gno.land/r/moul/x/daily/eightball/v0⧉

1// Package eightball is a Magic 8-Ball realm: ask a yes/no question and the2// block height decides your fate. Deterministic (no real randomness on-chain).3package eightball45import (6	"chain"7	"chain/runtime"8	"chain/runtime/unsafe"9	"strconv"10	"strings"11)1213// The 20 classic Magic 8-Ball answers.14var answers = []string{15	"It is certain.", "It is decidedly so.", "Without a doubt.",16	"Yes definitely.", "You may rely on it.", "As I see it, yes.",17	"Most likely.", "Outlook good.", "Yes.", "Signs point to yes.",18	"Reply hazy, try again.", "Ask again later.", "Better not tell you now.",19	"Cannot predict now.", "Concentrate and ask again.",20	"Don't count on it.", "My reply is no.", "My sources say no.",21	"Outlook not so good.", "Very doubtful.",22}2324type shake struct {25	asker    string26	question string27	answer   string28	height   int6429}3031var history []shake3233// answerIndex maps (block height, prior shakes) to an answer slot. Pure and34// deterministic so it can be tested without touching realm state.35func answerIndex(height int64, n int) int {36	i := (height + int64(n)) % int64(len(answers))37	if i < 0 {38		i += int64(len(answers))39	}40	return int(i)41}4243// Ask poses a question to the Magic 8-Ball and returns its answer. Crossing44// function: it mutates persistent state, so it takes `cur realm` (gno 0.9).45func Ask(cur realm, question string) string {46	question = strings.TrimSpace(question)47	if question == "" {48		panic("question must not be empty")49	}50	if len(question) > 200 {51		panic("question too long (max 200 chars)")52	}53	h := runtime.ChainHeight()54	ans := answers[answerIndex(h, len(history))]55	history = append(history, shake{56		asker:    unsafe.PreviousRealm().Address().String(),57		question: question,58		answer:   ans,59		height:   h,60	})61	chain.Emit("Shaken", "answer", ans, "height", strconv.FormatInt(h, 10))62	return ans63}6465// Asked returns how many questions have been asked. Read-only.66func Asked() int { return len(history) }6768// Render is the gnoweb Markdown view.69func Render(path string) string {70	var b strings.Builder71	b.WriteString("# 🎱 Magic 8-Ball\n\n")72	b.WriteString("> ⚠️ Experimental, auto-generated with no human supervision (MCP test corpus). ")73	b.WriteString("Not audited. See [r/moul/x/daily](https://github.com/moul/gno-contracts/blob/main/r/moul/x/daily/README.md).\n\n")74	b.WriteString("Ask a yes/no question — the block height decides your fate.\n\n")75	b.WriteString("**Questions asked:** ")76	b.WriteString(strconv.Itoa(len(history)))77	b.WriteString("\n\n")7879	if len(history) == 0 {80		b.WriteString("_No questions yet. Call `Ask(\"will it rain tomorrow?\")`._\n")81		return b.String()82	}8384	last := history[len(history)-1]85	b.WriteString("Last shake: 🎱 _")86	b.WriteString(last.answer)87	b.WriteString("_\n\n| # | asker | question | answer | height |\n")88	b.WriteString("|---|---|---|---|---|\n")8990	start := len(history) - 191	end := start - 1492	if end < 0 {93		end = 094	}95	for i := start; i >= end; i-- {96		e := history[i]97		b.WriteString("| ")98		b.WriteString(strconv.Itoa(i + 1))99		b.WriteString(" | ")100		b.WriteString(shortAddr(e.asker))101		b.WriteString(" | ")102		b.WriteString(e.question)103		b.WriteString(" | ")104		b.WriteString(e.answer)105		b.WriteString(" | ")106		b.WriteString(strconv.FormatInt(e.height, 10))107		b.WriteString(" |\n")108	}109	return b.String()110}111112func shortAddr(a string) string {113	if len(a) <= 13 {114		return a115	}116	return a[:8] + "…" + a[len(a)-4:]117}118