From f0cb6190e00b002d00f8ac921a22943de0e3d757 Mon Sep 17 00:00:00 2001
From: BuffelSaft <buffalojuice@gmail.com>
Date: Sat, 7 Aug 2021 20:56:10 +1200
Subject: [PATCH 1/4] Implement Burmy form change

Burmy changes form based on where it last battled.
---
 include/battle_util.h |  1 +
 src/battle_main.c     |  1 +
 src/battle_util.c     | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/include/battle_util.h b/include/battle_util.h
index e10305e564..521bb2693e 100644
--- a/include/battle_util.h
+++ b/include/battle_util.h
@@ -138,6 +138,7 @@ bool32 CanFling(u8 battlerId);
 bool32 IsTelekinesisBannedSpecies(u16 species);
 bool32 IsHealBlockPreventingMove(u32 battler, u32 move);
 bool32 HasEnoughHpToEatBerry(u32 battlerId, u32 hpFraction, u32 itemId);
+void DoBurmyFormChange(u32 monId);
 
 // ability checks
 bool32 IsRolePlayBannedAbilityAtk(u16 ability);
diff --git a/src/battle_main.c b/src/battle_main.c
index 94700bf969..d7fb7f6976 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -4879,6 +4879,7 @@ static void HandleEndTurn_FinishBattle(void)
         {
             UndoMegaEvolution(i);
             UndoFormChange(i, B_SIDE_PLAYER, FALSE);
+            DoBurmyFormChange(i);
         }
         gBattleMainFunc = FreeResetData_ReturnToOvOrDoEvolutions;
         gCB2_AfterEvolution = BattleMainCB2;
diff --git a/src/battle_util.c b/src/battle_util.c
index 7deebd25e3..19913781dc 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -8659,3 +8659,43 @@ bool32 IsEntrainmentTargetOrSimpleBeamBannedAbility(u16 ability)
     }
     return FALSE;
 }
+
++void DoBurmyFormChange(u32 monId)
+{
+    u16 newSpecies, currSpecies;
+    s32 sentIn;
+    struct Pokemon *party = gPlayerParty;
+
+    sentIn = gSentPokesToOpponent[(gBattlerFainted & 2) >> 1];
+    currSpecies = GetMonData(&party[monId], MON_DATA_SPECIES, NULL);
+
+    if ((gSpeciesToNationalPokedexNum[currSpecies - 1] == SPECIES_BURMY) && (gBitTable[monId] & sentIn))
+    {
+        switch (gBattleTerrain)
+        {  
+            case BATTLE_TERRAIN_GRASS:
+            case BATTLE_TERRAIN_LONG_GRASS:
+            case BATTLE_TERRAIN_POND:
+            case BATTLE_TERRAIN_MOUNTAIN:
+            case BATTLE_TERRAIN_PLAIN:
+                newSpecies = SPECIES_BURMY;
+                break;
+            case BATTLE_TERRAIN_CAVE:
+            case BATTLE_TERRAIN_SAND:
+                newSpecies = SPECIES_BURMY_SANDY_CLOAK;
+                break;
+            case BATTLE_TERRAIN_BUILDING:
+                newSpecies = SPECIES_BURMY_TRASH_CLOAK;
+                break;
+            default: // Don't change form if last battle was water-related
+                newSpecies = SPECIES_NONE;
+                break;
+        }
+
+        if (newSpecies != SPECIES_NONE)
+        {
+            SetMonData(&party[monId], MON_DATA_SPECIES, &newSpecies);
+            CalculateMonStats(&party[monId]);
+        }
+    }
+}

From 6c6363f7cf67a9f12a28a0126e3b4d84dafd6935 Mon Sep 17 00:00:00 2001
From: BuffelSaft <buffalojuice@gmail.com>
Date: Sat, 7 Aug 2021 20:59:04 +1200
Subject: [PATCH 2/4] Use form table in species check

---
 src/battle_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/battle_util.c b/src/battle_util.c
index 19913781dc..fa5cb5456a 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -8669,7 +8669,7 @@ bool32 IsEntrainmentTargetOrSimpleBeamBannedAbility(u16 ability)
     sentIn = gSentPokesToOpponent[(gBattlerFainted & 2) >> 1];
     currSpecies = GetMonData(&party[monId], MON_DATA_SPECIES, NULL);
 
-    if ((gSpeciesToNationalPokedexNum[currSpecies - 1] == SPECIES_BURMY) && (gBitTable[monId] & sentIn))
+    if ((GET_BASE_SPECIES_ID(currSpecies) == SPECIES_BURMY) && (gBitTable[monId] & sentIn))
     {
         switch (gBattleTerrain)
         {  

From e1ca2af8b3732df237f1025d8eca28c442bdd7f1 Mon Sep 17 00:00:00 2001
From: BuffelSaft <buffalojuice@gmail.com>
Date: Sun, 8 Aug 2021 00:52:27 +1200
Subject: [PATCH 3/4] Update src/battle_util.c

Fix copy/paste typo

Co-authored-by: LOuroboros <lunosouroboros@gmail.com>
---
 src/battle_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/battle_util.c b/src/battle_util.c
index fa5cb5456a..50a2a62230 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -8660,7 +8660,7 @@ bool32 IsEntrainmentTargetOrSimpleBeamBannedAbility(u16 ability)
     return FALSE;
 }
 
-+void DoBurmyFormChange(u32 monId)
+void DoBurmyFormChange(u32 monId)
 {
     u16 newSpecies, currSpecies;
     s32 sentIn;

From 30c983d9cac69431e5865ed6559c8c0541ad217f Mon Sep 17 00:00:00 2001
From: BuffelSaft <buffalojuice@gmail.com>
Date: Sun, 8 Aug 2021 13:14:51 +1200
Subject: [PATCH 4/4] Define Burmy forms in battle engine

Title. BE needs these to compile on its own.
---
 include/constants/battle_config.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/constants/battle_config.h b/include/constants/battle_config.h
index bf31c77b3b..cdeadfbf7c 100644
--- a/include/constants/battle_config.h
+++ b/include/constants/battle_config.h
@@ -37,6 +37,9 @@
     #define SPECIES_ZYGARDE                 0     // 50%
     #define SPECIES_ZYGARDE_10              10011 // 10 %
     #define SPECIES_ZYGARDE_COMPLETE        10012 // 100 %
+    #define SPECIES_BURMY                   0
+    #define SPECIES_BURMY_SANDY_CLOAK       10013
+    #define SPECIES_BURMY_TRASH_CLOAK       10014
 #endif
 
 // Items with peculiar battle effects.