AI: enable multiple leaders in castle_switch CA

Previously the CA would already move multiple leaders if all leaders were to be moved, but it would abandon moving any leader after finding one that should not move.

data/ai/lua/ca_castle_switch.lua

@@ -4,7 +4,7 @@ local AH = wesnoth.require "ai/lua/ai_helper.lua"
 local M = wesnoth.map
 
 local CS_leader_score
--- Note that leader_target is also needed by the recruiting CA, so it must be stored in 'data'
+-- Note that CS_leader and CS_leader_target are also needed by the recruiting CA, so they must be stored in 'data'
 
 local function get_reachable_enemy_leaders(unit, avoid_map)
     -- We're cheating a little here and also find hidden enemy leaders. That's
@@ -38,15 +38,16 @@ function ca_castle_switch:evaluation(cfg, data, filter_own)
         return 0
     end
 
-    local leader = AH.get_units_with_moves({
+    local leaders = AH.get_units_with_moves({
         side = wesnoth.current.side,
         canrecruit = 'yes',
         formula = '(movement_left = total_movement) and (hitpoints = max_hitpoints)',
         { "and", filter_own }
-    }, true)[1]
+    }, true)
-    if not leader then
+
+    if (not leaders[1]) then
         -- CA is irrelevant if no leader or the leader may have moved from another CA
-        data.leader_target = nil
+        data.CS_leader, data.CS_leader_target = nil, nil
         if AH.print_eval() then AH.done_eval_messages(start_time, ca_name) end
         return 0
     end
@@ -55,18 +56,23 @@ function ca_castle_switch:evaluation(cfg, data, filter_own)
 
     local avoid_map = AH.get_avoid_map(ai, nil, true)
 
-    if data.leader_target and wesnoth.sides[wesnoth.current.side].gold >= cheapest_unit_cost then
+    if data.CS_leader and wesnoth.sides[wesnoth.current.side].gold >= cheapest_unit_cost then
         -- make sure move is still valid
-        local path, cost = AH.find_path_with_avoid(leader, data.leader_target[1], data.leader_target[2], avoid_map)
+        local path, cost = AH.find_path_with_avoid(data.CS_leader, data.CS_leader_target[1], data.CS_leader_target[2], avoid_map)
-        local next_hop = AH.next_hop(leader, nil, nil, { path = path, avoid_map = avoid_map })
+        local next_hop = AH.next_hop(data.CS_leader, nil, nil, { path = path, avoid_map = avoid_map })
-        if next_hop and next_hop[1] == data.leader_target[1]
+        if next_hop and next_hop[1] == data.CS_leader_target[1]
-        and next_hop[2] == data.leader_target[2] then
+            and next_hop[2] == data.CS_leader_target[2]
+        then
             return CS_leader_score
         else
-        	data.leader_target = nil
+            data.CS_leader, data.CS_leader_target = nil, nil
         end
     end
 
+    -- Look for the best keep
+    local overall_best_score = 0
+    for _,leader in ipairs(leaders) do
+        local best_score, best_loc, best_turns, best_path = 0, {}, 3
         local keeps = AH.get_locations_no_borders {
             terrain = 'K*,K*^*,*^K*', -- Keeps
             { "not", { {"filter", {}} }}, -- That have no unit
@@ -91,8 +97,6 @@ function ca_castle_switch:evaluation(cfg, data, filter_own)
 
         local enemy_leaders = get_reachable_enemy_leaders(leader, avoid_map)
 
-    -- Look for the best keep
-    local best_score, best_loc, best_turns, best_path = 0, {}, 3
         for i,loc in ipairs(keeps) do
             -- Only consider keeps within 2 turns movement
             local path, cost = AH.find_path_with_avoid(leader, loc[1], loc[2], avoid_map)
@@ -165,10 +169,9 @@ function ca_castle_switch:evaluation(cfg, data, filter_own)
                 end
             end
 
-        data.leader_target = next_hop
 
             -- if we're on a keep, wait until there are no movable units on the castle before moving off
-        CS_leader_score = 195000
+            local leader_score = 195000
             if wesnoth.get_terrain_info(wesnoth.get_terrain(leader.x, leader.y)).keep then
                 local castle = AH.get_locations_no_borders {
                     { "and", {
@@ -187,10 +190,22 @@ function ca_castle_switch:evaluation(cfg, data, filter_own)
                     end
                 end
                 if should_wait then
-                CS_leader_score = 15000
+                    leader_score = 15000
                 end
             end
 
+            best_score = best_score + leader_score
+
+            if (best_score > overall_best_score) then
+                overall_best_score = best_score
+                CS_leader_score = leader_score
+                data.CS_leader = leader
+                data.CS_leader_target = next_hop
+            end
+        end
+    end
+
+    if (overall_best_score > 0) then
         if AH.print_eval() then AH.done_eval_messages(start_time, ca_name) end
         return CS_leader_score
     end
@@ -200,17 +215,11 @@ function ca_castle_switch:evaluation(cfg, data, filter_own)
 end
 
 function ca_castle_switch:execution(cfg, data, filter_own)
-    local leader = AH.get_units_with_moves({
-        side = wesnoth.current.side,
-        canrecruit = 'yes',
-        { "and", filter_own }
-    }, true)[1]
-
     if AH.print_exec() then AH.print_ts('   Executing castle_switch CA') end
     if AH.show_messages() then wesnoth.wml_actions.message { speaker = leader.id, message = 'Switching castles' } end
 
-    AH.checked_move(ai, leader, data.leader_target[1], data.leader_target[2])
+    AH.checked_move(ai, data.CS_leader, data.CS_leader_target[1], data.CS_leader_target[2])
-    data.leader_target = nil
+    data.CS_leader, data.CS_leader_target = nil
 end
 
 return ca_castle_switch

data/ai/lua/ca_recruit_rushers.lua

@@ -20,8 +20,8 @@ if ca_castle_switch then
     params.leader_takes_village = (function()
             if ca_castle_switch:evaluation({}, dummy_engine.data) > 0 then
                 local take_village = #(wesnoth.get_villages {
-                    x = dummy_engine.data.leader_target[1],
+                    x = dummy_engine.data.CS_leader_target[1],
-                    y = dummy_engine.data.leader_target[2]
+                    y = dummy_engine.data.CS_leader_target[2]
                 }) > 0
                 return take_village
             end