import { SSMClient, GetParameterCommand } from '@aws-sdk/client-ssm';
import { err, ok, Result, ResultAsync } from 'neverthrow';
import { ErrorWithCode, newError } from 'web-shared/src/types/errors';

const ssm = new SSMClient(
  !process.env.LAMBDA_TASK_ROOT
    ? { region: 'ap-southeast-2', profile: 'dev' }
    : { region: 'ap-southeast-2' },
);

const ssmSafeSend = ResultAsync.fromThrowable(
  (parameterName: string, decrypt?: boolean) =>
    ssm.send(
      new GetParameterCommand({
        Name: parameterName,
        WithDecryption: decrypt,
      }),
    ),
  () =>
    newError(
      'SecretFetchError',
      'An error occurred while fetching secret values',
    ),
);

const parameterCache: Record<string, string> = {};
export const getParameter = async (
  parameterName: string,
  decrypt?: boolean,
): Promise<
  Result<string, ErrorWithCode<'ServerError' | 'SecretFetchError'>>
> => {
  try {
    if (parameterCache[parameterName]) {
      return ok(parameterCache[parameterName]);
    }

    const result = await ssmSafeSend(parameterName, decrypt);

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

    parameterCache[parameterName] = result.value.Parameter?.Value || '';
    return ok(parameterCache[parameterName]);
  } catch (error) {
    return err(
      newError(
        'ServerError',
        'An unexpected error occurred while fetching secret values',
        { error },
      ),
    );
  }
};