fix(portfolios): replay corporate-action cost basis (#38)

app/api/v1_portfolios.py

@@ -1282,27 +1282,48 @@ def get_holdings_cost_basis(
     finally:
         _close_repo(repo)
 
-    # Build rows for domain function
-    rows = [
-        {
-            "side": e.side,
-            "quantity": e.quantity,
-            "price": e.price,
-            "fee_amount": e.fee_amount,
-            "executed_at": e.executed_at,
+    # Build rows for domain function, preserving joined corporate-action metadata.
+    rows = []
+    corporate_action_fields = (
+        "corporate_action_id",
+        "action_type",
+        "quantity_before",
+        "quantity_after",
+        "average_price_after",
+        "total_cost_basis",
+    )
+    for entry in ledger_entries:
+        row = {
+            "side": entry.side,
+            "quantity": entry.quantity,
+            "price": entry.price,
+            "fee_amount": entry.fee_amount,
+            "executed_at": entry.executed_at,
+            "ledger_entry_id": entry.ledger_entry_id,
         }
-        for e in ledger_entries
-    ]
+        if entry.corporate_action:
+            row.update(
+                {
+                    field: entry.corporate_action.get(field)
+                    for field in corporate_action_fields
+                }
+            )
+        rows.append(row)
 
     wac_result = calculate_current_wac(rows)
 
     current_quantity = portfolio.asset_quantity
-    cost_basis_per_unit = wac_result.current_wac if current_quantity > 0 else None
-    total_cost_basis = (
-        cost_basis_per_unit * current_quantity
-        if cost_basis_per_unit is not None and current_quantity > 0
-        else None
-    )
+    if wac_result.total_cost_basis is not None and wac_result.current_quantity > 0:
+        current_quantity = wac_result.current_quantity
+        total_cost_basis = wac_result.total_cost_basis
+        cost_basis_per_unit = total_cost_basis / current_quantity
+    else:
+        cost_basis_per_unit = wac_result.current_wac if current_quantity > 0 else None
+        total_cost_basis = (
+            cost_basis_per_unit * current_quantity
+            if cost_basis_per_unit is not None and current_quantity > 0
+            else None
+        )
 
     return HoldingsCostBasisResponse(
         portfolio_id=portfolio_id,