Lua AIs: get unit cost/level directly from proxy unit

These used to be accessible only through unit.__cfg or wesnoth.unit_types.  The Fast Micro AI is not included here as it requires a larger clean-up.

(cherry-picked from commit 8af988c697)

data/ai/lua/battle_calcs.lua

@@ -837,7 +837,7 @@ function battle_calcs.attack_rating(attacker, defender, dst, cfg, cache)
     -- In addition, potentially leveling up in this attack is a huge bonus,
     -- proportional to the chance of it happening and the chance of not dying itself
     local level_bonus = 0.
-    local defender_level = wesnoth.unit_types[defender.type].level
+    local defender_level = defender.level
     if (attacker.max_experience - attacker.experience <= defender_level) then
         level_bonus = 1. - att_stats.hp_chance[0]
     else
@@ -849,7 +849,7 @@ function battle_calcs.attack_rating(attacker, defender, dst, cfg, cache)
 
 
     -- Now convert this into gold-equivalent value
-    local attacker_value = wesnoth.unit_types[attacker.type].cost
+    local attacker_value = attacker.cost
 
     -- Being closer to leveling is good (this makes AI prefer units with lots of XP)
     local xp_bonus = attacker.experience / attacker.max_experience
@@ -886,7 +886,7 @@ function battle_calcs.attack_rating(attacker, defender, dst, cfg, cache)
     -- In addition, the defender potentially leveling up in this attack is a huge penalty,
     -- proportional to the chance of it happening and the chance of not dying itself
     local defender_level_penalty = 0.
-    local attacker_level = wesnoth.unit_types[attacker.type].level
+    local attacker_level = attacker.level
     if (defender.max_experience - defender.experience <= attacker_level) then
         defender_level_penalty = 1. - def_stats.hp_chance[0]
     else
@@ -897,7 +897,7 @@ function battle_calcs.attack_rating(attacker, defender, dst, cfg, cache)
     value_fraction = value_fraction - defender_level_penalty * defender_level_weight
 
     -- Now convert this into gold-equivalent value
-    local defender_value = wesnoth.unit_types[defender.type].cost
+    local defender_value = defender.cost
 
     -- If this is the enemy leader, make damage to it much more important
     if defender.canrecruit then
@@ -1011,7 +1011,7 @@ function battle_calcs.attack_combo_stats(tmp_attackers, tmp_dsts, defender, cach
 
             --for hp,p in pairs(tmp_def_stats[i].hp_chance) do
             --    if (p > 0) then
-            --        local dhp_norm = (hp - av) / defender.max_hitpoints * wesnoth.unit_types[defender.type].cost
+            --        local dhp_norm = (hp - av) / defender.max_hitpoints * defender.cost
             --        local dvar = p * dhp_norm^2
             --        outcome_variance = outcome_variance + dvar
             --        n_outcomes = n_outcomes + 1
@@ -1028,7 +1028,7 @@ function battle_calcs.attack_combo_stats(tmp_attackers, tmp_dsts, defender, cach
             -- Almost, bonus should not be quite as high as a really high CTK
             -- This isn't quite true in reality, but can be refined later
             if AH.has_weapon_special(attacker, "slow") then
-                rating = rating + wesnoth.unit_types[defender.type].cost / 2.
+                rating = rating + defender.cost / 2.
             end
 
             ratings[i] = { i, rating, base_rating, def_rating, att_rating }

data/ai/lua/ca_high_xp_attack.lua

@@ -242,14 +242,14 @@ function ca_attack_highxp:evaluation(cfg, data)
                         rating = 1000
 
                         local enemy_value_loss = (target.hitpoints - def_stats.average_hp) / target.max_hitpoints
-                        enemy_value_loss = enemy_value_loss * wesnoth.unit_types[target.type].cost
+                        enemy_value_loss = enemy_value_loss * target.cost
 
                         -- We want the _least_ damage to the enemy, so the minus sign is no typo!
                         rating = rating - enemy_value_loss
 
                         local own_value_loss = (attacker_copy.hitpoints - att_stats.average_hp) / attacker_copy.max_hitpoints
                         own_value_loss = own_value_loss + att_stats.hp_chance[0]
-                        own_value_loss = own_value_loss * wesnoth.unit_types[attacker_copy.type].cost
+                        own_value_loss = own_value_loss * attacker_copy.cost
 
                         rating = rating - own_value_loss
 

data/ai/lua/generic_rush_engine.lua

@@ -436,7 +436,7 @@ return {
                 local on_village = wesnoth.get_terrain_info(wesnoth.get_terrain(defender.x, defender.y)).village
 
                 -- Also, poisoning units that would level up through the attack or could level on their turn as a result is very bad
-                local about_to_level = defender.max_experience - defender.experience <= (wesnoth.unit_types[attacker.type].level * 2)
+                local about_to_level = defender.max_experience - defender.experience <= (attacker.level * 2)
 
                 if (not cant_poison) and (not on_village) and (not about_to_level) then
                     -- Strongest enemy gets poisoned first