plank countdown script in more of a functional style

plank-countdown-functional.ps1

# main entry point
function Main
{
    $total = 60 * 2 + 58
    $timings = Generate-Timings -Total $total
    Speak-Timings $timings
}

# int -> string[]
# generates an array of strings representing what should be said at each second.
function Generate-Timings($Total)
{
    $startCountdown = $total - 10

    # count up every 30 seconds
    $countup = 1..($startCountdown - 1) `
        | ForEach-Object {
            $seconds = $_
            switch ($seconds) {
                30 { "30 seconds passed" }
                60 { "1 minute passed" }
                default {
                    [string]$minutes = [Math]::Floor($seconds / 60)
                    switch ($seconds % 60) {
                        0 {  "$minutes minutes passed" }
                        30 { "$minutes 30 passed" }
                        default { "" }
                    }
                }
            }
         }

    # count down from 10 to 1
    $countdown = $startCountdown..$total `
        | ForEach-Object {
            $total - $_
        }

    $countup + $countdown
}

# string[] -> IO
function Speak-Timings($timings)
{
    Add-Type -AssemblyName System.Speech; 
    $speaker = (New-Object System.Speech.Synthesis.SpeechSynthesizer)
    $speaker.SelectVoice("Microsoft Zira Desktop")

    $speaker.Speak("Hi everyone, ready? Start planking in 3, 2, 1!")
    $timings | ForEach-Object {
        if($_) {
            Speak-Async $_
            write-host $_
        }
        sleep 1
    }
    sleep 1
    $speaker.Speak("Good job everyone. I knew you could do it")
}

# speak the text, but don't block the current thread
function Speak-Async($text)
{
    # not using $synth.SpeakAsync because execution is slow when we do the countdown
    Start-Process powershell -NoNewWindow -argument @"
        Add-Type -AssemblyName System.Speech; 
        `$synth = (New-Object System.Speech.Synthesis.SpeechSynthesizer)
        `$synth.SelectVoice('Microsoft Zira Desktop')
        `$synth.Speak('$text')
"@
}

Main