// Package rpsoracle is a rock-paper-scissors opponent that doesn't roll
// dice: it studies each player's move history and always throws the
// counter to whichever move that player has favored most. Play a fixed
// pattern and the oracle punishes it; play close to a uniform 1/3-1/3-1/3
// mix and it can't out-guess you better than chance.
package rpsoracle
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
)
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
}
// beats returns the move that defeats m.
func beats(m Move) Move {
return Move((int(m) + 1) % 3)
}
// playerState is the persisted record for one address.
type playerState struct {
Counts [3]int // history tally per move, what the oracle predicts from
Rounds int
Wins int // player beat the oracle
Losses int // oracle beat the player
Draws int
BestStreak int
streak int // current player win streak against the oracle
}
var (
players avl.Tree // address string -> *playerState
nonce int
totalRounds int
oracleCorrect int // rounds the oracle won by successfully countering
topOutwitter address
topOutwitterWins int
)
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
}
// predict guesses the player's next move as the most-played move in their
// history so far. Ties (including a fresh player's all-zero history) fall
// back to a chain-height-derived seed so the oracle doesn't always break
// ties the same way.
func predict(ps *playerState, seed int64) Move {
best := Rock
bestCount := ps.Counts[Rock]
tied := []Move{Rock}
for _, m := range []Move{Paper, Scissors} {
switch {
case ps.Counts[m] > bestCount:
bestCount = ps.Counts[m]
best = m
tied = []Move{m}
case ps.Counts[m] == bestCount:
tied = append(tied, m)
}
}
if len(tied) > 1 {
if seed < 0 {
seed = -seed
}
best = tied[int(seed)%len(tied)]
}
return best
}
// Play pits the caller against the oracle: it predicts your next move from
// your own move history and throws the counter. Accepts
// "rock"/"paper"/"scissors" or the single-letter shorthand "r"/"p"/"s".
func Play(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)
nonce++
seed := runtime.ChainHeight() + int64(nonce)
predicted := predict(ps, seed)
oracleMove := beats(predicted)
result := judge(playerMove, oracleMove)
ps.Counts[playerMove]++
ps.Rounds++
totalRounds++
var msg string
switch result {
case 1:
ps.Wins++
ps.streak++
if ps.streak > ps.BestStreak {
ps.BestStreak = ps.streak
}
if ps.Wins > topOutwitterWins {
topOutwitterWins = ps.Wins
topOutwitter = caller
}
msg = "you outwitted the oracle!"
case 2:
ps.Losses++
ps.streak = 0
oracleCorrect++
msg = "the oracle read you like a book."
default:
ps.Draws++
ps.streak = 0
msg = "a draw — you and the oracle picked the same move."
}
chain.Emit("RoundPlayed",
"player", caller.String(),
"playerMove", moveName(playerMove),
"oraclePredicted", moveName(predicted),
"oracleMove", moveName(oracleMove),
"result", strconv.Itoa(result),
)
return "you played " + moveName(playerMove) + ", the oracle predicted " +
moveName(predicted) + " and threw " + moveName(oracleMove) + " -> " + msg
}
func renderHome() string {
var b strings.Builder
b.WriteString("# Rock-Paper-Scissors Oracle\n\n")
b.WriteString("An adaptive opponent: it doesn't roll dice, it studies you. ")
b.WriteString("Every throw is logged, and the oracle always counters whichever ")
b.WriteString("move you've played most often. Play a uniform mixed strategy and ")
b.WriteString("it can't out-guess you; fall into a habit and it will.\n\n")
b.WriteString("- Total rounds played: " + strconv.Itoa(totalRounds) + "\n")
if totalRounds > 0 {
pct := oracleCorrect * 100 / totalRounds
b.WriteString("- Oracle win rate: " + strconv.Itoa(pct) + "%\n")
}
if topOutwitter.IsValid() {
b.WriteString("- Top outwitter: `" + topOutwitter.String() + "` (" +
strconv.Itoa(topOutwitterWins) + " wins against the oracle)\n")
} else {
b.WriteString("- No one has beaten the oracle yet.\n")
}
b.WriteString("\n## How to play\n\n")
b.WriteString("Call `Play(\"rock\"|\"paper\"|\"scissors\")` (or `r`/`p`/`s`). ")
b.WriteString("View your own record at this realm's path plus your address, ")
b.WriteString("e.g. `.../rpsoracle: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 rounds yet.\n"
}
ps := v.(*playerState)
var b strings.Builder
b.WriteString("# Player " + safe + "\n\n")
b.WriteString("- Rounds played: " + strconv.Itoa(ps.Rounds) + "\n")
b.WriteString("- Beat the oracle: " + strconv.Itoa(ps.Wins) + "\n")
b.WriteString("- Lost to the oracle: " + strconv.Itoa(ps.Losses) + "\n")
b.WriteString("- Draws: " + strconv.Itoa(ps.Draws) + "\n")
b.WriteString("- Best win streak vs oracle: " + strconv.Itoa(ps.BestStreak) + "\n")
b.WriteString("- Move history — rock: " + strconv.Itoa(ps.Counts[Rock]) +
", paper: " + strconv.Itoa(ps.Counts[Paper]) +
", scissors: " + strconv.Itoa(ps.Counts[Scissors]) + "\n")
if ps.Rounds > 0 {
maxCount := ps.Counts[Rock]
for _, c := range ps.Counts[1:] {
if c > maxCount {
maxCount = c
}
}
predictability := maxCount * 100 / ps.Rounds
b.WriteString("- Predictability score: " + strconv.Itoa(predictability) +
"% (lower is harder for the oracle to read)\n")
}
return b.String()
}
// Render shows the oracle's 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)
}