minecraft_launcher/src/shared/mojang.ts

import https from 'node:https'

interface MojangVersionEntry {
  id: string
  type: string
}

interface MojangVersionManifest {
  versions: MojangVersionEntry[]
}

const MANIFEST_URL = 'https://piston-meta.mojang.com/mc/game/version_manifest_v2.json'

let cachedReleases: string[] | null = null
let cachedAt = 0
const CACHE_TTL_MS = 60 * 60 * 1000

export async function fetchReleaseVersions(): Promise<string[]> {
  if (cachedReleases && Date.now() - cachedAt < CACHE_TTL_MS) {
    return cachedReleases
  }
  try {
    const data = await fetchJson<MojangVersionManifest>(MANIFEST_URL)
    const releases = data.versions.filter((entry) => entry.type === 'release').map((entry) => entry.id)
    cachedReleases = releases
    cachedAt = Date.now()
    return releases
  } catch {
    return cachedReleases ?? FALLBACK_RELEASES
  }
}

function fetchJson<T>(url: string): Promise<T> {
  return new Promise((resolve, reject) => {
    const request = https.get(url, { timeout: 8000 }, (response) => {
      if (response.statusCode !== 200) {
        response.resume()
        reject(new Error(`Mojang manifest HTTP ${response.statusCode}`))
        return
      }
      const chunks: Buffer[] = []
      response.on('data', (chunk: Buffer) => chunks.push(chunk))
      response.on('end', () => {
        try {
          resolve(JSON.parse(Buffer.concat(chunks).toString('utf8')) as T)
        } catch (error) {
          reject(error as Error)
        }
      })
    })
    request.on('error', reject)
    request.on('timeout', () => {
      request.destroy(new Error('Mojang manifest timeout'))
    })
  })
}

const FALLBACK_RELEASES = [
  '1.21', '1.20.6', '1.20.4', '1.20.2', '1.20.1', '1.19.4', '1.19.2', '1.18.2', '1.17.1', '1.16.5'
]