/**
 * MetaMask / EIP-1193 wallet error helpers.
 *
 * Previously the codebase detected user rejections by string-matching the
 * error message for "reject" or "denied". That breaks when MetaMask's UI
 * language is set to anything other than English (the message is translated
 * but our match string isn't). The reliable signal is the EIP-1193 error
 * code: 4001 = "User rejected the request".
 *
 * Wagmi sometimes wraps the underlying provider error inside `.cause`, so we
 * walk that chain too.
 */

interface WithCode { code?: number | string; cause?: unknown }

export function isUserRejection(err: unknown): boolean {
  // Walk a small depth of .cause chains since wagmi/viem wrap provider errors
  let cur: unknown = err
  for (let i = 0; i < 4 && cur; i++) {
    const c = (cur as WithCode)?.code
    if (c === 4001 || c === 'ACTION_REJECTED' || c === 'USER_REJECTED') return true
    cur = (cur as WithCode)?.cause
  }
  // Last-resort string fallback for providers that don't expose a code field.
  // Kept narrow — "reject" + "denied" + a couple of locale variants we've
  // actually seen from MetaMask zh-CN ("拒绝") and Rabby ("rejected by user").
  const m = err instanceof Error ? err.message : ''
  return /reject|denied|cancell|拒绝|已取消/i.test(m)
}

/**
 * Convenience: return either a friendly cancellation label or a truncated
 * version of the real error message — never raw user-facing crash text.
 */
export function walletErrorLabel(err: unknown, cancelledLabel = 'Cancelled', maxLen = 110): string {
  if (isUserRejection(err)) return cancelledLabel
  const m = err instanceof Error ? err.message : String(err ?? '')
  return m.slice(0, maxLen) || 'unknown error'
}