=100)`
- Returns orders where `printed_labels = 1`
- Used for "print lost labels" page
- Returns list of order dictionaries

##### `update_order_printed_status(order_id)`
- Updates `printed_labels = 1` for order
- Called after successful printing

---

### 3. API Routes in `/srv/quality_app/py_app/app/routes.py`

#### `/generate_label_pdf` (POST)
**Single Label Generation for QZ Tray**
```python
Accepts JSON:
{
    "comanda_productie": "CP00000711",
    "cantitate": 5,
    "piece_number": 1,
    "total_pieces": 5,
    ... (other order fields)
}

Returns: PDF binary data
Purpose: Generate single label for thermal printer via QZ Tray
```

#### `/generate_labels_pdf/<order_id>/true` (POST)
**Batch Label Generation for PDF Download**
```
Returns: Multi-page PDF with all labels for order
Purpose: Generate all labels for download/preview
Also marks order as printed (printed_labels = 1)
```

---

### 4. `/srv/quality_app/py_app/app/print_config.py`
**Print Service Configuration**

```python
WINDOWS_PRINT_SERVICE_URL = "http://192.168.1.XXX:8765"
PRINT_SERVICE_TIMEOUT = 30
PRINT_SERVICE_ENABLED = True
```

Note: Windows print service is configured but QZ Tray is the primary method.

---

## Label Printing Flow

### For Direct Printing (QZ Tray):
1. User selects order from table
2. Clicks "Print Labels" button
3. Frontend calls `/labels/api/generate-pdf` with order data and piece_number
4. Backend's `LabelPDFGenerator.generate_single_label_pdf()` creates PDF
5. Returns PDF binary to frontend
6. QZ Tray prints directly to thermal printer
7. After successful print, calls `/labels/api/update-printed-status/{id}`

### For PDF Download:
1. User selects order
2. Clicks "Generate PDF" button
3. Frontend calls `/labels/api/generate-pdf/{orderId}/true`
4. Backend's `LabelPDFGenerator.generate_labels_pdf()` creates multi-page PDF
5. Returns PDF for browser download/print
6. Order marked as printed

---

## Key Configuration Classes

### `LabelPDFGenerator` Parameters:
```python
# Label dimensions
label_width = 80mm
label_height = 105mm

# Content area
content_width = 60mm
content_height = 68mm
content_x = 4mm from left
content_y = 22mm from bottom

# Layout
row_height = 6.8mm (content_height / 10)
left_column_width = 40% (24mm)
right_column_width = 60% (36mm)

# Barcode areas
bottom_barcode: 80mm width x 12mm height
vertical_barcode: 12mm width x 68mm height (rotated 90°)
```

---

## Order Data Fields Used

```python
Required fields for label generation:
- comanda_productie: Production order number
- cod_articol: Article code
- descr_com_prod: Product description
- cantitate: Quantity
- com_achiz_client: Customer purchase order
- nr_linie_com_client: Customer order line
- customer_name: Customer name
- customer_article_number: Customer article number
- data_livrare: Delivery date
- dimensiune: Product size
- printed_labels: Status (0 = unprinted, 1 = printed)
```

---

## Thermal Printer Optimization

The PDF generator is specifically optimized for thermal label printers:

1. **No margins**: Fills entire label area
2. **High resolution**: 300 DPI quality
3. **Monochrome**: Black/white only (no colors)
4. **Compression**: Reduces file size
5. **Scaling**: 100% (no scaling in printer)
6. **Bar width**: Optimized for thermal resolution

Tested with:
- Epson TM-T20 (80mm thermal printer)
- Citizen CTS-310 (80mm thermal printer)