[CmdletBinding()]
param([string]$ListenIp = '', [string]$OutputPath = '')
$ErrorActionPreference = 'Stop'
if (-not $ListenIp) {
    $interfaces = @(Get-NetIPConfiguration | Where-Object { $_.IPv4DefaultGateway -and $_.IPv4Address })
    $addresses = @($interfaces | ForEach-Object { $_.IPv4Address.IPAddress } | Select-Object -Unique)
    if ($addresses.Count -ne 1) { throw 'Specify -ListenIp with the non-loopback IPv4 address assigned to this server NIC.' }
    $ListenIp = $addresses[0]
}
$address = $null
if (-not [Net.IPAddress]::TryParse($ListenIp,[ref]$address) -or
    $address.AddressFamily -ne [Net.Sockets.AddressFamily]::InterNetwork -or
    [Net.IPAddress]::IsLoopback($address) -or $ListenIp -eq '0.0.0.0') {
    throw 'Use an assigned non-loopback IPv4 NIC address; do not use 0.0.0.0.'
}
if (-not (Get-NetIPAddress -AddressFamily IPv4 -IPAddress $ListenIp -ErrorAction SilentlyContinue)) {
    throw "$ListenIp is not assigned to this server. On cloud hosts, use the NIC private IPv4, not the NAT public IPv4."
}
if (-not $OutputPath) { $OutputPath = Join-Path $PSScriptRoot 'BuddyDefense.caddyfile' }
$site = @"
https://BuddyDefense.xworld.ren:15888 {
    bind $ListenIp
    reverse_proxy 127.0.0.1:15888 {
        transport http {
            read_timeout 0
            write_timeout 0
        }
    }
}
"@
[IO.File]::WriteAllText([IO.Path]::GetFullPath($OutputPath),$site,(New-Object Text.UTF8Encoding($false)))
Write-Output "Generated $OutputPath. Merge this site into the existing Caddyfile, then validate and reload."
Write-Output $site