Enhance invoice validation logic to support existing invoices

- Updated the `validate_common` function to accept an optional `existing_invoice` parameter, allowing for more robust validation when updating invoices.
- Introduced a new helper function, `_normalize_invoice_currency_value`, to standardize currency code handling.
- Adjusted currency validation logic to ensure proper handling of existing invoice data, preventing changes to currency types when associated line items exist.
- Modified the `validate_update` functions in both imports and exports to pass the `existing_invoice` parameter, ensuring consistent validation across different update scenarios.

backend/api/v1/modules/a76/invoices/common/common_validators.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Any, Dict, Optional, Union
 from core.exceptions import ErrorCollector
 from sqlalchemy import func
 from sqlalchemy.orm import Session
@@ -17,8 +17,14 @@ from api.v1.modules.a76.manifests.manifest.models import Manifest
 from api.v1.modules.public.reference_data.incoterms.models import Incoterm
 from api.v1.modules.public.reference_data.currency_types.models import CurrencyType
 from api.v1.modules.public.reference_data.customs_sections.models import CustomsSection
-from core.exceptions import ErrorCollector
-from typing import Dict, Any
+
+
+def _normalize_invoice_currency_value(value) -> str:
+    """Lowercase currency code (foreign/local/manual) for comparisons."""
+    if value is None or value == "":
+        return ""
+    raw = getattr(value, "value", value)
+    return str(raw).lower()
 
 
 def invoice_exists(
@@ -174,10 +180,11 @@ def validate_required_fields_by_operation(
 
 def validate_common(
     db: Session,
-    invoice: schemas.InvoiceHeaderUpdate,
+    invoice: Union[schemas.InvoiceHeaderCreate, schemas.InvoiceHeaderUpdate],
     tenant_id: int,
     company_id: int,
     errors: ErrorCollector,
+    existing_invoice: Optional[models.InvoiceHeader] = None,
 ):
     if invoice.compliance_mx.pedimento_id:
         pedimento = (
@@ -560,69 +567,97 @@ def validate_common(
                         value=invoice.logistics.transport_num,
                     )
 
-    invoice.financials.currency = invoice.financials.currency or "foreign"
-
-    if invoice.financials.currency not in [c.value for c in Currency]:
-        errors.add_error(
-            field="financials.currency",
-            message="La Moneda proporcionada no es válida.",
-            solution=[f"Selecciona una Moneda válida: {[c.value for c in Currency]}"],
-            code="INVALID_CURRENCY",
-            value=invoice.financials.currency,
-        )
-    else:
-        # Only check for existing items during update operations (when invoice has an id)
-        if hasattr(invoice, "id"):
-            has_items = (
-                db.query(LineItem)
-                .filter(
-                    LineItem.invoice_id == invoice.id,
-                    LineItem.tenant_id == tenant_id,
-                    LineItem.company_id == company_id,
-                )
-                .first()
+    if invoice.financials:
+        submitted = invoice.financials.currency
+        stored_str = ""
+        if existing_invoice and existing_invoice.financials is not None:
+            stored_str = _normalize_invoice_currency_value(
+                existing_invoice.financials.currency
             )
-            if has_items:
-                errors.add_error(
-                    field="items",
-                    message=f"La opcion tipo de moneda {invoice.financials.currency} no puede ser modificada ya que la factura tiene items asociados.",
-                    solution=[
-                        "Verifica la moneda de los items asociados a la factura."
-                    ],
-                    code="CURRENCY_CANNOT_BE_CHANGED",
-                    value=invoice.financials.currency,
-                )
 
-    if invoice.financials.currency == "foreign":
-        invoice.financials.currency_type = "USD"
-    elif invoice.financials.currency == "local":
-        invoice.financials.currency_type = "MXN"
-    elif invoice.financials.currency == "manual":
-        if not invoice.financials.currency_type:
+        if submitted is None or submitted == "":
+            if stored_str:
+                invoice.financials.currency = stored_str
+            else:
+                invoice.financials.currency = "foreign"
+        else:
+            invoice.financials.currency = (
+                _normalize_invoice_currency_value(submitted) or "foreign"
+            )
+
+        if invoice.financials.currency not in [c.value for c in Currency]:
             errors.add_error(
-                field="financials.currency_type",
-                message="El Tipo de Moneda es obligatorio cuando la Moneda es 'manual'.",
-                solution=["Proporciona un Tipo de Moneda válido"],
-                code="REQUIRED_FIELD",
-                value=invoice.financials.currency_type,
+                field="financials.currency",
+                message="La Moneda proporcionada no es válida.",
+                solution=[f"Selecciona una Moneda válida: {[c.value for c in Currency]}"],
+                code="INVALID_CURRENCY",
+                value=invoice.financials.currency,
             )
         else:
-            currency_exists = (
-                db.query(CurrencyType)
-                .filter(CurrencyType.code == invoice.financials.currency_type)
-                .first()
-            )
-            if not currency_exists:
+            invoice_id = getattr(invoice, "id", None)
+            if (
+                invoice_id is not None
+                and existing_invoice is not None
+                and existing_invoice.financials is not None
+            ):
+                old_c = _normalize_invoice_currency_value(
+                    existing_invoice.financials.currency
+                )
+                new_c = invoice.financials.currency
+                if old_c != new_c:
+                    has_items = (
+                        db.query(LineItem)
+                        .filter(
+                            LineItem.invoice_id == invoice_id,
+                            LineItem.tenant_id == tenant_id,
+                            LineItem.company_id == company_id,
+                        )
+                        .first()
+                    )
+                    if has_items:
+                        errors.add_error(
+                            field="items",
+                            message=(
+                                "La opción tipo de moneda no puede ser modificada "
+                                "ya que la factura tiene partidas asociadas."
+                            ),
+                            solution=[
+                                "Verifica la moneda de las partidas asociadas a la factura."
+                            ],
+                            code="CURRENCY_CANNOT_BE_CHANGED",
+                            value=invoice.financials.currency,
+                        )
+
+        if invoice.financials.currency == "foreign":
+            invoice.financials.currency_type = "USD"
+        elif invoice.financials.currency == "local":
+            invoice.financials.currency_type = "MXN"
+        elif invoice.financials.currency == "manual":
+            if not invoice.financials.currency_type:
                 errors.add_error(
                     field="financials.currency_type",
-                    message="El Tipo de Moneda no existe en el Catálogo de Tipos de Moneda.",
-                    solution=[
-                        "Verifica el código del Tipo de Moneda",
-                        "Revisa el catálogo",
-                    ],
-                    code="NOT_FOUND",
+                    message="El Tipo de Moneda es obligatorio cuando la Moneda es 'manual'.",
+                    solution=["Proporciona un Tipo de Moneda válido"],
+                    code="REQUIRED_FIELD",
                     value=invoice.financials.currency_type,
                 )
+            else:
+                currency_exists = (
+                    db.query(CurrencyType)
+                    .filter(CurrencyType.code == invoice.financials.currency_type)
+                    .first()
+                )
+                if not currency_exists:
+                    errors.add_error(
+                        field="financials.currency_type",
+                        message="El Tipo de Moneda no existe en el Catálogo de Tipos de Moneda.",
+                        solution=[
+                            "Verifica el código del Tipo de Moneda",
+                            "Revisa el catálogo",
+                        ],
+                        code="NOT_FOUND",
+                        value=invoice.financials.currency_type,
+                    )
 
     if invoice.logistics.incoterm:
         incoterm_exists = (

backend/api/v1/modules/a76/invoices/exports/validators/update.py

@@ -55,7 +55,9 @@ def validate_update(
     )
     
     # Primero ejecutar validaciones comunes
-    validate_common(db, invoice, tenant_id, company_id, errors)
+    validate_common(
+        db, invoice, tenant_id, company_id, errors, existing_invoice=existing_invoice
+    )
 
     # Mapeo de columnas CSV a campos de la factura
     # Siguiendo la lógica del código Clarion original

backend/api/v1/modules/a76/invoices/imports/validators/update.py

@@ -55,7 +55,9 @@ def validate_update(
     )
     
     # Primero ejecutar validaciones comunes
-    validate_common(db, invoice, tenant_id, company_id, errors)
+    validate_common(
+        db, invoice, tenant_id, company_id, errors, existing_invoice=existing_invoice
+    )
 
     # Mapeo de columnas CSV a campos de la factura
     # Siguiendo la lógica del código Clarion original