ai_helper.get_closest_enemy: change return values

This is done for consistency with similar functions in mainline, and so that the function actual returns what it name says. This breaks backward compatibility, but note that the only practical difference for that is the order in which the arguments are returned, as both 'closest_enemy' and 'location' contain the enemy location in .x/.y format.

data/ai/lua/ai_helper.lua

@@ -1045,7 +1045,7 @@ function ai_helper.is_attackable_enemy(unit, side, cfg)
 end
 
 function ai_helper.get_closest_enemy(loc, side, cfg)
-    -- Return distance to and location of the enemy closest to @loc, or to the
+    -- Return the enemy closest to @loc and its distance from @loc, or to the
     -- leader of side with number @side if @loc is not specified
     --
     -- Optional parameters:
@@ -1066,16 +1066,16 @@ function ai_helper.get_closest_enemy(loc, side, cfg)
         x, y = loc[1], loc[2]
     end
 
-    local closest_distance, location = math.huge
+    local closest_distance, closest_enemy = math.huge
     for _,enemy in ipairs(enemies) do
         enemy_distance = M.distance_between(x, y, enemy.x, enemy.y)
         if (enemy_distance < closest_distance) then
+            closest_enemy = enemy
             closest_distance = enemy_distance
-            location = { x = enemy.x, y = enemy.y}
         end
     end
 
-    return closest_distance, location
+    return closest_enemy, closest_distance
 end
 
 function ai_helper.has_ability(unit, ability)

data/ai/lua/ca_grab_villages.lua

@@ -64,7 +64,7 @@ function ca_grab_villages:evaluation(cfg, data)
             if wesnoth.is_enemy(owner, wesnoth.current.side) then village_rating = village_rating + 20000 end
         end
 
-        local enemy_distance_from_village = AH.get_closest_enemy(v)
+        local _, enemy_distance_from_village = AH.get_closest_enemy(v)
 
         -- Now we go on to the unit-dependent rating
         local best_unit_rating = - math.huge
@@ -96,7 +96,7 @@ function ca_grab_villages:evaluation(cfg, data)
                         end
 
                         -- Prefer not backtracking and moving more distant units to capture villages
-                        local enemy_distance_from_unit = AH.get_closest_enemy({u.x, u.y})
+                        local _, enemy_distance_from_unit = AH.get_closest_enemy({u.x, u.y})
                         rating = rating - (enemy_distance_from_village + enemy_distance_from_unit)/5
 
                         if (rating > best_unit_rating) then

data/ai/lua/ca_move_to_any_enemy.lua

@@ -27,7 +27,7 @@ function ca_move_to_any_enemy:evaluation(cfg, data)
     local unit, destination
     -- Find a unit that has a path to an space close to an enemy
     for i,u in ipairs(units) do
-        local distance, target = AH.get_closest_enemy({u.x, u.y})
+        local target = AH.get_closest_enemy({u.x, u.y})
         if target then
             unit = u
 

data/ai/lua/generic_recruit_engine.lua

@@ -620,7 +620,7 @@ return {
                 local max_rating = -1
 
                 local enemy_leaders = AH.get_attackable_enemies { canrecruit = 'yes' }
-                local closest_enemy_distance, closest_enemy_location = AH.get_closest_enemy()
+                local closest_enemy = AH.get_closest_enemy()
 
                 for i,c in ipairs(data.castle.locs) do
                     local rating = 0
@@ -629,8 +629,8 @@ return {
                         for j,e in ipairs(enemy_leaders) do
                             rating = rating + 1 / M.distance_between(c[1], c[2], e.x, e.y) ^ 2.
                         end
-                        if closest_enemy_location then
-                            rating = rating + 1 / M.distance_between(c[1], c[2], closest_enemy_location.x, closest_enemy_location.y) ^ 2.
+                        if closest_enemy then
+                            rating = rating + 1 / M.distance_between(c[1], c[2], closest_enemy.x, closest_enemy.y) ^ 2.
                         end
                         if (rating > max_rating) then
                             max_rating, best_hex = rating, { c[1], c[2] }
@@ -657,7 +657,8 @@ return {
             local target_hex = recruit_data.recruit.target_hex
 
             local reference_hex = target_hex[1] and target_hex or best_hex
-            local distance_to_enemy, enemy_location = AH.get_closest_enemy(reference_hex, wesnoth.current.side, { viewing_side = 0 })
+            local enemy_location, distance_to_enemy = AH.get_closest_enemy(reference_hex, wesnoth.current.side, { viewing_side = 0 })
+
             -- If no enemy is on the map, then we first use closest enemy start hex,
             -- and if that does not exist either, a location mirrored w.r.t the center of the map
             if not enemy_location then