# Purchase Module Analysis

## Module Overview
The Purchase module is a comprehensive procurement system that handles vendor management, purchase requisitions, purchase orders, goods receipts, and billing. It integrates with the Inventory module for stock tracking.

## Module Structure

```
Modules/Purchase/
├── Actions/
│   ├── GenerateProductCodeAction.php
│   ├── GenerateServiceCodeAction.php
│   ├── GenerateVendorCodeAction.php
│   ├── GenerateBarcodeAction.php
│   ├── Bill/
│   ├── PurchaseOrder/
│   └── PurchaseRequisition/
├── Entities/
│   ├── PurchaseOrder.php
│   ├── PurchaseOrderDetail.php
│   ├── PurchaseRequisition.php
│   ├── PurchaseRequisitionDetail.php
│   ├── Bill.php
│   ├── BillDetail.php
│   ├── BillAdjust.php
│   ├── BillPayment.php
│   ├── BillLog.php
│   ├── BillFile.php
│   ├── GoodsReceipt.php
│   ├── GoodsReceiptDetail.php
│   ├── Vendor.php
│   ├── Product.php
│   ├── Service.php
│   ├── Warehouse.php
│   ├── PaymentRecord.php
│   ├── Customer.php
│   ├── PurchaseOrderLog.php
│   └── BillFile.php
├── Http/
│   ├── Controllers/
│   │   ├── PurchaseController.php
│   │   ├── PurchaseOrderController.php
│   │   ├── PurchaseRequisitionController.php
│   │   ├── BillController.php
│   │   ├── VendorController.php
│   │   └── API/
│   ├── Requests/V1/
│   │   ├── PurchaseOrder/
│   │   └── PurchaseRequisition/
│   └── Resources/V1/
│       ├── PurchaseOrder/
│       └── PurchaseRequisition/
├── Routes/
│   ├── web.php
│   ├── api.php
│   └── mobile.php
├── Database/
│   └── Migrations/
├── Tests/
├── Providers/
│   ├── RouteServiceProvider.php
│   └── PurchaseServiceProvider.php
└── Config/config.php
```

## Entity Relationships Diagram

```mermaid
erDiagram
    PURCHASE-REQUISITION ||--o{ PURCHASE-REQUISITION-DETAIL : contains
    PURCHASE-REQUISITION ||--o{ PURCHASE-ORDER : creates
    PURCHASE-REQUISITION }o--|| USER : "created_by"
    PURCHASE-REQUISITION }o--|| DEPARTMENT : references
    PURCHASE-REQUISITION }o--|| CUSTOMER : "pelanggan_id"
    PURCHASE-REQUISITION }o--|| PRODUCT : includes

    PURCHASE-ORDER ||--o{ PURCHASE-ORDER-DETAIL : contains
    PURCHASE-ORDER }o--|| VENDOR : "from"
    PURCHASE-ORDER }o--|| WAREHOUSE : "to"
    PURCHASE-ORDER }o--|| STATUS : "status_id"
    PURCHASE-ORDER }o--|| PURCHASE-REQUISITION : "references"
    PURCHASE-ORDER }o--|| TAX : "tax_id"
    PURCHASE-ORDER ||--o{ BILL : "po_number"
    PURCHASE-ORDER ||--o{ GOODS-RECEIPT : "purchase_order_id"
    PURCHASE-ORDER ||--o{ PURCHASE-ORDER-LOG : logs

    PURCHASE-ORDER-DETAIL }o--|| PRODUCT : "product_id"
    PURCHASE-ORDER-DETAIL }o--|| WAREHOUSE : "warehouse_id"
    PURCHASE-ORDER-DETAIL }o--|| TAX : "tax_id"

    BILL }o--|| VENDOR : "from"
    BILL }o--|| STATUS : "status_id"
    BILL ||--o{ BILL-DETAIL : contains
    BILL ||--o{ BILL-ADJUST : adjustments
    BILL ||--o{ BILL-PAYMENT : payments
    BILL ||--o{ BILL-FILE : attachments
    BILL ||--o{ BILL-LOG : logs
    BILL }o--|| PURCHASE-ORDER : "po_number"

    BILL-DETAIL }o--|| BILL : "bill_id"
    BILL-DETAIL }o--|| PRODUCT : "product_id"
    BILL-DETAIL }o--|| ACCOUNT : "expense_category_id"

    BILL-PAYMENT }o--|| BILL : "bill_id"

    GOODS-RECEIPT }o--|| PURCHASE-ORDER : "purchase_order_id"
    GOODS-RECEIPT ||--o{ GOODS-RECEIPT-DETAIL : contains
    GOODS-RECEIPT-DETAIL }o--|| PRODUCT : "product_id"

    VENDOR ||--o{ PURCHASE-ORDER : "supplies"
    VENDOR ||--o{ BILL : "sends"
    VENDOR }o--|| PROVINCE : location
    VENDOR }o--|| CITY : location

    PRODUCT }o--|| VENDOR : "from"
    SERVICE }o--|| VENDOR : "from"

    WAREHOUSE }o--|| LOCATION : represents

    PAYMENT-RECORD }o--|| BILL : tracks
```

## Core Workflows

### 1. Purchase Requisition Workflow
```
User Request → Create PR → Add PR Details → Submit → Approve → Create PO
```

### 2. Purchase Order Workflow
```
PO Creation (from PR or manual) → Add Details → Submit → Vendor Sends Goods → GR Creation → Match with PO
```

### 3. Goods Receipt Workflow
```
PO Dispatched → Goods Received → Create GR → Add GR Details → Match with PO Details → Confirm Receipt
```

### 4. Bill Processing Workflow
```
PO Created → Vendor Sends Bill → Create Bill → Add Bill Details → Adjustments (if needed) → Approve → Payment
```

## Key Entities Description

| Entity | Purpose | Key Fields |
|--------|---------|-----------|
| **PurchaseRequisition** | Request for purchasing goods/services | pr_number, pr_date, status, total |
| **PurchaseOrder** | Formal order sent to vendor | po_number, po_date, due_date, eta_date, vendor_id |
| **PurchaseOrderDetail** | Line items in PO | product_id, quantity, unit_price, tax |
| **Bill** | Vendor invoice | bill_number, bill_date, due_date, total_amount |
| **BillDetail** | Line items in bill | product_id, quantity, unit_price |
| **GoodsReceipt** | Record of received goods | purchase_order_id, receipt_date |
| **GoodsReceiptDetail** | Items received | product_id, quantity_received |
| **Vendor** | Supplier information | vendor_name, vendor_code, category, contact |
| **Product** | Purchasable products | name, code, vendor_id |
| **Warehouse** | Storage locations | name, address, location |

## Controllers

| Controller | Responsibilities |
|------------|------------------|
| **PurchaseController** | Main purchase module entry point |
| **PurchaseOrderController** | CRUD for POs, approvals, document generation |
| **PurchaseRequisitionController** | CRUD for PRs, status management |
| **BillController** | Bill management, payments, adjustments |
| **VendorController** | Vendor management, category management |

## Integration Points

- **Inventory Module**: GoodsReceipt integrates with inventory for stock updates
- **Accounting Module**: Bills linked to accounting entries via Account references
- **HR Module**: Department references for requisitions
- **Core App**: User, Status, Tax, Location (Province, City)

## Action Classes

- **GenerateProductCodeAction**: Auto-generates product codes
- **GenerateServiceCodeAction**: Auto-generates service codes
- **GenerateVendorCodeAction**: Auto-generates vendor codes
- **GenerateBarcodeAction**: Auto-generates barcodes
- **PurchaseOrder/Actions**: Actions for PO operations (create, duplicate, revert)
- **PurchaseRequisition/Actions**: Actions for PR operations (create, duplicate, revert)
- **Bill/Actions**: Actions for billing operations

## Status Flow

```
Purchase Requisition: Draft → Submitted → Approved → Rejected
Purchase Order: Draft → Sent → Confirmed → Received → Billed → Closed
Bill: Draft → Submitted → Approved → Paid → Archived
```

## Key Features

1. **Multi-step Purchase Process**: PR → PO → GR → Bill
2. **Vendor Management**: Master vendor data with categories and contact information
3. **Product/Service Catalog**: With vendor associations
4. **Bill Management**: With adjustments, payments, and file attachments
5. **Tax Handling**: Support for different tax formats and rates
6. **Document Generation**: PDF export for PRs, POs, and Bills
7. **Audit Trail**: Logging of all transactions and changes
8. **Warehouse Integration**: Track goods by warehouse location
9. **Payment Tracking**: Multiple payment records per bill
10. **Status Management**: Workflow states for all transaction types