module.exports = function (app) {
  return {
    group: 'course data',
    optionKey: 'steer_error',
    title:
      'Estimated steer error and direction from COGS, Bearing to next waypoint (true)',
    derivedFrom: ['navigation.courseOverGroundTrue', 'navigation.courseRhumbline.bearingToDestinationTrue'],
    calculator: function (courseOverGroundTrue, bearingToDestinationTrue) {
      var steererr
      var steer
      var leftSteer
      var rightSteer

      steererr = courseOverGroundTrue - bearingToDestinationTrue
      if (steererr > 3.14159265359) {
        steer = (steererr - 3.14159265359)*-1
      } else if (steererr < -3.14159265359) {
        steer = (steererr + 3.14159265359)*-1
      } else {
        steer = steererr
      }

      if (steer > 0) {
       leftSteer = steer,
       rightSteer = 0
      } else {
       leftSteer = 0,
       rightSteer = steer * -1
      }

     app.debug(`steer: ${steer} leftSteer: ${leftSteer} rightSteer: ${rightSteer}`)

      return [
      {
      path: 'navigation.courseGreatCircle.nextPoint.steerError', value: steer
         },
      {
      path: 'navigation.courseGreatCircle.nextPoint.leftSteerError', value: leftSteer
         },
      {
      path: 'navigation.courseGreatCircle.nextPoint.rightSteerError', value: rightSteer
         }]

  }}
}