// Why: a unique error class so callers (in particular the relay-lost retry
// loop in src/main/ipc/ssh.ts) can branch on `instanceof
// RelayVersionMismatchError` and treat the failure as terminal — i.e. skip
// the exponential-backoff retry and surface a user-visible "please reconnect
// manually" error. Any other transport failure remains transiently retryable.
//
// Trigger: the remote `--connect` process exits with code 42 after the
// daemon's wire-level handshake reports a version mismatch. See
// docs/ssh-relay-versioned-install-dirs.md.

export class RelayVersionMismatchError extends Error {
  readonly name = 'RelayVersionMismatchError'

  constructor(
    readonly expected: string | undefined,
    readonly got: string | undefined,
    readonly stderr?: string
  ) {
    super(
      `Remote relay version mismatch — expected=${expected ?? 'unknown'}, ` +
        `daemon=${got ?? 'unknown'}. The remote daemon was launched against a different ` +
        `relay binary than the local client expects. Please reconnect manually.`
    )
  }
}

export function isRelayVersionMismatchError(err: unknown): err is RelayVersionMismatchError {
  return err instanceof RelayVersionMismatchError
}

// Why: the remote --connect process uses this exit code to signal the wire
// handshake failed because of a version mismatch. The mapping daemon ⇄ exit
// code 42 lives in src/relay/relay-handshake.ts (EXIT_CODE_VERSION_MISMATCH).
export const RELAY_EXIT_CODE_VERSION_MISMATCH = 42