TimeToSanta.ps1

Function TimeToSanta {
    <#
.Synopsis
   Show how long you have to wait to open your presents
.DESCRIPTION
   Be able to leave your shopping to the very last minute with this state-of-the-art function to show 
   how long is left to 25th Dec 09:00. Two variations exist depending on whether the information is to be shown
   at the console prompt or as a message
.EXAMPLE
   TimeToSanta -purpose console

   This method returns a string that is a longer message
.EXAMPLE
   TimeToSanta -purpose prompt

   This method returns a string small enough to give a countdown in your console prompt
#>
    param(
        # This value is the decide if the output is for the commandline prompt or a console message
        [Parameter()]
        [ValidateSet("console", "prompt")]
        [string]
        $Purpose
    )
    # we need 'this year' and the day number of Christmas Day ...
    $Year = (get-date).Year
    $DOY = ([datetime]"25-dec-$year").DayOfYear

    # ... so that we can add a year on to Christmas Day if we are between 25th Dec and 1st Jan
    if ((get-date).DayOfYear -gt $DOY) {
        $Year ++
    }
    
    # ... so that we get the gap to a future 25th Dec
    $CDay = [datetime]"25-Dec-$Year 09:00:00"

    # TTS is a duration between two dates
    $TimeToSanta = New-TimeSpan -Start (get-date) -End $CDay

    # Construct the output string according to requirement of calling process 
    switch ($Purpose) {
        "console" {$msg = "Christmas Day in $($TimeToSanta.Days) Days $($TimeToSanta.hours) hours $($TimeToSanta.Minutes) Minutes"}

        "prompt" {$msg = "$($TimeToSanta.Days) days $(($TimeToSanta.Hours).tostring(00)):$(($TimeToSanta.Minutes).tostring(00)):$(($TimeToSanta.Seconds).tostring(00))"}
    }
    
    return ($msg)
}

<#
Edit your Prompt with the code below to have updates every time you run a command from your console
 if ((get-date).Month -eq 12 -and (get-date).Day -lt 25) {
        Write-Host $msg -NoNewline
        $msg = "["
        $msg += TimetoSanta -purpose Prompt
        $msg += "]"
        Write-Host $msg -NoNewline -BackgroundColor Red -ForegroundColor DarkBlue
    }
#>