/**
 * Check if an error is a programming error (code bug).
 * Programming errors should be re-thrown, not caught.
 */
export function isProgrammingError(error: unknown): boolean {
  return (
    error instanceof TypeError ||
    error instanceof ReferenceError ||
    error instanceof SyntaxError
  );
}

/**
 * Check if an error is a network error (temporary).
 * Network errors should return 503 (retry later).
 */
export function isNetworkError(error: unknown): boolean {
  if (!(error instanceof Error)) return false;
  const msg = error.message.toLowerCase();
  return (
    msg.includes("fetch failed") ||
    msg.includes("network") ||
    msg.includes("econnrefused") ||
    msg.includes("enotfound") ||
    msg.includes("timeout") ||
    msg.includes("etimedout") ||
    msg.includes("econnreset") ||
    msg.includes("enetunreach") ||
    msg.includes("service unavailable")
  );
}

/**
 * Check if an error is an authentication error (wrong credentials).
 * Auth errors should NOT be retried to avoid account lockouts.
 */
export function isAuthError(error: unknown): boolean {
  if (!(error instanceof Error)) return false;
  const message = error.message.toLowerCase();
  return (
    message.includes("invalid identifier") ||
    message.includes("invalid password") ||
    message.includes("authentication failed") ||
    message.includes("unauthorized")
  );
}

/**
 * Check if an error represents a database-layer failure.
 * These errors indicate temporary unavailability — user should retry.
 */
export function isDatabaseError(error: unknown): boolean {
  if (!(error instanceof Error)) return false;
  const msg = error.message.toLowerCase();
  return (
    msg.includes("pool") ||
    msg.includes("postgres") ||
    msg.includes("database") ||
    msg.includes("sql") ||
    // drizzle-orm wraps all failed queries as: "Failed query: <sql>\nparams: <params>"
    msg.includes("failed query")
  );
}