first ruggedy draft

packages/matching/mousehold_matching/scoring.py

@@ -0,0 +1,40 @@
+from __future__ import annotations
+
+from datetime import date
+from decimal import Decimal
+from difflib import SequenceMatcher
+
+from .fingerprints import normalize_counterparty
+
+
+def _date_distance(a: date, b: date) -> int:
+    return abs((a - b).days)
+
+
+def score_event_match(
+    *,
+    amount_a: Decimal,
+    amount_b: Decimal,
+    currency_a: str,
+    currency_b: str,
+    date_a: date,
+    date_b: date,
+    party_a: str | None,
+    party_b: str | None,
+) -> float:
+    if currency_a.upper() != currency_b.upper():
+        return 0.0
+
+    amount_score = (
+        1.0
+        if amount_a == amount_b
+        else max(0.0, 1.0 - (abs(amount_a - amount_b) / max(abs(amount_a), Decimal("1"))))
+    )
+    days = _date_distance(date_a, date_b)
+    date_score = 1.0 if days == 0 else max(0.0, 1.0 - (days / 14))
+    party_score = SequenceMatcher(
+        None,
+        normalize_counterparty(party_a),
+        normalize_counterparty(party_b),
+    ).ratio()
+    return round((amount_score * 0.45) + (date_score * 0.30) + (party_score * 0.25), 4)