// Package rpsmatch is a best-of-three rock-paper-scissors arena against the
// house. Unlike a single stateless throw, a match persists across calls:
// the first player to win two rounds takes the match, and every player's
// match record accumulates on-chain.
package rpsmatch
import (
"strconv"
"strings"
"chain"
"chain/runtime"
"gno.land/p/nt/avl/v0"
)
// Move is one of rock, paper, or scissors, ordered so that
// (winner - loser + 3) % 3 == 1 for every winning pair.
type Move int
const (
Rock Move = iota
Paper
Scissors
)
// winsNeeded is the number of round wins required to take a match.
const winsNeeded = 2
// match tracks an in-progress best-of-three series for one player.
type match struct {
PlayerWins int
HouseWins int
Rounds int
}
// playerState is the persisted record for one address.
type playerState struct {
Active *match
MatchWins int
MatchLosses int
MatchesPlayed int
RoundsPlayed int
}
var (
players avl.Tree // address string -> *playerState
nonce int
totalRounds int
champion address
championWins int
)
func moveName(m Move) string {
switch m {
case Rock:
return "rock"
case Paper:
return "paper"
case Scissors:
return "scissors"
default:
return "?"
}
}
func parseMove(s string) (Move, bool) {
switch strings.ToLower(strings.TrimSpace(s)) {
case "rock", "r":
return Rock, true
case "paper", "p":
return Paper, true
case "scissors", "s":
return Scissors, true
default:
return 0, false
}
}
// judge returns 0 for a tie, 1 if p beats h, 2 if h beats p.
func judge(p, h Move) int {
return (int(p) - int(h) + 3) % 3
}
// pickHouseMove derives a deterministic pseudo-random move from the current
// chain height, a monotonic per-realm nonce, and the caller's address, so
// repeated throws in the same block still diverge.
func pickHouseMove(caller address, n int) Move {
seed := runtime.ChainHeight() + int64(n)
s := caller.String()
for i := 0; i < len(s); i++ {
seed += int64(s[i])
}
if seed < 0 {
seed = -seed
}
return Move(seed % 3)
}
func getOrCreate(addr address) *playerState {
key := addr.String()
if v := players.Get(key); v != nil {
return v.(*playerState)
}
ps := &playerState{}
players.Set(key, ps)
return ps
}
// Throw plays one round of the caller's current match, starting a fresh
// match if none is in progress. Accepts "rock"/"paper"/"scissors" or the
// single-letter shorthand "r"/"p"/"s".
func Throw(cur realm, moveStr string) string {
if !cur.IsCurrent() {
panic("invalid realm")
}
caller := cur.Previous().Address()
playerMove, ok := parseMove(moveStr)
if !ok {
panic("invalid move: use rock, paper, or scissors (r/p/s)")
}
ps := getOrCreate(caller)
if ps.Active == nil {
ps.Active = &match{}
}
m := ps.Active
nonce++
houseMove := pickHouseMove(caller, nonce)
round := judge(playerMove, houseMove)
m.Rounds++
totalRounds++
ps.RoundsPlayed++
var roundMsg string
switch round {
case 1:
m.PlayerWins++
roundMsg = "you win the round"
case 2:
m.HouseWins++
roundMsg = "house wins the round"
default:
roundMsg = "round tied"
}
out := "round " + strconv.Itoa(m.Rounds) + ": you played " + moveName(playerMove) +
", house played " + moveName(houseMove) + " -> " + roundMsg +
" (score " + strconv.Itoa(m.PlayerWins) + "-" + strconv.Itoa(m.HouseWins) + ")"
if m.PlayerWins >= winsNeeded || m.HouseWins >= winsNeeded {
ps.Active = nil
ps.MatchesPlayed++
playerTookMatch := m.PlayerWins > m.HouseWins
if playerTookMatch {
ps.MatchWins++
if ps.MatchWins > championWins {
championWins = ps.MatchWins
champion = caller
}
out += ". MATCH WON!"
} else {
ps.MatchLosses++
out += ". match lost."
}
chain.Emit("MatchFinished",
"player", caller.String(),
"playerWins", strconv.Itoa(m.PlayerWins),
"houseWins", strconv.Itoa(m.HouseWins),
)
}
chain.Emit("RoundPlayed",
"player", caller.String(),
"playerMove", moveName(playerMove),
"houseMove", moveName(houseMove),
"result", strconv.Itoa(round),
)
return out
}
func renderHome() string {
var b strings.Builder
b.WriteString("# Rock-Paper-Scissors Arena\n\n")
b.WriteString("Best-of-three matches against the house. First to " +
strconv.Itoa(winsNeeded) + " round wins takes the match.\n\n")
b.WriteString("- Total rounds played: " + strconv.Itoa(totalRounds) + "\n")
if champion.IsValid() {
b.WriteString("- Reigning champion: `" + champion.String() +
"` (" + strconv.Itoa(championWins) + " match wins)\n")
} else {
b.WriteString("- No champion yet — be the first to win a match.\n")
}
b.WriteString("\n## How to play\n\n")
b.WriteString("Call `Throw(\"rock\"|\"paper\"|\"scissors\")` (or `r`/`p`/`s`). " +
"Your throw starts a new match if you don't have one in progress, " +
"and each call plays one round of it.\n\n")
b.WriteString("View your own record at this realm's path plus your address, " +
"e.g. `.../rpsmatch:g1youraddress...`\n")
return b.String()
}
// escapeInline neutralizes markdown-active characters in untrusted text
// before it's embedded inline in Render output.
func escapeInline(s string) string {
r := strings.NewReplacer(
"\\", "\\\\",
"`", "\\`",
"*", "\\*",
"_", "\\_",
"[", "\\[",
"]", "\\]",
"|", "\\|",
)
return r.Replace(s)
}
func renderPlayer(rawAddr string) string {
addr := strings.TrimSpace(rawAddr)
safe := escapeInline(addr)
v := players.Get(addr)
if v == nil {
return "# Player " + safe + "\n\nNo recorded throws yet.\n"
}
ps := v.(*playerState)
var b strings.Builder
b.WriteString("# Player " + safe + "\n\n")
b.WriteString("- Matches won: " + strconv.Itoa(ps.MatchWins) + "\n")
b.WriteString("- Matches lost: " + strconv.Itoa(ps.MatchLosses) + "\n")
b.WriteString("- Matches played: " + strconv.Itoa(ps.MatchesPlayed) + "\n")
b.WriteString("- Rounds played: " + strconv.Itoa(ps.RoundsPlayed) + "\n")
if ps.Active != nil {
b.WriteString("\n**Match in progress:** " + strconv.Itoa(ps.Active.PlayerWins) +
"-" + strconv.Itoa(ps.Active.HouseWins) + " through " +
strconv.Itoa(ps.Active.Rounds) + " round(s).\n")
}
return b.String()
}
// Render shows the arena dashboard at "", or one player's record when path
// is their bech32 address.
func Render(path string) string {
path = strings.TrimPrefix(strings.TrimSpace(path), "/")
if path == "" {
return renderHome()
}
return renderPlayer(path)
}