ABILITY_SYMBIOSIS

asm/macros/battle_script.inc

@@ -2132,3 +2132,8 @@
 	.macro skydropyawn
 	various 0, VARIOUS_SKY_DROP_YAWN
 	.endm
+
+	@ Used by effects that may proc Symbiosis but do not call removeitem.
+	.macro trysymbiosis
+	various BS_ATTACKER, VARIOUS_TRY_SYMBIOSIS
+	.endm

data/battle_scripts_1.s

@@ -706,6 +706,7 @@ BattleScript_EffectFlingConsumeBerry:
 	restorebattleritem BS_TARGET
 BattleScript_FlingEnd:
 	tryfaintmon BS_TARGET
+	trysymbiosis
 	goto BattleScript_MoveEnd
 
 BattleScript_FlingFlameOrb:
@@ -1392,6 +1393,7 @@ BattleScript_MoveEffectBugBite::
 	consumeberry BS_ATTACKER, TRUE  @ consume the berry, then restore the item from changedItems
 	bicword gHitMarker, HITMARKER_NO_ANIMATIONS
 	setbyte sBERRY_OVERRIDE, FALSE
+	trysymbiosis
 	return
 
 BattleScript_EffectCoreEnforcer:
@@ -1763,6 +1765,7 @@ BattleScript_EffectBestow:
 	waitanimation
 	printstring STRINGID_BESTOWITEMGIVING
 	waitmessage B_WAIT_TIME_LONG
+	trysymbiosis
 	goto BattleScript_MoveEnd
 
 BattleScript_EffectAfterYou:
@@ -9841,3 +9844,9 @@ BattleScript_MagicianActivates::
 	call BattleScript_AbilityPopUp
 	call BattleScript_ItemSteal
 	return
+
+BattleScript_SymbiosisActivates::
+	call BattleScript_AbilityPopUp
+	printstring STRINGID_SYMBIOSISITEMPASS
+	waitmessage B_WAIT_TIME_LONG
+	return

include/battle_scripts.h

@@ -428,6 +428,7 @@ extern const u8 BattleScript_BeakBlastBurn[];
 extern const u8 BattleScript_DefDownSpeedUp[];
 extern const u8 BattleScript_AffectionBasedStatusHeal[];
 extern const u8 BattleScript_AffectionBasedEndurance[];
+extern const u8 BattleScript_SymbiosisActivates[];
 
 // zmoves
 extern const u8 BattleScript_ZMoveActivateDamaging[];

include/constants/battle_config.h

@@ -103,6 +103,7 @@
 #define B_STURDY                    GEN_LATEST // In Gen5+, Sturdy causes the Pokémon to have 1 HP remaining if another Pokémon's attack or confusion damage would have brought it from full health to 0 HP.
 #define B_PLUS_MINUS_INTERACTION    GEN_LATEST // In Gen5+, Plus and Minus can be activated with themselves and the opposite ability. Before, only the opposing ability could activate it.
 #define B_WEATHER_FORMS             GEN_LATEST // In Gen5+, Castform and Cherrim revert to their base form upon losing their respective ability. Cherrim needs Flower Gift to swap forms.
+#define B_SYMBIOSIS_GEMS            GEN_LATEST // In Gen7+, Symbiosis passes an item after a gem-boosted attack. Previously, items are passed before the gem-boosted attack hits, making the item effect apply.
 
 // Item settings
 #define B_HP_BERRIES                GEN_LATEST // In Gen4+, berries which restore hp activate immediately after HP drops to half. In Gen3, the effect occurs at the end of the turn.

include/constants/battle_script_commands.h

@@ -242,6 +242,7 @@
 #define VARIOUS_SET_BEAK_BLAST                      151
 #define VARIOUS_SWAP_SIDE_STATUSES                  152
 #define VARIOUS_SET_Z_EFFECT                        153
+#define VARIOUS_TRY_SYMBIOSIS                       154
 
 // Cmd_manipulatedamage
 #define DMG_CHANGE_SIGN            0
@@ -312,8 +313,9 @@
 #define MOVEEND_DANCER                            28
 #define MOVEEND_EMERGENCY_EXIT                    29
 #define MOVEEND_WEATHER_FORM                      30
-#define MOVEEND_CLEAR_BITS                        31
-#define MOVEEND_COUNT                             32
+#define MOVEEND_SYMBIOSIS                         31
+#define MOVEEND_CLEAR_BITS                        32
+#define MOVEEND_COUNT                             33
 
 // switch cases
 #define B_SWITCH_NORMAL     0

src/battle_message.c

@@ -607,7 +607,7 @@ static const u8 sText_HarvestBerry[] = _("{B_ATK_NAME_WITH_PREFIX} harvested\nit
 static const u8 sText_LastAbilityRaisedBuff1[] = _("{B_ATK_NAME_WITH_PREFIX}'s {B_LAST_ABILITY}\nraised its {B_BUFF1}!");
 static const u8 sText_MagicBounceActivates[] = _("The {B_DEF_NAME_WITH_PREFIX} bounced the\n{B_ATK_NAME_WITH_PREFIX} back!");
 static const u8 sText_ProteanTypeChange[] = _("{B_ATK_NAME_WITH_PREFIX}'s {B_ATK_ABILITY} transformed\nit into the {B_BUFF1} type!");
-static const u8 sText_SymbiosisItemPass[] = _("{B_ATK_NAME_WITH_PREFIX} passed its {B_LAST_ITEM}\nto {B_SCR_ACTIVE_NAME_WITH_PREFIX} through {B_ATK_ABILITY}!");
+static const u8 sText_SymbiosisItemPass[] = _("{B_SCR_ACTIVE_NAME_WITH_PREFIX} passed its {B_LAST_ITEM}\nto {B_ATK_NAME_WITH_PREFIX} through {B_LAST_ABILITY}!");
 static const u8 sText_StealthRockDmg[] = _("Pointed stones dug into\n{B_SCR_ACTIVE_NAME_WITH_PREFIX}!");
 static const u8 sText_ToxicSpikesAbsorbed[] = _("The poison spikes disappeared\nfrom around the opposing team's feet!");
 static const u8 sText_ToxicSpikesPoisoned[] = _("{B_SCR_ACTIVE_NAME_WITH_PREFIX} was poisoned!");

src/battle_script_commands.c

@@ -317,6 +317,7 @@ static void PutMonIconOnLvlUpBanner(void);
 static void DrawLevelUpBannerText(void);
 static void SpriteCB_MonIconOnLvlUpBanner(struct Sprite *sprite);
 static bool32 CriticalCapture(u32 odds);
+static void BestowItem(u32 battlerAtk, u32 battlerDef);
 
 static void Cmd_attackcanceler(void);
 static void Cmd_accuracycheck(void);
@@ -5084,6 +5085,15 @@ static bool32 TryKnockOffBattleScript(u32 battlerDef)
     return FALSE;
 }
 
+#define SYMBIOSIS_CHECK(battler, ally)                                                                                               \
+    GetBattlerAbility(ally) == ABILITY_SYMBIOSIS                   \
+    && gBattleMons[battler].item == ITEM_NONE                      \
+    && gBattleMons[ally].item != ITEM_NONE                         \
+    && CanBattlerGetOrLoseItem(battler, gBattleMons[ally].item)    \
+    && CanBattlerGetOrLoseItem(ally, gBattleMons[ally].item)       \
+    && gBattleMons[battler].hp != 0                                \
+    && gBattleMons[ally].hp != 0
+
 static u32 GetNextTarget(u32 moveTarget)
 {
     u32 i;
@@ -5748,13 +5758,11 @@ static void Cmd_moveend(void)
                 switch (gBattleMons[i].species)
                 {
                 case SPECIES_CASTFORM:
-                case SPECIES_CHERRIM:
-#ifdef POKEMON_EXPANSION
                 case SPECIES_CASTFORM_RAINY:
                 case SPECIES_CASTFORM_SNOWY:
                 case SPECIES_CASTFORM_SUNNY:
+                case SPECIES_CHERRIM:
                 case SPECIES_CHERRIM_SUNSHINE:
-#endif
                     effect = TryWeatherFormChange(i);
                     if (effect)
                     {
@@ -5766,6 +5774,26 @@ static void Cmd_moveend(void)
             }
             gBattleScripting.moveendState++;
             break;
+        case MOVEEND_SYMBIOSIS:
+            for (i = 0; i < gBattlersCount; i++)
+            {
+                if ((gSpecialStatuses[i].berryReduced
+                #if B_SYMBIOSIS_GEMS >= GEN_7
+                    || gSpecialStatuses[i].gemBoost
+                #endif
+                    ) && SYMBIOSIS_CHECK(i, BATTLE_PARTNER(i)))
+                {
+                    BestowItem(BATTLE_PARTNER(i), i);
+                    gLastUsedAbility = gBattleMons[BATTLE_PARTNER(i)].ability;
+                    gBattleScripting.battler = gBattlerAbility = BATTLE_PARTNER(i);
+                    gBattlerAttacker = i;
+                    BattleScriptPushCursor();
+                    gBattlescriptCurrInstr = BattleScript_SymbiosisActivates;
+                    effect = TRUE;
+                }
+            }
+            gBattleScripting.moveendState++;
+            break;
         case MOVEEND_CLEAR_BITS: // Clear/Set bits for things like using a move for all targets and all hits.
             if (gSpecialStatuses[gBattlerAttacker].instructedChosenTarget)
                 *(gBattleStruct->moveTarget + gBattlerAttacker) = gSpecialStatuses[gBattlerAttacker].instructedChosenTarget & 0x3;
@@ -7244,6 +7272,49 @@ static bool32 TryCheekPouch(u32 battlerId, u32 itemId)
     return FALSE;
 }
 
+// Used by Bestow and Symbiosis to take an item from one battler and give to another.
+static void BestowItem(u32 battlerAtk, u32 battlerDef)
+{
+    gLastUsedItem = gBattleMons[battlerAtk].item;
+
+    gActiveBattler = battlerAtk;
+    gBattleMons[battlerAtk].item = ITEM_NONE;
+    BtlController_EmitSetMonData(BUFFER_A, REQUEST_HELDITEM_BATTLE, 0, sizeof(gBattleMons[battlerAtk].item), &gBattleMons[battlerAtk].item);
+    MarkBattlerForControllerExec(battlerAtk);
+    CheckSetUnburden(battlerAtk);
+
+    gActiveBattler = battlerDef;
+    gBattleMons[battlerDef].item = gLastUsedItem;
+    BtlController_EmitSetMonData(BUFFER_A, REQUEST_HELDITEM_BATTLE, 0, sizeof(gBattleMons[battlerDef].item), &gBattleMons[battlerDef].item);
+    MarkBattlerForControllerExec(battlerDef);
+    gBattleResources->flags->flags[battlerDef] &= ~RESOURCE_FLAG_UNBURDEN;
+}
+
+// Called by Cmd_removeitem. itemId represents the item that was removed, not being given.
+static bool32 TrySymbiosis(u32 battler, u32 itemId)
+{
+    if (!gBattleStruct->itemStolen[gBattlerPartyIndexes[battler]].stolen
+        && gBattleStruct->changedItems[battler] == ITEM_NONE
+        && GetBattlerHoldEffect(battler, TRUE) != HOLD_EFFECT_EJECT_BUTTON
+        && GetBattlerHoldEffect(battler, TRUE) != HOLD_EFFECT_EJECT_PACK
+    #if B_SYMBIOSIS_GEMS >= GEN_7
+        && !(gSpecialStatuses[battler].gemBoost)
+    #endif
+        && gCurrentMove != MOVE_FLING //Fling and damage-reducing berries are handled separately.
+        && !gSpecialStatuses[battler].berryReduced
+        && SYMBIOSIS_CHECK(battler, BATTLE_PARTNER(battler)))
+    {
+        BestowItem(BATTLE_PARTNER(battler), battler);
+        gLastUsedAbility = gBattleMons[BATTLE_PARTNER(battler)].ability;
+        gBattleScripting.battler = gBattlerAbility = BATTLE_PARTNER(battler);
+        gBattlerAttacker = battler;
+        BattleScriptPush(gBattlescriptCurrInstr + 2);
+        gBattlescriptCurrInstr = BattleScript_SymbiosisActivates;
+        return TRUE;
+    }
+    return FALSE;
+}
+
 static void Cmd_removeitem(void)
 {
     u16 itemId = 0;
@@ -7262,7 +7333,7 @@ static void Cmd_removeitem(void)
     MarkBattlerForControllerExec(gActiveBattler);
 
     ClearBattlerItemEffectHistory(gActiveBattler);
-    if (!TryCheekPouch(gActiveBattler, itemId))
+    if (!TryCheekPouch(gActiveBattler, itemId) && !TrySymbiosis(gActiveBattler, itemId))
         gBattlescriptCurrInstr += 2;
 }
 
@@ -9045,20 +9116,7 @@ static void Cmd_various(void)
         }
         else
         {
-            gLastUsedItem = gBattleMons[gBattlerAttacker].item;
-
-            gActiveBattler = gBattlerAttacker;
-            gBattleMons[gActiveBattler].item = ITEM_NONE;
-            BtlController_EmitSetMonData(BUFFER_A, REQUEST_HELDITEM_BATTLE, 0, sizeof(gBattleMons[gActiveBattler].item), &gBattleMons[gActiveBattler].item);
-            MarkBattlerForControllerExec(gActiveBattler);
-            CheckSetUnburden(gBattlerAttacker);
-
-            gActiveBattler = gBattlerTarget;
-            gBattleMons[gActiveBattler].item = gLastUsedItem;
-            BtlController_EmitSetMonData(BUFFER_A, REQUEST_HELDITEM_BATTLE, 0, sizeof(gBattleMons[gActiveBattler].item), &gBattleMons[gActiveBattler].item);
-            MarkBattlerForControllerExec(gActiveBattler);
-            gBattleResources->flags->flags[gBattlerTarget] &= ~RESOURCE_FLAG_UNBURDEN;
-
+            BestowItem(gBattlerAttacker, gBattlerTarget);
             gBattlescriptCurrInstr += 7;
         }
         return;
@@ -9788,6 +9846,18 @@ static void Cmd_various(void)
     case VARIOUS_SWAP_SIDE_STATUSES:
         CourtChangeSwapSideStatuses();
         break;
+    case VARIOUS_TRY_SYMBIOSIS: //called by Bestow, Fling, and Bug Bite, which don't work with Cmd_removeitem.
+        if (SYMBIOSIS_CHECK(gActiveBattler, BATTLE_PARTNER(gActiveBattler)))
+        {
+            BestowItem(BATTLE_PARTNER(gActiveBattler), gActiveBattler);
+            gLastUsedAbility = gBattleMons[BATTLE_PARTNER(gActiveBattler)].ability;
+            gBattleScripting.battler = gBattlerAbility = BATTLE_PARTNER(gActiveBattler);
+            gBattlerAttacker = gActiveBattler;
+            BattleScriptPushCursor();
+            gBattlescriptCurrInstr = BattleScript_SymbiosisActivates;
+            return;
+        }
+        break;
     } // End of switch (gBattlescriptCurrInstr[2])
 
     gBattlescriptCurrInstr += 3;