<#
 -----------------------------------------------------------------------------
 Script: Countdown2.ps1
 Version: 0.9
 Author: Jeffery Hicks
    http://jdhitsolutions.com/blog
    http://twitter.com/JeffHicks
    http://www.ScriptingGeek.com
 Date: 4/27/2012
 Keywords:
 Comments:
 This is a variation on the Start-Countdown script from Josh Atwell
 (http://www.vtesseract.com/post/21414227113/start-countdown-function-a-visual-for-start-sleep)

 "Those who forget to script are doomed to repeat their work."

  ****************************************************************
  * DO NOT USE IN A PRODUCTION ENVIRONMENT UNTIL YOU HAVE TESTED *
  * THOROUGHLY IN A LAB ENVIRONMENT. USE AT YOUR OWN RISK.  IF   *
  * YOU DO NOT UNDERSTAND WHAT THIS SCRIPT DOES OR HOW IT WORKS, *
  * DO NOT USE IT OUTSIDE OF A SECURE, TEST SETTING.             *
  ****************************************************************
 -----------------------------------------------------------------------------
 #>
 

Function Start-Countdown {
<#
	.Synopsis
	 Initiates a countdown before running a command
    
    .Description  
     This is a variation on the Start-Countdown script from Josh Atwell
     (http://www.vtesseract.com/post/21414227113/start-countdown-function-a-visual-for-start-sleep). 
     It can be used instead of Start-Sleep and provides a visual countdown 
     progress during "sleep" times. At the end of the countdown, your 
     command will execute. Press the ESC key any time during the countdown
     to abort. 
     
     USING START-COUNTDOWN IN THE POWERSHELL ISE
     Results will vary slightly in the PowerShell ISE. If you use this in
     the ISE, it is recommended to use -Clear. You also cannot use the ESC
     key to abort the script if using the console. You'll need to press
     Ctrl+C. If using the progress bar, there is a Stop button in the ISE.
     If you abort in the ISE, you won't get the warning message.
     
     .Parameter Seconds
     The number of seconds to countdown. The default is 10.
     
     .Parameter Scriptblock
     A PowerShell scriptblock to execute at the end of the countdown.
     
     .Parameter ProgressBar
     Use a progress bar instead of the console.
     
     .Parameter Clear
     Clear the screen. Other wise, the countdown will use the current location.
     
     .Parameter Message
     The message to be displayed at the end of the countdown before any
     scriptblock is executed.
     	 
	.Example
	 PS C:\> Start-Countdown -Seconds 10 -clear
	 
	 This method will clear the screen and display descending seconds
	
	.Example
	 PS C:\> Start-Countdown -Seconds 30 -ProgressBar -scriptblock {get-service -comp (get-content computers.txt)}
	 
	 This method will display a progress bar on screen. At the end of the countdown the scriptblock will execute.
	 	 
	.Link
	 http://jdhitsolutions.com/blog
     
     .Link
     Write-Progress
	
#>
Param(
[Parameter(Position=0,HelpMessage="Enter seconds to countdown from")]
[Int]$Seconds = 10,
[Parameter(Position=1,Mandatory=$False,
HelpMessage="Enter a scriptblock to execute at the end of the countdown")]
[scriptblock]$Scriptblock,
[Switch]$ProgressBar,
[Switch]$Clear,
[String]$Message = "Blast Off!"
)

#save beginning value for total seconds
$TotalSeconds=$Seconds

#get current cursor position
$Coordinate = New-Object System.Management.Automation.Host.Coordinates
$Coordinate.X=$host.ui.rawui.CursorPosition.X
$Coordinate.Y=$host.ui.rawui.CursorPosition.Y

If ($clear) {
    Clear-Host
    #find the middle of the current window
    $Coordinate.X=[int]($host.ui.rawui.WindowSize.Width/2)
    $Coordinate.Y=[int]($host.ui.rawui.WindowSize.Height/2)
}

#define the Escape key
$ESCKey = 27

#define a variable indicating if the user aborted the countdown
$Abort=$False

while ($seconds -ge 1) {

    if ($host.ui.RawUi.KeyAvailable)
    		{
    		$key = $host.ui.RawUI.ReadKey("NoEcho,IncludeKeyUp,IncludeKeyDown")

    		if ($key.VirtualKeyCode -eq $ESCkey)
    			{
                #ESC was pressed so quit the countdown and set abort flag to True
    			$Seconds = 0
                $Abort=$True 
    			}
    		}

    If($ProgressBar){
        #calculate percent time remaining, but in reverse so the progress bar
        #moves from left to right
        $percent=100 - ($seconds/$TotalSeconds)*100
    	Write-Progress -Activity "Countdown" -SecondsRemaining $Seconds -Status "Time Remaining" -PercentComplete $percent
    	Start-Sleep -Seconds 1
    } Else {
        if ($Clear) {
          Clear-Host
        } 
        $host.ui.rawui.CursorPosition=$Coordinate
        #write the seconds with padded trailing spaces to overwrite any extra digits such
        #as moving from 10 to 9
        $pad=($TotalSeconds -as [string]).Length
        if ($seconds -le 10) {
            $color="Red"
        }
        else {
            $color="Green"
        }
        Write-Host "$(([string]$Seconds).Padright($pad))" -foregroundcolor $color
    	Start-Sleep -Seconds 1
    }
    #decrement $Seconds
    $Seconds--
} #while

if ($Progress) {
        #set progress to complete
        Write-Progress -Completed
    }

if (-Not $Abort) {
    
    if ($clear) {
        #if $Clear was used, center the message in the console
        $Coordinate.X=$Coordinate.X - ([int]($message.Length)/2)
    }

    $host.ui.rawui.CursorPosition=$Coordinate
    
    Write-Host $Message -ForegroundColor Green
    #run the scriptblock if specified
    if ($scriptblock) {    
        Invoke-Command -ScriptBlock $Scriptblock
    }
}
else {
    Write-Warning "Countdown aborted"
}

} #end function