From 53424164c0343d3dca62aa3df061610e4f3fa30f Mon Sep 17 00:00:00 2001
From: cawtds <dennis.stamm@gmx.de>
Date: Tue, 4 Jun 2024 22:04:22 +0200
Subject: [PATCH] added exp share gen6+ functionality

---
 data/maps/ViridianCity_Mart/scripts.inc |  1 +
 include/event_data.h                    |  1 +
 include/item_use.h                      |  1 +
 include/strings.h                       |  4 ++++
 src/data/items.h                        |  2 +-
 src/event_data.c                        |  8 ++++++++
 src/item_use.c                          | 27 +++++++++++++++++++++++++
 src/strings.c                           |  3 +++
 8 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/data/maps/ViridianCity_Mart/scripts.inc b/data/maps/ViridianCity_Mart/scripts.inc
index 3e9c14354..5ab1b66da 100644
--- a/data/maps/ViridianCity_Mart/scripts.inc
+++ b/data/maps/ViridianCity_Mart/scripts.inc
@@ -142,6 +142,7 @@ ViridianCity_Mart_Items::
 	.2byte ITEM_N_LUNARIZER
 	.2byte ITEM_HONEY
 	.2byte ITEM_POKEMON_BOX_LINK
+	.2byte ITEM_EXP_SHARE
 	.2byte ITEM_NONE
 	release
 	end
diff --git a/include/event_data.h b/include/event_data.h
index 2d4f0f626..fe17d6470 100644
--- a/include/event_data.h
+++ b/include/event_data.h
@@ -45,6 +45,7 @@ bool8 VarSet(u16 id, u16 value);
 u8 VarGetObjectEventGraphicsId(u8 id);
 u8 *GetFlagPointer(u16 id);
 u8 FlagSet(u16 id);
+u8 FlagToggle(u16 id);
 u8 FlagClear(u16 id);
 bool8 FlagGet(u16 id);
 u16 * GetVarPointer(u16 id);
diff --git a/include/item_use.h b/include/item_use.h
index f09e4b2f5..11aea5e54 100644
--- a/include/item_use.h
+++ b/include/item_use.h
@@ -11,6 +11,7 @@ void ItemUseOutOfBattle_DynamaxCandy(u8 taskId);
 void ItemUseOutOfBattle_EscapeRope(u8 taskId);
 void ItemUseOutOfBattle_EnigmaBerry(u8 taskId);
 void ItemUseOutOfBattle_EvolutionStone(u8 taskId);
+void ItemUseOutOfBattle_ExpShare(u8 taskId);
 void ItemUseOutOfBattle_FameChecker(u8 taskId);
 void ItemUseOutOfBattle_FormChange(u8 taskId);
 void ItemUseOutOfBattle_FormChange_ConsumedOnUse(u8 taskId);
diff --git a/include/strings.h b/include/strings.h
index f19e8de6d..875ac85b1 100644
--- a/include/strings.h
+++ b/include/strings.h
@@ -1601,4 +1601,8 @@ extern const u8 gText_PkmnTransformed[];
 extern const u8 gText_WhichAppliance[];
 extern const u8 gText_NextFusionMon[];
 
+// Exp. Share
+extern const u8 gText_ExpShareOn[];
+extern const u8 gText_ExpShareOff[];
+
 #endif //GUARD_STRINGS_H
diff --git a/src/data/items.h b/src/data/items.h
index d9d7813bc..0ddc91296 100644
--- a/src/data/items.h
+++ b/src/data/items.h
@@ -7286,7 +7286,7 @@ const struct Item gItemsInfo[] =
         #endif
         .pocket = I_EXP_SHARE_ITEM >= GEN_6 ? POCKET_KEY_ITEMS : POCKET_ITEMS,
         .type = ITEM_TYPE_FIELD,
-        .fieldUseFunc = ItemUseOutOfBattle_CannotUse,
+        .fieldUseFunc = ItemUseOutOfBattle_ExpShare,
         .flingPower = 30,
     },
 
diff --git a/src/event_data.c b/src/event_data.c
index 86f74a5ea..dfda7dfde 100644
--- a/src/event_data.c
+++ b/src/event_data.c
@@ -302,6 +302,14 @@ bool8 FlagSet(u16 idx)
     return FALSE;
 }
 
+u8 FlagToggle(u16 id)
+{
+    u8 *ptr = GetFlagAddr(id);
+    if (ptr)
+        *ptr ^= 1 << (id & 7);
+    return FALSE;
+}
+
 bool8 FlagClear(u16 idx)
 {
     u8 *ptr = GetFlagAddr(idx);
diff --git a/src/item_use.c b/src/item_use.c
index a5ca60803..9b6f26186 100644
--- a/src/item_use.c
+++ b/src/item_use.c
@@ -211,6 +211,33 @@ static void CB2_CheckMail(void)
     ReadMail(&mail, CB2_BagMenuFromStartMenu, FALSE);
 }
 
+STATIC_ASSERT(I_EXP_SHARE_ITEM < GEN_6 || I_EXP_SHARE_FLAG > TEMP_FLAGS_END, YouNeedToSetAFlagToUseGen6ExpShare);
+
+void ItemUseOutOfBattle_ExpShare(u8 taskId)
+{
+#if I_EXP_SHARE_ITEM >= GEN_6
+    if (IsGen6ExpShareEnabled())
+    {
+        PlaySE(SE_PC_OFF);
+        if (!gTasks[taskId].data[2]) // to account for pressing select in the overworld
+            DisplayItemMessageOnField(taskId, FONT_NORMAL, gText_ExpShareOff, Task_ItemUse_CloseMessageBoxAndReturnToField);
+        else
+            DisplayItemMessageInBag(taskId, FONT_NORMAL, gText_ExpShareOff, Task_ReturnToBagFromContextMenu);
+    }
+    else
+    {
+        PlaySE(SE_EXP_MAX);
+        if (!gTasks[taskId].data[2]) // to account for pressing select in the overworld
+            DisplayItemMessageOnField(taskId, FONT_NORMAL, gText_ExpShareOn, Task_ItemUse_CloseMessageBoxAndReturnToField);
+        else
+            DisplayItemMessageInBag(taskId, FONT_NORMAL, gText_ExpShareOn, Task_ReturnToBagFromContextMenu);
+    }
+    FlagToggle(I_EXP_SHARE_FLAG);
+#else
+    PrintNotTheTimeToUseThat(taskId, gTasks[taskId].tUsingRegisteredKeyItem);
+#endif
+}
+
 void ItemUseOutOfBattle_Bike(u8 taskId)
 {
     s16 x, y;
diff --git a/src/strings.c b/src/strings.c
index 880f709aa..c1f23b127 100644
--- a/src/strings.c
+++ b/src/strings.c
@@ -1373,3 +1373,6 @@ const u8 gText_ChangeAbility[] = _("Change Ability");
 const u8 gText_PkmnTransformed[] = _("{STR_VAR_1} transformed!{PAUSE_UNTIL_PRESS}");
 const u8 gText_WhichAppliance[] = _("Order which\nappliance?");
 const u8 gText_NextFusionMon[] = _("Choose {PKMN} to fuse with.");
+
+const u8 gText_ExpShareOn[] = _("The Exp. Share has been turned on.{PAUSE_UNTIL_PRESS}");
+const u8 gText_ExpShareOff[] = _("The Exp. Share has been turned off.{PAUSE_UNTIL_PRESS}");