#requires -version 2.0

# -----------------------------------------------------------------------------
# Script: Convert-HistoryToScript.ps1
# Version: 2.0
# Author: Jeffery Hicks
#    http://jdhitsolutions.com/blog
#    http://twitter.com/JeffHicks
# Date: 1/10/2011
# Keywords: Get-History, Add-Content
# Comments: Convert history commands to a ps1 script file.
#
# "Those who neglect 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.             *
#  ****************************************************************
# -----------------------------------------------------------------------------

<#
   .Synopsis
    Convert history commands to a script file.
    .Description
    This script will take history commands and convert them into a text file, presumably
    a PowerShell script. The default is all history commands, but you can also specify a
    comma separated list of history items.
    .Parameter Path
    The filename and path to create.
    .Parameter ID
    The history IDs to convert, separated by commas.
   .Parameter NoClobber
   Do not overwrite an existing file.
   .Example
    PS C:\> Convert-HistoryToScript c:\scripts\Dev1.ps1  

    Directory: C:\scripts


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---         1/10/2011  11:03 AM       3227 dev.ps1h
  
    .Example
    PS S:\> 1,3,4 | .\Convert-HistoryToScript.ps1 Dev2.ps1


    Directory: C:\scripts


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---         1/10/2011  11:05 AM        400 Dev2.ps1

Export commands 1,3,4 to a script file.

    .Example
    PS S:\> (12..20),34,45,8,5 | .\Convert-HistoryToScript.ps1 -Path Dev3.ps1

    Directory: C:\scripts


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---         1/10/2011  11:10 AM        408 Dev3.ps1

Export commands 12 through 20 then commands 34, 45, 8 and 5 to a script file.
   .Notes
    NAME: Convert-HistoryToScript
    AUTHOR: Jeffery Hicks
    VERSION: 2.0
    LASTEDIT: 01/10/2011 
    
    Learn more with a copy of Windows PowerShell 2.0: TFM (SAPIEN Press 2010)
    
   .Link
    http://jdhitsolutions.com/blog/2011/01/convert-history-to-script/
    
    .Link
    Get-History
    
    .Inputs
    [int64]
    
    .Outputs
    FileObject
#>

Param(
    [Parameter(Position=0,Mandatory=$True,HelpMessage="Enter the filename and path for the script file",
    ValueFromPipeline=$False)]
    [ValidateNotNullorEmpty()]
    [string]$Path,
    
    [Parameter(Mandatory=$False,ValueFromPipeline=$True)]
    [int64[]]$ID,
    
    [switch]$NoClobber
)

Begin {
Set-StrictMode -Version 2.0

Write-Verbose "Starting $($myInvocation.mycommand)"

#delete the script if it already exists
if ((Test-Path -Path $Path) -AND ($NoClobber)) 
{
    $msg="$path already exists and NoClobber was specified."
    Write-Warning $msg
    #bail out
   Exit
}
Elseif (Test-Path -Path $path)
{    
    Write-Verbose "Removing existing version of $path"
    Remove-Item $Path
}

#get the file name and convert the last part to upper case
$FileName=(Split-Path -Path $path -Leaf).ToUpper()

#add a brief header
$header=@"
#Requires -Version 2.0

# $Filename
# Generated from PowerShell History $(Get-Date)
# Author: $env:username
# $("-"*80)

"@

$header | Out-File -FilePath $Path -Encoding ASCII

$history=@()

} #close Begin

Process {

if ($id)
{
    foreach ($i in $id)
    {
        Write-Verbose "Retrieving history item $([string]$i) $((Get-history -id $i).CommandLine)"
        $history+= Get-History -id $i
    }
}
else
{
    Write-Verbose "Retrieve All History"
    $history=Get-History -count $maximumhistorycount 
}
} #close Process

End {
Write-Verbose "Writing $($history.count) history commands to $path"

Add-Content -Path $path -Value ($history | select -expandproperty commandline ) -Encoding ASCII
#write the file object to the pipeline
Write-Verbose "Writing script file object to the pipeline"
Get-Item -Path $path
Write-Verbose "Finished"
} #close End