# Product Variant CSV Import Format

## Overview
As of the latest update, the CSV import system now correctly creates **ProductVariant** records instead of ProductMultiBuy records when using semicolon-delimited variations.

## CSV Column Format

```csv
Name,Description,Price,Weight,WeightUnit,StockQuantity,CategoryName,IsActive,Variations,PhotoUrls
```

### Product Base Price and Stock
- Set `Price` to **0** if using variants (variant prices override base price)
- Set `StockQuantity` to **0** if using variants (variant stock is tracked separately)

## Variations Column Format

### ProductVariant Format (Recommended)
Use pipe `|` to separate multiple variants, semicolons `;` to separate the three required parts:

```
"value; price; stock|value; price; stock|value; price; stock"
```

**Format Components:**
- `value`: Variant name/value (e.g., "10", "25", "3.5g", "7g")
- `price`: Price for this variant as decimal (e.g., 30.00)
- `stock`: Stock level for this variant as integer (e.g., 100)

**Example - Quantity-based variants:**
```csv
"Buprenorphine 2mg",0,150,Grams,0,Pharmaceuticals,true,"10; 30.00; 100|25; 70.00; 50|50; 130.00; 25",""
```
This creates:
- Variant "10" at £30.00 with 100 in stock
- Variant "25" at £70.00 with 50 in stock
- Variant "50" at £130.00 with 25 in stock

**Example - Weight-based variants:**
```csv
"Cannabis Flower",0,200,Grams,0,Botanicals,true,"3.5g; 35.00; 10|7g; 65.00; 8|14g; 120.00; 5",""
```
This creates:
- Variant "3.5g" at £35.00 with 10 in stock
- Variant "7g" at £65.00 with 8 in stock
- Variant "14g" at £120.00 with 5 in stock

### Legacy ProductMultiBuy Format (Still Supported)
Old multi-buy format using colons `:` (no semicolons):

```
"Name:Quantity:Price;Name:Quantity:Price"
```

**Example:**
```csv
"Example Product",29.99,150,Grams,50,Electronics,true,"Single:1:29.99;Twin Pack:2:55.00",""
```

## Variant Type Detection
The system automatically determines variant type based on the value:
- Contains "g" (grams): **Weight** variant type
- Otherwise: **Quantity** variant type

## CSV Import Behavior

1. **Semicolon Detection**: If the Variations column contains semicolons (`;`), it's treated as ProductVariant format
2. **Colon-Only Format**: If only colons (`:`) are present, it's treated as legacy ProductMultiBuy format
3. **Empty Variations**: Product uses base Price and StockQuantity

## Exporting Products

When exporting products to CSV:
- Products with **ProductVariants** export in the pipe-delimited format: `"value; price; stock|value; price; stock"`
- Products with **ProductMultiBuys** export in the legacy colon format: `"name:qty:price;name:qty:price"`

## Template Download

Download the CSV template from Admin Panel → Products → Import CSV → Download Template to see the correct format with examples.

## Migration from Old Format

If you previously imported products using the old format (semicolons but creating MultiBuys), you'll need to:

1. Delete existing products with incorrect MultiBuy data
2. Re-import using the corrected pipe-delimited format shown above
3. Ensure product base `Price` is set to 0 when using variants

## Order Creation

When customers order products with variants:
- **TeleBot** automatically passes the `ProductVariantId` to the order API
- **OrderService** uses the variant's `Price` property to calculate the order total
- If variant `Price` is null, it falls back to product base price (which should be 0 for variant-based products)

## Technical Implementation

See `ProductImportService.cs`:
- `ImportProductVariantsAsync()`: Handles pipe-delimited variant format
- `ImportProductMultiBuysAsync()`: Handles legacy colon-delimited multi-buy format
- Detection logic at line ~239