Merge pull request #1518 from Dilvish-fo/ai_trooper_design_and_produc…

…tion

fixes a problem with AI ship production location, which was particularly plaguing troopers, also limits total AI trooper size and allows AI trooper armor

default/python/AI/ProductionAI.py

@@ -128,11 +128,16 @@ def get_best_ship_info(priority, loc=None):
         if not best_designs:
             return None, None, None
 
+        # best_designs are already sorted by rating high to low, so the top rating is the first encountered within
+        # our planet search list
         for design_stats in best_designs:
             top_rating, pid, top_id, cost, stats = design_stats
             if pid in planet_ids:
                 break
-        valid_locs = [item[1] for item in best_designs if item[0] == top_rating and item[2] == top_id]
+        else:
+            return None, None, None  # apparently can't build for this priority within the desired planet group
+        valid_locs = [pid for rating, pid, design_id, _, _ in best_designs if
+                      rating == top_rating and design_id == top_id and pid in planet_ids]
         return top_id, fo.getShipDesign(top_id), valid_locs
     else:
         return None, None, None  # must be missing a Shipyard or other orbital (or missing tech)

default/python/AI/ShipDesignAI.py

@@ -84,6 +84,14 @@
 MISSING_REQUIREMENT_MULTIPLIER = -1000
 INVALID_DESIGN_RATING = -999  # this needs to be negative but greater than MISSING_REQUIREMENT_MULTIPLIER
 
+# For Trooper designs, set a maximum number of troopers per ship that will be considered for ratings purposes, to
+# prevent the AI from settling on trooper designs with the absolute largest hulls, which may nominally have the lowest
+# per-unit-cost but which then result in much trooper overkill/waste when actually deployed.  The application of this
+# limit does (in normal use) take into account shipbuilder species modifiers.
+# Current limit set to 48 to allow up to a grav hull filled with Advanced Troop Pods and Good offensive troopers (or
+# partly filled with Great advanced offensive troopers)
+MAX_TROOPERS_PER_SHIP = 48
+
 # Potentially, not adding techs to AIDependencies is intended for testing purposes.
 # Therefore, chat the player only once to inform him about the issue to prevent spam.
 _raised_warnings = set()
@@ -1796,7 +1804,7 @@ def _rating_function(self):
         if self.design_stats.troops == 0:
             return INVALID_DESIGN_RATING
         else:
-            return self.design_stats.troops/self._adjusted_production_cost()
+            return min(MAX_TROOPERS_PER_SHIP, self.design_stats.troops)/self._adjusted_production_cost()
 
     def _starting_guess(self, available_parts, num_slots):
         # fill completely with biggest troop pods. If none are available for this slot type, leave empty.
@@ -1817,7 +1825,8 @@ def _starting_guess(self, available_parts, num_slots):
 
     def _class_specific_filter(self, partname_dict):
         for slot in partname_dict:
-            remaining_parts = [part for part in partname_dict[slot] if get_part_type(part).partClass in TROOPS]
+            remaining_parts = [part for part in partname_dict[slot] if
+                               get_part_type(part).partClass in TROOPS.union(ARMOUR)]
             partname_dict[slot] = remaining_parts