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import { Router } from "express";
import rateLimit from "express-rate-limit";
import {
buildSessionToken,
getDailySong,
getUtcDate,
GuessEntry,
normalizeSignedState,
obfuscateSong,
SignedState,
signState,
verifySessionToken,
verifyStateSignature,
} from "./shared";
export const dailyRouter = Router();
const guessLimiter = rateLimit({
windowMs: 60 * 1000,
limit: 30,
standardHeaders: true,
legacyHeaders: false,
message: { error: "Too many requests. Please slow down." },
});
dailyRouter.get("/today", (_req, res) => {
const date = getUtcDate();
const song = getDailySong(date);
const initialState: SignedState = {
date,
currentTry: 0,
didGuess: false,
guesses: [],
};
res.json({
date,
data: obfuscateSong(song, date),
sessionToken: buildSessionToken(date),
initialSig: signState(initialState),
});
});
dailyRouter.post("/guess", guessLimiter, (req, res) => {
const today = getUtcDate();
const body = req.body as {
sessionToken?: unknown;
state?: unknown;
sig?: unknown;
guess?: unknown;
};
if (!verifySessionToken(body.sessionToken, today)) {
res.status(401).json({ error: "Invalid session token." });
return;
}
const state = normalizeSignedState(body.state);
if (!state) {
res.status(400).json({ error: "Invalid state payload." });
return;
}
if (state.date !== today) {
res.status(409).json({ error: "State date is not valid for today." });
return;
}
if (!verifyStateSignature(state, body.sig)) {
res.status(403).json({ error: "State signature mismatch." });
return;
}
if (state.didGuess || state.currentTry >= 6) {
res.status(409).json({ error: "Round already finished." });
return;
}
let nextGuess: GuessEntry;
const guess = body.guess as { artist?: unknown; name?: unknown } | null | undefined;
if (guess == null) {
nextGuess = {
state: "Skipped",
};
} else if (typeof guess.artist === "string" && typeof guess.name === "string") {
const solution = getDailySong(today);
if (guess.artist === solution.artist && guess.name === solution.name) {
nextGuess = {
song: { artist: guess.artist, name: guess.name },
state: "Correct",
};
} else if (guess.artist === solution.artist) {
nextGuess = {
song: { artist: guess.artist, name: guess.name },
state: "PartiallyCorrect",
};
} else {
nextGuess = {
song: { artist: guess.artist, name: guess.name },
state: "Incorrect",
};
}
} else {
res.status(400).json({ error: "Invalid guess payload." });
return;
}
const nextState: SignedState = {
date: state.date,
currentTry: Math.min(6, state.currentTry + 1),
didGuess: state.didGuess || nextGuess.state === "Correct",
guesses: [...state.guesses, nextGuess],
};
res.json({
state: nextState,
sig: signState(nextState),
guessState: nextGuess.state,
});
});
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