Updated Knock Off (#4333)

* added config for updated Knock Off behavior, added tests

* fixed unused var

* added item check in tests

* fixed item checks

include/config/battle.h

@@ -118,6 +118,7 @@
 #define B_IMPRISON                  GEN_LATEST // In Gen5+, Imprison doesn't fail if opposing pokemon don't have any moves the user knows.
 #define B_ALLY_SWITCH_FAIL_CHANCE   GEN_LATEST // In Gen9, using Ally Switch consecutively decreases the chance of success for each consecutive use.
 #define B_SKETCH_BANS               GEN_LATEST // In Gen9+, Sketch is unable to copy more moves than in previous generations.
+#define B_KNOCK_OFF_REMOVAL         GEN_LATEST // In Gen5+, Knock Off removes the foe's item instead of rendering it unusable.
 
 // Ability settings
 #define B_EXPANDED_ABILITY_NAMES    TRUE       // If TRUE, ability names are increased from 12 characters to 16 characters.

src/battle_script_commands.c

@@ -5341,9 +5341,19 @@ static bool32 TryKnockOffBattleScript(u32 battlerDef)
             gBattleMons[battlerDef].item = 0;
             if (gBattleMons[battlerDef].ability != ABILITY_GORILLA_TACTICS)
                 gBattleStruct->choicedMove[battlerDef] = 0;
-            gWishFutureKnock.knockedOffMons[side] |= gBitTable[gBattlerPartyIndexes[battlerDef]];
             CheckSetUnburden(battlerDef);
 
+            // In Gen 5+, Knock Off removes the target's item rather than rendering it unusable.
+            if (B_KNOCK_OFF_REMOVAL >= GEN_5)
+            {
+                BtlController_EmitSetMonData(battlerDef, BUFFER_A, REQUEST_HELDITEM_BATTLE, 0, sizeof(gBattleMons[battlerDef].item), &gBattleMons[battlerDef].item);
+                MarkBattlerForControllerExec(battlerDef);
+            }
+            else
+            {
+                gWishFutureKnock.knockedOffMons[side] |= gBitTable[gBattlerPartyIndexes[battlerDef]];
+            }
+
             BattleScriptPushCursor();
             gBattlescriptCurrInstr = BattleScript_KnockedOff;
         }

test/battle/move_effect/knock_off.c

@@ -21,6 +21,8 @@ SINGLE_BATTLE_TEST("Knock Off knocks a healing berry before it has the chance to
         }
         ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
         MESSAGE("Wobbuffet knocked off Foe Wobbuffet's Sitrus Berry!");
+    } THEN {
+        EXPECT(opponent->item == ITEM_NONE);
     }
 }
 
@@ -49,5 +51,145 @@ SINGLE_BATTLE_TEST("Knock Off activates after Rocky Helmet and Weakness Policy")
             ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
             MESSAGE("Wobbuffet knocked off Foe Wobbuffet's Rocky Helmet!");
         }
+    } THEN {
+        EXPECT(opponent->item == ITEM_NONE);
+    }
+}
+
+SINGLE_BATTLE_TEST("Knock Off deals additional damage to opponents holding an item in Gen 6+", s16 damage)
+{
+    u16 item = 0;
+
+    PARAMETRIZE { item = ITEM_NONE; }
+    PARAMETRIZE { item = ITEM_LEFTOVERS; }
+
+    GIVEN {
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET) { Item(item); };
+    } WHEN {
+        TURN { MOVE(player, MOVE_KNOCK_OFF); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_KNOCK_OFF, player);
+        HP_BAR(opponent, captureDamage: &results[i].damage);
+        if (item != ITEM_NONE)
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
+    } FINALLY {
+        if (B_KNOCK_OFF_DMG >= GEN_6)
+            EXPECT_MUL_EQ(results[0].damage, UQ_4_12(1.5), results[1].damage);
+        else
+            EXPECT_EQ(results[0].damage, results[1].damage);
+    } THEN {
+        EXPECT(opponent->item == ITEM_NONE);
+    }
+}
+
+
+SINGLE_BATTLE_TEST("Knock Off does not remove items through Substitute")
+{
+    GIVEN {
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET) { Item(ITEM_LEFTOVERS); };
+    } WHEN {
+        TURN { MOVE(opponent, MOVE_SUBSTITUTE); 
+               MOVE(player, MOVE_KNOCK_OFF); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_KNOCK_OFF, player);
+        NOT { ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF); }
+    } THEN {
+        EXPECT(opponent->item == ITEM_NONE);
+    }
+}
+
+SINGLE_BATTLE_TEST("Recycle cannot recover an item removed by Knock Off")
+{
+    GIVEN {
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET) { Item(ITEM_LEFTOVERS); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_KNOCK_OFF);
+               MOVE(opponent, MOVE_RECYCLE); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_KNOCK_OFF, player);
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
+        MESSAGE("Wobbuffet knocked off Foe Wobbuffet's Leftovers!");
+        
+        MESSAGE("Foe Wobbuffet used Recycle!");
+        MESSAGE("But it failed!");
+    } THEN {
+        EXPECT(opponent->item == ITEM_NONE);
+    }
+}
+
+SINGLE_BATTLE_TEST("Knock Off does not prevent targets from receiving another item in Gen 5+")
+{
+    GIVEN {
+        PLAYER(SPECIES_WOBBUFFET) { Item(ITEM_LEFTOVERS); }
+        OPPONENT(SPECIES_WOBBUFFET) { Item(ITEM_LEFTOVERS); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_KNOCK_OFF); }
+        TURN { MOVE(player, MOVE_BESTOW); }
+    } SCENE {
+        // turn 1
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_KNOCK_OFF, player);
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
+        MESSAGE("Wobbuffet knocked off Foe Wobbuffet's Leftovers!");
+        // turn 2
+        if (B_KNOCK_OFF_REMOVAL >= GEN_5) {
+            ANIMATION(ANIM_TYPE_MOVE, MOVE_BESTOW, player);
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_HELD_ITEM_EFFECT);
+            MESSAGE("Foe Wobbuffet's Leftovers restored its HP a little!");
+        } else {
+            NOT { ANIMATION(ANIM_TYPE_MOVE, MOVE_BESTOW, player); }
+            MESSAGE("But it failed!");
+        }
+    } THEN {
+        if (B_KNOCK_OFF_REMOVAL >= GEN_5)
+            EXPECT(opponent->item == ITEM_LEFTOVERS);
+        else
+            EXPECT(opponent->item == ITEM_NONE);
+    }
+}
+
+// Knock Off triggers Unburden regardless of whether the item is fully removed (Gen 5+) or not.
+SINGLE_BATTLE_TEST("Knock Off triggers Unburden")
+{
+    GIVEN {
+        PLAYER(SPECIES_WOBBUFFET) { Speed(60); }
+        OPPONENT(SPECIES_WOBBUFFET) { Ability(ABILITY_UNBURDEN); Item(ITEM_LEFTOVERS); Speed(50); }
+    } WHEN {
+        TURN { MOVE(player, MOVE_KNOCK_OFF); }
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        // turn 1
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_KNOCK_OFF, player);
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
+        MESSAGE("Wobbuffet knocked off Foe Wobbuffet's Leftovers!");
+        // turn 2
+        MESSAGE("Foe Wobbuffet used Celebrate!");
+        MESSAGE("Wobbuffet used Celebrate!");
+    } THEN {
+        EXPECT(opponent->item == ITEM_NONE);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Knock Off does not trigger the opposing ally's Symbiosis")
+{
+    GIVEN {
+        PLAYER(SPECIES_WOBBUFFET) { Item(ITEM_LEFTOVERS); }
+        PLAYER(SPECIES_FLORGES) { Item(ITEM_LEFTOVERS); }
+        OPPONENT(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(opponentLeft, MOVE_KNOCK_OFF, target: playerLeft); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_KNOCK_OFF, opponentLeft);
+        ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_ITEM_KNOCKOFF);
+        MESSAGE("Foe Wobbuffet knocked off Wobbuffet's Leftovers!");
+        NONE_OF {
+            ANIMATION(ANIM_TYPE_GENERAL, B_ANIM_HELD_ITEM_EFFECT);
+            MESSAGE("Wobbuffet's Leftovers restored health!");
+        }
+    } THEN {
+        EXPECT(playerLeft->item == ITEM_NONE);
     }
 }