feat: time calculation business logic

app/business/time_calc.py

@@ -0,0 +1,25 @@
+def minutes_to_str(minutes: int) -> str:
+    sign = "-" if minutes < 0 else ""
+    minutes = abs(minutes)
+    return f"{sign}{minutes // 60}h{minutes % 60:02d}"
+
+
+_REFERENCE_MINUTES = {
+    "WORK": 465,
+    "TT": 465,
+    "FORMATION": 465,
+    "GARDE": 600,
+    "ASTREINTE": 0,
+    "RTT": 0,
+    "CONGE": 0,
+    "MALADE": 0,
+    "FERIE": 0,
+}
+
+
+def work_minutes_reference(day_type: str) -> int:
+    return _REFERENCE_MINUTES.get(day_type, 465)
+
+
+def week_balance_minutes(actual_minutes: int, reference_minutes: int) -> int:
+    return actual_minutes - reference_minutes