feat: leave balance calculation (congés/RTT)

app/business/leave_calc.py

@@ -0,0 +1,36 @@
+from app import db
+from app.models import WorkEntry, LeaveBalance
+import sqlalchemy as sa
+from datetime import date
+
+
+def compute_leave_used(year: int) -> dict[str, int]:
+    start = date(year, 1, 1)
+    end = date(year, 12, 31)
+
+    conges = db.session.scalar(
+        sa.select(sa.func.count()).where(
+            WorkEntry.date.between(start, end),
+            WorkEntry.day_type == "CONGE",
+        )
+    ) or 0
+
+    rtt = db.session.scalar(
+        sa.select(sa.func.count()).where(
+            WorkEntry.date.between(start, end),
+            WorkEntry.day_type == "RTT",
+        )
+    ) or 0
+
+    return {"conges": conges, "rtt": rtt}
+
+
+def get_or_create_balance(year: int) -> LeaveBalance:
+    balance = db.session.scalar(
+        sa.select(LeaveBalance).where(LeaveBalance.year == year)
+    )
+    if balance is None:
+        balance = LeaveBalance(year=year)
+        db.session.add(balance)
+        db.session.commit()
+    return balance