Generate weather conditions at turn start.

Weather and exact time of day information is helpful during mission
planning, so generate it at the start of the turn rather than at
takeoff time.

Another advantage aside from planning is that we can now use the wind
information to set carrier headings and takeoff runways appropriately.

game/game.py

@@ -2,7 +2,7 @@ import logging
 import math
 import random
 import sys
-from datetime import datetime, timedelta
+from datetime import date, datetime, timedelta
 from typing import Any, Dict, List
 
 from dcs.action import Coalition
@@ -28,6 +28,7 @@ from .event.event import Event, UnitsDeliveryEvent
 from .event.frontlineattack import FrontlineAttackEvent
 from .infos.information import Information
 from .settings import Settings
+from .weather import Conditions, TimeOfDay
 
 COMMISION_UNIT_VARIETY = 4
 COMMISION_LIMITS_SCALE = 1.5
@@ -78,7 +79,7 @@ class Game:
         self.enemy_name = enemy_name
         self.enemy_country = db.FACTIONS[enemy_name]["country"]
         self.turn = 0
-        self.date = datetime(start_date.year, start_date.month, start_date.day)
+        self.date = date(start_date.year, start_date.month, start_date.day)
         self.game_stats = GameStats()
         self.game_stats.update(self)
         self.ground_planners: Dict[int, GroundPlanner] = {}
@@ -91,6 +92,8 @@ class Game:
         self.current_unit_id = 0
         self.current_group_id = 0
 
+        self.conditions = self.generate_conditions()
+
         self.blue_ato = AirTaskingOrder()
         self.red_ato = AirTaskingOrder()
 
@@ -101,6 +104,9 @@ class Game:
         self.sanitize_sides()
         self.on_load()
 
+    def generate_conditions(self) -> Conditions:
+        return Conditions.generate(self.theater, self.date,
+                                   self.current_turn_time_of_day, self.settings)
 
     def sanitize_sides(self):
         """
@@ -218,6 +224,12 @@ class Game:
     def on_load(self) -> None:
         ObjectiveDistanceCache.set_theater(self.theater)
 
+        # Save game compatibility.
+
+        # TODO: Remove in 2.3.
+        if not hasattr(self, "conditions"):
+            self.conditions = self.generate_conditions()
+
     def pass_turn(self, no_action=False):
         logging.info("Pass turn")
         self.informations.append(Information("End of turn #" + str(self.turn), "-" * 40, 0))
@@ -252,6 +264,8 @@ class Game:
         for cp in self.theater.controlpoints:
             self.aircraft_inventory.set_from_control_point(cp)
 
+        self.conditions = self.generate_conditions()
+
         # Plan flights & combat for next turn
         self.__culling_points = self.compute_conflicts_position()
         self.ground_planners = {}
@@ -340,11 +354,11 @@ class Game:
                 self.informations.append(info)
 
     @property
-    def current_turn_daytime(self):
-        return ["dawn", "day", "dusk", "night"][self.turn % 4]
+    def current_turn_time_of_day(self) -> TimeOfDay:
+        return list(TimeOfDay)[self.turn % 4]
 
     @property
-    def current_day(self):
+    def current_day(self) -> date:
         return self.date + timedelta(days=self.turn // 4)
 
     def next_unit_id(self):