Out-ConditionalColor.ps1


Function Out-ConditionalColor {

[cmdletbinding(DefaultParameterSetName="property")]
Param(
[Parameter(Position=0,Mandatory,
HelpMessage="Enter an hashtable of conditional properties and colors.",
ParameterSetName="property")]
[ValidateScript({
    #validate colors
    $allowed = [enum]::GetNames([system.consolecolor])
    $bad = $_.Values | Where-Object {$allowed -notcontains $_}
    if ($bad) {
        $valid = $allowed -join ','
        Throw "You are using one or more invalid colors: $($bad -join ','). Valid colors are $Valid"
    }    
    else {
        $True
    }
})]
[hashtable]$PropertyConditions,

[Parameter(Mandatory,HelpMessage="Enter a property name.",
ParameterSetName="property")]
[string]$Property,

[Parameter(Position=0,Mandatory,
HelpMessage="Enter an ordered hashtable of conditions and colors.",
ParameterSetName="conditions")]
[System.Collections.Specialized.OrderedDictionary]$Conditions,

[Parameter(Mandatory,ValueFromPipeline)]
[PSObject[]]$InputObject

)

Begin {
    Write-Debug "Starting $($MyInvocation.MyCommand)"
    write-Debug "Using parameter set $($pscmdlet.ParameterSetName)"
    #save original color
    $saved = $Host.UI.RawUI.ForegroundColor
    
    Write-Debug "Original foreground color is $saved"  
   
    if ($PSCmdlet.ParameterSetName -eq 'conditions') {
        #we'll need this later in the Process script block
        #if doing complex processing
        Write-Debug "Getting hash table enumerator and names"
        $compare = $conditions.GetEnumerator().name
        Write-Debug $($compare | out-string)
        #build an If/ElseIf construct on the fly
#the Here strings must be left justified
$If=@"
 if ($($compare[0])) {
  `$host.ui.RawUI.ForegroundColor = '$($conditions.item($($compare[0])))'
 }
"@
        #now add the remaining comparisons as ElseIf
        for ($i=1;$i -lt $conditions.count;$i++) {
         $If+="elseif ($($compare[$i])) { 
         `$host.ui.RawUI.ForegroundColor = '$($conditions.item($($compare[$i])))'
         }
         "
        } #for

#add the final else
$if+=@"
Else { 
`$host.ui.RawUI.ForegroundColor = `$saved 
}
"@

        Write-Debug "Complex comparison:"
        Write-Debug $If
    } #if complex parameter set   

} #Begin

Process {

    If ($PSCmdlet.ParameterSetName -eq 'conditions') {
        #Use complex processing
        Invoke-Expression $if
  } #end complex
  else {
        #get property value as a string
        $value = $Inputobject.$Property.ToString()
        Write-Debug "Testing property value $value"
        if ($PropertyConditions.containsKey($value)) {
         Write-Debug "Property match"
         $host.ui.RawUI.ForegroundColor= $PropertyConditions.item($value)
        }
        else {
         #use orginal color
         Write-Debug "No matches found"
         $host.ui.RawUI.ForegroundColor= $saved
        }        
  } #simple

    #write the object to the pipeline
    Write-Debug "Write the object to the pipeline"
    $_
} #Process

End {
    Write-Debug "Restoring original foreground color"
    #set color back
    $host.ui.RawUI.ForegroundColor = $saved
    } #end

} #close function