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import express from 'express';
import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'fs';
import path from 'path';
import { songs } from './data/songs';
import cors from 'cors';
import dotenv from 'dotenv';
dotenv.config();
const app = express();
app.use(cors());
app.use(express.json());
const SERVER_PORT = process.env.SERVER_PORT || 3001;
const SALT = process.env.VITE_HEARDLE_SALT ?? 'changeme';
const DAILY_SONGS_FILE = path.resolve(
process.env.DAILY_SONGS_FILE ?? 'server/data/daily-songs.json',
);
type Song = (typeof songs)[number];
type DailySongs = Record<string, Song>;
function getObfuscationKey(): Buffer {
const date = new Date().toISOString().split('T')[0];
return Buffer.from(SALT + date);
}
function xorBuffer(data: Buffer, key: Buffer): Buffer {
const output = Buffer.alloc(data.length);
for (let i = 0; i < data.length; i++) {
output[i] = data[i] ^ key[i % key.length];
}
return output;
}
function getUtcDate(): string {
return new Date().toISOString().slice(0, 10);
}
function hashString(str: string): number {
let hash = 0;
for (let i = 0; i < str.length; i++) {
hash = (hash * 31 + str.charCodeAt(i)) >>> 0;
}
return hash;
}
function readDailySongs(): DailySongs {
if (!existsSync(DAILY_SONGS_FILE)) {
return {};
}
return JSON.parse(readFileSync(DAILY_SONGS_FILE, 'utf8')) as DailySongs;
}
function writeDailySongs(dailySongs: DailySongs): void {
mkdirSync(path.dirname(DAILY_SONGS_FILE), { recursive: true });
writeFileSync(DAILY_SONGS_FILE, JSON.stringify(dailySongs, null, 2));
}
function getDailySong(date: string): Song {
const dailySongs = readDailySongs();
const savedSong = dailySongs[date];
if (savedSong) {
return savedSong;
}
const seed = hashString(date);
const index = seed % songs.length;
const song = songs[index];
dailySongs[date] = song;
writeDailySongs(dailySongs);
return song;
}
app.get('/today', (_req, res) => {
const date = getUtcDate();
const song = getDailySong(date);
const obfuscationKey = getObfuscationKey();
const songJson = JSON.stringify(song);
const obfuscatedData = xorBuffer(Buffer.from(songJson, 'utf8'), obfuscationKey);
res.json({
data: obfuscatedData.toString('hex'),
});
});
app.get('/select', (_req, res) => {
const song = songs[Math.floor(Math.random() * songs.length)];
const obfuscationKey = getObfuscationKey();
const songJson = JSON.stringify(song);
const obfuscatedData = xorBuffer(Buffer.from(songJson, 'utf8'), obfuscationKey);
res.json({
data: obfuscatedData.toString('hex'),
});
});
app.get('/songs', (_req, res) => {
res.json(songs.map(({ artist, name }) => ({ artist, name })));
});
app.listen(SERVER_PORT, () => console.log(`Server running on :${SERVER_PORT}`));
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