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SwitchItemsInBag:
ld a, [wSwitchItem]
and a
jr z, .init
ld b, a
ld a, [wScrollingMenuCursorPosition]
inc a
cp b
jr z, .trivial
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_GetNthItem
ld a, [hl]
cp -1
ret z
ld a, [wSwitchItem]
dec a
ld [wSwitchItem], a
call .try_combining_stacks
jp c, .combine_stacks
ld a, [wScrollingMenuCursorPosition]
ld c, a
ld a, [wSwitchItem]
cp c
jr c, .above
jr .below
.init:
ld a, [wScrollingMenuCursorPosition]
inc a
ld [wSwitchItem], a
ret
.trivial:
xor a
ld [wSwitchItem], a
ret
.below:
ld a, [wSwitchItem]
call ItemSwitch_CopyItemToBuffer
ld a, [wScrollingMenuCursorPosition]
ld d, a
ld a, [wSwitchItem]
ld e, a
call ItemSwitch_GetItemOffset
push bc
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
dec hl
push hl
call ItemSwitch_GetItemFormatSize
add hl, bc
ld d, h
ld e, l
pop hl
pop bc
call ItemSwitch_BackwardsCopyBytes
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_CopyBufferToItem
xor a
ld [wSwitchItem], a
ret
.above:
ld a, [wSwitchItem]
call ItemSwitch_CopyItemToBuffer
ld a, [wScrollingMenuCursorPosition]
ld d, a
ld a, [wSwitchItem]
ld e, a
call ItemSwitch_GetItemOffset
push bc
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
ld d, h
ld e, l
call ItemSwitch_GetItemFormatSize
add hl, bc
pop bc
call CopyBytes
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_CopyBufferToItem
xor a
ld [wSwitchItem], a
ret
.try_combining_stacks:
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
ld d, h
ld e, l
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_GetNthItem
ld a, [de]
cp [hl]
jr nz, .no_combine
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_GetItemQuantity
cp MAX_ITEM_STACK
jr z, .no_combine
ld a, [wSwitchItem]
call ItemSwitch_GetItemQuantity
cp MAX_ITEM_STACK
jr nz, .combine
.no_combine
and a
ret
.combine
scf
ret
.combine_stacks:
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
inc hl
push hl
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_GetNthItem
inc hl
ld a, [hl]
pop hl
add [hl]
cp MAX_ITEM_STACK + 1
jr c, .merge_stacks
sub MAX_ITEM_STACK
push af
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_GetNthItem
inc hl
ld [hl], MAX_ITEM_STACK
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
inc hl
pop af
ld [hl], a
xor a
ld [wSwitchItem], a
ret
.merge_stacks:
push af
ld a, [wScrollingMenuCursorPosition]
call ItemSwitch_GetNthItem
inc hl
pop af
ld [hl], a
ld hl, wMenuData_ItemsPointerAddr
ld a, [hli]
ld h, [hl]
ld l, a
ld a, [wSwitchItem]
cp [hl]
jr nz, .not_combining_last_item
dec [hl]
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
ld [hl], -1 ; end
xor a
ld [wSwitchItem], a
ret
.not_combining_last_item:
dec [hl]
call ItemSwitch_GetItemFormatSize
push bc
ld a, [wSwitchItem]
call ItemSwitch_GetNthItem
pop bc
push hl
add hl, bc
pop de
.copy_loop
ld a, [hli]
ld [de], a
inc de
cp -1 ; end?
jr nz, .copy_loop
xor a
ld [wSwitchItem], a
ret
ItemSwitch_CopyItemToBuffer:
call ItemSwitch_GetNthItem
ld de, wSwitchItemBuffer
call ItemSwitch_GetItemFormatSize
call CopyBytes
ret
ItemSwitch_CopyBufferToItem:
call ItemSwitch_GetNthItem
ld d, h
ld e, l
ld hl, wSwitchItemBuffer
call ItemSwitch_GetItemFormatSize
call CopyBytes
ret
ItemSwitch_GetNthItem:
push af
call ItemSwitch_GetItemFormatSize
ld hl, wMenuData_ItemsPointerAddr
ld a, [hli]
ld h, [hl]
ld l, a
inc hl
pop af
call AddNTimes
ret
ItemSwitch_GetItemOffset:
push hl
call ItemSwitch_GetItemFormatSize
ld a, d
sub e
jr nc, .dont_negate
dec a
cpl
.dont_negate
ld hl, 0
call AddNTimes
ld b, h
ld c, l
pop hl
ret
ItemSwitch_GetItemFormatSize:
push hl
ld a, [wMenuData_ScrollingMenuItemFormat]
ld c, a
ld b, 0
ld hl, .item_format_sizes
add hl, bc
add hl, bc
ld c, [hl]
inc hl
ld b, [hl]
pop hl
ret
.item_format_sizes:
; entries correspond to SCROLLINGMENU_ITEMS_* constants
dw 0 ; unused
dw 1 ; SCROLLINGMENU_ITEMS_NORMAL
dw 2 ; SCROLLINGMENU_ITEMS_QUANTITY
ItemSwitch_GetItemQuantity:
push af
call ItemSwitch_GetItemFormatSize
ld a, c
cp 2
jr nz, .no_quantity
pop af
call ItemSwitch_GetNthItem
inc hl
ld a, [hl]
ret
.no_quantity
pop af
ld a, 1
ret
ItemSwitch_BackwardsCopyBytes:
.loop
ld a, [hld]
ld [de], a
dec de
dec bc
ld a, b
or c
jr nz, .loop
ret
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