export def lumen-assono-backup-nexttape [dateinput: datetime]: nothing -> nothing {
  $dateinput | get-backup-string
  print 'Next Required Tape:'
  print $'($dateinput | get-backup-string)'
  print ''
  print 'Tapes after that:'

  ..9 | each {|i|
    print $'($i): (($dateinput + ((7 * $i) | into duration -u day)) | get-backup-string)'
  }
}

def get-backup-string []: datetime -> string {
  print $in
  let saturdayOfMonth = $in | get-week-of-month 6 
  let monthOfQuarter = $in | get-month-of-quarter 
  let quarter = $in | get-quarter 
  let year = $in | get-year 
  if ($saturdayOfMonth == 1) {
    if ($monthOfQuarter == 1) {
      if ($quarter == 1) {
        $'TapeLTO5-Y($year)'
      } else {
        $'TapeLTO5-Q($quarter)'
      }
    } else {
      $'TapeLTO5-M($monthOfQuarter)'
    }
  } else {
    $'TapeLTO5-W($saturdayOfMonth)'
  }
}

def get-week-of-month [weekdayindex: int]: datetime -> int {
  ($in + ($weekdayindex | into duration -u day) - (($in | format date '%w' ) | into duration -u day)) | format date %w
}

def get-month-of-quarter []: datetime -> int {
  mut month = $in | format date '%m' | into int
  while ($month > 3) {
    $month -= 3
  }
  $month
}

def get-quarter []: datetime -> int {
  (($in | format date '%m') | into int) / 3 | math ceil 
}

def get-year []: datetime -> int {
  $in | format date '%Y'
}