1 files changed, 142 insertions, 0 deletions
diff --git a/src/engine/menus/deck_check.asm b/src/engine/menus/deck_check.asm
new file mode 100644
index 0000000..040e472
--- /dev/null
+++ b/src/engine/menus/deck_check.asm
@@ -0,0 +1,142 @@
+; handle player input in check menu
+; works out which cursor coordinate to go to
+; and sets carry flag if A or B are pressed
+; returns a =  $1 if A pressed
+; returns a = $ff if B pressed
+HandleCheckMenuInput:
+	xor a
+	ld [wPlaysSfx], a
+	ld a, [wCheckMenuCursorXPosition]
+	ld d, a
+	ld a, [wCheckMenuCursorYPosition]
+	ld e, a
+
+; d = cursor x position
+; e = cursor y position
+
+	ldh a, [hDPadHeld]
+	or a
+	jr z, .no_pad
+	bit D_LEFT_F, a
+	jr nz, .horizontal
+	bit D_RIGHT_F, a
+	jr z, .check_vertical
+
+; handle horizontal input
+.horizontal
+	ld a, d
+	xor $1 ; flips x coordinate
+	ld d, a
+	jr .okay
+.check_vertical
+	bit D_UP_F, a
+	jr nz, .vertical
+	bit D_DOWN_F, a
+	jr z, .no_pad
+
+; handle vertical input
+.vertical
+	ld a, e
+	xor $01 ; flips y coordinate
+	ld e, a
+
+.okay
+	ld a, TRUE
+	ld [wPlaysSfx], a
+	push de
+	call EraseCheckMenuCursor
+	pop de
+
+; update x and y cursor positions
+	ld a, d
+	ld [wCheckMenuCursorXPosition], a
+	ld a, e
+	ld [wCheckMenuCursorYPosition], a
+
+; reset cursor blink
+	xor a
+	ld [wCheckMenuCursorBlinkCounter], a
+.no_pad
+	ldh a, [hKeysPressed]
+	and A_BUTTON | B_BUTTON
+	jr z, .no_input
+	and A_BUTTON
+	jr nz, .a_press
+	ld a, $ff ; cancel
+	call PlaySFXConfirmOrCancel
+	scf
+	ret
+
+.a_press
+	call DisplayCheckMenuCursor
+	ld a, $01
+	call PlaySFXConfirmOrCancel
+	scf
+	ret
+
+.no_input
+	ld a, [wPlaysSfx]
+	or a
+	jr z, .check_blink
+	call PlaySFX
+
+.check_blink
+	ld hl, wCheckMenuCursorBlinkCounter
+	ld a, [hl]
+	inc [hl]
+	and %00001111
+	ret nz  ; only update cursor if blink's lower nibble is 0
+
+	ld a, SYM_CURSOR_R ; cursor byte
+	bit 4, [hl] ; only draw cursor if blink counter's fourth bit is not set
+	jr z, DrawCheckMenuCursor
+
+; draws in the cursor position
+EraseCheckMenuCursor:
+	ld a, SYM_SPACE ; empty cursor
+; fallthrough
+
+; draws in the cursor position
+; input:
+; a = tile byte to draw
+DrawCheckMenuCursor:
+	ld e, a
+	ld a, 10
+	ld l, a
+	ld a, [wCheckMenuCursorXPosition]
+	ld h, a
+	call HtimesL
+
+	ld a, l
+	add 1
+	ld b, a
+	ld a, [wCheckMenuCursorYPosition]
+	sla a
+	add 14
+	ld c, a
+
+	ld a, e
+	call WriteByteToBGMap0
+	or a
+	ret
+
+DisplayCheckMenuCursor:
+	ld a, SYM_CURSOR_R
+	jr DrawCheckMenuCursor
+
+; plays sound depending on value in a
+; input:
+; a  = $ff: play cancel sound
+; a != $ff: play confirm sound
+PlaySFXConfirmOrCancel:
+	push af
+	inc a
+	jr z, .asm_9103
+	ld a, SFX_02 ; confirmation sfx
+	jr .asm_9105
+.asm_9103
+	ld a, SFX_03 ; cancellation sfx
+.asm_9105
+	call PlaySFX
+	pop af
+	ret