use crate::config::{Config, NamespaceName};
use crate::link::{LinkError, LinkManager};
use crate::namespace::NetNs;
use main_error::MainResult;
use tracing::error;

pub fn up(config: Config) -> MainResult {
    let mut namespaces = NetNs::existing(false)?
        .map(NetNs::new)
        .collect::<Result<Vec<_>, _>>()?;

    for removed in namespaces.extract_if(.., |namespace| {
        config.get_namespace(namespace.name()).is_none()
    }) {
        removed.delete()?;
    }

    for new in config.namespaces {
        if !has_namespace(&namespaces, &new.name) {
            namespaces.push(NetNs::new(new.name.clone())?);
        }
        let namespace = get_namespace(&namespaces, &new.name).expect("namespace is just created");
        for device in new.devices {
            if let Err(error) = namespace.move_device(&device) {
                error!(%error, "failed to move device into namespace");
            }
        }
        for route in new.routes {
            namespace.handle().run_in(|| {
                let manager = LinkManager::new()?;
                let link = manager.get_link(&route.device)?;
                manager.add_route(&link, route.destination)?;
                Ok::<_, LinkError>(())
            })??;
        }
    }

    Ok(())
}

fn has_namespace(namespaces: &[NetNs], name: &NamespaceName) -> bool {
    namespaces.iter().any(|existing| existing.name() == name)
}

fn get_namespace<'a>(namespaces: &'a [NetNs], name: &NamespaceName) -> Option<&'a NetNs> {
    namespaces.iter().find(|existing| existing.name() == name)
}