import { encode } from "@toon-format/toon";

export type OutputFormat = "toon" | "json" | "text";

const VALID = new Set<OutputFormat>(["toon", "json", "text"]);

/** Valid --format values, for usage messages. */
export const VALID_FORMATS: readonly OutputFormat[] = ["toon", "json", "text"];

/** True iff `flag` is one of the recognized output formats. */
export function isValidFormat(flag: string): flag is OutputFormat {
  return VALID.has(flag as OutputFormat);
}

export function resolveFormat(flag: string | undefined, isTTY: boolean): OutputFormat {
  if (flag && VALID.has(flag as OutputFormat)) return flag as OutputFormat;
  // TTY-aware default: humans at a terminal get text; pipes/agents get TOON.
  return isTTY ? "text" : "toon";
}

export function toonEncode(value: unknown): string {
  return encode(value);
}