start-demo.ps1

## Start-Demo.ps1
##################################################################################################
## This is an overhaul of Jeffrey Snover's original Start-Demo script by Joel "Jaykul" Bennett
##
## I've switched it to using ReadKey instead of ReadLine (you don't have to hit Enter each time)
## As a result, I've changed the names and keys for a lot of the operations, so that they make
## sense with only a single letter to tell them apart (sorry if you had them memorized).
##
## I've also been adding features as I come across needs for them, and you'll contribute your
## improvements back to the PowerShell Script repository as well.
##################################################################################################
## Revision History (version 3.3)
## 3.3.3 Fixed: Script no longer says "unrecognized key" when you hit shift or ctrl, etc.
## Fixed: Blank lines in script were showing as errors (now printed like comments)
## 3.3.2 Fixed: Changed the "x" to match the "a" in the help text
## 3.3.1 Fixed: Added a missing bracket in the script
## 3.3 - Added: Added a "Clear Screen" option
## - Added: Added a "Rewind" function (which I'm not using much)
## 3.2 - Fixed: Put back the trap { continue; }
## 3.1 - Fixed: No Output when invoking Get-Member (and other cmdlets like it???)
## 3.0 - Fixed: Commands which set a variable, like: $files = ls
## - Fixed: Default action doesn't continue
## - Changed: Use ReadKey instead of ReadLine
## - Changed: Modified the option prompts (sorry if you had them memorized)
## - Changed: Various time and duration strings have better formatting
## - Enhance: Colors are settable: prompt, command, comment
## - Added: NoPauseAfterExecute switch removes the extra pause
## If you set this, the next command will be displayed immediately
## - Added: Auto Execute mode (FullAuto switch) runs the rest of the script
## at an automatic speed set by the AutoSpeed parameter (or manually)
## - Added: Automatically append an empty line to the end of the demo script
## so you have a chance to "go back" after the last line of you demo
##################################################################################################
##
param(
    $file = ".\demo.txt",
    [int]$command = 0,
    [System.ConsoleColor]$promptColor = "Yellow",
    [System.ConsoleColor]$commandColor = "White",
    [System.ConsoleColor]$commentColor = "Green",
    [switch]$FullAuto,
    [int]$AutoSpeed = 3,
    [switch]$NoPauseAfterExecute
)

$RawUI = $Host.UI.RawUI
$hostWidth = $RawUI.BufferSize.Width

# A function for reading in a character
function Read-Char() {
    $_OldColor = $RawUI.ForeGroundColor
    $RawUI.ForeGroundColor = "Red"
    $inChar = $RawUI.ReadKey("IncludeKeyUp")
    # loop until they press a character, so Shift or Ctrl, etc don't terminate us
    while ($inChar.Character -eq 0) {
        $inChar = $RawUI.ReadKey("IncludeKeyUp")
    }
    $RawUI.ForeGroundColor = $_OldColor
    return $inChar.Character
}

function Rewind($lines, $index, $steps = 1) {
    $started = $index;
    $index -= $steps;
    while (($index -ge 0) -and ($lines[$index].Trim(" `t").StartsWith("#"))) {
        $index--
    }
    if ( $index -lt 0 ) { $index = $started }
    return $index
}

$file = Resolve-Path $file
while (-not(Test-Path $file)) {
    $file = Read-Host "Please enter the path of your demo script (Crtl+C to cancel)"
    $file = Resolve-Path $file
}

Clear-Host

$_lines = Get-Content $file
# Append an extra (do nothing) line on the end so we can still go back after the last line.
$_lines += "Write-Host 'The End'"
$_starttime = [DateTime]::now
#$FullAuto = $false


Write-Host -nonew -back black -fore $promptColor $(" " * $hostWidth)
Write-Host -nonew -back black -fore $promptColor @"
<Demo Started :: $(split-path $file -leaf)>$(' ' * ($hostWidth -(18 + $(split-path $file -leaf).Length)))
"@

Write-Host -nonew -back black -fore $promptColor "Press"
Write-Host -nonew -back black -fore Red " ? "
Write-Host -nonew -back black -fore $promptColor "for help.$(' ' * ($hostWidth -17))"
Write-Host -nonew -back black -fore $promptColor $(" " * $hostWidth)

# We use a FOR and an INDEX ($_i) instead of a FOREACH because
# it is possible to start at a different location and/or jump
# around in the order.
for ($_i = $Command; $_i -lt $_lines.count; $_i++) {
    # Put the current command in the Window Title along with the demo duration
    $Dur = [DateTime]::Now - $_StartTime
    $RawUI.WindowTitle = "$(if($dur.Hours -gt 0){'{0}h '})$(if($dur.Minutes -gt 0){'{1}m '}){2}s {3}" -f
    $dur.Hours, $dur.Minutes, $dur.Seconds, $($_Lines[$_i])

    # Echo out the commmand to the console with a prompt as though it were real
    Write-Host -nonew -fore $promptColor "[$_i]$([char]0x2265) "
    if ($_lines[$_i].Trim(" ").StartsWith("#") -or $_lines[$_i].Trim(" ").Length -le 0) {
        Write-Host -fore $commentColor "$($_Lines[$_i]) "
        continue
    }
    else {
        Write-Host -nonew -fore $commandColor "$($_Lines[$_i]) "
    }

    if ( $FullAuto ) { Start-Sleep $autoSpeed; $ch = [char]13 } else { $ch = Read-Char }
    switch ($ch) {
        "?" {
            Write-Host -Fore $promptColor @"
 
Running demo: $file
(n) Next (p) Previous
(q) Quit (s) Suspend
(t) Timecheck (v) View $(split-path $file -leaf)
(g) Go to line by number
(f) Find lines by string
(a) Auto Execute mode
(c) Clear Screen
"@

            $_i-- # back a line, we're gonna step forward when we loop
        }
        "n" {
            # Next (do nothing)
            Write-Host -Fore $promptColor "<Skipping Line>"
        }
        "p" {
            # Previous
            Write-Host -Fore $promptColor "<Back one Line>"
            while ($_lines[--$_i].Trim(" ").StartsWith("#")) {}
            $_i-- # back a line, we're gonna step forward when we loop
        }
        "a" {
            # EXECUTE (Go Faster)
            $AutoSpeed = [int](Read-Host "Pause (seconds)")
            $FullAuto = $true;
            Write-Host -Fore $promptColor "<eXecute Remaining Lines>"
            $_i-- # Repeat this line, and then just blow through the rest
        }
        "q" {
            # Quit
            Write-Host -Fore $promptColor "<Quiting demo>"
            $_i = $_lines.count;
            break;
        }
        "v" {
            # View Source
            $lines[0..($_i - 1)] | Write-Host -Fore Yellow
            $lines[$_i]        | Write-Host -Fore Green
            $lines[($_i + 1)..$lines.Count] | Write-Host -Fore Yellow
            $_i-- # back a line, we're gonna step forward when we loop
        }
        "t" {
            # Time Check
            $dur = [DateTime]::Now - $_StartTime
            Write-Host -Fore $promptColor $(
                "{3} -- $(if($dur.Hours -gt 0){'{0}h '})$(if($dur.Minutes -gt 0){'{1}m '}){2}s" -f
                $dur.Hours, $dur.Minutes, $dur.Seconds, ([DateTime]::Now.ToShortTimeString()))
            $_i-- # back a line, we're gonna step forward when we loop
        }
        "s" {
            # Suspend (Enter Nested Prompt)
            Write-Host -Fore $promptColor "<Suspending demo - type 'Exit' to resume>"
            $Host.EnterNestedPrompt()
            $_i-- # back a line, we're gonna step forward when we loop
        }
        "g" {
            # GoTo Line Number
            $i = [int](Read-Host "line number")
            if ($i -le $_lines.Count) {
                if ($i -gt 0) {
                    # extra line back because we're gonna step forward when we loop
                    $_i = Rewind $_lines $_i (($_i - $i) + 1)
                }
                else {
                    $_i = -1 # Start negative, because we step forward when we loop
                }
            }
        }
        "f" {
            # Find by pattern
            $match = $_lines | Select-String (Read-Host "search string")
            if ($match -eq $null) {
                Write-Host -Fore Red "Can't find a matching line"
            }
            else {
                $match | % { Write-Host -Fore $promptColor $("[{0,2}] {1}" -f ($_.LineNumber - 1), $_.Line) }
                if ($match.Count -lt 1) {
                    $_i = $match.lineNumber - 2  # back a line, we're gonna step forward when we loop
                }
                else {
                    $_i-- # back a line, we're gonna step forward when we loop
                }
            }
        }
        "c" {
            Clear-Host
            $_i-- # back a line, we're gonna step forward when we loop
        }
        "$([char]13)" {
            # on enter
            Write-Host
            trap [System.Exception] {Write-Error $_; continue; }
            Invoke-Expression ($_lines[$_i]) | out-default
            if (-not $NoPauseAfterExecute -and -not $FullAuto) {
                $null = $RawUI.ReadKey("NoEcho,IncludeKeyUp")  # Pause after output for no apparent reason... ;)
            }
        }
        default {
            Write-Host -Fore Green "`nKey not recognized. Press ? for help, or ENTER to execute the command."
            $_i-- # back a line, we're gonna step forward when we loop
        }
    }
}
$dur = [DateTime]::Now - $_StartTime
Write-Host -Fore $promptColor $(
    "<Demo Complete -- $(if($dur.Hours -gt 0){'{0}h '})$(if($dur.Minutes -gt 0){'{1}m '}){2}s>" -f
    $dur.Hours, $dur.Minutes, $dur.Seconds, [DateTime]::Now.ToLongTimeString())
Write-Host -Fore $promptColor $([DateTime]::now)
Write-Host