path: root/internal/casino/video_poker_rules.go

package casino

import (
	"strings"
	"unicode"
)

type pokerSchedule struct {
	name string
	pays map[string]int
}

// pokerCategories is the fixed pay-table row order, top payout first.
var pokerCategories = []string{"Natural royal flush", "Royal flush", "Four deuces", "Five of a kind", "Wild royal flush", "Straight flush", "Four aces with 2-4 kicker", "Four 2s-4s with A-4 kicker", "Four aces", "Four 2s-4s", "Four 5s-Ks", "Four of a kind", "Full house", "Flush", "Straight", "Three of a kind", "Two pair", "Jacks or better", "Kings or better"}

// pokerPayTable resolves the per-coin (five-coin) rates for a resolved
// game/pay-table pair. Every listed schedule is a published one; see
// dev_guide/video_poker.md for the sources.
func pokerPayTable(c VideoPokerConfig) (pokerSchedule, bool) {
	c = c.Normalize()
	if c.Variant == "" {
		return pokerSchedule{}, false
	}
	p := map[string]int{"Royal flush": 800, "Straight flush": 50, "Four of a kind": 25, "Straight": 4, "Three of a kind": 3, "Two pair": 2, "Jacks or better": 1}
	name := variantTitle(c.Variant)
	switch c.Variant {
	case "jacks_or_better":
		if !switchTwo(&p, c.PayTable, map[string][2]int{"9/6": {9, 6}, "9/5": {9, 5}, "8/6": {8, 6}, "8/5": {8, 5}, "7/5": {7, 5}}) {
			return pokerSchedule{}, false
		}
	case "bonus_poker":
		if !switchTwo(&p, c.PayTable, map[string][2]int{"8/5": {8, 5}, "7/5": {7, 5}, "6/5": {6, 5}}) {
			return pokerSchedule{}, false
		}
		p["Four aces"], p["Four 2s-4s"], p["Four 5s-Ks"] = 80, 40, 25
		delete(p, "Four of a kind")
	case "bonus_poker_deluxe":
		if !switchTwo(&p, c.PayTable, map[string][2]int{"9/6": {9, 6}, "9/5": {9, 5}, "8/6": {8, 6}, "8/5": {8, 5}, "7/5": {7, 5}}) {
			return pokerSchedule{}, false
		}
		p["Four of a kind"], p["Two pair"] = 80, 1
	case "double_bonus", "double_double_bonus":
		p["Two pair"] = 1
		delete(p, "Four of a kind")
		p["Four aces"], p["Four 2s-4s"], p["Four 5s-Ks"] = 160, 80, 50
		if c.Variant == "double_bonus" {
			p["Straight"] = 5
			switch c.PayTable {
			case "10/7":
				p["Full house"], p["Flush"] = 10, 7
			case "9/7":
				p["Full house"], p["Flush"] = 9, 7
			case "9/6/5":
				p["Full house"], p["Flush"] = 9, 6
			case "9/6/4":
				p["Full house"], p["Flush"], p["Straight"] = 9, 6, 4
			case "9/5/4":
				p["Full house"], p["Flush"], p["Straight"] = 9, 5, 4
			case "8/5":
				p["Full house"], p["Flush"], p["Straight"] = 8, 5, 4
			default:
				return pokerSchedule{}, false
			}
		} else {
			name = "Double Double Bonus"
			p["Four aces with 2-4 kicker"], p["Four 2s-4s with A-4 kicker"] = 400, 160
			switch c.PayTable {
			case "10/6":
				p["Full house"], p["Flush"] = 10, 6
			case "9/6":
				p["Full house"], p["Flush"] = 9, 6
			case "9/5":
				p["Full house"], p["Flush"] = 9, 5
			case "8/6":
				p["Full house"], p["Flush"] = 8, 6
			case "8/5":
				p["Full house"], p["Flush"] = 8, 5
			default:
				return pokerSchedule{}, false
			}
		}
	case "deuces_wild":
		name = "Deuces Wild"
		p = map[string]int{"Natural royal flush": 800, "Four deuces": 200, "Wild royal flush": 25, "Five of a kind": 15, "Straight flush": 9, "Four of a kind": 5, "Full house": 3, "Flush": 2, "Straight": 2, "Three of a kind": 1}
		switch c.PayTable {
		case "25/15/9/5/3/2":
		case "25/15/9/4/4/3":
			p["Four of a kind"], p["Full house"], p["Flush"] = 4, 4, 3
		case "25/16/13/4/3/2":
			p["Five of a kind"], p["Straight flush"], p["Four of a kind"] = 16, 13, 4
		case "20/12/10/4/4/3":
			p["Wild royal flush"], p["Five of a kind"], p["Straight flush"], p["Four of a kind"], p["Full house"], p["Flush"] = 20, 12, 10, 4, 4, 3
		default:
			return pokerSchedule{}, false
		}
	case "joker_poker":
		if c.PayTable != "50/17/7/5/3" && c.PayTable != "50/16/7/5/3" && c.PayTable != "50/15/7/5/3" {
			return pokerSchedule{}, false
		}
		name = "Joker Poker (Kings or Better)"
		p = map[string]int{"Natural royal flush": 800, "Five of a kind": 200, "Wild royal flush": 100, "Straight flush": 50, "Four of a kind": 17, "Full house": 7, "Flush": 5, "Straight": 3, "Three of a kind": 2, "Two pair": 1, "Kings or better": 1}
		if c.PayTable == "50/16/7/5/3" {
			p["Four of a kind"] = 16
		}
		if c.PayTable == "50/15/7/5/3" {
			p["Four of a kind"] = 15
		}
	default:
		return pokerSchedule{}, false
	}
	return pokerSchedule{name + " / " + c.PayTable, p}, true
}

// switchTwo applies a full-house/flush pair to the schedule map and reports
// whether the pay-table name was one of the listed editions.
func switchTwo(p *map[string]int, payTable string, editions map[string][2]int) bool {
	if edition, ok := editions[payTable]; ok {
		(*p)["Full house"], (*p)["Flush"] = edition[0], edition[1]
		return true
	}
	return false
}

func pokerRules(c VideoPokerConfig) string {
	c = c.Normalize()
	schedule, ok := pokerPayTable(c)
	if !ok {
		return "This cabinet is not configured with a playable game."
	}
	lines := []string{c.CabinetLabel() + " / " + schedule.name,
		"One fresh deck per deal. bet 1-4 loads coins (up to five per hand);",
		"bet max loads five. Bare bet repeats the previous selection. deal",
		"charges the full wager and deals; numbers toggle holds; d draws.",
		"denom 1|10|50 sets credits per coin. paytable shows this box again.",
		"Payouts are total coins per hand (stake included), not profit odds.",
		c.PairRule(),
	}
	if c.Feature != "" {
		lines = append(lines, c.FeatureRules())
	}
	lines = append(lines, "Only the highest-paying category pays on each line.")
	return strings.Join(lines, "\n")
}

// PairRule names the lowest paying hand family of the selected game.
func (c VideoPokerConfig) PairRule() string {
	c = c.Normalize()
	switch c.Variant {
	case "deuces_wild":
		return "Every 2 is wild. Three of a kind is the lowest win; only the highest category pays."
	case "joker_poker":
		return "One joker is wild. A pair of kings or aces is the lowest win; a wild royal is not a natural royal."
	case "bonus_poker", "bonus_poker_deluxe", "double_bonus", "double_double_bonus":
		return "A pair of jacks or better is the lowest win; four of a kind carries bonus rates by rank."
	}
	return "A pair of jacks or better is the lowest win."
}

// ParsePokerDigits accepts the unordered digits of a hold selection: every
// distinct digit toggles that card once per command; spacing and order do not matter.
func ParsePokerDigits(input string) ([]int, bool) {
	var digits []int
	var seen [5]bool
	for _, r := range input {
		if unicode.IsSpace(r) {
			continue
		}
		if r < '1' || r > '5' {
			return nil, false
		}
		i := int(r - '1')
		if !seen[i] {
			digits = append(digits, i)
			seen[i] = true
		}
	}
	return digits, len(digits) > 0
}

func pokerRank(c card) int {
	switch c.rank {
	case "A":
		return 14
	case "K":
		return 13
	case "Q":
		return 12
	case "J":
		return 11
	}
	return c.blackjackValue()
}

// evaluatePoker scores one five-card line against the resolved schedule. Wild
// evaluation uses rank deficits instead of enumerating wild-card assignments.
func evaluatePoker(cards [5]card, cfg VideoPokerConfig) (string, int) {
	cfg = cfg.Normalize()
	schedule, ok := pokerPayTable(cfg)
	if !ok {
		return "No win", 0
	}
	counts := [15]int{}
	wild := 0
	suit := ""
	flush := true
	for _, c := range cards {
		r := pokerRank(c)
		if cfg.Variant == "deuces_wild" && r == 2 || cfg.Variant == "joker_poker" && c.rank == "JK" {
			wild++
			continue
		}
		counts[r]++
		if suit == "" {
			suit = c.suit
		} else if suit != c.suit {
			flush = false
		}
	}
	straight, royal := false, false
	for high := 5; high <= 14; high++ {
		fits := true
		for r := 2; r <= 14; r++ {
			if counts[r] == 0 {
				continue
			}
			in := r >= high-4 && r <= high
			if high == 5 && r == 14 {
				in = true
			}
			if !in || counts[r] > 1 {
				fits = false
				break
			}
		}
		if fits {
			straight = true
			if high == 14 {
				royal = true
			}
		}
	}
	maxCount, quad, kicker, pairs := 0, 0, 0, 0
	for r := 2; r <= 14; r++ {
		if counts[r] > maxCount {
			maxCount = counts[r]
		}
		if counts[r] == 4 {
			quad = r
		}
		if counts[r] == 1 {
			kicker = r
		}
		if counts[r] == 2 {
			pairs++
		}
	}
	var candidates []string
	add := func(ok bool, k string) {
		if ok {
			candidates = append(candidates, k)
		}
	}
	if cfg.Variant == "deuces_wild" || cfg.Variant == "joker_poker" {
		add(flush && royal && wild == 0, "Natural royal flush")
		add(cfg.Variant == "deuces_wild" && wild == 4, "Four deuces")
		add(flush && royal && wild > 0, "Wild royal flush")
		add(maxCount+wild >= 5, "Five of a kind")
		add(maxCount+wild >= 4, "Four of a kind")
		if cfg.Variant == "joker_poker" {
			add(pairs == 2 || pairs == 1 && wild == 1, "Two pair")
			add(counts[13]+wild >= 2 || counts[14]+wild >= 2, "Kings or better")
		}
	} else {
		add(flush && royal, "Royal flush")
		add(quad > 0, "Four of a kind")
		add(quad == 14, "Four aces")
		add(quad >= 2 && quad <= 4, "Four 2s-4s")
		add(quad >= 5 && quad <= 13, "Four 5s-Ks")
		add(quad == 14 && kicker >= 2 && kicker <= 4, "Four aces with 2-4 kicker")
		add(quad >= 2 && quad <= 4 && (kicker == 14 || kicker >= 2 && kicker <= 4), "Four 2s-4s with A-4 kicker")
		add(pairs == 2, "Two pair")
		add(counts[11] == 2 || counts[12] == 2 || counts[13] == 2 || counts[14] == 2, "Jacks or better")
	}
	full := false
	for a := 2; a <= 14; a++ {
		for b := 2; b <= 14; b++ {
			if a == b || counts[a] > 3 || counts[b] > 2 {
				continue
			}
			if counts[a]+counts[b]+wild == 5 {
				full = true
			}
		}
	}
	add(flush && straight, "Straight flush")
	add(full, "Full house")
	add(flush, "Flush")
	add(straight, "Straight")
	add(maxCount+wild >= 3, "Three of a kind")
	best, pay := "No win", 0
	for _, k := range candidates {
		if schedule.pays[k] > pay {
			best, pay = k, schedule.pays[k]
		}
	}
	return best, pay
}