#Requires -RunAsAdministrator
param([Parameter(Mandatory=$true)][string]$InterfaceAlias)
$ErrorActionPreference = 'Stop'
if (-not (Get-Command Add-DnsClientDohServerAddress -ErrorAction SilentlyContinue)) {
    throw 'This Windows version lacks system DoH support. Use router DNS or browser secure DNS.'
}
$null = Get-NetAdapter -Name $InterfaceAlias -ErrorAction Stop
$Address = '31.76.89.94'
$Template = 'https://doh.anonka.tech/dns-query'
$Existing = Get-DnsClientDohServerAddress | Where-Object ServerAddress -eq $Address
if ($Existing) {
    Set-DnsClientDohServerAddress -ServerAddress $Address -DohTemplate $Template -AllowFallbackToUdp $false -AutoUpgrade $true
} else {
    Add-DnsClientDohServerAddress -ServerAddress $Address -DohTemplate $Template -AllowFallbackToUdp $false -AutoUpgrade $true
}
$Backup = Join-Path $env:TEMP ('anonka-dns-before-' + (Get-Date -Format yyyyMMdd-HHmmss) + '.json')
Get-DnsClientServerAddress -InterfaceAlias $InterfaceAlias | ConvertTo-Json -Depth 4 | Set-Content $Backup
Set-DnsClientServerAddress -InterfaceAlias $InterfaceAlias -ServerAddresses $Address
Clear-DnsClientCache
Write-Host "Anonka DoH enabled on $InterfaceAlias. Previous DNS saved to $Backup"
Write-Host 'To return to DHCP DNS: Set-DnsClientServerAddress -InterfaceAlias YOUR_ADAPTER -ResetServerAddresses'