Finish moving gen into game.

game/callsigns.py

@@ -0,0 +1,35 @@
+"""Support for working with DCS group callsigns."""
+import logging
+import re
+from typing import Any
+
+from dcs.unitgroup import FlyingGroup
+from dcs.flyingunit import FlyingUnit
+
+
+def callsign_for_support_unit(group: FlyingGroup[Any]) -> str:
+    # Either something like Overlord11 for Western AWACS, or else just a number.
+    # Convert to either "Overlord" or "Flight 123".
+    lead = group.units[0]
+    raw_callsign = lead.callsign_as_str()
+    try:
+        return f"Flight {int(raw_callsign)}"
+    except ValueError:
+        return raw_callsign.rstrip("1234567890")
+
+
+def create_group_callsign_from_unit(lead: FlyingUnit) -> str:
+    raw_callsign = lead.callsign_as_str()
+    if not lead.callsign_is_western:
+        # Callsigns for non-Western countries are just a number per flight,
+        # similar to tail numbers.
+        return f"Flight {raw_callsign}"
+
+    # Callsign from pydcs is in the format `<name><group ID><unit ID>`,
+    # where unit ID is guaranteed to be a single digit but the group ID may
+    # be more.
+    match = re.search(r"^(\D+)(\d+)(\d)$", raw_callsign)
+    if match is None:
+        logging.error(f"Could not parse unit callsign: {raw_callsign}")
+        return f"Flight {raw_callsign}"
+    return f"{match.group(1)} {match.group(2)}"