From c978a5a37d78a065a57d6dbf664c6a40c160aa56 Mon Sep 17 00:00:00 2001
From: Szymon Osiecki <szymonos@outlook.com>
Date: Sat, 30 Sep 2023 01:01:02 +0200
Subject: [PATCH] feat(ps): wsl_get_distros

---
 wsl/wsl_get_distros.ps1 | 98 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 wsl/wsl_get_distros.ps1

diff --git a/wsl/wsl_get_distros.ps1 b/wsl/wsl_get_distros.ps1
new file mode 100644
index 00000000..54e9be39
--- /dev/null
+++ b/wsl/wsl_get_distros.ps1
@@ -0,0 +1,98 @@
+#!/usr/bin/pwsh -nop
+<#
+.SYNOPSIS
+Script synopsis.
+.EXAMPLE
+wsl/wsl_get_distros.ps1
+wsl/wsl_get_distros.ps1 -FromRegistry
+wsl/wsl_get_distros.ps1 -Online
+#>
+[CmdletBinding()]
+param (
+    [switch]$Online,
+
+    [switch]$FromRegistry
+)
+
+begin {
+    $ErrorActionPreference = 'Stop'
+
+    if ($FromRegistry) {
+        # specify list of properties to get from Windows registry lxss
+        $prop = @(
+            @{ Name = 'Name'; Expression = { $_.DistributionName } }
+            'DefaultUid'
+            @{ Name = 'Version'; Expression = { $_.Flags -lt 8 ? 1 : 2 } }
+        )
+    } else {
+        $distros = [Collections.Generic.List[PSCustomObject]]::new()
+        $outputEncoding = [Console]::OutputEncoding
+    }
+}
+
+process {
+    if ($FromRegistry) {
+        # get list of WSL distros from Windows Registry
+        $distros = Get-ChildItem HKCU:\Software\Microsoft\Windows\CurrentVersion\Lxss `
+        | ForEach-Object { $_ | Get-ItemProperty } `
+        | Where-Object { $_.DistributionName -notmatch '^docker-desktop' } `
+        | Select-Object $prop
+    } else {
+        # change console encoding to utf-16
+        [Console]::OutputEncoding = [System.Text.Encoding]::Unicode
+        if ($Online) {
+            # get list of online WSL distros
+            [string[]]$result = wsl.exe --list --online | Where-Object { $_ }
+            # get distros header
+            [string]$head = $result | Select-String 'NAME\s+FRIENDLY' -CaseSensitive | Select-Object -ExpandProperty Line
+            # calculate header line index
+            $idx = $result.IndexOf($head)
+            $dataIdx = if ($idx -ge 0) {
+                $idx + 1
+            } else {
+                $result.Count - 1
+            }
+            # calculate header columns indexes
+            $nameIdx = $head.IndexOf('NAME')
+            $friendlyIdx = $head.IndexOf('FRIENDLY')
+            # add results to the distros list
+            for ($i = $dataIdx; $i -lt $result.Count; $i++) {
+                $distro = [PSCustomObject]@{
+                    Name         = $result[$i].Substring($nameIdx, $friendlyIdx - $nameIdx).TrimEnd()
+                    FriendlyName = $result[$i].Substring($friendlyIdx, $result[$i].Length - $friendlyIdx).TrimEnd()
+                }
+                $distros.Add($distro)
+            }
+        } else {
+            # get list of installed locally WSL distros
+            [string[]]$result = wsl.exe --list --verbose
+            # get distros header
+            [string]$head = $result | Select-String 'NAME\s+STATE\s+VERSION' -CaseSensitive | Select-Object -ExpandProperty Line
+            # calculate header line index
+            $idx = $result.IndexOf($head)
+            $dataIdx = if ($idx -ge 0) {
+                $idx + 1
+            } else {
+                $result.Count - 1
+            }
+            # calculate header columns indexes
+            $nameIdx = $head.IndexOf('NAME')
+            $stateIdx = $head.IndexOf('STATE')
+            $versionIdx = $head.IndexOf('VERSION')
+            # add results to the distros list
+            for ($i = $dataIdx; $i -lt $result.Count; $i++) {
+                $distro = [PSCustomObject]@{
+                    Name    = $result[$i].Substring($nameIdx, $stateIdx - $nameIdx).TrimEnd()
+                    State   = $result[$i].Substring($stateIdx, $versionIdx - $stateIdx).TrimEnd()
+                    Version = $result[$i].Substring($versionIdx, $result[$i].Length - $versionIdx).TrimEnd()
+                }
+                $distros.Add($distro)
+            }
+        }
+        [Console]::OutputEncoding = $outputEncoding
+    }
+}
+
+end {
+    return $distros
+}