import { err, ok, Result, ResultAsync } from 'neverthrow';
import {
  ClientErrors,
  ErrorCodes,
  ErrorWithCode,
  newError,
} from '../types/errors';

export const safeDecode = ResultAsync.fromThrowable(
  <T>(response: Response) => response.json() as Promise<T>,
  (error): ErrorWithCode<ClientErrors> =>
    newError('DecodeError', 'Unable to decode response', {
      error,
    }),
);

export const safeFetch = async <T, E extends ErrorCodes>(
  input: string | URL | globalThis.Request,
  init?: RequestInit,
): Promise<Result<T, ErrorWithCode<E | ClientErrors>>> => {
  const response = await fetch(input, init);

  if (!response.ok) {
    const notOkDecodeResult = await safeDecode<ErrorWithCode<E>>(response);

    if (notOkDecodeResult.isErr()) {
      return err(notOkDecodeResult.error);
    }

    return err(notOkDecodeResult.value);
  }

  const okDecodeResult = await safeDecode<T>(response);

  if (okDecodeResult.isErr()) {
    return err(okDecodeResult.error);
  }

  return ok(okDecodeResult.value);
};