Attribute VB_Name = "copy2026"
Option Explicit

Public Sub Copy2026MonthSheetsToCurrentSheet()
    Dim destinationSheet As Worksheet
    Dim sourceWorkbook As Workbook
    Dim sourceSheets() As Worksheet
    Dim sheet As Worksheet
    Dim sheetCount As Long
    Dim sourceIndex As Long
    Dim nextRow As Long
    Dim lastDataRow As Long
    Dim totalRow As Long
    Dim totalColumn As Variant

    Set destinationSheet = ActiveSheet
    Set sourceWorkbook = destinationSheet.Parent

    If Is2026MonthSheet(destinationSheet.Name) Then
        MsgBox "Select the destination sheet before running this macro. " & _
               "A 2026-xx monthly sheet cannot be used as the destination.", vbExclamation
        Exit Sub
    End If

    'Collect valid monthly sheets before changing the destination.
    For Each sheet In sourceWorkbook.Worksheets
        If Not sheet Is destinationSheet Then
            If Is2026MonthSheet(sheet.Name) Then
                sheetCount = sheetCount + 1
                ReDim Preserve sourceSheets(1 To sheetCount)
                Set sourceSheets(sheetCount) = sheet
            End If
        End If
    Next sheet

    If sheetCount = 0 Then
        MsgBox "No sheets named 2026-01 through 2026-12 were found.", vbExclamation
        Exit Sub
    End If

    SortSheetsByName sourceSheets

    Application.ScreenUpdating = False
    On Error GoTo CopyFailed

    'The user requested that all present destination records be overwritten.
    destinationSheet.Cells.Clear

    'Copy one header and the source column widths.
    sourceSheets(1).Range("A1:U1").Copy Destination:=destinationSheet.Range("A1")
    sourceSheets(1).Columns("A:U").Copy
    destinationSheet.Columns("A:U").PasteSpecial Paste:=xlPasteColumnWidths
    Application.CutCopyMode = False

    nextRow = 2

    For sourceIndex = 1 To sheetCount
        With sourceSheets(sourceIndex)
            'Column A contains dates; this excludes each sheet's totals row.
            lastDataRow = .Cells(.Rows.Count, 1).End(xlUp).Row

            If lastDataRow >= 2 Then
                .Range(.Cells(2, 1), .Cells(lastDataRow, 21)).Copy _
                    Destination:=destinationSheet.Cells(nextRow, 1)
                nextRow = nextRow + lastDataRow - 1
            End If
        End With
    Next sourceIndex

    'Create one totals row for the combined records.
    If nextRow > 2 Then
        totalRow = nextRow
        For Each totalColumn In Array(5, 6, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
            destinationSheet.Cells(totalRow, CLng(totalColumn)).Formula = _
                "=SUM(" & destinationSheet.Cells(2, CLng(totalColumn)).Address(False, False) & _
                ":" & destinationSheet.Cells(totalRow - 1, CLng(totalColumn)).Address(False, False) & ")"
            destinationSheet.Cells(totalRow, CLng(totalColumn)).Font.Bold = True
        Next totalColumn
    End If

    Application.ScreenUpdating = True
    destinationSheet.Activate
    MsgBox sheetCount & " monthly sheet(s) copied. " & _
           (nextRow - 2) & " transaction row(s) imported.", vbInformation
    Exit Sub

CopyFailed:
    Application.CutCopyMode = False
    Application.ScreenUpdating = True
    MsgBox "The copy failed: " & Err.Description, vbCritical
End Sub

Private Function Is2026MonthSheet(ByVal sheetName As String) As Boolean
    Dim monthNumber As Long

    If Not sheetName Like "2026-##" Then Exit Function

    monthNumber = CLng(Right$(sheetName, 2))
    Is2026MonthSheet = (monthNumber >= 1 And monthNumber <= 12)
End Function

Private Sub SortSheetsByName(ByRef sheets() As Worksheet)
    Dim firstIndex As Long
    Dim secondIndex As Long
    Dim temporarySheet As Worksheet

    For firstIndex = LBound(sheets) To UBound(sheets) - 1
        For secondIndex = firstIndex + 1 To UBound(sheets)
            If sheets(secondIndex).Name < sheets(firstIndex).Name Then
                Set temporarySheet = sheets(firstIndex)
                Set sheets(firstIndex) = sheets(secondIndex)
                Set sheets(secondIndex) = temporarySheet
            End If
        Next secondIndex
    Next firstIndex
End Sub