Improve Windows converter downloading

autodl_files/get_aria2.ps1

@@ -0,0 +1,64 @@
+try {
+    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+} catch {
+    Write-Error "Outdated operating systems are not supported."
+    Exit 1
+}
+
+$file = 'aria2c.exe'
+$url = 'https://uupdump.net/misc/aria2c.exe';
+$hash = '0ae98794b3523634b0af362d6f8c04a9bbd32aeda959b72ca0e7fc24e84d2a66';
+
+function Test-Existece {
+    param (
+        [String]$File
+    )
+
+    return Test-Path -PathType Leaf -Path "files\$File"
+}
+
+function Retrieve-File {
+    param (
+        [String]$File,
+        [String]$Url
+    )
+
+    Write-Host -BackgroundColor Black -ForegroundColor Yellow "Downloading ${File}..."
+    Invoke-WebRequest -UseBasicParsing -Uri $Url -OutFile "files\$File" -ErrorAction Stop
+}
+
+function Test-Hash {
+    param (
+        [String]$File,
+        [String]$Hash
+    )
+
+    Write-Host -BackgroundColor Black -ForegroundColor Cyan "Verifying ${File}..."
+
+    $fileHash = (Get-FileHash -Path "files\$File" -Algorithm SHA256 -ErrorAction Stop).Hash
+    return ($fileHash.ToLower() -eq $Hash)
+}
+
+if((Test-Existece -File $file) -and (Test-Hash -File $file -Hash $hash)) {
+    Write-Host -BackgroundColor Black -ForegroundColor Green "Ready."
+    Exit 0
+}
+
+if(-not (Test-Path -PathType Container -Path "files")) {
+    $null = New-Item -Path "files" -ItemType Directory
+}
+
+try {
+    Retrieve-File -File $file -Url $url
+} catch {
+    Write-Host "Failed to download $file"
+    Write-Host $_
+    Exit 1
+}
+
+if(-not (Test-Hash -File $file -Hash $hash)) {
+    Write-Error "$file appears to be tampered with"
+    Exit 1
+}
+
+Write-Host -BackgroundColor Black -ForegroundColor Green "Ready."