posh prompt nonsense

promptstuff.ps1

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##  Prompt                                                                                                                                ##
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Clear-Host
[ScriptBlock]$Prompt = {
    $origLastExitCode = $global:LASTEXITCODE
    Set-StrictMode -Version 'Latest'
    $gitLoaded = $false # skip stupid git module, adds ~1000ms to startup time.

    #
    # PATHS
    #
    <#
        A UNC path has no drive so it's better to use the ProviderPath e.g. "\\server\share".
        However for any path with a drive defined, it's better to use the Path property.
        In this case, ProviderPath is "\LocalMachine\My"" whereas Path is "Cert:\LocalMachine\My".
        The latter is more desirable.
    #>
    $CurrentLocation = $ExecutionContext.SessionState.Path.CurrentLocation
    $_CD_ = if($CurrentLocation.Drive){ $CurrentLocation.Path }else{ $CurrentLocation.ProviderPath }
    $tpwd = $_CD_ -Replace [Regex]::Escape("$HOME"),'~' -Replace '^[^:]+::','' # Replace any paths containing $HOME with '~'
    $spwd = $tpwd -Replace '\\(\.?)([^\\])[^\\]*(?=\\)','\$1$2'                # Abreviates each dir to 1 char except for last
    $PWDMaxLen = [int]'32' # Max chars in current tilde'd path before switching to abreviation
    $PPWD = if($tpwd.Length -and ($tpwd.Length -le $PWDMaxLen)){ $tpwd }else{ $spwd }

    # check vars if not set
    $PS_VERSION = [string]$PSVersionTable.PSVersion
    $SHELL      = [string]$ShellId+'.'+$PSEdition+' '+$PS_Version
    if(!$USER){ $USER = $env:UserName }
    if(!$HOME){ $HOME = $env:UserProfile }
    if(!$HOSTNAME){ $HOSTNAME = [Net.Dns]::GetHostName() }
    if($null -eq $IsAdmin){ [bool]$IsAdmin = ([Security.Principal.WindowsPrincipal](
                                                [Security.Principal.WindowsIdentity]::GetCurrent()
                                                )).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator) }
    #
    # Colors (Note: PS5 has issues with backtick escape color codes, so use [char] for escapes)
    #
    $fg = @{
        # 'black'   = "$([char]0x1b)[30m"
        # 'red'     = "$([char]0x1b)[31m"
        'green'     = "$([char]0x1b)[32m"
        'yellow'    = "$([char]0x1b)[33m"
        # 'blue'    = "$([char]0x1b)[34m"
        # 'magenta' = "$([char]0x1b)[35m"
        # 'cyan'    = "$([char]0x1b)[36m"
        # 'white'   = "$([char]0x1b)[37m"
    }
    # bold, though technically "bright", but same difference
    $fg_bold = @{
        # 'gray'    = "$([char]0x1b)[90m"
        # 'black'   = "$([char]0x1b)[90m"
        'red'       = "$([char]0x1b)[91m"
        # 'green'   = "$([char]0x1b)[92m"
        # 'yellow'  = "$([char]0x1b)[93m"
        'blue'      = "$([char]0x1b)[94m"
        # 'magenta' = "$([char]0x1b)[95m"
        # 'cyan'    = "$([char]0x1b)[96m"
        # 'white'   = "$([char]0x1b)[97m"
    }
    $c_reset      = "$([char]0x1b)[0m"
    $c_user       = if($IsAdmin){ "$($fg_bold['red'])" }else{ "$($fg['green'])" }
    $nl           = "$([char]10)" # newline

    #
    # Main prompt line: User@Hostname shell.name.edition n.n.nn ~\foo\bar + newline + '> '
    #
    "$($c_user+$USER+'@'+$HOSTNAME+$fg_bold['blue']+' '+$SHELL+' '+$fg['yellow']+$PPWD+$c_reset+$(if($gitLoaded-and(Test-Path ${_CD_}\.git)){Write-VcsStatus})+
    $nl+$('>' * ($nestedPromptLevel + 1)) ) "

    #
    # Window Title (short path or only current directory if Length <= 7)
    #
    $wpwd = if($spwd.Length -le 7){ $spwd }else{ try{ Split-Path $_CD_ -Leaf }catch{ "$([char]8734)" } }
    $Host.UI.RawUI.WindowTitle = "$($(if($IsAdmin){'Admin: '})+$wpwd)" # prefix 'Admin: ' if elevated, else just path or cwd

    #
    # [Environment]::CurrentDirectory
    #
    [ScriptBlock]$locationChangedHandler = {
        try {
            # Update CurrentDirectory so .NET sees same PSPath as powershell
            # Note: Must use Filesystem provider, PSDrives and network paths are invalid
            [System.Environment]::CurrentDirectory = $ExecutionContext.SessionState.Path.CurrentFileSystemLocation
        } catch [System.UnauthorizedAccessException],
                [System.Management.Automation.MethodInvocationException],
                [System.Management.Automation.SetValueInvocationException] {
            # Catch UnauthorizedAccessException if any directories in path not readable
            $Error.Remove($error[0])
            # And as a last ditch effort, try `Get-Location` cmdlet
            try {
                [System.Environment]::CurrentDirectory = Get-Location -PSProvider FileSystem
            } catch {}
        }
    }
    # Note: PS < v6 does not have LocationChangedAction, so invoke scriptblock instead for compatibility.
    #       PS6: `$ExecutionContext.InvokeCommand.LocationChangedAction = $locationChangedHandler`
    & $locationChangedHandler

    # Restore LastExitCode in case we contaminated it
    $global:LASTEXITCODE = $origLastExitCode
    Remove-Variable origLASTEXITCODE
    return " "
    # .Link
    # https://go.microsoft.com/fwlink/?LinkID=225750
    # .ExternalHelp System.Management.Automation.dll-help.xml
}

# Tell PSReadline which part of the prompt to change red for interactive syntax validation. (PS6 only or PSReadline >= 2)
if ($IsCoreCLR -or (Get-Module PSReadLine).Version.Major -ge 2) {
    Set-PSReadLineOption -PromptText '> ' 
}
# Set prompt readonly to prevent unexpected altering of prompt (without -Force)
Set-Item 'Function:\Prompt' -Value $Prompt -Force -Option:ReadOnly -ErrorAction:Ignore -Verbose:$false