if (Get-Module posh-ssh) {
    return
}

$cmdNames = "ssh"
$cmdNames += Get-Alias -Definition $cmdNames -ErrorAction Ignore | ForEach-Object Name

$configFile = "$env:USERPROFILE/.ssh/config"

Register-ArgumentCompleter -CommandName $cmdNames -Native -ScriptBlock {
    param($wordToComplete, $commandAst, $cursorPosition)

    Get-Content $configFile | Select-String -Pattern "^Host(\s+([.A-Za-z0-9\-_]+))+\s*$" | ForEach-Object {
        $_.Matches.Groups[2].Captures.Value
    } | Where-Object {
        $_ -like "$wordToComplete*"
    } | ForEach-Object {
        "$_"
    }
}