Automating SAP ERP 3-Way Match Invoice Reconciliation with AI Agents

from decimal import Decimal
from pyodata.client import Client

def reconcile_sap_invoice_3way(
    sap_client: Client,
    invoice_id: str,
    po_number: str,
    tolerance_percent: float = 1.0
) -> dict:
    """Executes 3-way line item verification between SAP PO, Goods Receipt, and Invoice."""
    
    # 1. Fetch Purchase Order Item Details via SAP OData API
    po_items = sap_client.entity_sets.A_PurchaseOrderItem.get_entities() \
        .filter(f"PurchaseOrder eq '{po_number}'").execute()
        
    # 2. Fetch Goods Receipt Details
    gr_items = sap_client.entity_sets.A_MaterialDocumentItem.get_entities() \
        .filter(f"PurchaseOrder eq '{po_number}'").execute()
        
    total_po_amount = sum(Decimal(str(item.NetPriceAmount)) * Decimal(str(item.OrderQuantity)) for item in po_items)
    total_gr_qty = sum(Decimal(str(item.QuantityInEntryUnit)) for item in gr_items)
    
    # 3. Calculate Variance and Apply Enterprise Rules
    status = "CLEARED_FOR_PAYMENT"
    block_reason = None
    
    if total_gr_qty == 0:
        status = "BLOCKED"
        block_reason = "GOODS_RECEIPT_MISSING"
        
    return {
        "invoice_id": invoice_id,
        "po_number": po_number,
        "status": status,
        "block_reason": block_reason,
        "calculated_po_total": float(total_po_amount)
    }