C4Context
    title BizTalk Order-to-Cash - Context
    Person_Ext(customer_user, "Customer", "Places orders and tracks delivery")
    Person_Ext(supplier_user, "Supplier", "Sends product and invoice data")
    Person_Ext(logistics_user, "Logistics Partner", "Sends shipment and delivery events")
    System(portal, "Portal", "Receives orders and returns confirmations")
    System(erp, "ERP", "Order management and inventory")
    System(erp_finance, "ERP-Finance", "Invoice generation and finance processing")
    System(wms, "Warehouse Management System", "Fulfillment and pick-pack-ship")
    System_Ext(payment_gateway, "Payment Gateway", "External payment processor")
    System_Ext(tax_authority, "Tax Authority Portal", "External e-invoice authority")
    SystemDb_Ext(carrier_tracking, "Carrier Tracking DB", "External delivery confirmation store")
    SystemQueue_Ext(edi_gateway, "EDI Gateway", "External B2B queue for partner exchange")
    System(biztalk_hub, "BizTalk Server", "Canonical transform, route, and protocol mediation")
    Rel(customer_user, portal, "Submit order and check status", "HTTPS / JSON")
    Rel(portal, biztalk_hub, "Forward order and confirmation flow", "SOAP / REST")
    Rel(supplier_user, biztalk_hub, "Send price list and invoice", "SFTP / FILE")
    Rel(logistics_user, biztalk_hub, "Send shipment status", "REST / FILE")
    Rel(biztalk_hub, erp, "Create and update order", "SOAP")
    Rel(biztalk_hub, erp_finance, "Post invoice and settlement status", "SOAP / SQL")
    Rel(biztalk_hub, wms, "Send fulfillment request", "FILE / FTP")
    Rel(biztalk_hub, payment_gateway, "Authorize payment", "REST")
    Rel(biztalk_hub, tax_authority, "Submit e-invoice", "REST")
    Rel(biztalk_hub, carrier_tracking, "Read delivery status", "REST")
    BiRel(biztalk_hub, edi_gateway, "Exchange order and invoice documents", "AS2")