Set-RedditWallpapersAsDesktop.ps1

#Set-RedditWallpapersAsDesktop.ps1 - JorgTheElder@Outlook.com
# Great help from: https://www.kittell.net/code/powershell-remove-windows-wallpaper-per-user/

#$DebugPreference = 'Continue'; #uncomment if you want to see all the steps

#region types

Add-Type @"
using System;
using System.Runtime.InteropServices;
using Microsoft.Win32;
namespace Wallpaper
{
   public class Setter {

      public const int SetDesktopWallpaper = 20;
      public const int UpdateIniFile = 0x01;
      public const int SendWinIniChange = 0x02;

      [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
      private static extern int SystemParametersInfo (int uAction, int uParam, string lpvParam, int fuWinIni);

      public static void SetWallpaper ( string path ) {
         SystemParametersInfo( SetDesktopWallpaper, 0, path, UpdateIniFile | SendWinIniChange );
      }
   }
}
"@

#endregion types


#region functions

Function Invoke-Update {

  $cmd = $env:windir + '\System32\RUNDLL32.EXE user32.dll,UpdatePerUserSystemParameters';
  Invoke-Expression -Command $cmd;

}

Function Set-WallPaper
{
  param (

    [Parameter(Mandatory)]
    [ValidateScript({ Test-Path $_ })]
    [string]$WallPaper,

    [ValidateSet('Fill', 'Fit', 'Stretch', 'Center', 'Tile', 'Span')]
    [string]$WallpaperStyle = 'Fill',

    [switch]$AutoColorization

  )

  #Affected Reg Keys
  #AutoColorization REG_DWORD 1 or 0
  #WallpaperStyle REG_SZ 10, 6, 2, 0, 22
  #Wallpaper REG_SZ path-to-image

  #remove cached files to help change happen
  #Remove-Item -Path "$($env:APPDATA)\Microsoft\Windows\Themes\CachedFiles" -Recurse -Force -ErrorAction SilentlyContinue

  $fit = @{ 'Fill' = 10; 'Fit' = 6; 'Stretch' = 2; 'Center' = 0; 'Tile' = '99'; 'Span' = '22' }

  if($AutoColorization) {

    Set-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name AutoColorization -value 1;

  } else {

    Set-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name AutoColorization -value 0;

  }

  if($WallpaperStyle -eq 'Tile') {

    Set-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name WallpaperStyle -value 0;
    Set-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name TileWallpaper -value 1;

  } else {

    Set-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name WallpaperStyle -value $fit[$WallpaperStyle];
    Set-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name TileWallpaper -value 0;

  }

  [Wallpaper.Setter]::SetWallpaper($WallPaper);

}
#endregion functions

$folder = Join-Path ([Environment]::GetFolderPath("MyDocuments")) 'RedditWallPapers';

if(-not(Test-Path $folder)) { $nul = New-Item $folder -ItemType Directory -ErrorAction Stop; }

$folder = Join-Path $folder (Get-Date).ToString('yyyy-MM');

if(-not(Test-Path $folder)) { $nul = New-Item $folder -ItemType Directory -ErrorAction Stop; }

$base = 'https://www.reddit.com/r/wallpapers/new/.rss?sort=top&t=day';
Write-Debug ('$base: ' + $base);

$data = Invoke-WebRequest -Uri $base;

$xml = [xml]$data.Content;

$links = $xml.feed.entry.link.href;

$images = @();

$links | ForEach-Object {
  $commentXML = [xml](Invoke-WebRequest ($_ + '.rss')).Content;
  if($commentXML.feed.entry[0].content.InnerText -match '"([^"]+\.(jpg|png))">\[link\]') {
    $images += $matches[1];
  }
}

$count = $images.Count;

if($count -lt 1) {
  throw 'Failed to get reddit images';
  return;
}

$use = Get-Random -Maximum $count;
$forDesktop = '';

$currentWP = (Get-ItemProperty -Path 'HKCU:\Control Panel\Desktop' -Name WallPaper).WallPaper;

for ($i=0;$i -lt $count;$i++) {

  $imageURI = $images[$i]
  Write-Debug ('$imageURI: ' + $imageURI);

  $file = Split-Path $imageURI -Leaf; #filename for local use

  $savePath = Join-Path $folder $file;
  Write-Debug ('$savePath: ' + $savePath);

  if($i -eq $use -or $savePath -eq '') {
   if($forDesktop -ne $currentWP) { $forDesktop = $savePath; } #don't use current image
  }

  #don't download if it already exists
  if(Test-Path $savePath) {
    Write-Host ('Image exists: ' + $file);
    continue;
  }

  Write-Host ('Retreiving image: ' + $file);
  $result = Invoke-WebRequest -Uri $imageURI -OutFile $savePath;

}

Write-Host ('Setting wallpaper: ' + $forDesktop);

Set-wallpaper -Wallpaper $forDesktop -WallpaperStyle Fill -AutoColorization;