# Purchase System Fixes

## Summary
Fixed the purchase functionality with proper pagination showing 30 records per page and resolved various issues in both backend and frontend.

## Backend Fixes

### 1. Purchase View (shop_management/views/data/purchase.py)
- **Discount Calculation**: Fixed discount handling to accept percentage from frontend and convert to amount
- **Pagination**: Confirmed 30 records per page default in CustomPagination
- **Date Filtering**: Added PurchaseFilter class for date range filtering
- **Stock Management**: Improved stock update methods for create, update, and delete operations

### 2. Pagination (shop_management/views/data/pagination.py)
- **Default Page Size**: Set to 30 records per page
- **Dynamic Page Size**: Supports page_size query parameter
- **All Records**: Supports page_size='all' to return all records

## Frontend Fixes

### 3. Purchase Index (frontend/src/shop/Purchase/PurchaseIndex.js)
- **Default Pagination**: Changed from 10 to 30 records per page
- **Pagination Options**: Added 50 and 100 records per page options
- **Consistent UI**: Maintained existing search and filter functionality

### 4. Purchase Add (frontend/src/shop/Purchase/PurchaseAdd.js)
- **Discount Handling**: Fixed to send percentage instead of amount
- **Date Format**: Fixed date format to YYYY-MM-DD
- **Default Date**: Set purchase date to today's date by default
- **Validation**: Improved form validation and error handling

### 5. Purchase Edit (frontend/src/shop/Purchase/PurchaseEdit.js)
- **API Endpoint**: Fixed supplier endpoint from 'shop/supplier' to 'shop/suppliers'
- **Discount Calculation**: Fixed discount percentage calculation and display
- **Date Handling**: Fixed date format for both purchase date and expire date
- **Form Validation**: Improved validation and error handling

## Key Features Implemented

### Pagination
- ✅ Default 30 records per page
- ✅ Options: 10, 20, 30, 50, 100 records per page
- ✅ Proper pagination controls with page numbers
- ✅ Total count display

### Purchase Form
- ✅ Shop selection (required)
- ✅ Supplier selection (required)
- ✅ Currency selection (required)
- ✅ Purchase date with default to today
- ✅ Discount percentage calculation
- ✅ Multiple purchase items with:
  - Product selection
  - Unit selection
  - Quantity
  - Buy price
  - Sale price
  - Expire date (optional)

### Purchase Management
- ✅ Create new purchases
- ✅ Edit existing purchases
- ✅ Delete purchases (with stock adjustment)
- ✅ Print purchase receipts
- ✅ Search and filter functionality
- ✅ Expandable rows showing purchase items

### Stock Integration
- ✅ Automatic stock updates on purchase create
- ✅ Stock adjustments on purchase edit
- ✅ Stock removal on purchase delete
- ✅ Duplicate stock consolidation

## API Endpoints
- `GET /api/shop/purchases/` - List purchases with pagination
- `POST /api/shop/purchases/` - Create new purchase
- `PUT /api/shop/purchases/{id}/` - Update purchase
- `DELETE /api/shop/purchases/{id}/` - Delete purchase
- `GET /api/shop/purchases/?page_size=30` - Get 30 records per page
- `GET /api/shop/purchases/?search=term` - Search purchases
- `GET /api/shop/purchases/?shop=1&supplier=2` - Filter by shop and supplier

## Testing Recommendations
1. Test pagination with different page sizes
2. Test purchase creation with various discount percentages
3. Test purchase editing and stock updates
4. Test search and filter functionality
5. Test date handling and validation
6. Test form validation with missing required fields

## Notes
- All changes maintain backward compatibility
- Stock management is properly integrated
- Error handling is improved throughout
- UI/UX remains consistent with existing design
- Pagination performance is optimized for large datasets