From 234f3290c34b78e64b8e821487849361d617701d Mon Sep 17 00:00:00 2001
From: LOuroboros <lunosouroboros@gmail.com>
Date: Sat, 25 Sep 2021 20:16:30 -0300
Subject: [PATCH] Added a day time exclusive equivalent to `FORM_USE_ITEM`
 Primarily for Shaymin, since it can only change its form with the Gracidea
 during the day. Special thanks to AsparagusEduardo.

---
 include/constants/pokemon.h           |  1 +
 src/data/pokemon/form_change_tables.h |  6 +++++-
 src/party_menu.c                      |  4 +++-
 src/pokemon.c                         | 14 ++++++++++++--
 4 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/include/constants/pokemon.h b/include/constants/pokemon.h
index 5fc78df332..edec3a9db3 100644
--- a/include/constants/pokemon.h
+++ b/include/constants/pokemon.h
@@ -354,6 +354,7 @@
 #define FORM_ITEM_USE         2
 #define FORM_MOVE             3
 #define FORM_WITHDRAW         4
+#define FORM_ITEM_USE_DAY     5
 
 // Evolution 'modes,' for GetEvolutionTargetSpecies
 #define EVO_MODE_NORMAL     0
diff --git a/src/data/pokemon/form_change_tables.h b/src/data/pokemon/form_change_tables.h
index 737a05ee87..f58b69b547 100644
--- a/src/data/pokemon/form_change_tables.h
+++ b/src/data/pokemon/form_change_tables.h
@@ -17,6 +17,10 @@ FORM_MOVE:
 FORM_WITHDRAW:
     Form change activates when the Pokemon is withdrawn from the PC or Daycare.
     no parameters
+
+FORM_ITEM_USE_DAY:
+    Same as FORM_ITEM_USE, but only works during day time.
+    Used by Shaymin's Gracidea-based form change.
 */
 
 #define WHEN_LEARNED    FALSE
@@ -28,7 +32,7 @@ static const struct FormChange sGiratinaFormChangeTable[] = {
 };
 
 static const struct FormChange sShayminFormChangeTable[] = {
-    {FORM_ITEM_USE, SPECIES_SHAYMIN_SKY, ITEM_GRACIDEA},
+    {FORM_ITEM_USE_DAY, SPECIES_SHAYMIN_SKY, ITEM_GRACIDEA},
     {FORM_CHANGE_END},
 };
 
diff --git a/src/party_menu.c b/src/party_menu.c
index a88e07be5e..46c5283024 100755
--- a/src/party_menu.c
+++ b/src/party_menu.c
@@ -5171,7 +5171,9 @@ bool32 TryItemUseFormChange(u8 taskId, TaskFunc task)
 {
     struct Pokemon *mon = &gPlayerParty[gPartyMenu.slotId];
     u16 species = GetMonData(mon, MON_DATA_SPECIES);
-    u16 targetSpecies = GetFormChangeTargetSpecies(mon, FORM_ITEM_USE, gSpecialVar_ItemId);
+    u16 targetSpecies = GetFormChangeTargetSpecies(mon, FORM_ITEM_USE_DAY, gSpecialVar_ItemId);
+    if (targetSpecies == SPECIES_NONE)
+        targetSpecies = GetFormChangeTargetSpecies(mon, FORM_ITEM_USE, gSpecialVar_ItemId);
     if (targetSpecies != SPECIES_NONE)
     {
         gPartyMenuUseExitCallback = TRUE;
diff --git a/src/pokemon.c b/src/pokemon.c
index c5bb10d70c..bc04c42f9c 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -8056,16 +8056,20 @@ u16 GetFormChangeTargetSpecies(struct Pokemon *mon, u16 method, u32 arg)
     u16 targetSpecies = SPECIES_NONE;
     u16 originalSpecies = GetMonData(mon, MON_DATA_SPECIES, NULL);
     const struct FormChange *formChanges = gFormChangeTablePointers[originalSpecies];
+
     if (formChanges == NULL)
         return SPECIES_NONE;
 
-    for (i = 0; formChanges[i].method != FORM_CHANGE_END; i++) {
-        if (method == formChanges[i].method) {
+    for (i = 0; formChanges[i].method != FORM_CHANGE_END; i++)
+    {
+        if (method == formChanges[i].method)
+        {
             u32 ability = GetAbilityBySpecies(originalSpecies, GetMonData(mon, MON_DATA_ABILITY_NUM, NULL));
             switch (method)
             {
             case FORM_ITEM_HOLD:
                 if (GetMonData(mon, MON_DATA_HELD_ITEM, NULL) == formChanges[i].param1 && (ability == formChanges[i].param2 || formChanges[i].param2 == ABILITY_NONE))
+                    targetSpecies = formChanges[i].targetSpecies;
                 break;
             case FORM_ITEM_USE: 
                 if (arg == formChanges[i].param1 && (ability == formChanges[i].param2 || formChanges[i].param2 == ABILITY_NONE))
@@ -8075,6 +8079,12 @@ u16 GetFormChangeTargetSpecies(struct Pokemon *mon, u16 method, u32 arg)
                 if (MonKnowsMove(mon, formChanges[i].param1) != formChanges[i].param2)
                     targetSpecies = formChanges[i].targetSpecies;
                 break;
+            case FORM_ITEM_USE_DAY:
+                RtcCalcLocalTime();
+                if (arg == formChanges[i].param1 && (ability == formChanges[i].param2 || formChanges[i].param2 == ABILITY_NONE)
+                 && (gLocalTime.hours >= 12 && gLocalTime.hours < 24))
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
             default:
                 targetSpecies = formChanges[i].targetSpecies; 
                 break;