import {
  Either,
  type IEither,
  type ITraceable,
  LogLevel,
  TraceUtil,
} from "@emprespresso/pengueno";

type Command = string[] | string;
type CommandOutputDecoded = {
  code: number;
  stdoutText: string;
  stderrText: string;
};

export class ProcessError extends Error {}
export const getStdout = <Trace>(
  c: ITraceable<Command, Trace>,
  options: Deno.CommandOptions = {},
): Promise<IEither<ProcessError, string>> =>
  c.bimap(TraceUtil.withFunctionTrace(getStdout))
    .map(({ item: cmd, trace }) => {
      trace.trace(`:> im gonna run this command! ${cmd}`);
      const [exec, ...args] = (typeof cmd === "string") ? cmd.split(" ") : cmd;
      return new Deno.Command(exec, {
        args,
        stdout: "piped",
        stderr: "piped",
        ...options,
      }).output();
    })
    .map(({ item: p }) =>
      Either.fromFailableAsync<Error, Deno.CommandOutput>(p)
    )
    .map(
      TraceUtil.promiseify(({ item: eitherOutput, trace }) =>
        eitherOutput.flatMap(({ code, stderr, stdout }) =>
          Either
            .fromFailable<Error, CommandOutputDecoded>(() => {
              const stdoutText = new TextDecoder().decode(stdout);
              const stderrText = new TextDecoder().decode(stderr);
              return { code, stdoutText, stderrText };
            })
            .mapLeft((e) => {
              trace.addTrace(LogLevel.ERROR).trace(`o.o wat ${e}`);
              return new ProcessError(`${e}`);
            })
            .flatMap((decodedOutput): Either<ProcessError, string> => {
              const { code, stdoutText, stderrText } = decodedOutput;
              trace.addTrace(LogLevel.DEBUG).trace(
                `stderr hehehe ${stderrText}`,
              );
              if (code !== 0) {
                const msg =
                  `i weceived an exit code of ${code} i wanna zewoooo :<`;
                trace.addTrace(LogLevel.ERROR).trace(msg);
                return Either.left(new ProcessError(msg));
              }
              return Either.right(stdoutText);
            })
        )
      ),
    ).item;