From 08dd7da30cfbd22919de70d2a4a39fee088e6a0c Mon Sep 17 00:00:00 2001
From: GGbond <z2621915516@163.com>
Date: Fri, 30 Jan 2026 01:33:36 +0800
Subject: [PATCH] Fix AI wakeup-turn detection to consider Early Bird (#9053)

---
 src/battle_ai_util.c                | 27 ++++++++---------
 test/battle/ability/early_bird.c    | 47 ++++++++++++++++++++++++++++-
 test/battle/ai/ai_check_viability.c | 19 ++++++++++++
 3 files changed, 77 insertions(+), 16 deletions(-)

diff --git a/src/battle_ai_util.c b/src/battle_ai_util.c
index 70683fc420..6bb814b66f 100644
--- a/src/battle_ai_util.c
+++ b/src/battle_ai_util.c
@@ -3829,24 +3829,21 @@ bool32 HasChoiceEffect(u32 battler)
     }
 }
 
-static u32 FindMoveUsedXTurnsAgo(u32 battlerId, u32 x)
-{
-    s32 i, index = gBattleHistory->moveHistoryIndex[battlerId];
-    for (i = 0; i < x; i++)
-    {
-        if (--index < 0)
-            index = AI_MOVE_HISTORY_COUNT - 1;
-    }
-    return gBattleHistory->moveHistory[battlerId][index];
-}
-
 bool32 IsWakeupTurn(u32 battler)
 {
-    // Check if rest was used 2 turns ago
-    if ((gBattleMons[battler].status1 & STATUS1_SLEEP) == 1 && GetMoveEffect(FindMoveUsedXTurnsAgo(battler, 2)) == EFFECT_REST)
-        return TRUE;
-    else // no way to know
+    u32 sleepTurns = gBattleMons[battler].status1 & STATUS1_SLEEP;
+    u32 toSub;
+
+    if (sleepTurns == 0)
         return FALSE;
+
+    // Early Bird reduces the sleep timer twice as fast.
+    if (gAiLogicData->abilities[battler] == ABILITY_EARLY_BIRD)
+        toSub = 2;
+    else
+        toSub = 1;
+
+    return sleepTurns <= toSub;
 }
 
 bool32 AnyPartyMemberStatused(u32 battlerId, bool32 checkSoundproof)
diff --git a/test/battle/ability/early_bird.c b/test/battle/ability/early_bird.c
index 9b368970f6..0f41fffc03 100644
--- a/test/battle/ability/early_bird.c
+++ b/test/battle/ability/early_bird.c
@@ -1,4 +1,49 @@
 #include "global.h"
 #include "test/battle.h"
 
-TO_DO_BATTLE_TEST("TODO: Write Early Bird (Ability) test titles")
+SINGLE_BATTLE_TEST("Early Bird wakes up if 1 sleep turn is preset")
+{
+    GIVEN {
+        PLAYER(SPECIES_DODUO) { Ability(ABILITY_EARLY_BIRD); Status1(STATUS1_SLEEP_TURN(1)); Moves(MOVE_CELEBRATE); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        MESSAGE("Doduo woke up!");
+        STATUS_ICON(player, none: TRUE);
+        MESSAGE("Doduo used Celebrate!");
+    }
+}
+
+SINGLE_BATTLE_TEST("Early Bird turns a 3-turn sleep into one missed turn")
+{
+    GIVEN {
+        PLAYER(SPECIES_DODUO) { Ability(ABILITY_EARLY_BIRD); Status1(STATUS1_SLEEP_TURN(3)); Moves(MOVE_CELEBRATE); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        MESSAGE("Doduo is fast asleep.");
+        MESSAGE("Doduo woke up!");
+        STATUS_ICON(player, none: TRUE);
+        MESSAGE("Doduo used Celebrate!");
+    }
+}
+
+SINGLE_BATTLE_TEST("Early Bird reduces Rest sleep to one turn")
+{
+    GIVEN {
+        PLAYER(SPECIES_DODUO) { Ability(ABILITY_EARLY_BIRD); MaxHP(99); HP(66); Moves(MOVE_REST, MOVE_CELEBRATE); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_REST); }
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        MESSAGE("Doduo is fast asleep.");
+        MESSAGE("Doduo woke up!");
+        STATUS_ICON(player, none: TRUE);
+        MESSAGE("Doduo used Celebrate!");
+    }
+}
diff --git a/test/battle/ai/ai_check_viability.c b/test/battle/ai/ai_check_viability.c
index 0e6170b5fa..f5bd39b27b 100644
--- a/test/battle/ai/ai_check_viability.c
+++ b/test/battle/ai/ai_check_viability.c
@@ -135,6 +135,25 @@ AI_SINGLE_BATTLE_TEST("AI will only use Dream Eater if target is asleep")
     }
 }
 
+AI_SINGLE_BATTLE_TEST("AI chooses Sleep Talk only when it will not wake up with Early Bird")
+{
+    enum Ability ability;
+
+    PARAMETRIZE { ability = ABILITY_RUN_AWAY; }
+    PARAMETRIZE { ability = ABILITY_EARLY_BIRD; }
+
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT);
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_DODRIO) { Ability(ability); Status1(STATUS1_SLEEP_TURN(2)); Moves(MOVE_SLEEP_TALK, MOVE_TACKLE); }
+    } WHEN {
+        if (ability == ABILITY_EARLY_BIRD)
+            TURN { EXPECT_MOVE(opponent, MOVE_TACKLE); }
+        else
+            TURN { EXPECT_MOVE(opponent, MOVE_SLEEP_TALK); }
+    }
+}
+
 AI_SINGLE_BATTLE_TEST("AI sees increased base power of Spit Up")
 {
     GIVEN {