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

  1..9 | each {|i|
    print $'($i): (($dateinput + ((7 * $i) | into duration -u day)) | get-backup-string)'
  } | ignore
}

def get-backup-string []: datetime -> string {
  let backupDay = $in - ($in | format date '%w' | into duration -u day) + 6day
  let saturdayOfMonth = $backupDay | get-week-of-month 
  let monthOfQuarter = $backupDay | get-month-of-quarter 
  let quarter = $backupDay | get-quarter 
  let year = $backupDay | get-year 
  if ($saturdayOfMonth == 1) {
    if ($monthOfQuarter == 1) {
      if ($quarter == 1) {
        $'TapeLTO5-Y(($year | into string | str substring 3..))'
      } else {
        $'TapeLTO5-Q($quarter)'
      }
    } else {
      $'TapeLTO5-M($monthOfQuarter)'
    }
  } else {
    $'TapeLTO5-W($saturdayOfMonth)'
  }
}

def get-week-of-month []: datetime -> int {
  let firstDay = ($in - ($in | format date '%d' | into duration -u day) + 1day)
  let $firstSpecificDay = $firstDay + (((($in | format date '%w' | into int) + 7 - ($firstDay | format date '%w' | into int)) mod 7) | into duration -u day)
  ((($in - $firstSpecificDay) | into int | into datetime | format date '%d' | into int) / 7 | math floor) + 1
 }

def get-month-of-quarter []: datetime -> int {
  let month = ($in | format date '%m' | into int) + 3
  ($month..($month - 3)..1) | last
}

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

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