Imports System.Collections
Imports System.Collections.Generic
Imports System.Linq
Imports System.IO


Public Class ControlChart

    Friend myData As New List(Of ControlChart.CalPoint)

    Public Sub New()
    End Sub


    Public Sub ExportData(ByVal FilePath As String)
        Try
            Dim Data As String
            Data = "Date" & vbTab & "Measured Value" & vbTab & "Measured Unc" & vbTab & "Predicted Value" & vbTab & "Predicted Unc" & vbTab & "Upper Bound" & vbTab & "Lower Bound" & vbCrLf

            'Add The DataPoints
            For Each item In Me.myData
                Data = Data & item.vDate & vbTab & item.CalValue & vbTab & item.Unc & vbTab & PredictedValue(item.vDate) & vbTab & PredictedUnc(item.vDate) & vbTab & PredictedValue(item.vDate) + (2 * PredictedUnc(item.vDate)) & vbTab & PredictedValue(item.vDate) - (2 * PredictedUnc(item.vDate)) & vbCrLf
            Next

            File.WriteAllText(FilePath, Data)

        Catch ex As Exception
            ' ErrorLog.Log(ex)
            Throw ex
        End Try
    End Sub

    Public Sub AddCalPoint(ByVal CalPoint As CalPoint)
        Try
            myData.Add(CalPoint)
        Catch ex As Exception
            'ErrorLog.Log(ex)
        End Try
    End Sub


    Public Function CalcSlope() As Double
        Try
            Dim Data As IEnumerable(Of CalPoint) = Me.myData
            Dim averageX As Double = Data.Average(Function(d) d.Days)
            Dim averageY As Double = Data.Average(Function(d) d.CalValue)

            Return Data.Sum(Function(d) (d.Days - averageX) * (d.CalValue - averageY)) / Data.Sum(Function(d) Math.Pow(d.Days - averageX, 2))
        Catch ex As Exception
            'ErrorLog.Log(ex)
            Return "39e39"
        End Try
    End Function


    Public Function CalcIntercept() As Double
        Try
            Dim Data As IEnumerable(Of CalPoint) = Me.myData

            Dim slope As Double = CalcSlope()
            Return Data.Average(Function(d) d.CalValue) - slope * Data.Average(Function(d) d.Days)
        Catch ex As Exception
            'ErrorLog.Log(ex)
            Return "39e39"
        End Try
    End Function


    Public Function PredictedValue(ByVal dDate As Date) As Double
        Try
            Dim Data As IEnumerable(Of CalPoint) = Me.myData

            Dim RefDate As Date = New Date(1900, 1, 1)
            Dim days As Double = dDate.Subtract(RefDate).Days

            Return days * CalcSlope() + CalcIntercept()
        Catch ex As Exception
            'ErrorLog.Log(ex)
            Return "39e39"
        End Try
    End Function


    Public Function PredictedUnc(ByVal dDate As Date) As Double
        Try
            Dim Data As IEnumerable(Of CalPoint) = Me.myData

            Dim LastCal As Date = Data.Max(Function(d) d.vDate)
            Dim FirstCal As Date = Data.Min(Function(d) d.vDate)
            Dim StartDays As Double = Data.Min(Function(d) d.Days)
            Dim SumSqrVal As Double
            Dim SumSqrDay As Double
            Dim SumDay As Double

            'Get all the Values
            For Each DataPoint In Me.myData
                SumSqrVal = SumSqrVal + (DataPoint.CalValue - PredictedValue(DataPoint.vDate)) ^ 2
                SumDay = SumDay + (DataPoint.Days - StartDays)
                SumSqrDay = SumSqrDay + ((DataPoint.Days - StartDays) ^ 2)
            Next

            Dim StdErr = Math.Sqrt(SumSqrVal) / 2
            Dim Sxx = SumSqrDay - ((SumDay ^ 2) / (Me.myData.Count))

            Dim MeanCalTime = SumDay / Me.myData.Count
            Dim DaysFromLastcal = dDate.Subtract(LastCal).Days
            Dim CalDays As Double = LastCal.Subtract(FirstCal).Days

            Dim Value As Double = StdErr * (Math.Sqrt(1 + (1 / (Me.myData.Count)) + ((((CalDays + DaysFromLastcal) - MeanCalTime) ^ 2) / Sxx)))
            Return Value
        Catch ex As Exception
            'ErrorLog.Log(ex)
            Return "39e39"
        End Try

    End Function


    Public Function PredictedPoint(ByVal dDate As Date) As CalcPoint
        Try
            Dim Data As IEnumerable(Of CalPoint) = Me.myData
            Dim RefDate As Date = New Date(1900, 1, 1)
            Dim days As Double = dDate.Subtract(RefDate).Days

            Dim LastCal As Date = Data.Max(Function(d) d.vDate)
            Dim FirstCal As Date = Data.Min(Function(d) d.vDate)
            Dim StartDays As Double = Data.Min(Function(d) d.Days)
            Dim SumSqrVal As Double
            Dim SumSqrDay As Double
            Dim SumDay As Double

            'Get all the Values
            For Each DataPoint In Me.myData
                SumSqrVal = SumSqrVal + (DataPoint.CalValue - PredictedValue(DataPoint.vDate)) ^ 2
                SumDay = SumDay + (DataPoint.Days - StartDays)
                SumSqrDay = SumSqrDay + ((DataPoint.Days - StartDays) ^ 2)
            Next

            Dim StdErr = Math.Sqrt(SumSqrVal) / 2
            Dim Sxx = SumSqrDay - ((SumDay ^ 2) / (Me.myData.Count))

            Dim MeanCalTime = SumDay / Me.myData.Count
            Dim DaysFromLastcal = dDate.Subtract(LastCal).Days
            Dim CalDays As Double = LastCal.Subtract(FirstCal).Days

            Dim Unc As Double = StdErr * (Math.Sqrt(1 + (1 / (Me.myData.Count)) + ((((CalDays + DaysFromLastcal) - MeanCalTime) ^ 2) / Sxx)))
            Dim Value As Double = days * CalcSlope() + CalcIntercept()

            Return CalcPoint.NewDataPoint(Value, Unc)
        Catch ex As Exception
            'ErrorLog.Log(ex)
            Return CalcPoint.NewDataPoint(Val("39e39"), Val("39e39"))
        End Try

    End Function

    Public Class CalPoint
        Public Property vDate As Date
        Public Property Days As Double
        Public Property CalValue As Double
        Public Property Unc As Double

        Public Sub New()
        End Sub

        Shared Function NewDataPoint(ByVal vDate As Date, ByVal Value As Double, ByVal Unc As Double) As CalPoint
            Dim NewData As New CalPoint
            Dim RefDate As Date = New Date(1900, 1, 1)
            Dim days As Double = vDate.Subtract(RefDate).Days
            NewData.vDate = vDate
            NewData.Days = days
            NewData.CalValue = Value
            NewData.Unc = Unc
            Return NewData
        End Function

    End Class

    Public Class CalcPoint
        Public Property CalValue As Double
        Public Property Unc As Double


        Shared Function NewDataPoint(ByVal Value As Double, ByVal Unc As Double) As CalcPoint
            Dim NewData As New CalcPoint
            NewData.CalValue = Value
            NewData.Unc = Unc
            Return NewData
        End Function

    End Class


End Class