module.exports.executeWorkflow = function (event, context) {
  if ('Records' in event) {
    const stateMachineName = process.env.STEP_FUNCTION_NAME;
    const stepfunctions = new AWS.StepFunctions();

    async.waterfall([
      (next) => {
        console.log('Fetching the list of available workflows');
        return stepfunctions.listStateMachines({}, next);
      },
      (data, next) => {
        console.log(data, next);
        console.log('Searching for the step function', data);

        for (var i = 0; i < data.stateMachines.length; i++) {
          const item = data.stateMachines[i];
          if (item.name === stateMachineName) {
            console.log('Found the step function', item);
            return next(null, item.stateMachineArn);
          }
        }

        throw 'Step function with the given name doesn\'t exist';
      },
      (stateMachineArn, next) => {
        console.log('Executing the step function', stateMachineArn);
        const eventData = event.Records[0];
        return stepfunctions.startExecution({
          stateMachineArn: stateMachineArn,
          input: JSON.stringify({ objectKey: eventData.s3.object.key, bucketName: eventData.s3.bucket.name })
        }, next);
      },
      () => {
        return context.succeed('OK');
      }
    ]);
  } else {
    return context.fail('Incoming message doesn\'t contain "Records", it will be ignored', event);
  }
};