JJ aware powershell prompt

README.md

jj Aware Powershell Prompt

This is a simple script to create a nice powershell prompt with jj version control integration.

Path names are abbreviated approximately like fish does out of the box, and $HOME is abbreviated to ~. The VCS information appears on the far right when in a jj repository.

Window/tab title is set to the working directory, or, if in a jj repository, the jj root name.

The format for VCS information is derived from hroi’s fish prompt

jj_pwsh_prompt.ps1

function JJPrompt() {
    if (-not (Get-Command jj -errorAction SilentlyContinue)) {
        return
    }
   
    $root = (jj root --quiet 2> $null)

    if (-not $root) {
        return
    }

    $status = jj log --ignore-working-copy --no-graph --color always -r `@ -T '
        separate(
            " ",
            bookmarks.join(", "),
            coalesce(
                surround(
                    "\"",
                    "\"",
                    if(
                        description.first_line().substr(0, 24).starts_with(description.first_line()),
                        description.first_line().substr(0, 24),
                        description.first_line().substr(0, 23) ++ "…"
                    )
                ),
                "(no description)"
            ),
            change_id.shortest(),
            commit_id.shortest(),
            if(conflict, "(conflict)"),
            if(empty, "(empty)"),
            if(divergent, "(divergent)"),
            if(hidden, "(hidden)"),
        )
    '

    return $status #.Replace("UΓǪ", "…") # Theres some encoding weirdness going on with ellipsis. Patch in this fix
}


function setTitle() {
    $root = [System.IO.Path]::GetFileNameWithoutExtension($(jj root --quiet)) 2> $null

    if ($root) {
        $host.UI.RawUI.WindowTitle = "jj: $root";
    }

    else {
        $host.UI.RawUI.WindowTitle = [System.IO.Path]::GetFileNameWithoutExtension($pwd)
    }
}


function PathList($path) {
    $list = New-Object Collections.Generic.List[String]

    $remainder = $path
    while ($null -ne $remainder) {
        $fn = [System.IO.Path]::GetFileName($remainder)
        if ($fn) {
            $list.Add($fn)
        }

        $remainder = [System.IO.Path]::GetDirectoryName($remainder)
    }

    $root = [System.IO.Path]::GetPathRoot($path);
    if ($root) {
        $list.Add($root)
    }

    $list.Reverse()

    return $list
}

function AbbreviatedPath($path) {
    $rawSegments = PathList $path

    if (($rawSegments.Count) -lt 3) {
        return $path
    }

    $abbreviated = New-Object Collections.Generic.List[string]
    $abbreviated.Add($rawSegments[0])

    foreach ($segment in $rawSegments[1..($rawSegments.Count - 2)]) { 
        $abbreviated.Add($segment[0]) 
    }
    
    $abbreviated.Add($rawSegments[-1]);

    return [System.IO.Path]::Combine($abbreviated)
}


function writeRight($message, $color) {
    $foreColor = $host.ui.RawUI.ForegroundColor
    $cur = $Host.UI.RawUI.CursorPosition

    $length = ($message -replace '\x1b\[\d+(;\d+)*m').Length
    $startposx = $Host.UI.RawUI.windowsize.width - $length
    $startposy = $Host.UI.RawUI.CursorPosition.Y
    $Host.UI.RawUI.CursorPosition = New-Object System.Management.Automation.Host.Coordinates $startposx,$startposy
    $host.UI.RawUI.ForegroundColor = $color
    $Host.UI.Write($message)
    
    # reset cursor and color
    $host.UI.RawUI.ForegroundColor = $foreColor
    $Host.UI.RawUI.CursorPosition = $cur
}

$Global:PromptTerminator = "▷"

function Global:prompt {    
    setTitle

    $foreColor = $host.ui.RawUI.ForegroundColor
    $host.UI.RawUI.ForegroundColor = "Yellow"
    $Host.UI.Write((AbbreviatedPath ([string]$pwd).Replace($HOME, "~")))

    writeRight (JjPrompt) "Gray"

    $host.UI.RawUI.ForegroundColor = $foreColor
    $Host.UI.Write(" $($global:PromptTerminator ?? ">")")

    return " "
}