From 4ceb61b1dda908dcdb52c928d380be3036342128 Mon Sep 17 00:00:00 2001
From: AgustinGDLV <agustingomezdelavega@gmail.com>
Date: Mon, 20 Mar 2023 21:50:55 -0700
Subject: [PATCH] updated Gigantamax form changing + tests

---
 src/battle_dynamax.c |  8 +-------
 src/battle_util.c    |  7 +++++++
 test/dynamax.c       | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/src/battle_dynamax.c b/src/battle_dynamax.c
index 7d84872544..87f7c2291f 100644
--- a/src/battle_dynamax.c
+++ b/src/battle_dynamax.c
@@ -150,12 +150,7 @@ void PrepareBattlerForDynamax(u16 battlerId)
 	gBattleStruct->choicedMove[battlerId] = MOVE_NONE;
 
 	// Try Gigantamax form change.
-	newSpecies = GetBattleFormChangeTargetSpecies(battlerId, FORM_CHANGE_BATTLE_GIGANTAMAX);
-	if (newSpecies != SPECIES_NONE)
-	{
-		gBattleStruct->changedSpecies[gBitTable[gBattlerPartyIndexes[battlerId]]] = gBattleMons[battlerId].species;
-		TryBattleFormChange(battlerId, FORM_CHANGE_BATTLE_GIGANTAMAX);
-	}
+	TryBattleFormChange(battlerId, FORM_CHANGE_BATTLE_GIGANTAMAX);
 }
 
 // Sets flags needed for undoing Dynamax and undoes Gigantamax forms.
@@ -164,7 +159,6 @@ void UndoDynamax(u16 battlerId)
 	u8 side = GetBattlerSide(battlerId);
 	gBattleStruct->dynamax.dynamaxed[battlerId] = FALSE;
 	gBattleStruct->dynamax.dynamaxTurns[battlerId] = 0; // safety check for switch-in / faint
-	TryBattleFormChange(battlerId, FORM_CHANGE_BATTLE_SWITCH); // TODO: maybe nicer way to do this?
 }
 
 // Weight-based moves (and some other moves in Raids) are blocked by Dynamax.
diff --git a/src/battle_util.c b/src/battle_util.c
index 034e2b93a7..6f2f8b56fe 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -10232,6 +10232,9 @@ bool32 CanBattlerFormChange(u8 battlerId, u16 method)
         return TRUE;
     else if (IsBattlerPrimalReverted(battlerId) && (method == FORM_CHANGE_END_BATTLE))
         return TRUE;
+    // Gigantamaxed Pokemon should revert upon fainting, switching, or ending the battle.
+    else if (IsDynamaxed(battlerId) && (method == FORM_CHANGE_FAINT || method == FORM_CHANGE_BATTLE_SWITCH || method == FORM_CHANGE_END_BATTLE))
+        return TRUE;
     return DoesSpeciesHaveFormChangeMethod(gBattleMons[battlerId].species, method);
 }
 
@@ -10272,6 +10275,10 @@ bool32 TryBattleFormChange(u8 battlerId, u16 method)
         else if (IsBattlerPrimalReverted(battlerId) && (method == FORM_CHANGE_END_BATTLE))
             restoreSpecies = TRUE;
 
+        // Gigantamax Pokemon have their forms reverted after fainting, switching, or ending the battle.
+        else if (IsDynamaxed(battlerId) && (method == FORM_CHANGE_FAINT || method == FORM_CHANGE_BATTLE_SWITCH || method == FORM_CHANGE_END_BATTLE))
+            restoreSpecies = TRUE;
+
         if (restoreSpecies)
         {
             // Reverts the original species
diff --git a/test/dynamax.c b/test/dynamax.c
index 31434c50fc..114b5b51e7 100644
--- a/test/dynamax.c
+++ b/test/dynamax.c
@@ -436,6 +436,46 @@ DOUBLE_BATTLE_TEST("(DYNAMAX) Dynamaxed Pokemon are immune to Instruct")
     }
 }
 
+// TODO: Gigantamax factor
+SINGLE_BATTLE_TEST("(DYNAMAX) Pokemon with Gigantamax forms change upon Dynamaxing")
+{
+    GIVEN {
+        PLAYER(SPECIES_VENUSAUR);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_TACKLE, dynamax: TRUE); }
+    } FINALLY {
+        EXPECT_EQ(gBattleMons[B_POSITION_PLAYER_LEFT].species, SPECIES_VENUSAUR_GMAX);
+    }
+}
+
+SINGLE_BATTLE_TEST("(DYNAMAX) Pokemon with Gigantamax forms revert upon switching")
+{
+    GIVEN {
+        PLAYER(SPECIES_VENUSAUR);
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_TACKLE, dynamax: TRUE); }
+        TURN { SWITCH(player, 1); }
+        TURN { SWITCH(player, 0); }
+    } FINALLY {
+        EXPECT_EQ(gBattleMons[B_POSITION_PLAYER_LEFT].species, SPECIES_VENUSAUR);
+    }
+}
+
+SINGLE_BATTLE_TEST("(DYNAMAX) Pokemon with Gigantamax forms revert upon fainting")
+{
+    GIVEN {
+        PLAYER(SPECIES_VENUSAUR) { HP(1); };
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_TACKLE, dynamax: TRUE); MOVE(opponent, MOVE_TACKLE); }
+    } FINALLY {
+        EXPECT_EQ(gBattleMons[B_POSITION_PLAYER_LEFT].species, SPECIES_VENUSAUR);
+    }
+}
+
 // Move selection tests can't be simulated :(
 SINGLE_BATTLE_TEST("(DYNAMAX) Dynamaxed Pokemon are not affected by Choice items", s16 damage)
 {