Add asset records, claims, and credit workflows

src/ccma/domain/contributions.py

@@ -14,6 +14,7 @@ CLAIM_STATUS_LABELS = {
     "paid": "BEZAHLT",
     "overpaid": "ÜBERZAHLT",
     "overdue": "ÜBERFÄLLIG",
+    "credit": "GUTSCHRIFT",
     "cancelled": "STORNIERT",
 }
 
@@ -57,10 +58,17 @@ def claim_total(claim: dict[str, Any]) -> Decimal:
     return sum((decimal_value(item.get("amount", "0")) for item in claim_items(claim)), Decimal("0"))
 
 
+def allocation_effect(data: ContributionData, allocation: dict[str, Any]) -> Decimal:
+    amount = decimal_value(allocation.get("amount", "0"))
+    if str(allocation.get("credit_id", "")):
+        return -amount
+    return amount
+
+
 def allocated_total(data: ContributionData, claim_id: str) -> Decimal:
     return sum(
         (
-            decimal_value(allocation.get("amount", "0"))
+            allocation_effect(data, allocation)
             for allocation in data.allocations
             if str(allocation.get("claim_id", "")) == claim_id
         ),
@@ -79,6 +87,17 @@ def payment_allocated_total(data: ContributionData, payment_id: str) -> Decimal:
     )
 
 
+def credit_allocated_total(data: ContributionData, credit_id: str) -> Decimal:
+    return sum(
+        (
+            decimal_value(allocation.get("amount", "0"))
+            for allocation in data.allocations
+            if str(allocation.get("credit_id", "")) == credit_id
+        ),
+        Decimal("0"),
+    )
+
+
 def claim_balance(data: ContributionData, claim: dict[str, Any]) -> Decimal:
     return (claim_total(claim) - allocated_total(data, str(claim.get("claim_id", "")))).quantize(CENT)
 
@@ -89,6 +108,8 @@ def claim_status(data: ContributionData, claim: dict[str, Any], *, today: date |
     total = claim_total(claim)
     paid = allocated_total(data, str(claim.get("claim_id", "")))
     balance = total - paid
+    if total < 0:
+        return "credit"
     if balance < 0:
         return "overpaid"
     if balance == 0: