commit b373f2616e97bccfad3b18502f910815e73f2833
Author: Mika <kontakt@donau2space.de>
Date:   Wed Feb 11 12:51:44 2026 +0000

    Add unknown_case_counter/src/unknown_case_counter/core.py

diff --git a/unknown_case_counter/src/unknown_case_counter/core.py b/unknown_case_counter/src/unknown_case_counter/core.py
new file mode 100644
index 0000000..425d9a0
--- /dev/null
+++ b/unknown_case_counter/src/unknown_case_counter/core.py
@@ -0,0 +1,65 @@
+import csv
+import json
+from collections import Counter
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Dict
+
+
+@dataclass
+class DeltaCase:
+    case_id: str
+    previous_status: str
+    new_status: str
+    unknown_reason: str | None = None
+
+
+@dataclass
+class UnknownReasonsSummary:
+    reason: str
+    count: int
+
+
+def count_unknown_reasons(file_path: str) -> Dict[str, int]:
+    """Liest delta_cases.csv ein und zählt alle Unknown-Fälle gruppiert nach unbekanntem Grund.
+
+    Args:
+        file_path: Pfad zur CSV-Datei mit den Delta-Cases.
+
+    Returns:
+        Dictionary mit Gründen ('reason') als Schlüssel und Anzahl der Unknown-Vorkommen als Wert.
+    """
+    path = Path(file_path)
+    if not path.exists() or not path.is_file():
+        raise FileNotFoundError(f"Eingabedatei nicht gefunden: {file_path}")
+
+    counts = Counter()
+
+    with path.open(newline='', encoding='utf-8') as csvfile:
+        reader = csv.DictReader(csvfile)
+
+        required_fields = {"case_id", "previous_status", "new_status", "unknown_reason"}
+        if not required_fields.issubset(reader.fieldnames or []):
+            missing = required_fields - set(reader.fieldnames or [])
+            raise ValueError(f"CSV-Datei fehlt notwendige Felder: {', '.join(sorted(missing))}")
+
+        for row in reader:
+            case = DeltaCase(
+                case_id=row.get("case_id", "").strip(),
+                previous_status=row.get("previous_status", "").strip(),
+                new_status=row.get("new_status", "").strip(),
+                unknown_reason=row.get("unknown_reason", "").strip() or None,
+            )
+
+            assert isinstance(case.case_id, str)
+            assert isinstance(case.previous_status, str)
+            assert isinstance(case.new_status, str)
+
+            if case.new_status.lower() == "unknown":
+                reason = case.unknown_reason or "Unspecified"
+                counts[reason] += 1
+
+    # Optional: serialize to JSON-like string for stdout reference
+    summary = {reason: count for reason, count in counts.items()}
+    print(json.dumps(summary, ensure_ascii=False))
+    return summary