; function to add an item (in varying quantities) to the player's bag or PC box
; INPUT:
; hl = address of inventory (either wNumBagItems or wNumBoxItems)
; [wCurItem] = item ID
; [wItemQuantity] = item quantity
; sets carry flag if successful, unsets carry flag if unsuccessful
AddItemToInventory_::
ld a, [wItemQuantity] ; a = item quantity
push af
push bc
push de
push hl
push hl
ld d, PC_ITEM_CAPACITY ; how many items the PC can hold
ld a, LOW(wNumBagItems)
cp l
jr nz, .checkIfInventoryFull
ld a, HIGH(wNumBagItems)
cp h
jr nz, .checkIfInventoryFull
; if the destination is the bag
ld d, BAG_ITEM_CAPACITY ; how many items the bag can hold
.checkIfInventoryFull
ld a, [hl]
sub d
ld d, a
ld a, [hli]
and a
jr z, .addNewItem
.notAtEndOfInventory
ld a, [hli]
ld b, a ; b = ID of current item in table
ld a, [wCurItem] ; a = ID of item being added
cp b ; does the current item in the table match the item being added?
jp z, .increaseItemQuantity ; if so, increase the item's quantity
inc hl
ld a, [hl]
cp $ff ; is it the end of the table?
jr nz, .notAtEndOfInventory
.addNewItem ; add an item not yet in the inventory
pop hl
ld a, d
and a ; is there room for a new item slot?
jr z, .done
; if there is room
inc [hl] ; increment the number of items in the inventory
ld a, [hl] ; the number of items will be the index of the new item
add a
dec a
ld c, a
ld b, 0
add hl, bc ; hl = address to store the item
ld a, [wCurItem]
ld [hli], a ; store item ID
ld a, [wItemQuantity]
ld [hli], a ; store item quantity
ld [hl], $ff ; store terminator
jp .success
.increaseItemQuantity ; increase the quantity of an item already in the inventory
ld a, [wItemQuantity]
ld b, a ; b = quantity to add
ld a, [hl] ; a = existing item quantity
add b ; a = new item quantity
cp 100
jp c, .storeNewQuantity ; if the new quantity is less than 100, store it
; if the new quantity is greater than or equal to 100,
; try to max out the current slot and add the rest in a new slot
sub 99
ld [wItemQuantity], a ; a = amount left over (to put in the new slot)
ld a, d
and a ; is there room for a new item slot?
jr z, .increaseItemQuantityFailed
; if so, store 99 in the current slot and store the rest in a new slot
ld a, 99
ld [hli], a
jp .notAtEndOfInventory
.increaseItemQuantityFailed
pop hl
and a
jr .done
.storeNewQuantity
ld [hl], a
pop hl
.success
scf
.done
pop hl
pop de
pop bc
pop bc
ld a, b
ld [wItemQuantity], a ; restore the initial value from when the function was called
ret
; function to remove an item (in varying quantities) from the player's bag or PC box
; INPUT:
; hl = address of inventory (either wNumBagItems or wNumBoxItems)
; [wWhichPokemon] = index (within the inventory) of the item to remove
; [wItemQuantity] = quantity to remove
RemoveItemFromInventory_::
push hl
inc hl
ld a, [wWhichPokemon] ; index (within the inventory) of the item being removed
sla a
add l
ld l, a
jr nc, .noCarry
inc h
.noCarry
inc hl
ld a, [wItemQuantity] ; quantity being removed
ld e, a
ld a, [hl] ; a = current quantity
sub e
ld [hld], a ; store new quantity
ld [wMaxItemQuantity], a
and a
jr nz, .skipMovingUpSlots
; if the remaining quantity is 0,
; remove the emptied item slot and move up all the following item slots
.moveSlotsUp
ld e, l
ld d, h
inc de
inc de ; de = address of the slot following the emptied one
.loop ; loop to move up the following slots
ld a, [de]
inc de
ld [hli], a
cp $ff
jr nz, .loop
; update menu info
xor a
ld [wListScrollOffset], a
ld [wCurrentMenuItem], a
ld [wBagSavedMenuItem], a
ld [wSavedListScrollOffset], a
pop hl
ld a, [hl] ; a = number of items in inventory
dec a ; decrement the number of items
ld [hl], a ; store new number of items
ld [wListCount], a
cp 2
jr c, .done
ld [wMaxMenuItem], a
jr .done
.skipMovingUpSlots
pop hl
.done
ret
