import { SSMClient, DescribeParametersCommand, GetParameterCommand } from '@aws-sdk/client-ssm';

/**
 * Gets a parameter from AWS Systems Manager Parameter Store
 * @param name - The name of the parameter
 * @returns - The parameter string value, or undefined if the parameter not found.
 */
export const getSsmParameter = async (name: string): Promise<string | undefined> => {
  const client = new SSMClient();

  // Check if the parameter exists.
  const describeParametersCommand = new DescribeParametersCommand({
    ParameterFilters: [
      {
        Key: 'Name',
        Option: 'Equals',
        Values: [name],
      },
    ],
  });
  const describeParametersResponse = await client.send(describeParametersCommand);
  if (!describeParametersResponse.Parameters?.length) {
    return;
  }

  // Get the parameter value.
  const getParameterCommand = new GetParameterCommand({
    Name: name,
    WithDecryption: true,
  });
  const getParameterResponse = await client.send(getParameterCommand);

  return getParameterResponse.Parameter?.Value;
};