param (
    [string]$FolderPath,
    [string]$ExcelFile,
    [string]$ExcelSheet
)

################################################
#Validate parameters

if ($FolderPath.Length -eq 0) {
  Write-Host("FolderPath is a required parameter. Set it to the path of the input Excel file.  This is the same folder where the resulting PDF file will be created.")
}

if ($ExcelFile.Length -eq 0) {
  Write-Host("ExcelFile is a required parameter. Set it to the name of the Excel file you wish to print to PDF.")
}

if ($ExcelSheet.Length -eq 0) {
  Write-Host("ExcelSheet is a required parameter.  Set to the sheet, or sheets you wish to print to PDF.  The sheet list can be comma, pipe or semi-colon delimited.  Each sheet will be printed as it's own PDF.")
}

if (($ExcelFile.Length -eq 0) -or ($FolderPath.Length -eq 0) -or ($ExcelSheet.Length -eq 0)){
    Exit
}

if (-not(Test-Path($FolderPath +"\" +$ExcelFile))) {
    Write-Host("The source Excel file: " + $FolderPath +"\" +$ExcelFile + " does not exist.  Please check the path and try again.")
    Exit
}
###############################
$path = $FolderPath
$sheetNames = @()

#default to a comma separated list
$delimiter = ","

#For the sheet list, check comma delimiters
if ($ExcelSheet.IndexOfAny(",") -ge 0) {
    $delimiter = ","
}
elseif ($ExcelSheet.IndexOfAny("|") -ge 0) {
    $delimiter = "|"
}
elseif ($ExcelSheet.IndexOfAny(";") -ge 0) {
    $delimiter = ";"
}

#Trim any spaces in the delimited sheet list
foreach ($sheet in $ExcelSheet.Split($delimiter)){
    $sheetNames += $sheet.Trim()
}


$xlFixedFormat = "Microsoft.Office.Interop.Excel.xlFixedFormatType" -as [type]
$excelFiles = Get-ChildItem -Path $path -Name $ExcelFile
$objExcel = New-Object -ComObject excel.application
$objExcel.visible = $false

foreach($wb in $excelFiles) {
  $excelpath = Join-Path -Path $path $wb
  $workbook = $objExcel.workbooks.open($excelpath)

  foreach($worksheet in $workbook.WorkSheets) {
      #Print out the AUM Summary page
      if($sheetNames -contains $worksheet.name) {
        #Create the output file path/name
        $pdfFile = $worksheet.name + ".pdf"
        $filepath = Join-Path -Path $path $pdfFile

        #Create the PDF
        $worksheet.ExportAsFixedFormat($xlFixedFormat::xlTypePDF, $filepath)
      }
  }
  $objExcel.Workbooks.close()
}
$objExcel.Quit()