Set-TabColor.ps1

<#
.SYNOPSIS
Set the color of the current terminal tab and background.
.DESCRIPTION
This script sets the color of the current terminal tab and background based on various input parameters.
It supports random colors, hexadecimal color codes, console colors, known colors, and RGBA values
for more precise color control.
.PARAMETER Random
If specified, a random color will be generated.
.PARAMETER Hex
A hexadecimal color code (6 or 8 characters) to set the color.
.PARAMETER ConsoleColor
A System.ConsoleColor value to set the color.
.PARAMETER KnownColor
A System.Drawing.KnownColor value to set the color.
.PARAMETER Red
The red component of the color (0-255).
.PARAMETER Green
The green component of the color (0-255).
.PARAMETER Blue
The blue component of the color (0-255).
.PARAMETER Alpha
The alpha (transparency) component of the color (0-255).
.PARAMETER TabScale
A percentage (1-100) to scale the tab color brightness. Default is 100.
.PARAMETER BackgroundScale
A percentage (1-100) to scale the background color brightness. Default is 30.
.PARAMETER TabOnly
If specified, only the tab color will be set, not the terminal background.
.PARAMETER BlacklistCurrent
If specified, the current tab color will be added to a blacklist file to avoid reuse in future random selections.
.EXAMPLE
Set-TabColor -Random
Sets a random color for the terminal tab and background.
.EXAMPLE
Set-TabColor -Hex 'FF5733'
Sets the terminal tab and background color to the specified hexadecimal color code.
.EXAMPLE
Set-TabColor -ConsoleColor 'DarkCyan'
Sets the terminal tab and background color to the specified console color.
.EXAMPLE
Set-TabColor -KnownColor 'Coral'
Sets the terminal tab and background color to the specified known color.
#>
[CmdletBinding( DefaultParameterSetName = 'Random' )]
param(
    [Parameter( ParameterSetName = 'Random' )]
    [switch]
    $Random,
    [Parameter( ParameterSetName = 'Hex', Mandatory )]
    [ValidateScript({
        if ( $_ -match '[^a-f\d]' ) {
            throw 'Hex must be a valid hexadecimal string.'
        }
        if ( $_.Length -ne 6 -and $_.Length -ne 8 ) {
            throw 'Hex must be exactly 6 or 8 characters long.'
        }
        return $true
    })]
    [string]
    $Hex,
    [Parameter( ParameterSetName = 'ConsoleColor', Mandatory )]
    [System.ConsoleColor]
    $ConsoleColor,
    [Parameter( ParameterSetName = 'KnownColor', Mandatory )]
    [System.Drawing.KnownColor]
    $KnownColor,
    [Parameter( ParameterSetName = 'RGBA', Mandatory )]
    [ValidateRange( 0, 255 )]
    [System.Nullable[UInt32]]
    $Red,
    [Parameter( ParameterSetName = 'RGBA', Mandatory )]
    [ValidateRange( 0, 255 )]
    [System.Nullable[UInt32]]
    $Green,
    [Parameter( ParameterSetName = 'RGBA', Mandatory )]
    [ValidateRange( 0, 255 )]
    [System.Nullable[UInt32]]
    $Blue,
    [ValidateRange( 1, 100 )]
    [UInt32]
    $TabScale = 100,
    [UInt32]
    $BackgroundScale = 30,
    [switch]
    $TabOnly,
    [Parameter( ParameterSetName = 'BlacklistCurrent' )]
    [switch]
    $BlacklistCurrent
)

#Requires -PSEdition Core

$BlackListPath = [IO.Path]::Combine( $env:USERPROFILE, '.config', 'PowerShell', 'TabColorBlacklist.txt' )

if ( $BlacklistCurrent ) {

    if ( -not $env:__TabColor ) {
        throw 'No current tab color found in environment variable __TabColor.'
    }
    
    # append to the blacklist file
    $BlackListFolder = [IO.Path]::GetDirectoryName( $BlackListPath )
    New-Item -Path $BlackListFolder -ItemType Directory -Force > $null
    [string[]] $Blacklist = Get-Content -Path $BlackListPath -ErrorAction SilentlyContinue
    if ( $env:__TabColor -notin $Blacklist ) {
        Write-Verbose ( 'Adding {0} to color blacklist at {1}' -f $env:__TabColor, $BlackListPath )
        Add-Content -Path $BlackListPath -Value $env:__TabColor -Force
    } else {
        Write-Verbose ( '{0} is already in the color blacklist at {1}' -f $env:__TabColor, $BlackListPath )
    }

}

[System.Drawing.Color] $Color = switch ( $PSCmdlet.ParameterSetName ) {

    'ConsoleColor' {
        Write-Verbose ( 'Using ConsoleColor: {0}' -f $ConsoleColor )
        $ColorKeyName = 'ColorTable{0:00}' -f [int] $ConsoleColor
        $ColorValue = Get-ItemProperty -Path HKCU:\Console\ -Name $ColorKeyName -ErrorAction Stop | Select-Object -ExpandProperty $ColorKeyName
        $R, $G, $B, $null = [BitConverter]::GetBytes($ColorValue)
        [System.Drawing.Color]::FromArgb( $R, $G, $B )
    }

    'KnownColor' {
        Write-Verbose ( 'Using KnownColor: {0}' -f $KnownColor )
        [System.Drawing.Color]::FromKnownColor( $KnownColor )
    }

    'Hex' {
        Write-Verbose ( 'Using Hex: {0}' -f $Hex )
        $R = [Convert]::ToInt32( $Hex.Substring( 0, 2 ), 16 )
        $G = [Convert]::ToInt32( $Hex.Substring( 2, 2 ), 16 )
        $B = [Convert]::ToInt32( $Hex.Substring( 4, 2 ), 16 )
        if ( $Hex.Length -eq 8 ) {
            $A = [Convert]::ToInt32( $Hex.Substring( 6, 2 ), 16 )
        } else {
            $A = 255
        }
        [System.Drawing.Color]::FromArgb( $A, $R, $G, $B )
    }

    'RGBA' {
        Write-Verbose ( 'Using RGBA: {0}, {1}, {2}, {3}' -f $Red, $Green, $Blue, $Alpha )
        [System.Drawing.Color]::FromArgb( $Alpha, $Red, $Green, $Blue )
    }

    default {
        # enumerate the color blacklist
        [string[]] $Blacklist = ( Test-Path -Path '~\.config\PowerShell\TabColorBlacklist.txt' -PathType Leaf ) ?
            ( Get-Content -Path '~\.config\PowerShell\TabColorBlacklist.txt' | Where-Object { -not [string]::IsNullOrWhiteSpace($_) -and -not $_[0] -eq '#' } ) :
            @()
        
        Write-Verbose 'Selecting a random KnownColor...'
        [System.Drawing.KnownColor].GetEnumNames() |
            ForEach-Object { [System.Drawing.Color]::FromKnownColor($_) } |
            Where-Object {
                $_.Name -notin $Blacklist -and
                $_.IsSystemColor -eq $false -and
                (
                    $_.R -ne $_.G -or
                    $_.G -ne $_.B -or
                    $_.B -ne $_.R
                )
            } | Get-Random
    }

}

$Red   = $Color.R
$Green = $Color.G
$Blue  = $Color.B
$Alpha = $Color.A

# store the current color for blacklisting if requested
$ColorHex = '{0:x2}{1:x2}{2:x2}{3:x2}' -f [int] $Red, [int] $Green, [int] $Blue, [int] $Alpha
$env:__TabColor = $ColorHex

Write-Verbose ( 'Starting Color: {0}' -f $ColorHex )

$TabRed   = $Red   * $TabScale / 100
$TabGreen = $Green * $TabScale / 100
$TabBlue  = $Blue  * $TabScale / 100

Write-Verbose ( 'Tab Color: {0:x2}{1:x2}{2:x2}{3:x2}' -f [int] $TabRed, [int] $TabGreen, [int] $TabBlue, [int] $Alpha )

$TabColor = 'rgb:{0:x2}/{1:x2}/{2:x2}' -f [int] $TabRed, [int] $TabGreen, [int] $TabBlue
Write-Host "`e]4;264;$TabColor`a"

# If only setting the tab color, exit here
if ( $TabOnly ) { return }

$BackgroundRed   = $TabRed   * $BackgroundScale / 100
$BackgroundGreen = $TabGreen * $BackgroundScale / 100
$BackgroundBlue  = $TabBlue  * $BackgroundScale / 100

Write-Verbose ( 'Background Color: {0:x2}{1:x2}{2:x2}' -f [int] $BackgroundRed, [int] $BackgroundGreen, [int] $BackgroundBlue )
$BackgroundColor = 'rgb:{0:x2}/{1:x2}/{2:x2}' -f [int] ($BackgroundRed), [int] ($BackgroundGreen), [int] ($BackgroundBlue)
Write-Host "`e]4;262;$BackgroundColor`a"