Draft of powershell Tab completion for pydoit

doit_completion.ps1

# doit completion

function WriteLog([string] $Message) {
    $timestamp = Get-Date -Format HH:mm:ss
    "[$timestamp] $Message" | Out-File -Append "${env:Home}\tablog.txt"
}

Register-ArgumentCompleter -CommandName doit -Native -ScriptBlock {
    param(
        [String] $wordToComplete, 
        [System.Management.Automation.Language.CommandAst] $commandAst, 
        [Int] $cursorPosition
    )
    
    WriteLog "Complete '$wordToComplete' in '$commandAst' cursor at $cursorPosition"

    $elements = $commandAst.CommandElements;
    $global:ast = $commandAst

    $sub_cmds = "auto", "clean", "dumpdb", "forget", "help", "ignore", "info", "list", "reset-dep", "run", "strace", "tabcompletion"

    for ($i = 1; $i -lt $elements.Count; $i++) {
        $element = $elements[$i]
        if ($element.Extent.EndOffset -ge $cursorPosition) {
            break
        }
    }

    $prev = $elements[$i - 1].ToString()

    # if ($wordToComplete.Length.Equals(0)) {
    #     $prev = $elements[$i - 1]
    # } else {
    #     $prev = $elements[$i - 2]
    # }

    WriteLog "At $i prev: '$prev'"

    function completePath([String] $str) {
        $results = if (Split-Path -Path $str* -IsAbsolute) {
            $(Resolve-Path $str*)
        }
        else {
            $(Resolve-Path -Relative $str*)
        }
        return $results | ForEach-Object {
            $value = $_.ToString()
            if ($value.Contains(' ')) {
                $value = "'$value'"
            }
            [System.Management.Automation.CompletionResult]::new($value, $_, 'ParameterValue', $_)
        }
    }

    if ($prev.Equals("-f") -or $prev.Equals("-d") -or $prev.Equals("-o")) {
        return completePath $wordToComplete
    }
 
    if ($wordToComplete.Contains('=')) {
        $cmd, $arg = $wordToComplete.Split('=', 2)
        WriteLog "cmd '$cmd', arg '$arg'"
        if ($cmd.Equals('--file') -or $cmd.Equals('--dir') -or $cmd.Equals('--output-file')) {
            return completePath $arg | ForEach-Object {
                # "--cmd=$_"
                $value = "$cmd=" + $_.completionText
                $description = $_.listItemText 
                [System.Management.Automation.CompletionResult]::new($value, $description, 'ParameterValue', $description)
            }
        }
    }

    if ($wordToComplete.Contains(':')) {
        $base, $suffix = $wordToComplete.Split(':', 2)
        return $(doit list -q --all $base | Where-Object { $_.StartsWith($wordToComplete) })
    }
    else {
        return $(doit list -q | ForEach-Object { $_.Trim() } | Where-Object { $_.StartsWith($wordToComplete) })
    }
}