path: root/src/engine/ai/common.asm

; runs through Player's whole deck and
; sets carry if there's any Pokemon other
; than Mewtwo1.
CheckIfPlayerHasPokemonOtherThanMewtwo1: ; 227a9 (8:67a9)
	call SwapTurn
	ld e, 0
.loop_deck
	ld a, e
	push de
	call LoadCardDataToBuffer2_FromDeckIndex
	pop de
	ld a, [wLoadedCard2Type]
	cp TYPE_ENERGY
	jp nc, .next ; can be a jr
	ld a, [wLoadedCard2ID]
	cp MEWTWO1
	jr nz, .not_mewtwo1
.next
	inc e
	ld a, DECK_SIZE
	cp e
	jr nz, .loop_deck

; no carry
	call SwapTurn
	or a
	ret

.not_mewtwo1
	call SwapTurn
	scf
	ret

; returns no carry if, given the Player is using a Mewtwo1 mill deck,
; the AI already has a Bench fully set up, in which case it
; will process some Trainer cards in hand (namely Energy Removals).
; this is used to check whether to skip some normal AI routines
; this turn and jump right to the attacking phase.
HandleAIAntiMewtwoDeckStrategy: ; 227d3 (8:67d3)
; return carry if Player is not playing Mewtwo1 mill deck
	ld a, [wAIBarrierFlagCounter]
	bit AI_MEWTWO_MILL_F, a
	jr z, .set_carry

; else, check if there's been less than 2 turns
; without the Player using Barrier.
	cp AI_MEWTWO_MILL + 2
	jr c, .count_bench

; if there has been, reset wAIBarrierFlagCounter
; and return carry.
	xor a
	ld [wAIBarrierFlagCounter], a
	jr .set_carry

; else, check number of Pokemon that are set up in Bench
; if less than 4, return carry.
.count_bench
	farcall CountNumberOfSetUpBenchPokemon
	cp 4
	jr c, .set_carry

; if there's at least 4 Pokemon in the Bench set up,
; process Trainer hand cards of AI_TRAINER_CARD_PHASE_05
	ld a, AI_TRAINER_CARD_PHASE_05
	farcall AIProcessHandTrainerCards
	or a
	ret

.set_carry
	scf
	ret

; lists in wDuelTempList all the basic energy cards
; in card location of a.
; outputs in a number of cards found.
; returns carry if none were found.
; input:
;   a = CARD_LOCATION_* to look
; output:
;   a = number of cards found
FindBasicEnergyCardsInLocation: ; 227f6 (8:67f6)
	ld [wTempAI], a
	lb de, 0, 0
	ld hl, wDuelTempList

; d = number of basic energy cards found
; e = current card in deck
; loop entire deck
.loop
	ld a, DUELVARS_CARD_LOCATIONS
	add e
	push hl
	call GetTurnDuelistVariable
	ld hl, wTempAI
	cp [hl]
	pop hl
	jr nz, .next_card

; is in the card location we're looking for
	ld a, e
	push de
	push hl
	call GetCardIDFromDeckIndex
	pop hl
	ld a, e
	pop de
	cp DOUBLE_COLORLESS_ENERGY
	; only basic energy cards
	; will set carry here
	jr nc, .next_card

; is a basic energy card
; add this card to the TempList
	ld a, e
	ld [hli], a
	inc d
.next_card
	inc e
	ld a, DECK_SIZE
	cp e
	jr nz, .loop

; check if any were found
	ld a, d
	or a
	jr z, .set_carry

; some were found, add the termination byte on TempList
	ld a, $ff
	ld [hl], a
	ld a, d
	ret

.set_carry
	scf
	ret

; returns in a the card index of energy card
; attached to Pokémon in Play Area location a,
; that is to be discarded by the AI for an effect.
; outputs $ff is none was found.
; input:
;	a = PLAY_AREA_* constant of card
; output:
;	a = deck index of attached energy card chosen
AIPickEnergyCardToDiscard: ; 2282e (8:682e)
; load Pokémon's attached energy cards.
	ldh [hTempPlayAreaLocation_ff9d], a
	call CreateArenaOrBenchEnergyCardList
	ldh a, [hTempPlayAreaLocation_ff9d]
	ld e, a
	call GetPlayAreaCardAttachedEnergies
	ld a, [wTotalAttachedEnergies]
	or a
	jr z, .no_energy

; load card's ID and type.
	ldh a, [hTempPlayAreaLocation_ff9d]
	ld b, a
	ld a, DUELVARS_ARENA_CARD
	add b
	call GetTurnDuelistVariable
	call GetCardIDFromDeckIndex
	ld a, e
	ld [wTempCardID], a
	call LoadCardDataToBuffer1_FromCardID
	ld a, [wLoadedCard1Type]
	or TYPE_ENERGY
	ld [wTempCardType], a

; find a card that is not useful.
; if none is found, just return the first energy card attached.
	ld hl, wDuelTempList
.loop
	ld a, [hl]
	cp $ff
	jr z, .not_found
	farcall CheckIfEnergyIsUseful
	jr nc, .found
	inc hl
	jr .loop

.found
	ld a, [hl]
	ret
.not_found
	ld hl, wDuelTempList
	ld a, [hl]
	ret
.no_energy
	ld a, $ff
	ret

; returns in a the deck index of an energy card attached to card
; in player's Play Area location a to remove.
; prioritizes double colorless energy, then any useful energy,
; then defaults to the first energy card attached if neither
; of those are found.
; returns $ff in a if there are no energy cards attached.
; input:
;   a = Play Area location to check
; output:
;   a = deck index of attached energy card
PickAttachedEnergyCardToRemove: ; 22875 (8:6875)
; construct energy list and check if there are any energy cards attached
	ldh [hTempPlayAreaLocation_ff9d], a
	call CreateArenaOrBenchEnergyCardList
	ldh a, [hTempPlayAreaLocation_ff9d]
	ld e, a
	call GetPlayAreaCardAttachedEnergies
	ld a, [wTotalAttachedEnergies]
	or a
	jr z, .no_energy

; load card data and store its type
	ldh a, [hTempPlayAreaLocation_ff9d]
	ld b, a
	ld a, DUELVARS_ARENA_CARD
	add b
	call GetTurnDuelistVariable
	call GetCardIDFromDeckIndex
	ld a, e
	ld [wTempCardID], a
	call LoadCardDataToBuffer1_FromCardID
	ld a, [wLoadedCard1Type]
	or TYPE_ENERGY
	ld [wTempCardType], a

; first look for any double colorless energy
	ld hl, wDuelTempList
.loop_1
	ld a, [hl]
	cp $ff
	jr z, .check_useful
	push hl
	call GetCardIDFromDeckIndex
	ld a, e
	cp DOUBLE_COLORLESS_ENERGY
	pop hl
	jr z, .found
	inc hl
	jr .loop_1

; then look for any energy cards that are useful
.check_useful
	ld hl, wDuelTempList
.loop_2
	ld a, [hl]
	cp $ff
	jr z, .default
	farcall CheckIfEnergyIsUseful
	jr c, .found
	inc hl
	jr .loop_2

; return the energy card that was found
.found
	ld a, [hl]
	ret

; if none were found with the above criteria,
; just return the first option
.default
	ld hl, wDuelTempList
	ld a, [hl]
	ret

; return $ff if no energy cards attached
.no_energy
	ld a, $ff
	ret

; stores in wTempAI and wCurCardCanAttack the deck indices
; of energy cards attached to card in Play Area location a.
; prioritizes double colorless energy, then any useful energy,
; then defaults to the first two energy cards attached if neither
; of those are found.
; returns $ff in a if there are no energy cards attached.
; input:
;   a = Play Area location to check
; output:
;   [wTempAI] = deck index of attached energy card
;   [wCurCardCanAttack] = deck index of attached energy card
PickTwoAttachedEnergyCards: ; 228d1 (8:68d1)
	ldh [hTempPlayAreaLocation_ff9d], a
	call CreateArenaOrBenchEnergyCardList
	ldh a, [hTempPlayAreaLocation_ff9d]
	ld e, a
	farcall CountNumberOfEnergyCardsAttached
	cp 2
	jp c, .not_enough

; load card data and store its type
	ldh a, [hTempPlayAreaLocation_ff9d]
	ld b, a
	ld a, DUELVARS_ARENA_CARD
	add b
	call GetTurnDuelistVariable
	call GetCardIDFromDeckIndex
	ld a, e
	ld [wTempCardID], a
	call LoadCardDataToBuffer1_FromCardID
	ld a, [wLoadedCard1Type]
	or TYPE_ENERGY
	ld [wTempCardType], a
	ld a, $ff
	ld [wTempAI], a
	ld [wCurCardCanAttack], a

; first look for any double colorless energy
	ld hl, wDuelTempList
.loop_1
	ld a, [hl]
	cp $ff
	jr z, .check_useful
	push hl
	call GetCardIDFromDeckIndex
	ld a, e
	cp DOUBLE_COLORLESS_ENERGY
	pop hl
	jr z, .found_double_colorless
	inc hl
	jr .loop_1
.found_double_colorless
	ld a, [wTempAI]
	cp $ff
	jr nz, .already_chosen_1
	ld a, [hli]
	ld [wTempAI], a
	jr .loop_1
.already_chosen_1
	ld a, [hl]
	ld [wCurCardCanAttack], a
	jr .done

; then look for any energy cards that are useful
.check_useful
	ld hl, wDuelTempList
.loop_2
	ld a, [hl]
	cp $ff
	jr z, .default
	farcall CheckIfEnergyIsUseful
	jr c, .found_useful
	inc hl
	jr .loop_2
.found_useful
	ld a, [wTempAI]
	cp $ff
	jr nz, .already_chosen_2
	ld a, [hli]
	ld [wTempAI], a
	jr .loop_2
.already_chosen_2
	ld a, [hl]
	ld [wCurCardCanAttack], a
	jr .done

; if none were found with the above criteria,
; just return the first 2 options
.default
	ld hl, wDuelTempList
	ld a, [wTempAI]
	cp $ff
	jr nz, .pick_one_card

; pick 2 cards
	ld a, [hli]
	ld [wTempAI], a
	ld a, [hl]
	ld [wCurCardCanAttack], a
	jr .done
.pick_one_card
	ld a, [wTempAI]
	ld b, a
.loop_3
	ld a, [hli]
	cp b
	jr z, .loop_3 ; already picked
	ld [wCurCardCanAttack], a

.done
	ld a, [wCurCardCanAttack]
	ld b, a
	ld a, [wTempAI]
	ret

; return $ff if no energy cards attached
.not_enough
	ld a, $ff
	ret

; copies $ff terminated buffer from hl to de
CopyBuffer: ; 2297b (8:697b)
	ld a, [hli]
	ld [de], a
	cp $ff
	ret z
	inc de
	jr CopyBuffer

; zeroes a bytes starting at hl
ClearMemory_Bank8: ; 22983 (8:6983)
	push af
	push bc
	push hl
	ld b, a
	xor a
.loop
	ld [hli], a
	dec b
	jr nz, .loop
	pop hl
	pop bc
	pop af
	ret

; counts number of energy cards found in hand
; and outputs result in a
; sets carry if none are found
; output:
;	a = number of energy cards found
CountOppEnergyCardsInHand: ; 22990 (8:6990)
	farcall CreateEnergyCardListFromHand
	ret c
	ld b, -1
	ld hl, wDuelTempList
.loop
	inc b
	ld a, [hli]
	cp $ff
	jr nz, .loop
	ld a, b
	or a
	ret

; converts HP in a to number of equivalent damage counters
; input:
;	a = HP
; output:
;	a = number of damage counters
ConvertHPToCounters: ; 229a3 (8:69a3)
	push bc
	ld c, 0
.loop
	sub 10
	jr c, .carry
	inc c
	jr .loop
.carry
	ld a, c
	pop bc
	ret

; calculates floor(hl / 10)
CalculateWordTensDigit: ; 229b0 (8:69b0)
	push bc
	push de
	lb bc, $ff, -10
	lb de, $ff, -1
.asm_229b8
	inc de
	add hl, bc
	jr c, .asm_229b8
	ld h, d
	ld l, e
	pop de
	pop bc
	ret

; returns in a division of b by a
CalculateBDividedByA_Bank8: ; 229c1 (8:69c1)
	push bc
	ld c, a
	ld a, b
	ld b, c
	ld c, 0
.loop
	sub b
	jr c, .done
	inc c
	jr .loop
.done
	ld a, c
	pop bc
	ret

; returns in a the deck index of the first
; instance of card with ID equal to the ID in e
; in card location a.
; returns carry if found.
; input:
;   a = CARD_LOCATION_*
;   e = card ID to look for
LookForCardIDInLocation: ; 229d0 (8:69d0)
	ld b, a
	ld c, e
	lb de, $00, 0 ; d is never used
.loop
	ld a, DUELVARS_CARD_LOCATIONS
	add e
	call GetTurnDuelistVariable
	cp b
	jr nz, .next
	ld a, e
	push de
	call GetCardIDFromDeckIndex
	ld a, e
	pop de
	cp c
	jr z, .found
.next
	inc e
	ld a, DECK_SIZE
	cp e
	jr nz, .loop

; not found
	or a
	ret
.found
	ld a, e
	scf
	ret

; return carry if card ID loaded in a is found in hand
; and outputs in a the deck index of that card
; input:
;	a = card ID
; output:
;	a = card deck index, if found
;	carry set if found
LookForCardIDInHandList_Bank8: ; 229f3 (8:69f3)
	ld [wTempCardIDToLook], a
	call CreateHandCardList
	ld hl, wDuelTempList

.loop
	ld a, [hli]
	cp $ff
	ret z

	ldh [hTempCardIndex_ff98], a
	call LoadCardDataToBuffer1_FromDeckIndex
	ld b, a
	ld a, [wTempCardIDToLook]
	cp b
	jr nz, .loop

	ldh a, [hTempCardIndex_ff98]
	scf
	ret

; searches in deck for card ID 1 in a, and
; if found, searches in Hand/Play Area for card ID 2 in b, and
; if found, searches for card ID 1 in Hand/Play Area, and
; if none found, return carry and output deck index
; of the card ID 1 in deck.
; input:
;   a = card ID 1
;   b = card ID 2
; output:
;   a = index of card ID 1 in deck
LookForCardIDInDeck_GivenCardIDInHandAndPlayArea: ; 22a10 (8:6a10)
; store a in wCurCardCanAttack
; and b in wTempAI
	ld c, a
	ld a, b
	ld [wTempAI], a
	ld a, c
	ld [wCurCardCanAttack], a

; look for the card ID 1 in deck
	ld e, a
	ld a, CARD_LOCATION_DECK
	call LookForCardIDInLocation
	ret nc

; was found, store its deck index in memory
	ld [wTempAIPokemonCard], a

; look for the card ID 2
; in Hand and Play Area, return if not found.
	ld a, [wTempAI]
	call LookForCardIDInHandAndPlayArea
	ret nc

; look for the card ID 1 in the Hand and Play Area
; if any card is found, return no carry.
	ld a, [wCurCardCanAttack]
	call LookForCardIDInHandAndPlayArea
	jr c, .no_carry
; none found

	ld a, [wTempAIPokemonCard]
	scf
	ret

.no_carry
	or a
	ret

; returns carry if card ID in a
; is found in Play Area or in hand
; input:
;	a = card ID
LookForCardIDInHandAndPlayArea: ; 22a39 (8:6a39)
	ld b, a
	push bc
	call LookForCardIDInHandList_Bank8
	pop bc
	ret c

	ld a, b
	ld b, PLAY_AREA_ARENA
	call LookForCardIDInPlayArea_Bank8
	ret c
	or a
	ret

; searches in deck for card ID 1 in a, and
; if found, searches in Hand Area for card ID 2 in b, and
; if found, searches for card ID 1 in Hand/Play Area, and
; if none found, return carry and output deck index
; of the card ID 1 in deck.
; input:
;   a = card ID 1
;   b = card ID 2
; output:
;   a = index of card ID 1 in deck
LookForCardIDInDeck_GivenCardIDInHand: ; 22a49 (8:6a49)
; store a in wCurCardCanAttack
; and b in wTempAI
	ld c, a
	ld a, b
	ld [wTempAI], a
	ld a, c
	ld [wCurCardCanAttack], a

; look for the card ID 1 in deck
	ld e, a
	ld a, CARD_LOCATION_DECK
	call LookForCardIDInLocation
	ret nc

; was found, store its deck index in memory
	ld [wTempAIPokemonCard], a

; look for the card ID 2 in hand, return if not found.
	ld a, [wTempAI]
	call LookForCardIDInHandList_Bank8
	ret nc

; look for the card ID 1 in the Hand and Play Area
; if any card is found, return no carry.
	ld a, [wCurCardCanAttack]
	call LookForCardIDInHandAndPlayArea
	jr c, .no_carry
; none found

	ld a, [wTempAIPokemonCard]
	scf
	ret

.no_carry
	or a
	ret

; returns carry if card ID in a
; is found in Play Area, starting with
; location in b
; input:
;	a = card ID
;	b = PLAY_AREA_* to start with
; output:
;	a = PLAY_AREA_* of found card
;	carry set if found
LookForCardIDInPlayArea_Bank8: ; 22a72 (8:6a72)
	ld [wTempCardIDToLook], a
.loop
	ld a, DUELVARS_ARENA_CARD
	add b
	call GetTurnDuelistVariable
	cp $ff
	ret z

	call LoadCardDataToBuffer1_FromDeckIndex
	ld c, a
	ld a, [wTempCardIDToLook]
	cp c
	jr z, .is_same

	inc b
	ld a, MAX_PLAY_AREA_POKEMON
	cp b
	jr nz, .loop
	ld b, $ff
	or a
	ret

.is_same
	ld a, b
	scf
	ret

; runs through list avoiding card in e.
; removes first card in list not equal to e
; and that has a type allowed to be removed, in d.
; returns carry if successful in finding a card.
; input:
;   d = type of card allowed to be removed
;       ($00 = Trainer, $01 = Pokemon, $02 = Energy)
;   e = card deck index to avoid removing
; output:
;   a = card index of removed card
RemoveFromListDifferentCardOfGivenType: ; 22a95 (8:6a95)
	push hl
	push de
	push bc
	call CountCardsInDuelTempList
	call ShuffleCards

; loop list until a card with
; deck index different from e is found.
.loop_list
	ld a, [hli]
	cp $ff
	jr z, .no_carry
	cp e
	jr z, .loop_list

; get this card's type
	ldh [hTempCardIndex_ff98], a
	push de
	call GetCardIDFromDeckIndex
	call GetCardType
	pop de
	cp TYPE_ENERGY
	jr c, .pkmn_card
	cp TYPE_TRAINER
	jr nz, .energy

; only remove from list specific type.

; trainer
	ld a, d
	or a
	jr nz, .loop_list
	jr .remove_card
.energy
	ld a, d
	cp $02
	jr nz, .loop_list
	jr .remove_card
.pkmn_card
	ld a, d
	cp $01
	jr nz, .loop_list
	; fallthrough

.remove_card
	ld d, h
	ld e, l
	dec hl
.loop_remove
	ld a, [de]
	inc de
	ld [hli], a
	cp $ff
	jr nz, .loop_remove

; success
	ldh a, [hTempCardIndex_ff98]
	pop bc
	pop de
	pop hl
	scf
	ret
.no_carry
	pop bc
	pop de
	pop hl
	or a
	ret

; used in Pokemon Trader checks to look for a specific
; card in the deck to trade with a card in hand that
; has a card ID different from e.
; returns carry if successful.
; input:
;   a = card ID 1
;   e = card ID 2
; output:
;   a = deck index of card ID 1 found in deck
;   e = deck index of Pokemon card in hand different than card ID 2
LookForCardIDToTradeWithDifferentHandCard: ; 22ae0 (8:6ae0)
	ld hl, wCurCardCanAttack
	ld [hl], e
	ld [wTempAI], a

; if card ID 1 is in hand, return no carry.
	call LookForCardIDInHandList_Bank8
	jr c, .no_carry

; if card ID 1 is not in deck, return no carry.
	ld a, [wTempAI]
	ld e, a
	ld a, CARD_LOCATION_DECK
	call LookForCardIDInLocation
	jr nc, .no_carry

; store its deck index
	ld [wTempAI], a

; look in hand for Pokemon card ID that
; is different from card ID 2.
	ld a, [wCurCardCanAttack]
	ld c, a
	call CreateHandCardList
	ld hl, wDuelTempList

.loop_hand
	ld a, [hli]
	cp $ff
	jr z, .no_carry
	ld b, a
	call LoadCardDataToBuffer1_FromDeckIndex
	cp c
	jr z, .loop_hand
	ld a, [wLoadedCard1Type]
	cp TYPE_ENERGY
	jr nc, .loop_hand

; found, output deck index of card ID 1 in deck
; and deck index of card found in hand, and set carry
	ld e, b
	ld a, [wTempAI]
	scf
	ret

.no_carry
	or a
	ret

; returns carry if at least one card in the hand
; has the card ID of input. Outputs its index.
; input:
;   a = card ID to look for
; output:
;   a = deck index of card in hand found
CheckIfHasCardIDInHand: ; 22b1f (8:6b1f)
	ld [wTempCardIDToLook], a
	call CreateHandCardList
	ld hl, wDuelTempList
	ld c, 0

.loop_hand
	ld a, [hli]
	cp $ff
	ret z
	ldh [hTempCardIndex_ff98], a
	call LoadCardDataToBuffer1_FromDeckIndex
	ld b, a
	ld a, [wTempCardIDToLook]
	cp b
	jr nz, .loop_hand
	ld a, c
	or a
	jr nz, .set_carry
	inc c
	jr nz, .loop_hand

.set_carry
	ldh a, [hTempCardIndex_ff98]
	scf
	ret

; outputs in a total number of Pokemon cards in hand
; plus Pokemon in Turn Duelist's Play Area.
CountPokemonCardsInHandAndInPlayArea: ; 22b45 (8:6b45)
	ld a, DUELVARS_NUMBER_OF_POKEMON_IN_PLAY_AREA
	call GetTurnDuelistVariable
	ld [wTempAI], a
	call CreateHandCardList
	ld hl, wDuelTempList
.loop_hand
	ld a, [hli]
	cp $ff
	jr z, .done
	call GetCardIDFromDeckIndex
	call GetCardType
	cp TYPE_ENERGY
	jr nc, .loop_hand
	ld a, [wTempAI]
	inc a
	ld [wTempAI], a
	jr .loop_hand
.done
	ld a, [wTempAI]
	ret

; returns carry if a duplicate Pokemon card is found in hand.
; outputs in a the deck index of one of them.
FindDuplicatePokemonCards: ; 22b6f (8:6b6f)
	ld a, $ff
	ld [wTempAI], a
	call CreateHandCardList
	ld hl, wDuelTempList
	push hl

.loop_hand_outer
	pop hl
	ld a, [hli]
	cp $ff
	jr z, .done
	call GetCardIDFromDeckIndex
	ld b, e
	push hl

.loop_hand_inner
	ld a, [hli]
	cp $ff
	jr z, .loop_hand_outer
	ld c, a
	call GetCardIDFromDeckIndex
	ld a, e
	cp b
	jr nz, .loop_hand_inner

; found two cards with same ID,
; if they are Pokemon cards, store its deck index.
	push bc
	call GetCardType
	pop bc
	cp TYPE_ENERGY
	jr nc, .loop_hand_outer
	ld a, c
	ld [wTempAI], a
	; for some reason loop still continues
	; even though if some other duplicate
	; cards are found, it overwrites the result.
	jr .loop_hand_outer

.done
	ld a, [wTempAI]
	cp $ff
	jr z, .no_carry

; found
	scf
	ret
.no_carry
	or a
	ret

; return carry flag if attack is not high recoil.
AICheckIfAttackIsHighRecoil: ; 22bad (8:6bad)
	farcall AIProcessButDontUseAttack
	ret nc
	ld a, [wSelectedAttack]
	ld e, a
	ld a, DUELVARS_ARENA_CARD
	call GetTurnDuelistVariable
	ld d, a
	call CopyAttackDataAndDamage_FromDeckIndex
	ld a, ATTACK_FLAG1_ADDRESS | HIGH_RECOIL_F
	call CheckLoadedAttackFlag
	ccf
	ret