use super::DnsState;
use anyhow::Result;
use std::net::IpAddr;
use std::os::windows::process::CommandExt;
use tracing::info;

const CREATE_NO_WINDOW: u32 = 0x0800_0000;

pub async fn set_dns(
    interface: &str,
    if_index: Option<u32>,
    dns_servers: &[IpAddr],
    state: &mut DnsState,
) -> Result<()> {
    if dns_servers.is_empty() {
        return Ok(());
    }

    let addrs: Vec<String> = dns_servers.iter().map(|ip| ip.to_string()).collect();
    let addrs_str = addrs.join(",");

    let iface_arg = if let Some(idx) = if_index {
        format!("-InterfaceIndex {}", idx)
    } else {
        format!("-InterfaceAlias '{}'", interface)
    };

    info!("Setting DNS on {} to {}", interface, addrs_str);

    let script = format!(
        "Set-DnsClientServerAddress {} -ServerAddresses {}",
        iface_arg, addrs_str
    );
    let status = std::process::Command::new("powershell")
        .args(["-NoProfile", "-NonInteractive", "-Command", &script])
        .creation_flags(CREATE_NO_WINDOW)
        .status()?;

    if !status.success() {
        anyhow::bail!("PowerShell failed to set DNS on {}", interface);
    }

    state.configured = true;
    Ok(())
}

pub async fn restore(
    interface: &str,
    if_index: Option<u32>,
    state: &mut DnsState,
) -> Result<()> {
    info!("Restoring DNS on {} to automatic", interface);

    let iface_arg = if let Some(idx) = if_index {
        format!("-InterfaceIndex {}", idx)
    } else {
        format!("-InterfaceAlias '{}'", interface)
    };

    let script = format!("Set-DnsClientServerAddress {} -ResetServerAddresses", iface_arg);
    let _ = std::process::Command::new("powershell")
        .args(["-NoProfile", "-NonInteractive", "-Command", &script])
        .creation_flags(CREATE_NO_WINDOW)
        .status();

    state.configured = false;
    Ok(())
}