AI should keep some creatures in reserve for castle defense (ihhub#5571)

AnnaSavvy · Jun 28, 2022 · 6b9da53 · 6b9da53
1 parent 60bc59a
commit 6b9da53
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Showing 7 changed files with 69 additions and 25 deletions.
diff --git a/src/fheroes2/ai/ai.h b/src/fheroes2/ai/ai.h
@@ -138,7 +138,6 @@ namespace AI
     bool BuildIfAvailable( Castle & castle, int building );
     bool BuildIfEnoughResources( Castle & castle, int building, uint32_t minimumMultiplicator );
     uint32_t GetResourceMultiplier( uint32_t min, uint32_t max );
-    void ReinforceHeroInCastle( Heroes & hero, Castle & castle, const Funds & budget );
     void OptimizeTroopsOrder( Army & hero );
 
     StreamBase & operator<<( StreamBase &, const AI::Base & );

diff --git a/src/fheroes2/ai/ai_common.cpp b/src/fheroes2/ai/ai_common.cpp
@@ -57,26 +57,6 @@ namespace AI
         return Rand::Get( min, max );
     }
 
-    void ReinforceHeroInCastle( Heroes & hero, Castle & castle, const Funds & budget )
-    {
-        if ( !hero.HaveSpellBook() && castle.GetLevelMageGuild() > 0 && !hero.IsFullBagArtifacts() ) {
-            // this call will check if AI kingdom have enough resources to buy book
-            hero.BuySpellBook( &castle );
-        }
-
-        Army & heroArmy = hero.GetArmy();
-        const double armyStrength = heroArmy.GetStrength();
-
-        heroArmy.UpgradeTroops( castle );
-        castle.recruitBestAvailable( budget );
-        heroArmy.JoinStrongestFromArmy( castle.GetArmy() );
-        OptimizeTroopsOrder( heroArmy );
-
-        if ( std::fabs( armyStrength - heroArmy.GetStrength() ) > 0.001 ) {
-            hero.unmarkHeroMeeting();
-        }
-    }
-
     void OptimizeTroopsOrder( Army & army )
     {
         // Optimize troops placement before the battle

diff --git a/src/fheroes2/ai/normal/ai_normal.h b/src/fheroes2/ai/normal/ai_normal.h
@@ -192,6 +192,7 @@ namespace AI
         void HeroesActionComplete( Heroes & hero, int32_t tileIndex, const MP2::MapObjectType objectType ) override;
 
         bool recruitHero( Castle & castle, bool buyArmy, bool underThreat );
+        void reinforceHeroInCastle( Heroes & hero, Castle & castle, const Funds & budget );
         void evaluateRegionSafety();
         std::set<int> findCastlesInDanger( const KingdomCastles & castles, const std::vector<std::pair<int, const Army *>> & enemyArmies, int myColor );
         std::vector<AICastle> getSortedCastleList( const KingdomCastles & castles, const std::set<int> & castlesInDanger );

diff --git a/src/fheroes2/ai/normal/ai_normal_hero.cpp b/src/fheroes2/ai/normal/ai_normal_hero.cpp
@@ -1357,7 +1357,7 @@ namespace AI
     {
         Castle * castle = hero.inCastleMutable();
         if ( castle ) {
-            ReinforceHeroInCastle( hero, *castle, castle->GetKingdom().GetFunds() );
+            reinforceHeroInCastle( hero, *castle, castle->GetKingdom().GetFunds() );
         }
 
         if ( isMonsterStrengthCacheable( objectType ) ) {

diff --git a/src/fheroes2/ai/normal/ai_normal_kingdom.cpp b/src/fheroes2/ai/normal/ai_normal_kingdom.cpp
@@ -125,12 +125,76 @@ namespace AI
 
         if ( recruit && buyArmy ) {
             CastleTurn( castle, underThreat );
-            ReinforceHeroInCastle( *recruit, castle, kingdom.GetFunds() );
+            reinforceHeroInCastle( *recruit, castle, kingdom.GetFunds() );
         }
 
         return recruit != nullptr;
     }
 
+    void Normal::reinforceHeroInCastle( Heroes & hero, Castle & castle, const Funds & budget )
+    {
+        if ( !hero.HaveSpellBook() && castle.GetLevelMageGuild() > 0 && !hero.IsFullBagArtifacts() ) {
+            // this call will check if AI kingdom have enough resources to buy book
+            hero.BuySpellBook( &castle );
+        }
+
+        Army & heroArmy = hero.GetArmy();
+        Army & garrison = castle.GetArmy();
+        const double armyStrength = heroArmy.GetStrength();
+
+        heroArmy.UpgradeTroops( castle );
+        castle.recruitBestAvailable( budget );
+        heroArmy.JoinStrongestFromArmy( garrison );
+
+        const uint32_t regionID = world.GetTiles( castle.GetIndex() ).GetRegion();
+        // check if we should leave some troops in the garrison
+        // TODO: amount of troops left could depend on region's safetyFactor
+        if ( castle.isCastle() && _regions[regionID].safetyFactor <= 100 && !garrison.isValid() ) {
+            const Heroes::Role heroRole = hero.getAIRole();
+            const bool isFigtherHero = ( heroRole == Heroes::Role::FIGHTER || heroRole == Heroes::Role::CHAMPION );
+
+            bool onlyHalf = false;
+            Troop * unitToSwap = heroArmy.GetSlowestTroop();
+            if ( unitToSwap ) {
+                const double significanceRatio = isFigtherHero ? 20.0 : 10.0;
+                if ( unitToSwap->GetStrength() > armyStrength / significanceRatio ) {
+                    Troop * weakest = heroArmy.GetWeakestTroop();
+
+                    assert( weakest != nullptr );
+                    if ( weakest ) {
+                        unitToSwap = weakest;
+                        if ( weakest->GetStrength() > armyStrength / significanceRatio ) {
+                            if ( isFigtherHero ) {
+                                // if it's an important hero and all troops are significant - keep the army
+                                unitToSwap = nullptr;
+                            }
+                            else {
+                                onlyHalf = true;
+                            }
+                        }
+                    }
+                }
+            }
+            if ( unitToSwap ) {
+                const uint32_t count = unitToSwap->GetCount();
+                const uint32_t toMove = onlyHalf ? count / 2 : count;
+                if ( garrison.JoinTroop( unitToSwap->GetMonster(), toMove, true ) ) {
+                    if ( !onlyHalf ) {
+                        unitToSwap->Reset();
+                    }
+                    else {
+                        unitToSwap->SetCount( count - toMove );
+                    }
+                }
+            }
+        }
+
+        OptimizeTroopsOrder( heroArmy );
+        if ( std::fabs( armyStrength - heroArmy.GetStrength() ) > 0.001 ) {
+            hero.unmarkHeroMeeting();
+        }
+    }
+
     void Normal::evaluateRegionSafety()
     {
         std::vector<std::pair<size_t, int>> regionsToCheck;

diff --git a/src/fheroes2/army/army.cpp b/src/fheroes2/army/army.cpp
@@ -486,7 +486,7 @@ Troop * Troops::GetWeakestTroop() const
     return *lowest;
 }
 
-const Troop * Troops::GetSlowestTroop() const
+Troop * Troops::GetSlowestTroop() const
 {
     const_iterator first = begin();
     const_iterator last = end();

diff --git a/src/fheroes2/army/army.h b/src/fheroes2/army/army.h
@@ -94,7 +94,7 @@ class Troops : protected std::vector<Troop *>
 
     Troop * GetFirstValid();
     Troop * GetWeakestTroop() const;
-    const Troop * GetSlowestTroop() const;
+    Troop * GetSlowestTroop() const;
 
     void SortStrongest();
     void ArrangeForBattle( bool = false );