Fix #130: Add invoice processing and three-way match functionality

src/invoice_processing.py

@@ -0,0 +1,108 @@
+import csv
+import json
+from datetime import datetime
+from typing import List, Dict, Optional
+
+class Invoice:
+    def __init__(self, invoice_id: str, vendor: str, amount: float, date: str, po_number: Optional[str] = None):
+        self.invoice_id = invoice_id
+        self.vendor = vendor
+        self.amount = amount
+        self.date = datetime.strptime(date, '%Y-%m-%d')
+        self.po_number = po_number
+
+class PurchaseOrder:
+    def __init__(self, po_number: str, vendor: str, amount: float, items: List[Dict]):
+        self.po_number = po_number
+        self.vendor = vendor
+        self.amount = amount
+        self.items = items
+
+class Receipt:
+    def __init__(self, receipt_id: str, po_number: str, items_received: List[Dict]):
+        self.receipt_id = receipt_id
+        self.po_number = po_number
+        self.items_received = items_received
+
+def load_invoices(file_path: str) -> List[Invoice]:
+    invoices = []
+    with open(file_path, 'r') as f:
+        reader = csv.DictReader(f)
+        for row in reader:
+            invoice = Invoice(
+                invoice_id=row['invoice_id'],
+                vendor=row['vendor'],
+                amount=float(row['amount']),
+                date=row['date'],
+                po_number=row.get('po_number')
+            )
+            invoices.append(invoice)
+    return invoices
+
+def load_purchase_orders(file_path: str) -> List[PurchaseOrder]:
+    with open(file_path, 'r') as f:
+        data = json.load(f)
+    return [PurchaseOrder(**po) for po in data]
+
+def load_receipts(file_path: str) -> List[Receipt]:
+    with open(file_path, 'r') as f:
+        data = json.load(f)
+    return [Receipt(**rec) for rec in data]
+
+def three_way_match(invoice: Invoice, po: PurchaseOrder, receipt: Receipt) -> Dict:
+    """
+    Perform three-way matching between invoice, purchase order, and receipt.
+    Returns a dictionary with match status and details.
+    """
+    result = {
+        'invoice_id': invoice.invoice_id,
+        'po_number': po.po_number if po else None,
+        'receipt_id': receipt.receipt_id if receipt else None,
+        'vendor_match': False,
+        'amount_match': False,
+        'items_match': False,
+        'overall_match': False
+    }
+
+    # Vendor match
+    if invoice.vendor == po.vendor:
+        result['vendor_match'] = True
+
+    # Amount match (allow small tolerance)
+    if abs(invoice.amount - po.amount) <= 0.01:
+        result['amount_match'] = True
+
+    # Items match (check if received items match invoice items)
+    if receipt and po:
+        po_items = {item['sku']: item['quantity'] for item in po.items}
+        rec_items = {item['sku']: item['quantity'] for item in receipt.items_received}
+        if po_items == rec_items:
+            result['items_match'] = True
+
+    # Overall match
+    if result['vendor_match'] and result['amount_match'] and result['items_match']:
+        result['overall_match'] = True
+
+    return result
+
+def process_invoices(invoice_file: str, po_file: str, receipt_file: str) -> List[Dict]:
+    invoices = load_invoices(invoice_file)
+    pos = load_purchase_orders(po_file)
+    receipts = load_receipts(receipt_file)
+
+    results = []
+    for invoice in invoices:
+        # Find matching PO
+        po = next((p for p in pos if p.po_number == invoice.po_number), None)
+        # Find matching receipt
+        receipt = next((r for r in receipts if r.po_number == invoice.po_number), None)
+        match_result = three_way_match(invoice, po, receipt)
+        results.append(match_result)
+
+    return results
+
+if __name__ == '__main__':
+    # Example usage
+    results = process_invoices('invoices.csv', 'purchase_orders.json', 'receipts.json')
+    for r in results:
+        print(r)

tests/test_invoice_processing.py

@@ -0,0 +1,78 @@
+import unittest
+from src.invoice_processing import Invoice, PurchaseOrder, Receipt, three_way_match
+
+class TestThreeWayMatch(unittest.TestCase):
+
+    def setUp(self):
+        self.invoice = Invoice(
+            invoice_id='INV-001',
+            vendor='Acme Corp',
+            amount=1000.00,
+            date='2023-01-15',
+            po_number='PO-123'
+        )
+        self.po = PurchaseOrder(
+            po_number='PO-123',
+            vendor='Acme Corp',
+            amount=1000.00,
+            items=[{'sku': 'A1', 'quantity': 10}, {'sku': 'B2', 'quantity': 5}]
+        )
+        self.receipt = Receipt(
+            receipt_id='RCP-001',
+            po_number='PO-123',
+            items_received=[{'sku': 'A1', 'quantity': 10}, {'sku': 'B2', 'quantity': 5}]
+        )
+
+    def test_full_match(self):
+        result = three_way_match(self.invoice, self.po, self.receipt)
+        self.assertTrue(result['overall_match'])
+        self.assertTrue(result['vendor_match'])
+        self.assertTrue(result['amount_match'])
+        self.assertTrue(result['items_match'])
+
+    def test_vendor_mismatch(self):
+        invoice = Invoice(
+            invoice_id='INV-002',
+            vendor='Other Corp',
+            amount=1000.00,
+            date='2023-01-15',
+            po_number='PO-123'
+        )
+        result = three_way_match(invoice, self.po, self.receipt)
+        self.assertFalse(result['vendor_match'])
+        self.assertFalse(result['overall_match'])
+
+    def test_amount_mismatch(self):
+        invoice = Invoice(
+            invoice_id='INV-003',
+            vendor='Acme Corp',
+            amount=999.99,
+            date='2023-01-15',
+            po_number='PO-123'
+        )
+        result = three_way_match(invoice, self.po, self.receipt)
+        self.assertFalse(result['amount_match'])
+        self.assertFalse(result['overall_match'])
+
+    def test_items_mismatch(self):
+        receipt = Receipt(
+            receipt_id='RCP-002',
+            po_number='PO-123',
+            items_received=[{'sku': 'A1', 'quantity': 9}, {'sku': 'B2', 'quantity': 5}]
+        )
+        result = three_way_match(self.invoice, self.po, receipt)
+        self.assertFalse(result['items_match'])
+        self.assertFalse(result['overall_match'])
+
+    def test_no_po(self):
+        result = three_way_match(self.invoice, None, self.receipt)
+        self.assertFalse(result['overall_match'])
+        self.assertIsNone(result['po_number'])
+
+    def test_no_receipt(self):
+        result = three_way_match(self.invoice, self.po, None)
+        self.assertFalse(result['overall_match'])
+        self.assertIsNone(result['receipt_id'])
+
+if __name__ == '__main__':
+    unittest.main()