PowerShell Core custom prompt (use a PowerLine or nerdfonts.com font) and history persistence per machine

Profile.ps1

#requires -Version 6

function Get-BranchName
{
    $currentPath = Get-Location

    while ($true)
    {
        try
        {
            if ([string]::IsNullOrEmpty($currentPath))
            {
                return
            }

            $git = (Join-Path $currentPath "\.git")

            if (Test-Path $git)
            {
                $head = (Get-Content (Join-Path $git "\HEAD") | Out-String).Trim().Replace("ref: refs/heads/", "")

                if ([string]::IsNullOrEmpty($head))
                {
                    return
                }

                return $head
            }

            $currentPath = Split-Path $currentPath
        }
        catch
        {
            throw "GetBranchName failed..."

            return
        }
    }
}

function Write-AnsiVT100
{
    param(
        [Parameter(Mandatory = $true)]
        [ValidateNotNull()]
        [string]$Message
        ,
        [Parameter(Mandatory = $false)]
        [ValidateNotNull()]
        [int]$ForegroundColor = 255
        ,
        [Parameter(Mandatory = $false)]
        [ValidateNotNull()]
        [int]$BackgroundColor = 0
    )

    $esc = "$([char]27)"

    return "$esc[38;5;$ForegroundColor`m$esc[48;5;$BackgroundColor`m$Message$esc[0m$esc[0m"
}

# persistent history on exit
Register-EngineEvent -SupportEvent PowerShell.Exiting -Action {
    # setup
    $historyRootPath = Join-Path $PSScriptRoot "\History"
    $mergeFilePath = Join-Path $historyRootPath ("\merged-{0}.csv" -f $env:COMPUTERNAME)

    # save history
    Get-History | Export-Csv -Path (Join-Path $historyRootPath ("\history-{0}-{1}.csv" -f $env:COMPUTERNAME, $PID)) -Append

    # merge session history
    Get-ChildItem -Path $historyRootPath -Filter ("history-{0}-*.csv" -f $env:COMPUTERNAME) | ForEach-Object {
        Import-Csv -Path $_.FullName
    } | Sort-Object -Property CommandLine -Unique | Export-Csv -Path $mergeFilePath -Append

    # delete old session history
    Get-ChildItem -Path $historyRootPath -Filter ("history-{0}-*.csv" -f $env:COMPUTERNAME) | Remove-Item -Force;
}

# setup prompt
function Prompt
{
    # was the last command executed successful ?
    [bool]$script:success = $?

    # shorten and decorate current path
    $pathArray = ($ExecutionContext.SessionState.Path.CurrentLocation) -split "\\"

    if ($pathArray.Count -gt 3)
    {
        $driveSegement = $pathArray | Select-Object -First 1
        $pathSegment = ($pathArray | Select-Object -Last 3) -join " `u{e0b1} "
        $currentLocation = "$driveSegement `u{e0b1} $([char]0x2026) `u{e0b1} $pathSegment"
    }
    else
    {
        $currentLocation = $pathArray -join " `u{e0b1} "
    }

    # measure how long the last command took to execute
    $lastCommand = Get-History -Count 1

    if ($lastCommand)
    {
        $duration = $lastCommand.EndExecutionTime - $lastCommand.StartExecutionTime
        $elapsed = "{0:h\:mm\:ss\.ffff}" -f $duration
    }
    else
    {
        $elapsed = "0:00:00.0000"
    }

    # get branch name
    $branch = Get-BranchName

    if ([string]::IsNullOrEmpty($branch))
    {
        $branch = "n/a"
    }

    # write prompt
    $seperator = "`u{e0b0}"

    $prompt = ""
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 0 -BackgroundColor 23
    $prompt += Write-AnsiVT100 " `u{26a1} " -ForegroundColor 226 -BackgroundColor 23
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 23 -BackgroundColor 31

    $prompt += Write-AnsiVT100 " $elapsed " -ForegroundColor 255 -BackgroundColor 31
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 31 -BackgroundColor 38

    $prompt += Write-AnsiVT100 (" {0:HH\:mm\:ss\.ffff} " -f (Get-Date)) -ForegroundColor 0 -BackgroundColor 38
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 38 -BackgroundColor 236

    $prompt += Write-AnsiVT100 " $($MyInvocation.HistoryId - 1) " -ForegroundColor 250 -BackgroundColor 236
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 236 -BackgroundColor 36

    $prompt += Write-AnsiVT100 " `u{e0a0} $branch " -ForegroundColor 254 -BackgroundColor 36
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 36 -BackgroundColor 237

    $prompt += Write-AnsiVT100 " $currentLocation " -ForegroundColor 253 -BackgroundColor 237
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 237 -BackgroundColor 0

    $prompt += "`n"

    $commandStateColor = @{ $true = 254; $false = 9 }[$script:success]

    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 0 -BackgroundColor $commandStateColor
    $prompt += Write-AnsiVT100 " `u{2665} " -ForegroundColor 160 -BackgroundColor $commandStateColor
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor $commandStateColor -BackgroundColor 251

    $prompt += Write-AnsiVT100 " PS " -ForegroundColor 234 -BackgroundColor 251
    $prompt += Write-AnsiVT100 "$seperator" -ForegroundColor 251 -BackgroundColor 0

    return $prompt
}