Erster Checkin: Tool arbeitet

app/aggregator.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+from collections import Counter
+from dataclasses import dataclass
+from typing import List
+from .models import WorkingWithRelation
+
+
+@dataclass
+class DepartmentLink:
+    source_department: str
+    destination_department: str
+    weight: int
+
+
+def aggregate_department_links(relations: List[WorkingWithRelation]) -> List[DepartmentLink]:
+    counter: Counter[tuple[str, str]] = Counter()
+    for rel in relations:
+        src = (rel.source.department or "").strip()
+        dst = (rel.destination.department or "").strip()
+        if not src or not dst:
+            continue
+        counter[(src, dst)] += 1
+
+    links: List[DepartmentLink] = [
+        DepartmentLink(source_department=s, destination_department=d, weight=w)
+        for (s, d), w in counter.items()
+    ]
+    return sorted(links, key=lambda l: l.weight, reverse=True)