Dynamic AI Functions (#4908)

* dynamic ai func

* add AI_TagBattlePreferFoe as an example

* Update src/battle_ai_main.c

* Update src/battle_ai_main.c

---------

Co-authored-by: ghoulslash <pokevoyager0@gmail.com>
Co-authored-by: Alex <93446519+AlexOn1ine@users.noreply.github.com>

asm/macros/event.inc

@@ -2094,6 +2094,11 @@
 	setvar VAR_0x8006, \item
 	special CreateEnemyEventMon
 	.endm
+    
+	.macro setdynamicaifunc func:req
+	callnative ScriptSetDynamicAiFunc
+	.4byte \func
+	.endm
 
 	@ Set up a totem boost for the next battle.
 	@ 'battler' is the position of the mon you want to gain a boost. see B_POSITION_xx in include/constants/battle.h.

include/battle_ai_main.h

@@ -1,6 +1,9 @@
 #ifndef GUARD_BATTLE_AI_MAIN_H
 #define GUARD_BATTLE_AI_MAIN_H
 
+
+typedef s32 (*AiScoreFunc)(u32, u32, u32, s32);
+
 #define UNKNOWN_NO_OF_HITS UINT32_MAX
 
 // return vals for BattleAI_ChooseMoveOrAction
@@ -101,6 +104,7 @@ void Ai_InitPartyStruct(void);
 void Ai_UpdateSwitchInData(u32 battler);
 void Ai_UpdateFaintData(u32 battler);
 void SetAiLogicDataForTurn(struct AiLogicData *aiData);
+void ResetDynamicAiFunc(void);
 
 extern u8 sBattler_AI;
 

include/constants/battle_ai.h

@@ -51,6 +51,7 @@
 #define AI_FLAG_COUNT                       20
 
 // 'other' ai logic flags
+#define AI_FLAG_DYNAMIC_FUNC          (1 << 28)  // Create custom AI functions for specific battles via "setdynamicaifunc" cmd
 #define AI_FLAG_ROAMING               (1 << 29)
 #define AI_FLAG_SAFARI                (1 << 30)
 #define AI_FLAG_FIRST_BATTLE          (1 << 31)

src/battle_ai_main.c

@@ -18,6 +18,7 @@
 #include "random.h"
 #include "recorded_battle.h"
 #include "util.h"
+#include "script.h"
 #include "constants/abilities.h"
 #include "constants/battle_ai.h"
 #include "constants/battle_move_effects.h"
@@ -39,6 +40,7 @@ static bool32 IsPinchBerryItemEffect(u32 holdEffect);
 // ewram
 EWRAM_DATA const u8 *gAIScriptPtr = NULL;   // Still used in contests
 EWRAM_DATA u8 sBattler_AI = 0;
+EWRAM_DATA AiScoreFunc sDynamicAiFunc = NULL;
 
 // const rom data
 static s32 AI_CheckBadMove(u32 battlerAtk, u32 battlerDef, u32 move, s32 score);
@@ -54,6 +56,7 @@ static s32 AI_Safari(u32 battlerAtk, u32 battlerDef, u32 move, s32 score);
 static s32 AI_FirstBattle(u32 battlerAtk, u32 battlerDef, u32 move, s32 score);
 static s32 AI_DoubleBattle(u32 battlerAtk, u32 battlerDef, u32 move, s32 score);
 static s32 AI_PowerfulStatus(u32 battlerAtk, u32 battlerDef, u32 move, s32 score);
+static s32 AI_DynamicFunc(u32 battlerAtk, u32 battlerDef, u32 move, s32 score);
 
 
 static s32 (*const sBattleAiFuncTable[])(u32, u32, u32, s32) =
@@ -86,7 +89,7 @@ static s32 (*const sBattleAiFuncTable[])(u32, u32, u32, s32) =
     [25] = NULL,                     // Unused
     [26] = NULL,                     // Unused
     [27] = NULL,                     // Unused
-    [28] = NULL,                     // Unused
+    [28] = AI_DynamicFunc,          // AI_FLAG_DYNAMIC_FUNC
     [29] = AI_Roaming,              // AI_FLAG_ROAMING
     [30] = AI_Safari,               // AI_FLAG_SAFARI
     [31] = AI_FirstBattle,          // AI_FLAG_FIRST_BATTLE
@@ -179,6 +182,9 @@ static u32 GetAiFlags(u16 trainerId)
     // Automatically includes AI_FLAG_SMART_MON_CHOICES to improve smart switching
     if (flags & AI_FLAG_SMART_SWITCHING)
         flags |= AI_FLAG_SMART_MON_CHOICES;
+    
+    if (sDynamicAiFunc != NULL)
+        flags |= AI_FLAG_DYNAMIC_FUNC;
 
     return flags;
 }
@@ -5335,3 +5341,47 @@ static s32 AI_FirstBattle(u32 battlerAtk, u32 battlerDef, u32 move, s32 score)
 
     return score;
 }
+
+
+// Dynamic AI Functions
+// For specific battle scenarios
+
+// Example - prefer attacking opposite foe in a tag battle
+s32 AI_TagBattlePreferFoe(u32 battlerAtk, u32 battlerDef, u32 move, s32 score)
+{
+    if (!(gBattleTypeFlags & BATTLE_TYPE_INGAME_PARTNER))
+    {
+        /* not a partner battle */
+        return score;
+    }
+    else if (!IsBattlerAlive(BATTLE_OPPOSITE(battlerAtk)) || !IsBattlerAlive(BATTLE_PARTNER(BATTLE_OPPOSITE(battlerAtk))))
+    {
+        /* partner is defeated so attack normally */
+        return score;
+    }
+    else if (battlerDef == BATTLE_OPPOSITE(battlerAtk))
+    {
+        /* attacking along the diagonal */
+        ADJUST_SCORE(-20);
+    }
+    
+    return score;
+}
+
+static s32 AI_DynamicFunc(u32 battlerAtk, u32 battlerDef, u32 move, s32 score)
+{
+    if (sDynamicAiFunc != NULL)
+        score = sDynamicAiFunc(battlerAtk, battlerDef, move, score);
+    return score;
+}
+
+void ScriptSetDynamicAiFunc(struct ScriptContext *ctx)
+{
+    AiScoreFunc func = (AiScoreFunc)ScriptReadWord(ctx);
+    sDynamicAiFunc = func;
+}
+
+void ResetDynamicAiFunc(void)
+{
+    sDynamicAiFunc = NULL;
+}

src/battle_main.c

@@ -1766,6 +1766,7 @@ static void FreeRestoreBattleData(void)
     FreeMonSpritesGfx();
     FreeBattleSpritesData();
     FreeBattleResources();
+    ResetDynamicAiFunc();
 }
 
 void CB2_QuitRecordedBattle(void)
@@ -5530,6 +5531,7 @@ static void FreeResetData_ReturnToOvOrDoEvolutions(void)
     if (gBattleStruct != NULL && !(gBattleTypeFlags & BATTLE_TYPE_LINK))
     {
         ZeroEnemyPartyMons();
+        ResetDynamicAiFunc();
         FreeMonSpritesGfx();
         FreeBattleResources();
         FreeBattleSpritesData();