/** Which step of the desktop update failed (the native side prefixes its errors). */
export type UpdatePhase = 'check' | 'download' | 'install';

/** Where to get the installer by hand when the in-app update keeps failing. */
export const MANUAL_DOWNLOAD_URL = {
  windows:
    'https://code.lotusguild.org/LotusGuild/cinny-desktop/releases/download/latest/LotusChat-x86_64-setup.exe',
  other: 'https://code.lotusguild.org/LotusGuild/cinny-desktop/releases/tag/latest',
};

export const manualDownloadUrl = (userAgent: string): string =>
  /Windows/i.test(userAgent) ? MANUAL_DOWNLOAD_URL.windows : MANUAL_DOWNLOAD_URL.other;

const NETWORK_PATTERN =
  /error sending request|timed out|timeout|connection|connect|dns|network|reset|refused|unreachable|Could not fetch a valid release/i;

export const isNetworkUpdateError = (message: string): boolean => NETWORK_PATTERN.test(message);

/** Split `download: error sending request …` into its phase and the raw message. */
export const parseUpdateError = (
  raw: string,
  fallback: UpdatePhase,
): { phase: UpdatePhase; message: string } => {
  const match = /^(check|download|install): ([\s\S]*)$/.exec(raw);
  return match
    ? { phase: match[1] as UpdatePhase, message: match[2] }
    : { phase: fallback, message: raw };
};

/**
 * A plain-language sentence for an update failure. The raw error ("error
 * sending request for url (…nsis.zip)") told users nothing about what to do.
 */
export const describeUpdateError = (phase: UpdatePhase, message: string): string => {
  const network = isNetworkUpdateError(message);
  if (phase === 'check') {
    return network
      ? 'Couldn’t reach the update server. It may be busy, or your connection dropped. Lotus Chat still works; try again in a minute.'
      : 'Couldn’t check for updates. Lotus Chat still works; try again later.';
  }
  if (phase === 'download') {
    return network
      ? 'The update didn’t finish downloading after several tries. The update server may be busy. Try again in a minute, or download the installer yourself.'
      : /signature|minisign|base64/i.test(message)
        ? 'The downloaded update didn’t pass its safety check, so it wasn’t installed. Try again, or download the installer yourself.'
        : 'The update couldn’t be downloaded. Try again, or download the installer yourself.';
  }
  return 'The update downloaded but couldn’t be installed. Download the installer yourself and run it; your chats and settings are kept.';
};