openemacs.ps1

# openemacs.ps1

# example
#  powershell -nologo -NonInteractive -ExecutionPolicy Unrestricted "C:\Path\To\openemacs.ps1" "C:\Path\to\Target"

## variables

$server_dir = "${Env:USERPROFILE}\AppData\Roaming\.emacs.d\server\"
$emacsclient_bin = "C:\ProgramData\chocolatey\bin\emacsclientw.exe"
$runemacs_bin = "C:\ProgramData\chocolatey\bin\runemacs.exe"


## functions

function open_with_emacs($p, $s){
    if ($s -eq $null) {
	Start-Process -FilePath $emacsclient_bin -ArgumentList "-a $runemacs_bin $p"
    }
    else {
	Start-Process -FilePath $emacsclient_bin -ArgumentList "-f $s -a $runemacs_bin $p"
    }
}

function get_z_order($hWnd) {
    $source = @"
using System;
using System.Runtime.InteropServices;
public static class HwndHelper
{
    [DllImport("user32.dll", SetLastError = true)]
    static extern IntPtr GetWindow(IntPtr hWnd, uint uCmd);
    
    public static int GetWindowZOrder(IntPtr hWnd)
    {
	var zOrder = -1;
	while ((hWnd = GetWindow(hWnd, 2 /* GW_HWNDNEXT */)) != IntPtr.Zero) zOrder++;
	return zOrder;
    }
}
"@
    Add-Type -TypeDefinition $source
    [HwndHelper]::GetWindowZOrder($hWnd)
}

function list_emacs_servers($dir) {
    $array = @()
    $items = Get-ChildItem $dir
    foreach($i in $items) {
	$name = $i.Name
	$processid = ($i | Get-Content)[0].Split("")[1]
	$hwnd = (Get-Process -Id $processid).MainWindowHandle
	$z_order = get_z_order($hwnd)
	$array += [pscustomobject]@{"name" =  $name; "pid" = $processid; "hwnd" = $hwnd; "z_order" = $z_order}
    }
    return $array
}

function get_server_of_top_window($array) {
    return ($array | Sort-Object -Property z_order -Descending)[0]
}


## main

if ($Args.length -ne 1) {
    Write-Host "Invalid args."
    exit
}
    
$filepath = $Args[0]
$list = list_emacs_servers $server_dir

if ($list.length -eq 0) {
    open_with_emacs $filepath
}
else {
    $s = get_server_of_top_window $list
    open_with_emacs $filepath $s.name
}