Implemented a CannotUseItemsInBattle function (#3524)

* Implemented a CannotUseItemsInBattle function
This fucntion is the result of merging CannotUseBagBattleItem and CannotUsePartyBattleItem. No reason to split the work between 2 functions when you can do it all with just 1.

Misc. Changes:
-Turned most of the if statements inside the function into "else if" statements for performance reasons.
-Refactored how the local variable "cannotUse" was used turning it into a bool.

* Made CannotUseItemsInBattle use a switch statement

Misc. Changes:
-Removed pointless parentheses from case EFFECT_ITEM_SET_FOCUS_ENERGY
-Removed pointless i loop variable from case EFFECT_ITEM_INCREASE_ALL_STATS and replaced a hardcoded 1 in its for loop.
-Turned the i loop variable declared at the top of the function into a u32 variable
-Removed pointless comments. The EFFECT_ITEM constants are readable enough to convey what sort of items they affect.

---------

Co-authored-by: Alex <93446519+AlexOn1ine@users.noreply.github.com>

include/item_use.h

@@ -53,5 +53,6 @@ enum {
 };
 
 bool32 CanThrowBall(void);
+bool32 CannotUseItemsInBattle(u16 itemId, struct Pokemon *mon);
 
 #endif // GUARD_ITEM_USE_H

src/item_use.c

@@ -78,7 +78,6 @@ static void SetDistanceOfClosestHiddenItem(u8, s16, s16);
 static void CB2_OpenPokeblockFromBag(void);
 static void ItemUseOnFieldCB_Honey(u8 taskId);
 static bool32 IsValidLocationForVsSeeker(void);
-static bool32 CannotUseBagBattleItem(u16 itemId);
 
 // EWRAM variables
 EWRAM_DATA static void(*sItemUseOnFieldCB)(u8 taskId) = NULL;
@@ -1142,89 +1141,119 @@ void ItemUseInBattle_PartyMenuChooseMove(u8 taskId)
 }
 
 // Returns whether an item can be used in battle and sets the fail text.
-static bool32 CannotUseBagBattleItem(u16 itemId)
+bool32 CannotUseItemsInBattle(u16 itemId, struct Pokemon *mon)
 {
- u8 cannotUse = FALSE;
  u16 battleUsage = ItemId_GetBattleUsage(itemId);
+ bool8 cannotUse = FALSE;
  const u8* failStr = NULL;
+ u32 i;
+ u16 hp = GetMonData(mon, MON_DATA_HP);
 
  // Embargo Check
  if ((gPartyMenu.slotId == 0 && gStatuses3[B_POSITION_PLAYER_LEFT] & STATUS3_EMBARGO)
  || (gPartyMenu.slotId == 1 && gStatuses3[B_POSITION_PLAYER_RIGHT] & STATUS3_EMBARGO))
  {
  return TRUE;
  }
- // X-Items
- if (battleUsage == EFFECT_ITEM_INCREASE_STAT
- && gBattleMons[gBattlerInMenuId].statStages[gItemEffectTable[itemId][1]] == MAX_STAT_STAGE)
- {
- cannotUse++;
- }
- // Dire Hit
- if (battleUsage == EFFECT_ITEM_SET_FOCUS_ENERGY
- && (gBattleMons[gBattlerInMenuId].status2 & STATUS2_FOCUS_ENERGY))
- {
- cannotUse++;
- }
- // Guard Spec
- if (battleUsage == EFFECT_ITEM_SET_MIST
- && gSideStatuses[GetBattlerSide(gBattlerInMenuId)] & SIDE_STATUS_MIST)
- {
- cannotUse++;
- }
- // Escape Items
- if (battleUsage == EFFECT_ITEM_ESCAPE
- && gBattleTypeFlags & BATTLE_TYPE_TRAINER)
- {
- cannotUse++;
- }
- // Poke Balls
- if (battleUsage == EFFECT_ITEM_THROW_BALL)
+
+ // battleUsage checks
+ switch (battleUsage)
  {
+ case EFFECT_ITEM_INCREASE_STAT:
+ if (gBattleMons[gBattlerInMenuId].statStages[gItemEffectTable[itemId][1]] == MAX_STAT_STAGE)
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_SET_FOCUS_ENERGY:
+ if (gBattleMons[gBattlerInMenuId].status2 & STATUS2_FOCUS_ENERGY)
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_SET_MIST:
+ if (gSideStatuses[GetBattlerSide(gBattlerInMenuId)] & SIDE_STATUS_MIST)
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_ESCAPE:
+ if (gBattleTypeFlags & BATTLE_TYPE_TRAINER)
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_THROW_BALL:
  switch (GetBallThrowableState())
  {
-  case BALL_THROW_UNABLE_TWO_MONS:
-  failStr = sText_CantThrowPokeBall_TwoMons;
-  cannotUse++;
-  break;
-  case BALL_THROW_UNABLE_NO_ROOM:
-  failStr = gText_BoxFull;
-  cannotUse++;
-  break;
-  case BALL_THROW_UNABLE_SEMI_INVULNERABLE:
-  failStr = sText_CantThrowPokeBall_SemiInvulnerable;
-  cannotUse++;
-  break;
-  case BALL_THROW_UNABLE_DISABLED_FLAG:
-  failStr = sText_CantThrowPokeBall_Disabled;
-  cannotUse++;
-  break;
+ case BALL_THROW_UNABLE_TWO_MONS:
+ failStr = sText_CantThrowPokeBall_TwoMons;
+ cannotUse = TRUE;
+ break;
+ case BALL_THROW_UNABLE_NO_ROOM:
+ failStr = gText_BoxFull;
+ cannotUse = TRUE;
+ break;
+ case BALL_THROW_UNABLE_SEMI_INVULNERABLE:
+ failStr = sText_CantThrowPokeBall_SemiInvulnerable;
+ cannotUse = TRUE;
+ break;
+ case BALL_THROW_UNABLE_DISABLED_FLAG:
+ failStr = sText_CantThrowPokeBall_Disabled;
+ cannotUse = TRUE;
+ break;
  }
- }
- // Max Mushrooms
- if (battleUsage == EFFECT_ITEM_INCREASE_ALL_STATS)
- {
- u32 i;
- for (i = 1; i < NUM_STATS; i++)
+ break;
+ case EFFECT_ITEM_INCREASE_ALL_STATS:
+ for (i = STAT_ATK; i < NUM_STATS; i++)
  {
  if (CompareStat(gBattlerInMenuId, i, MAX_STAT_STAGE, CMP_EQUAL))
  {
- cannotUse++;
+ cannotUse = TRUE;
  break;
  }
  }
+ break;
+ case EFFECT_ITEM_RESTORE_HP:
+ if (hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP))
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_CURE_STATUS:
+ if (!((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
+ || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_HEAL_AND_CURE_STATUS:
+ if ((hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP))
+ && !((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
+ || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_REVIVE:
+ if (hp != 0)
+ cannotUse = TRUE;
+ break;
+ case EFFECT_ITEM_RESTORE_PP:
+ if (GetItemEffect(itemId)[6] == ITEM4_HEAL_PP)
+ {
+ for (i = 0; i < MAX_MON_MOVES; i++)
+ {
+ if (GetMonData(mon, MON_DATA_PP1 + i) < CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + i), GetMonData(mon, MON_DATA_PP_BONUSES), i));
+ break;
+ }
+ if (i == MAX_MON_MOVES)
+ cannotUse = TRUE;
+ }
+ else if (GetMonData(mon, MON_DATA_PP1 + gPartyMenu.data1) == CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + gPartyMenu.data1), GetMonData(mon, MON_DATA_PP_BONUSES), gPartyMenu.data1))
+ {
+ cannotUse = TRUE;
+ }
+ break;
  }
 
  if (failStr != NULL)
  StringExpandPlaceholders(gStringVar4, failStr);
  else
  StringExpandPlaceholders(gStringVar4, gText_WontHaveEffect);
+
  return cannotUse;
 }
 
 void ItemUseInBattle_BagMenu(u8 taskId)
 {
- if (CannotUseBagBattleItem(gSpecialVar_ItemId))
+ if (CannotUseItemsInBattle(gSpecialVar_ItemId, NULL))
  {
  if (!InBattlePyramid())
  DisplayItemMessage(taskId, FONT_NORMAL, gStringVar4, CloseItemMessage);

src/party_menu.c

@@ -504,7 +504,6 @@ static bool8 SetUpFieldMove_Dive(void);
 void TryItemHoldFormChange(struct Pokemon *mon);
 static void ShowMoveSelectWindow(u8 slot);
 static void Task_HandleWhichMoveInput(u8 taskId);
-static bool32 CannotUsePartyBattleItem(u16 itemId, struct Pokemon* mon);
 
 // static const data
 #include "data/party_menu.h"
@@ -4557,70 +4556,11 @@ static bool8 IsItemFlute(u16 item)
  return FALSE;
 }
 
-static bool32 CannotUsePartyBattleItem(u16 itemId, struct Pokemon* mon)
-{
- u8 i;
- u8 cannotUse = FALSE;
- u16 battleUsage = ItemId_GetBattleUsage(itemId);
- u16 hp = GetMonData(mon, MON_DATA_HP);
-
- // Embargo Check
- if ((gPartyMenu.slotId == 0 && gStatuses3[B_POSITION_PLAYER_LEFT] & STATUS3_EMBARGO)
- || (gPartyMenu.slotId == 1 && gStatuses3[B_POSITION_PLAYER_RIGHT] & STATUS3_EMBARGO))
- {
- return FALSE;
- }
- // Items that restore HP (Potions, Sitrus Berry, etc.)
- if (battleUsage == EFFECT_ITEM_RESTORE_HP && (hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP)))
- {
- cannotUse++;
- }
- // Items that cure status (Burn Heal, Awakening, etc.)
- if (battleUsage == EFFECT_ITEM_CURE_STATUS
- && !((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
- || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
- {
- cannotUse++;
- }
- // Items that restore HP and cure status (Full Restore)
- if (battleUsage == EFFECT_ITEM_HEAL_AND_CURE_STATUS
- && (hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP))
- && !((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
- || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
- {
- cannotUse++;
- }
- // Items that revive a party member
- if (battleUsage == EFFECT_ITEM_REVIVE && hp != 0)
- {
- cannotUse++;
- }
- // Items that restore PP (Elixir, Ether, Leppa Berry)
- if (battleUsage == EFFECT_ITEM_RESTORE_PP)
- {
- if (GetItemEffect(itemId)[6] == ITEM4_HEAL_PP)
- {
- for (i = 0; i < MAX_MON_MOVES; i++)
- {
- if (GetMonData(mon, MON_DATA_PP1 + i) < CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + i), GetMonData(mon, MON_DATA_PP_BONUSES), i));
- break;
- }
- if (i == MAX_MON_MOVES)
- cannotUse++;
- }
- else if (GetMonData(mon, MON_DATA_PP1 + gPartyMenu.data1) == CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + gPartyMenu.data1), GetMonData(mon, MON_DATA_PP_BONUSES), gPartyMenu.data1))
- {
- cannotUse++;
- }
- }
- return cannotUse;
-}
-
 // Battle scripts called in HandleAction_UseItem
 void ItemUseCB_BattleScript(u8 taskId, TaskFunc task)
 {
  struct Pokemon *mon = &gPlayerParty[gPartyMenu.slotId];
- if (CannotUsePartyBattleItem(gSpecialVar_ItemId, mon))
+ if (CannotUseItemsInBattle(gSpecialVar_ItemId, mon))
  {
  gPartyMenuUseExitCallback = FALSE;
  PlaySE(SE_SELECT);
@@ -5129,7 +5069,7 @@ static void TryUseItemOnMove(u8 taskId)
  // In battle, set appropriate variables to be used in battle script.
  if (gMain.inBattle)
  {
- if (CannotUsePartyBattleItem(gSpecialVar_ItemId, mon))
+ if (CannotUseItemsInBattle(gSpecialVar_ItemId, mon))
  {
  gPartyMenuUseExitCallback = FALSE;
  PlaySE(SE_SELECT);