Add proportional quantity calculation and caching for line items in discharge ledger processing

- Introduced `_proportional_qty` function to calculate prorated quantities based on consumed amounts.
- Implemented caching for line items and import invoice numbers to optimize database queries during discharge ledger registration.
- Enhanced `register_discharge_ledger` function to utilize cached data for improved performance and reduced N+1 query issues.
- Updated discharge detail creation to include denormalized fields for reporting, such as net and gross weights, and customs information.

backend/api/v1/modules/a76/invoices/exports/process/sub_process/register_discharge_ledger.py

@@ -30,6 +30,8 @@ from api.v1.modules.a24.discharges.models import (
     DischargeStatus,
     DischargeType,
 )
+from api.v1.modules.a76.invoices.models import InvoiceHeader as A76InvoiceHeader
+from api.v1.modules.a76.items.models import LineItem
 from .discharge_types import DownloadEntry, AvailableLot
 
 logger = logging.getLogger(__name__)
@@ -66,6 +68,20 @@ def _proportional_value(
     return (consume / lot_consumed_total) * lot_value
 
 
+def _proportional_qty(consume: Decimal, base_qty: Optional[Decimal], base_total: Optional[Decimal]) -> Optional[Decimal]:
+    """
+    Proratea un valor (peso/valor) en proporción a lo consumido.
+    - consume: cantidad consumida del lote
+    - base_qty: valor total del lote (ej. peso neto total del lote)
+    - base_total: cantidad total del lote (ej. quantity del lote)
+    """
+    if base_qty is None:
+        return None
+    if base_total is None or base_total <= 0:
+        return None
+    return (consume / base_total) * base_qty
+
+
 # ---------------------------------------------------------------------------
 # Public entry point
 # ---------------------------------------------------------------------------
@@ -91,6 +107,11 @@ def register_discharge_ledger(
     op_date = _export_date(export_invoice)
     discharge_type = _discharge_type_for_invoice(export_invoice)
 
+    # Caches to avoid N+1 queries in loops
+    export_line_cache: dict[int, LineItem] = {}
+    import_line_cache: dict[int, LineItem] = {}
+    import_invoice_number_cache: dict[int, str] = {}
+
     # ── 1. DischargeHeader ────────────────────────────────────────────────
     header = DischargeHeader(
         tenant_id=export_invoice.tenant_id,
@@ -108,6 +129,14 @@ def register_discharge_ledger(
     for entry in active:
         export_line_id: Optional[int] = entry.line_item_id
 
+        export_line_obj: Optional[LineItem] = None
+        if export_line_id:
+            export_line_obj = export_line_cache.get(export_line_id)
+            if export_line_obj is None:
+                export_line_obj = db.get(LineItem, export_line_id)
+                if export_line_obj is not None:
+                    export_line_cache[export_line_id] = export_line_obj
+
         # Only iterate lots that were actually consumed
         consumed_lots: List[AvailableLot] = [
             lot for lot in entry.available_lots if lot.consumed_qty > Decimal(0)
@@ -116,6 +145,23 @@ def register_discharge_ledger(
         for lot in consumed_lots:
             consume = lot.consumed_qty
 
+            # Load import-line object for denormalized customs/weights fields
+            import_line_obj = import_line_cache.get(lot.import_item_line_id)
+            if import_line_obj is None:
+                import_line_obj = db.get(LineItem, lot.import_item_line_id)
+                if import_line_obj is not None:
+                    import_line_cache[lot.import_item_line_id] = import_line_obj
+
+            # Import invoice number (for origin_import_invoice in DischargeDetail)
+            origin_import_invoice: Optional[str] = None
+            if lot.import_invoice_id:
+                origin_import_invoice = import_invoice_number_cache.get(lot.import_invoice_id)
+                if origin_import_invoice is None:
+                    inv = db.get(A76InvoiceHeader, lot.import_invoice_id)
+                    origin_import_invoice = inv.invoice_number if inv else None
+                    if origin_import_invoice:
+                        import_invoice_number_cache[lot.import_invoice_id] = origin_import_invoice
+
             # ── 2. BalanceMovement (CONSUMPTION) ──────────────────────────
             # Proportional value: consume / lot_consumed_total × lot_value
             # lot_consumed_total == consume for single-lot entries (most cases)
@@ -146,6 +192,14 @@ def register_discharge_ledger(
             movement.order_peps = movement.id  # rule 4: monotonic
 
             # ── 3. DischargeDetail ─────────────────────────────────────────
+            # Denormalized fields expected by reports:
+            imp_cust = import_line_obj.customs if import_line_obj else None
+            imp_qty = import_line_obj.quantity if import_line_obj else None
+            imp_total_qty = imp_qty.quantity if imp_qty else None
+
+            net_weight = _proportional_qty(consume, imp_qty.net_weight if imp_qty else None, imp_total_qty)
+            gross_weight = _proportional_qty(consume, imp_qty.gross_weight if imp_qty else None, imp_total_qty)
+
             detail = DischargeDetail(
                 tenant_id=export_invoice.tenant_id,
                 company_id=export_invoice.company_id,
@@ -157,8 +211,21 @@ def register_discharge_ledger(
                 unit_of_measure=entry.unit_of_measure or None,
                 value_me=value_me,
                 value_mn=value_mn,
+                net_weight=net_weight,
+                gross_weight=gross_weight,
+                tariff_fraction=imp_cust.fraction if imp_cust else None,
+                fraction_type=imp_cust.fraction_type if imp_cust else None,
+                ad_valorem=imp_cust.advalorem if imp_cust else None,
+                country_of_origin=imp_cust.origin_country if imp_cust else None,
+                sector=imp_cust.sector if imp_cust else None,
                 procedence=entry.origin_procedure or None,
                 part_number=entry.part_number or None,
+                export_part_number=(
+                    export_line_obj.part_info.part_number
+                    if export_line_obj and export_line_obj.part_info and export_line_obj.part_info.part_number
+                    else None
+                ),
+                origin_import_invoice=origin_import_invoice,
             )
             db.add(detail)
             total_movements += 1