ConfirmHost.psm1

function Confirm-Host {
    <#
    .SYNOPSIS
        Prompts the user to OK or Cancel an operation via the host.
    .DESCRIPTION
        Prompts the user to OK an operation by hitting ENTER or cancel
        it by hitting ESC.
    .EXAMPLE
        if(Confirm-Host) { ... }
    .OUTPUTS
        [bool]
    #>
    [CmdletBinding()]
    param(
        # Prompt string to display to the user
        [string]$Prompt = "Press ENTER to continue, or ESC to cancel",
        # Timeout value, in seconds
        [int]$Timeout = 0,
        # Default value to use if the operation times-out
        [bool]$TimeoutDefault = $true,
        # The color to use for the prompt
        [ConsoleColor]$PromptColor = 'DarkGray'
    )    
    $oldcolor = $host.UI.RawUI.ForegroundColor
    $oldctrlc = [console]::TreatControlCAsInput
    $enterdown = $false
    $escdown = $false
    $timeoutCount = $timeout * 20
    $result = $TimeoutDefault

    [console]::TreatControlCAsInput = $true
    Invoke-Command { $host.UI.RawUI.FlushInputBuffer() } -ErrorAction SilentlyContinue
    try {
        $host.UI.RawUI.ForegroundColor = $PromptColor
        Write-Host -NoNewline "$prompt"
        :outerloop while((-not $timeout) -or ($timeoutCount -gt 0)) {
            if($timeout -and (($timeoutCount % 20) -eq 0)) {
                Write-Host -NoNewline "`r$prompt ($([int]($timeoutCount/20)))    `r"
            }
            Start-Sleep -Milliseconds 50
            $timeoutCount = $timeoutCount - 1
            while($host.ui.RawUI.KeyAvailable) {
                $key = $host.ui.RawUI.ReadKey("AllowCtrlC,IncludeKeyUp,IncludeKeyDown,NoEcho")
                if($key.KeyDown) {
                    if($key.VirtualKeyCode -eq 27) { $escdown = $true }
                    if($key.VirtualKeyCode -eq 13) { $enterdown = $true }
                } else {
                    if(($key.VirtualKeyCode -eq 27) -and $escdown) { $result = $false; break outerloop }
                    if(($key.VirtualKeyCode -eq 13) -and $enterdown) { $result = $true; break outerloop }
                }
            }
        }
    } finally {
        Write-Host "`r$prompt        "
        $host.UI.RawUI.ForegroundColor = $oldcolor
        [console]::TreatControlCAsInput = $oldctrlc
    }
    return $result
}