path: root/internal/casino/baccarat.go

package casino

import (
	"fmt"
	"math/rand"
)

// Baccarat uses the shared table phases; these aliases keep the call sites
// readable.
const (
	baccaratWaiting = phaseWaiting
	baccaratBetting = phaseBetting
)

// baccaratSpots are the outcomes a participant may wager on.
const (
	baccaratSpotPlayer = "player"
	baccaratSpotBanker = "banker"
	baccaratSpotTie    = "tie"
)

type baccaratPlayer struct {
	Participant
	lastBet  int
	lastSpot string
	// stakeID is the wallet handle of the wager record committed this
	// round; the settlement returns it inside the payout.
	stakeID string
}

func (p *baccaratPlayer) participantPtr() *Participant { return &p.Participant }

type baccaratTable struct {
	tableCore[*baccaratPlayer]
	Rules BaccaratConfig
	shoe  *shoe
}

func newBaccaratTable(roomID int, cfg TableConfig, rng *rand.Rand) *baccaratTable {
	cfg = cfg.Normalize()
	rules := cfg.Baccarat.Normalize()
	return &baccaratTable{
		tableCore: newTableCore[*baccaratPlayer](&tableBase{RoomID: roomID, Config: cfg}),
		Rules:     rules,
		shoe:      newShoe(rules.Decks, rules.ShuffleAt, rng),
	}
}

func (t *baccaratTable) menuEvent(name string) Event {
	if p := t.players.get(name); p != nil && p.HasBet {
		return t.committedMenu(name)
	}
	commands := []MenuCommand{}
	if p := t.players.get(name); p != nil && p.lastBet > 0 {
		commands = append(commands, MenuCommand{Command: "bet", Desc: fmt.Sprintf("Repeat %d on %s (also: rebet)", p.lastBet, p.lastSpot)}, MenuCommand{Command: "bet <amount>", Desc: "Change amount; keep " + p.lastSpot})
	}
	commands = append(commands, MenuCommand{Command: fmt.Sprintf("bet %d banker", t.Config.MinBet), Desc: "Choose banker (b), player (p), or tie (t)"}, MenuCommand{Command: "bet <amount> on <target>", Desc: "One wager per round; targets: table rules"}, MenuCommand{Command: "stop", Desc: "Leave; during a round, leave afterward"}, MenuCommand{Command: "table / sitout", Desc: "Check the table / skip betting until you rejoin"})
	e := t.betMenuEvent(name, commands)
	if p := t.players.get(name); p != nil {
		e.Menu.Repeat = p.lastBet > 0
	}
	return e
}

func (t *baccaratTable) join(name string) []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	if t.players.has(name) {
		return []Event{t.menuEvent(name)}
	}
	if t.players.count() >= t.Config.MaxPlayers {
		return []Event{t.private(name, "That baccarat table is full.")}
	}
	events := []Event{t.addSeatLocked(name, &baccaratPlayer{Participant: Participant{Name: name, Connected: true}})}
	events = append(events, t.private(name, t.Config.BaccaratRulesText()), t.menuEvent(name))
	return events
}

func (t *baccaratTable) leave(name string) []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	p := t.players.get(name)
	if p == nil {
		return nil
	}
	// A wager is committed for the round in flight; everyone else may stand
	// up whenever they like.
	if p.HasBet {
		return []Event{t.private(name, "You're in the middle of a baccarat round!")}
	}
	t.removeSeatLocked(name)
	events := []Event{t.playerAction(name, fmt.Sprintf("%s stands up.", name), "You stand up.")}
	return t.closeIfEmptyLocked(events)
}

func (t *baccaratTable) bet(name, spot string, amount int, wallet Wallet) []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	p := t.players.get(name)
	if p == nil {
		return []Event{t.private(name, "You aren't playing baccarat.")}
	}
	if spot == "" {
		spot = p.lastSpot
	}
	if spot == "" {
		return []Event{t.private(name, "Bet on what? Try bet <amount> on "+t.Rules.betChoices()+".")}
	}
	if !t.Rules.allowsSpot(spot) {
		return []Event{t.private(name, "Baccarat bets must be on player, banker, or tie, or an enabled optional bet. Available: "+t.Rules.betChoices()+".")}
	}
	if p.HasBet {
		return []Event{t.private(name, "You have already bet this round.")}
	}
	if amount < t.Config.MinBet || amount > t.Config.MaxBet {
		return []Event{t.private(name, fmt.Sprintf("Baccarat bets must be %s.", betRangeText(t.Config.MinBet, t.Config.MaxBet)))}
	}
	wager, err := wallet.Wager(amount)
	if err != nil {
		return []Event{t.private(name, walletErrorMessage(err))}
	}
	p.SittingOut = false
	p.HasBet, p.Wager, p.Wallet, p.lastBet, p.lastSpot, p.stakeID = true, wager, wallet, amount, spot, wager.ID
	events := []Event{t.playerAction(name,
		fmt.Sprintf("%s bets %d credits on %s.", name, amount, spot),
		fmt.Sprintf("You bet %d credits on %s.", amount, spot))}
	events = t.openBettingLocked(events)
	if allBet(t.players.participants()) {
		events = append(events, t.deal()...)
	}
	return events
}

func (t *baccaratTable) tick() []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	if t.phase != baccaratBetting {
		return nil
	}
	return t.advanceBettingLocked(t.deal, t.resetRound)
}

func (t *baccaratTable) action(name, action string) []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	if events, handled := t.controlLocked(name, action); handled {
		if t.phase == baccaratBetting && allBet(t.players.participants()) {
			return append(events, t.deal()...)
		}
		return events
	}
	return []Event{t.private(name, "That game has no player actions.")}
}

func (t *baccaratTable) rebet(name string) (string, int) {
	t.mu.Lock()
	defer t.mu.Unlock()
	if p := t.players.get(name); p != nil && p.lastBet > 0 {
		return p.lastSpot, p.lastBet
	}
	return "", t.Config.MinBet
}

// deal plays out the hand by the punto banco tableau, settles every wager,
// and resets the table for the next round.
func (t *baccaratTable) deal() []Event {
	// The cut-card reshuffle and the round-coverage guarantee both happen at
	// this boundary, before a single card of the coup is dealt (deal() is
	// synchronous, so a wager here has never had a card dealt for it):
	// draw() rebuilds an exhausted shoe in place, which mid-coup could deal
	// a card the coup already holds.
	t.shoe.shuffleIfDue()
	t.shoe.ensureForRound(baccaratRoundCards)
	player, banker := playTableau(t.shoe)
	playerTotal, bankerTotal := baccaratTotal(player), baccaratTotal(banker)
	round := t.event("New baccarat hand!", true)
	round.Snapshot = t.snapshot(player, banker)
	events := []Event{round, t.event(baccaratOutcomeMessage(playerTotal, bankerTotal), true)}
	if explanation := baccaratVariantOutcome(player, banker, t.Rules); explanation != "" {
		events = append(events, t.event(explanation, true))
	}
	for _, p := range t.players.ordered() {
		if !p.HasBet {
			continue
		}
		result, payout, settleErr := settleBaccaratHand(p.lastSpot, p.Wager.Total, player, banker, t.Rules)
		// The shared settlement path pays before announcing and leaves the
		// stake pending on any failure, so a refund can never be paid on top
		// of a payout that was not durable.
		payoutFailed := settleStakeOutcome(p.Wallet, payout, []string{p.stakeID}, settleErr)
		publicResult, _ := baccaratResultMessages(p.Name, result, payout)
		line := settlementLine{Label: p.lastSpot, Result: result, Stake: p.Wager.Total, Returned: payout}
		if result == "win" && p.lastSpot == baccaratSpotTie {
			line.Tag = "casino_jackpot_win"
		}
		privateResult := settlementText([]settlementLine{line})
		if payoutFailed {
			privateResult = payoutFailedMessage()
			publicResult = p.Name + "’s settlement is pending recovery."
		}
		settlement := t.playerAction(p.Name, publicResult, privateResult)
		// Returning players get their balance in the next bet menu; only
		// departures/sit-outs need it attached to the settlement.
		settlement.ShowBalance = !payoutFailed && (p.LeaveAfter || p.SitOutAfter || !p.Connected)
		if !payoutFailed {
			switch {
			case line.Tag != "":
				settlement.Color = line.Tag
			case result == "win":
				settlement.Color = "casino_result_win"
			case result == "push":
				settlement.Color = "casino_result_push"
			default:
				settlement.Color = "casino_result_loss"
			}
		}
		events = append(events, settlement)
		// settleStakeOutcome already consumed this stake by handle (a payout
		// removed it, a push/loss resolved it). Deliberately do NOT call the
		// player-wide ResolveStakes here: it would also consume a stake left
		// pending by an earlier failed payout, which must stay refundable.
	}
	t.resetRound()
	events = append(events, t.finishControlsLocked()...)
	for _, p := range t.players.ordered() {
		if p.Connected && !p.SittingOut {
			events = append(events, t.menuEvent(p.Name))
		}
	}
	return events
}

func (t *baccaratTable) snapshot(player, banker []card) *BaccaratSnapshot {
	snapshot := &BaccaratSnapshot{
		PlayerScore: fmt.Sprintf("%d", baccaratTotal(player)),
		BankerScore: fmt.Sprintf("%d", baccaratTotal(banker)),
	}
	for _, c := range player {
		snapshot.Player = append(snapshot.Player, CardView{Rank: c.rank, Suit: c.suit})
	}
	for _, c := range banker {
		snapshot.Banker = append(snapshot.Banker, CardView{Rank: c.rank, Suit: c.suit})
	}
	for _, p := range t.players.ordered() {
		if !p.HasBet {
			continue
		}
		snapshot.Bets = append(snapshot.Bets, BaccaratBetView{Name: p.Name, Spot: p.lastSpot, Amount: p.Wager.Total})
	}
	return snapshot
}

func (t *baccaratTable) resetRound() {
	t.phase = baccaratWaiting
	t.window.close()
	clearBets(t.players.participants())
	for _, p := range t.players.ordered() {
		p.stakeID = ""
	}
}

// markDisconnected removes the player from the table. A committed wager is
// REFUNDED rather than forfeited: deal() is synchronous, so a seated bettor
// whose wager is still outstanding has had no card dealt for it (the coup
// only starts once every connected seat has bet) and nothing is revealed by
// returning the stake. An open betting window then resolves or resets on the
// next tick now that they no longer hold it open.
func (t *baccaratTable) markDisconnected(name string) []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	if !t.players.has(name) {
		return nil
	}
	if p := t.players.get(name); p != nil && p.HasBet && p.Wallet != nil {
		if _, _, err := p.Wallet.RefundOutstanding(); err != nil {
			// The stake stays pending on disk and startup recovery will return
			// it, but tell the departing player instead of silently swallowing
			// the failure.
			t.removeSeatLocked(name)
			events := []Event{t.event(fmt.Sprintf("%s stands up.", name), true)}
			events = append(events, t.private(name, "Your stake could not be returned just now; it stays pending and will be refunded after the next server restart."))
			return t.closeIfEmptyLocked(events)
		}
	}
	t.removeSeatLocked(name)
	events := []Event{t.event(fmt.Sprintf("%s stands up.", name), true)}
	return t.closeIfEmptyLocked(events)
}

// baccaratTotal scores a hand modulo 10.
func baccaratTotal(hand []card) int {
	total := 0
	for _, c := range hand {
		total += c.baccaratValue()
	}
	return total % 10
}

// playTableau deals the initial four cards and applies the punto banco
// drawing rules, returning the final player and banker hands.
func playTableau(sh *shoe) (player, banker []card) {
	player = []card{sh.draw(), sh.draw()}
	banker = []card{sh.draw(), sh.draw()}
	playerTotal, bankerTotal := baccaratTotal(player), baccaratTotal(banker)
	if playerTotal >= 8 || bankerTotal >= 8 {
		// A natural 8 or 9 ends the hand immediately.
		return player, banker
	}
	playerThird := -1
	if playerTotal <= 5 {
		c := sh.draw()
		playerThird = c.baccaratValue()
		player = append(player, c)
	}
	if playerThird < 0 {
		if bankerTotal <= 5 {
			banker = append(banker, sh.draw())
		}
		return player, banker
	}
	if bankerDraws(bankerTotal, playerThird) {
		banker = append(banker, sh.draw())
	}
	return player, banker
}

// bankerDraws applies the banker tableau when the player took a third card.
func bankerDraws(bankerTotal, playerThird int) bool {
	switch bankerTotal {
	case 0, 1, 2:
		return true
	case 3:
		return playerThird != 8
	case 4:
		return playerThird >= 2 && playerThird <= 7
	case 5:
		return playerThird >= 4 && playerThird <= 7
	case 6:
		return playerThird == 6 || playerThird == 7
	default: // 7
		return false
	}
}

// settleBaccaratBet is the ordinary main-wager payout helper. Gameplay must
// use settleBaccaratHand first to apply variant exceptions and optional bets;
// totals alone cannot identify a three-card Banker seven.
// It returns the result label and total payout (stake plus winnings).
// Player and banker bets push on a tie. Winnings
// round down to whole credits, so the banker commission effectively rounds
// up: never bet less than one commission unit.
func settleBaccaratBet(spot string, bet int, playerTotal, bankerTotal int, rules BaccaratConfig) (string, int, error) {
	switch {
	case playerTotal > bankerTotal:
		if spot == baccaratSpotPlayer {
			return "win", bet * 2, nil
		}
	case bankerTotal > playerTotal:
		if spot == baccaratSpotBanker {
			bankerWin, err := MulPayout(bet, rules.BankerPayout)
			if err != nil {
				return "win", bet + bankerWin, err
			}
			// The banker commission rounds UP, not down: when the wager is
			// too small for a whole credit of commission, a winning banker
			// bet returns only the stake. MulPayout's positive-stake floor
			// would otherwise round the commission to zero and make the
			// banker bet +EV (it wins more often than it loses, and ties
			// push), which the "never bet less than one commission unit"
			// rule exists to prevent.
			if float64(bet)*rules.BankerPayout < 1 {
				return "push", bet, nil
			}
			return "win", bet + bankerWin, nil
		}
	default:
		if spot == baccaratSpotTie {
			tieWin, err := MulPayout(bet, rules.TiePayout)
			if err != nil {
				return "win", bet + tieWin, err
			}
			return "win", bet + tieWin, nil
		}
		return "push", bet, nil
	}
	return "loss", 0, nil
}

func baccaratOutcomeMessage(playerTotal, bankerTotal int) string {
	switch {
	case playerTotal > bankerTotal:
		return fmt.Sprintf("Player wins %d over %d.", playerTotal, bankerTotal)
	case bankerTotal > playerTotal:
		return fmt.Sprintf("Banker wins %d over %d.", bankerTotal, playerTotal)
	default:
		return fmt.Sprintf("Player and banker tie at %d.", playerTotal)
	}
}

func baccaratResultMessages(name, result string, payout int) (string, string) {
	switch result {
	case "win":
		return name + " wins!", fmt.Sprintf("You win! +%d credits", payout)
	case "push":
		return name + " pushes.", fmt.Sprintf("You push. +%d credits", payout)
	default:
		return name + " loses.", "You lose!"
	}
}

// refundAll refunds every committed wager at this table (graceful
// shutdown/eviction): the wallet returns every outstanding stake exactly
// once. It then RESETS the round, so a refunded round can never settle (and
// pay) afterwards: calling it twice, or letting the table keep running,
// cannot pay the same round twice.
func (t *baccaratTable) refundAll() []Event {
	t.mu.Lock()
	defer t.mu.Unlock()
	events := t.refundAllLocked()
	t.resetRound()
	return events
}