#Requires -version 2.0

# -----------------------------------------------------------------------------
# Script: Start-TypedDemo.ps1
# Version: 0.9
# Author: Jeffery Hicks
#    http://jdhitsolutions.com/blog
#    http://twitter.com/JeffHicks
# Date: 5/3/2011
# Keywords:
# Comments:
#
# "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-TypedDemo {

<#
.SYNOPSIS
Simulate a PowerShell session
.DESCRIPTION
This command simulates an interactive PowerShell session. It will process a text file of PowerShell 
commands.  EACH COMMAND MUST BE A ONE LINE EXPRESSION. The function will insert your prompt and "type" 
out each command when you press any key. At the end of the typed command or whenever a pipe character
is inserted, the script will pause. Press Enter or any key to continue. If it is the end of the command
pressing Enter will executew the command. Use the -NoExecute parameter to run through the demo without
executing any commands. Commented lines will be skipped.

The Pause parameter is the "typing" speed interval in milliseconds. The default is 100.

Press 'q' or ESC at any pause to quit the demo.

This function will NOT run in the ISE.
.PARAMETER File
The file name of PowerShell commands to execute
.PARAMETER Pause
The typing speed interval between characters in milliseconds. The default is 100.
.PARAMETER NoExecute
Do not execute any of the commands. 
.EXAMPLE
PS C:\> Start-TypedDemo c:\work\demo.txt
Run the commands in c:\work\demo.txt
.NOTES
NAME        :  Start-TypedDemo
VERSION     :  0.9   
LAST UPDATED:  5/3/2011
AUTHOR      :  SERENITY\Jeff
.LINK
http://jdhitsolutions.com/blog/2011/05/start-typeddemo/
.LINK
Write-Host 
Invoke-Command 
.INPUTS
None
.OUTPUTS
None
#>

Param(
[Parameter(Position=0,Mandatory=$True,HelpMessage="Enter the name of a text file with your demo commands")]
[ValidateScript({Test-Path $_})]
[string]$File,
[ValidateScript({$_ -gt 0})]
[int]$Pause=100,
[switch]$NoExecute
)

#this is an internal function so I'm not worried about the name
Function PauseIt {

Param()
    #wait for a key press
    $Running=$true
    #keep looping until a key is pressed
    While ($Running)
    {
     if ($host.ui.RawUi.KeyAvailable) {
     $key = $host.ui.RawUI.ReadKey("NoEcho,IncludeKeyDown")
        if ($key) {
         $Running=$False  
         #check the value and if it is q or ESC, then bail out
         if ($key -match "q|27") {
           Write-Host `r
           #Exit
           Return "quit"
           }        
        }
      }
      start-sleep -millisecond 100
    } #end While
} #PauseIt function

#abort if running in the ISE
if ($host.name -match "PowerShell ISE") {
    Write-Warning "This will not work in the ISE. Use the PowerShell console host."
    Return
}

Clear-Host

#strip out all comments
$commands=Get-Content -Path $file | Where {-NOT $_.StartsWith("#")}
$count=0

#write a prompt using your current prompt function
Write-Host $(prompt) -NoNewline
 
foreach ($command in $commands) {
   $count++
   #pause until a key is pressed which will then process the next command
   $p=PauseIt
   If ($p -eq "quit") {Return}
        
    for ($i=0;$i -lt $command.length;$i++) {
     write-host $command[$i] -NoNewline
     Start-sleep -Milliseconds $Pause
     #if character is a pipe ( | ) pause in case an 
     #explanation is needed
     if ($command[$i] -eq "|") {
        $p=PauseIt
        If ($p -eq "quit") {Return}
     }
    }
    
    #Pause until ready to run the command 
    $p=PauseIt
    If ($p -eq "quit") {Return}
    Write-host `n
    #execute the command unless -NoExecute was specified
    if (-NOT $NoExecute) {
        Invoke-Expression $command | Out-Default
    }
   
   #reset the prompt unless we've just done the last command
   if ($count -lt $commands.count) {
    Write-Host $(prompt) -NoNewline 
   }
    
  } #foreach  
} #function

#uncomment if you want the alias
#Set-Alias -Name std -Value Start-TypedDemo