import initWasm, { solve } from './pow-solver/pow_solver'
import wasmUrl from './pow-solver/pow_solver_bg.wasm?url'

let ready: Promise<void> | null = null

function ensureReady() {
  ready ??= initWasm({ module_or_path: wasmUrl }).then(() => {})
  return ready
}

/**
 * Solve a SHA-256 leading-zero-bits proof-of-work challenge.
 * Returns the decimal answer string expected by the backend
 * (pow-solver: sha256(`${nonce}:${answer}`) with >= difficulty leading zero bits).
 */
export async function solvePow(
  nonce: string,
  difficulty: number,
  maxAttempts = 20_000_000,
): Promise<string> {
  await ensureReady()
  return solve(nonce, difficulty, maxAttempts)
}