1 files changed, 194 insertions, 0 deletions
diff --git a/engine/battle/move_effects/baton_pass.asm b/engine/battle/move_effects/baton_pass.asm
new file mode 100644
index 00000000..bf9e3235
--- /dev/null
+++ b/engine/battle/move_effects/baton_pass.asm
@@ -0,0 +1,194 @@
+BattleCommand_BatonPass:
+; batonpass
+
+	ldh a, [hBattleTurn]
+	and a
+	jp nz, .Enemy
+
+; Need something to switch to
+	call CheckAnyOtherAlivePartyMons
+	jp z, FailedBatonPass
+
+	call UpdateBattleMonInParty
+	call AnimateCurrentMove
+
+	ld c, 50
+	call DelayFrames
+
+; Transition into switchmon menu
+	call LoadStandardMenuHeader
+	farcall SetUpBattlePartyMenu_NoLoop
+
+	farcall ForcePickSwitchMonInBattle
+
+; Return to battle scene
+	call ClearPalettes
+	farcall _LoadBattleFontsHPBar
+	call CloseWindow
+	call ClearSprites
+	hlcoord 1, 0
+	lb bc, 4, 10
+	call ClearBox
+	ld b, SCGB_BATTLE_COLORS
+	call GetSGBLayout
+	call SetPalettes
+	call BatonPass_LinkPlayerSwitch
+
+	ld hl, PassedBattleMonEntrance
+	call CallBattleCore
+
+	call ResetBatonPassStatus
+	ret
+
+.Enemy:
+; Wildmons don't have anything to switch to
+	ld a, [wBattleMode]
+	dec a ; WILDMON
+	jp z, FailedBatonPass
+
+	call CheckAnyOtherAliveEnemyMons
+	jp z, FailedBatonPass
+
+	call UpdateEnemyMonInParty
+	call AnimateCurrentMove
+	call BatonPass_LinkEnemySwitch
+
+; Passed enemy PartyMon entrance
+	xor a
+	ld [wEnemySwitchMonIndex], a
+	ld hl, EnemySwitch_SetMode
+	call CallBattleCore
+	ld hl, ResetBattleParticipants
+	call CallBattleCore
+	ld a, TRUE
+	ld [wApplyStatLevelMultipliersToEnemy], a
+	ld hl, ApplyStatLevelMultiplierOnAllStats
+	call CallBattleCore
+
+	ld hl, SpikesDamage
+	call CallBattleCore
+
+	jr ResetBatonPassStatus
+
+BatonPass_LinkPlayerSwitch:
+	ld a, [wLinkMode]
+	and a
+	ret z
+
+	ld a, BATTLEPLAYERACTION_USEITEM
+	ld [wBattlePlayerAction], a
+
+	call LoadStandardMenuHeader
+	ld hl, LinkBattleSendReceiveAction
+	call CallBattleCore
+	call CloseWindow
+
+	xor a ; BATTLEPLAYERACTION_USEMOVE
+	ld [wBattlePlayerAction], a
+	ret
+
+BatonPass_LinkEnemySwitch:
+	ld a, [wLinkMode]
+	and a
+	ret z
+
+	call LoadStandardMenuHeader
+	ld hl, LinkBattleSendReceiveAction
+	call CallBattleCore
+	jp CloseWindow
+
+FailedBatonPass:
+	call AnimateFailedMove
+	jp PrintButItFailed
+
+ResetBatonPassStatus:
+; Reset status changes that aren't passed by Baton Pass.
+
+	; Nightmare isn't passed.
+	ld a, BATTLE_VARS_STATUS
+	call GetBattleVar
+	and SLP
+	jr nz, .ok
+
+	ld a, BATTLE_VARS_SUBSTATUS1
+	call GetBattleVarAddr
+	res SUBSTATUS_NIGHTMARE, [hl]
+.ok
+
+	; Disable isn't passed.
+	call ResetActorDisable
+
+	; Attraction isn't passed.
+	ld hl, wPlayerSubStatus1
+	res SUBSTATUS_IN_LOVE, [hl]
+	ld hl, wEnemySubStatus1
+	res SUBSTATUS_IN_LOVE, [hl]
+	ld hl, wPlayerSubStatus5
+
+	ld a, BATTLE_VARS_SUBSTATUS5
+	call GetBattleVarAddr
+	res SUBSTATUS_TRANSFORMED, [hl]
+	res SUBSTATUS_ENCORED, [hl]
+
+	; New mon hasn't used a move yet.
+	ld a, BATTLE_VARS_LAST_MOVE
+	call GetBattleVarAddr
+	ld [hl], 0
+
+	xor a
+	ld [wPlayerWrapCount], a
+	ld [wEnemyWrapCount], a
+	ret
+
+CheckAnyOtherAlivePartyMons:
+	ld hl, wPartyMon1HP
+	ld a, [wPartyCount]
+	ld d, a
+	ld a, [wCurBattleMon]
+	ld e, a
+	jr CheckAnyOtherAliveMons
+
+CheckAnyOtherAliveEnemyMons:
+	ld hl, wOTPartyMon1HP
+	ld a, [wOTPartyCount]
+	ld d, a
+	ld a, [wCurOTMon]
+	ld e, a
+
+	; fallthrough
+
+CheckAnyOtherAliveMons:
+; Check for nonzero HP starting from partymon
+; HP at hl for d partymons, besides current mon e.
+
+; Return nz if any are alive.
+
+	xor a
+	ld b, a
+	ld c, a
+.loop
+	ld a, c
+	cp d
+	jr z, .done
+	cp e
+	jr z, .next
+
+	ld a, [hli]
+	or b
+	ld b, a
+	ld a, [hld]
+	or b
+	ld b, a
+
+.next
+	push bc
+	ld bc, PARTYMON_STRUCT_LENGTH
+	add hl, bc
+	pop bc
+	inc c
+	jr .loop
+
+.done
+	ld a, b
+	and a
+	ret