import { Either } from "./mod.ts";

export class ProcessError extends Error {}
export const getStdout = async (
  cmd: string[] | string,
  options: Deno.CommandOptions = {},
): Promise<Either<ProcessError, string>> => {
  const [exec, ...args] = (typeof cmd === "string") ? cmd.split(" ") : cmd;
  const command = new Deno.Command(exec, {
    args,
    stdout: "piped",
    stderr: "piped",
    ...options,
  });

  try {
    const { code, stdout, stderr } = await command.output();
    const stdoutText = new TextDecoder().decode(stdout);
    const stderrText = new TextDecoder().decode(stderr);

    if (code !== 0) {
      return Either.left<ProcessError, string>(
        new ProcessError(`command failed\n${stderrText}`),
      );
    }
    return Either.right<ProcessError, string>(stdoutText);
  } catch (e) {
    if (e instanceof Error) {
      return Either.left<ProcessError, string>(e);
    }
    throw new Error("unknown error " + e);
  }
};