first commit

app/services/categorization.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from ..models import Expense
+
+
+def suggest_category_id(user_id: int, vendor: str = '', title: str = '') -> int | None:
+    vendor = (vendor or '').strip().lower()
+    title = (title or '').strip().lower()
+    if not vendor and not title:
+        return None
+    recent = (
+        Expense.query.filter_by(user_id=user_id, is_deleted=False)
+        .filter(Expense.category_id.isnot(None))
+        .order_by(Expense.id.desc())
+        .limit(100)
+        .all()
+    )
+    for expense in recent:
+        ev = (expense.vendor or '').strip().lower()
+        et = (expense.title or '').strip().lower()
+        if vendor and ev == vendor:
+            return expense.category_id
+        if title and et == title:
+            return expense.category_id
+    return None