Form1.vb

Imports System.IO
Imports System.Math
Imports iTextSharp.text.pdf

Public Class Form1


    Private pdfPath As String = ""

    ' === CHKALLTC EVENT ===  
    Private Sub chkAlltc_CheckedChanged(sender As Object, e As EventArgs) Handles chkAlltc.CheckedChanged
        If chkAlltc.Checked Then
            For i = 2 To 9
                Dim tcControl As TextBox = TryCast(Me.Controls("txtTC" & i), TextBox)
                If tcControl IsNot Nothing Then
                    tcControl.Text = txtTC1.Text
                End If
            Next
        End If
    End Sub

    ' === CHKALLEW EVENT ===  
    Private Sub chkAllew_CheckedChanged(sender As Object, e As EventArgs) Handles chkAllew.CheckedChanged
        If chkAllew.Checked Then
            For i = 2 To 9
                Dim varControl As TextBox = TryCast(Me.Controls("txtVAR" & i), TextBox)
                If varControl IsNot Nothing Then
                    varControl.Text = txtVAR1.Text
                End If
            Next
        End If
    End Sub

    ' === CHKTOTAL EVENT ===  
    Private Sub chkTotal_CheckedChanged(sender As Object, e As EventArgs) Handles chkTotal.CheckedChanged
        CalculateTotalDistance()
    End Sub

    ' Calculate total distance from txtDIS1 to txtDIS9, update txtDISTOTAL if checkbox checked
    Public Sub CalculateTotalDistance()
        Dim totalDist As Double = 0
        For i = 1 To 9
            Dim disControl As TextBox = TryCast(Me.Controls("txtDIS" & i), TextBox)
            If disControl IsNot Nothing Then
                totalDist += Val(disControl.Text)
            End If
        Next
        If chkTotal.Checked Then
            txtDISTOTAL.Text = totalDist.ToString("F2")
        End If
    End Sub

    ' === LOAD PDF BUTTON ===  
    Private Sub btnUp_Click(sender As Object, e As EventArgs) Handles btnUp.Click
        Dim openPDF As New OpenFileDialog()
        openPDF.Filter = "PDF files (*.pdf)|*.pdf"
        If openPDF.ShowDialog() = DialogResult.OK Then
            pdfPath = openPDF.FileName
            MessageBox.Show("Selected PDF: " & pdfPath)
        End If
    End Sub

    ' === LOAD TXT BUTTON ===  
    Private Sub btnWB_Click(sender As Object, e As EventArgs) Handles btnWB.Click
        Dim openTxt As New OpenFileDialog()
        openTxt.Filter = "Text files (*.txt)|*.txt"

        If openTxt.ShowDialog() = DialogResult.OK Then
            Dim filePath As String = openTxt.FileName
            Try
                Dim lines() As String = File.ReadAllLines(filePath)

                ' Assuming lines 2 to 6 contain A1 to A5 values like "A1=123"
                For i As Integer = 1 To 5
                    If lines.Length > i Then
                        Dim lineParts() As String = lines(i).Split("="c)
                        If lineParts.Length = 2 Then
                            Dim value = lineParts(1).Trim()
                            Dim txtBox As TextBox = TryCast(Me.Controls("txtA" & i.ToString()), TextBox)
                            If txtBox IsNot Nothing Then
                                txtBox.Text = value
                            End If
                        End If
                    End If
                Next

                MessageBox.Show("Values loaded into A1-5 successfully.")
            Catch ex As Exception
                MessageBox.Show("Error reading file: " & ex.Message)
            End Try
        End If
    End Sub

    ' === FILL PDF BUTTON ===  
    Private Sub btnInput_Click(sender As Object, e As EventArgs) Handles btnInput.Click
        ProcessPDF()
    End Sub

    ' Main PDF processing and form filling method
    Public Sub ProcessPDF()

        If pdfPath = "" Then
            MessageBox.Show("Please select a PDF first.")
            Return
        End If

        Try
            Dim reader As New PdfReader(pdfPath)
            Dim outputPDF As String = Path.Combine(Path.GetDirectoryName(pdfPath), "Filled-" & Path.GetFileName(pdfPath))
            Dim stamper As New PdfStamper(reader, New FileStream(outputPDF, FileMode.Create))
            Dim fields As AcroFields = stamper.AcroFields

            Dim totalETE As Double = 0
            Dim totalDIS As Double = 0
            Dim remDist As Double = 0

            ' Process calculation fields for legs 1 to 9
            For i = 1 To 9
                Dim DIS As Double = Val(GetText("txtDIS" & i))
                Dim TAS As Double = Val(GetText("txtTAS" & i))
                Dim WS As Double = Val(GetText("txtVEL" & i))
                Dim WNDDIR As Double = Val(GetText("txtDIR" & i))
                Dim TC As Double = Val(GetText("txtTC" & i))
                Dim VAR As Double = Val(GetText("txtVAR" & i))
                Dim ALT As String = GetText("txtALT" & i)
                Dim TEMP As Double = Val(GetText("txtTMP" & i))

                If DIS > 0 Then
                    fields.SetField("DIS" & i, DIS.ToString() & " nm")
                    totalDIS += DIS
                End If
                If TAS > 0 Then fields.SetField("TAS" & i, Math.Round(TAS).ToString() & " kt")
                If WS > 0 Then fields.SetField("VEL" & i, Math.Round(WS).ToString() & " kt")
                If WNDDIR <> 0 Then fields.SetField("DIR" & i, Math.Round(WNDDIR).ToString())
                If TC <> 0 Then fields.SetField("TC" & i, Math.Round(TC).ToString())
                If VAR <> 0 Then fields.SetField("VAR" & i, Math.Round(VAR).ToString())
                If ALT <> "" Then fields.SetField("ALT" & i, ALT)
                If TEMP <> 0 Then fields.SetField("TEM" & i, Math.Round(TEMP).ToString())

                ' Perform wind correction calculations only if needed values are valid
                If TAS > 0 And DIS > 0 Then
                    Dim angleDiff As Double = WNDDIR - TC
                    Dim ratio As Double = WS / TAS
                    Dim sinValue As Double = Sin(angleDiff * PI / 180)
                    Dim WCA As Double = 0
                    If Abs(ratio * sinValue) <= 1 Then
                        WCA = Asin(ratio * sinValue) * 180 / PI
                    End If
                    WCA = Math.Round(WCA)
                    fields.SetField("COR" & i, WCA.ToString())

                    Dim GS As Double = Math.Sqrt(TAS ^ 2 + WS ^ 2 - 2 * TAS * WS * Cos(angleDiff * PI / 180))
                    GS = Math.Round(GS)
                    fields.SetField("GS" & i, GS.ToString() & " kt")

                    Dim ETE As Double = (DIS / GS) * 60
                    ETE = Math.Round(ETE * 2) / 2
                    totalETE += ETE
                    fields.SetField("ETE" & i, ETE.ToString() & " m")

                    Dim TH As Double = TC + WCA
                    fields.SetField("TH" & i, Math.Round(TH).ToString())

                    Dim MH As Double = TH + VAR
                    fields.SetField("MH" & i, Math.Round(MH).ToString())

                    remDist -= DIS
                    fields.SetField("REM" & i, remDist.ToString() & " nm")
                End If
            Next

            ' Direct textbox-to-PDF fields mapping
            Dim fieldCounts As New Dictionary(Of String, Integer) From {
                {"txtFLD", 5}, {"txtELV", 5}, {"txtRWY", 5}, {"txtRD", 5},
                {"txtLOCT", 3}, {"txtTAF", 3}, {"txtLOCM", 2}, {"txtMETAR", 2},
                {"txtLOCW", 3}, {"txtWALT", 4},
                {"txtWND1A", 3}, {"txtWND2A", 3}, {"txtWND3A", 3}, {"txtWND4A", 3},
                {"txtLOCP", 4}, {"txtPSN", 4}, {"txtW", 5}, {"txtA", 5}
            }

            For Each prefix In fieldCounts.Keys
                Dim maxCount As Integer = fieldCounts(prefix)
                For i = 1 To maxCount
                    Dim value As String = GetText(prefix & i)
                    If value <> "" Then
                        Dim pdfField As String = Replace(prefix & i, "txt", "")
                        fields.SetField(pdfField, value)
                    End If
                Next
            Next

            ' Single weight field
            Dim wtValue As String = GetText("txtWT")
            If wtValue <> "" Then
                fields.SetField("WT", wtValue)
            End If

            ' Set totals fields
            fields.SetField("ETETOTAL", Math.Round(totalETE * 2) / 2 & " m")
            If chkTotal.Checked Then
                fields.SetField("DISTOTAL", totalDIS.ToString() & " nm")
            End If
            ' Calculate W*A, set M1-5, and sum WT and MT
            Dim totalW As Double = 0
            Dim totalM As Double = 0

            For i As Integer = 1 To 5
                Dim wVal As Double = Val(GetText("txtW" & i))
                Dim aVal As Double = Val(GetText("txtA" & i))
                Dim product As Double = wVal * aVal

                ' Update M textboxes and PDF fields
                Dim mTextBox As TextBox = TryCast(Me.Controls("txtM" & i), TextBox)
                If mTextBox IsNot Nothing Then mTextBox.Text = product.ToString("F2")
                fields.SetField("M" & i, product.ToString("F2"))

                totalW += wVal
                totalM += product
            Next

            ' Set WT and MT totals in PDF and textboxes
            fields.SetField("WT", totalW.ToString("F2"))
            Dim wtTextBox As TextBox = TryCast(Me.Controls("txtWT"), TextBox)
            If wtTextBox IsNot Nothing Then wtTextBox.Text = totalW.ToString("F2")

            fields.SetField("MT", totalM.ToString("F2"))
            Dim mtTextBox As TextBox = TryCast(Me.Controls("txtMT"), TextBox)
            If mtTextBox IsNot Nothing Then mtTextBox.Text = totalM.ToString("F2")

            ' Calculate CG and set it
            Dim cgValue As Double = 0
            If totalW <> 0 Then
                cgValue = totalM / totalW
            End If

            ' Debug line: confirm calculation
            Console.WriteLine("Calculated CG: " & cgValue.ToString("F2"))

            ' Set value into the PDF field named "CG"
            fields.SetField("CG", cgValue.ToString("F2"))

            ' Set value into your form TextBox named "txtCG"
            If txtCG IsNot Nothing Then
                txtCG.Text = cgValue.ToString("F2")
            End If


            stamper.Close()
            reader.Close()

            MessageBox.Show("PDF completed and saved as:" & vbCrLf & outputPDF)

        Catch ex As Exception
            MessageBox.Show("Error: " & ex.Message)
        End Try
    End Sub

    ' Helper method to get TextBox text by name safely
    Private Function GetText(name As String) As String
        Dim ctrl As Control = Me.Controls(name)
        If ctrl IsNot Nothing AndAlso TypeOf ctrl Is TextBox Then
            Return CType(ctrl, TextBox).Text
        Else
            Return ""
        End If
    End Function

    ' === EXIT BUTTON ===
    Private Sub btnClose_Click(sender As Object, e As EventArgs) Handles btnClose.Click
        Dim result As DialogResult = MessageBox.Show("Are you sure you want to exit?", "Exit", MessageBoxButtons.YesNo)
        If result = DialogResult.Yes Then
            Application.Exit()
        End If
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub
    'test


End Class