/// <summary>
/// compare the new state to the last values and determine if a tack has occured
/// if so, update the state with the new tack
/// </summary>
/// <param name="state"></param>
private void CheckForTack(State state)
{
var latest = _history.Last();
var deltas = _history.Where(x=>x.Time > latest.Time - _tackThresholdTime).Select(x => Math.Abs(AngleUtilities.AngleDifference(latest.CourseOverGroundRadians, x.CourseOverGroundRadians))).Max();
if(deltas>_tackThreshold)
{
//tack detected
_lastTackAt = latest.Time;
var priorToTack = _history.Where(x => x.Time < latest.Time - _dataExclusionTime).OrderByDescending(x => x.Time).FirstOrDefault();
if (priorToTack != null)
{
_previousTackCourseOverGroundRadians = priorToTack.CourseOverGroundRadians;
}
else
{
_previousTackCourseOverGroundRadians = null;
}
_history.Clear();
_currentTackStartCourseOverGroundRadians = null;
var difference = AngleUtilities.AngleDifference(_previousTackCourseOverGroundRadians.Value, latest.CourseOverGroundRadians);
var differenceDegrees = AngleUtilities.RadiansToDegrees(difference);
string message = string.Format("Tack: {0:0.0}°", differenceDegrees);
_logger.Info(message);
state.AddMessage(MessageCategory.Tactical, MessagePriority.Normal, 5, message);
//record the tack in the state
if (state.RaceStarted && _currentTack != null) {
_currentTack.CourseOverGround = AngleUtilities.RadiansToDegrees (_previousTackCourseOverGroundRadians.Value);
state.Tacks.Add (_currentTack);
}
_currentTack = new Tack ();
_currentTack.At = latest.Time;
}
}
public void RecordTack (Tack tack)
{
//TODO: consider adding true wind angle or dir?
_connection.Execute ("insert into Tack (start,endcourseoverground) values (@At,@CourseOverGround)", tack);
//TODO: there has to be a better way to do this
tack.Id = (long)_connection.ExecuteScalar ("select max(id) from Tack");
}