import type { ChallengeResponse, PowProofRequest } from '@/shared/api'
import { t } from '@/shared/i18n'
import { AuthError } from './error'

export function solve(challenge: ChallengeResponse, payload: string, signal: AbortSignal): Promise<PowProofRequest> {
  signal.throwIfAborted()
  return new Promise((resolve, reject) => {
    const worker = new Worker(new URL('./pow.worker.ts', import.meta.url), { type: 'module' })
    const finish = () => {
      worker.terminate()
      signal.removeEventListener('abort', cancel)
    }
    const cancel = () => {
      finish()
      reject(signal.reason)
    }
    signal.addEventListener('abort', cancel, { once: true })
    worker.onmessage = (event: MessageEvent<{ nonce?: number; error?: string }>) => {
      finish()
      if (event.data.error || event.data.nonce === undefined)
        reject(new AuthError('expired', event.data.error || t('error.expired')))
      else resolve({ nonce: event.data.nonce, payload: Array.from(new TextEncoder().encode(payload)) })
    }
    worker.onerror = () => {
      finish()
      reject(new AuthError('proof', t('pow.unavailable')))
    }
    worker.postMessage({ challenge, payload })
  })
}