package main

import (
	"context"
	"fmt"
	"isle/bootstrap"
	"isle/daemon"
	"isle/yamlutil"
	"net"
	"path/filepath"

	"code.betamike.com/micropelago/pmux/pmuxlib"
)

// waitForNebula waits for the nebula interface to have been started up. It does
// this by attempting to create a UDP connection which has the nebula IP set as
// its source. If this succeeds we can assume that at the very least the nebula
// interface has been initialized.
func waitForNebula(ctx context.Context, hostBootstrap bootstrap.Bootstrap) error {

	ip := hostBootstrap.ThisHost().IP()

	lUdpAddr := &net.UDPAddr{IP: ip, Port: 0}
	rUdpAddr := &net.UDPAddr{IP: ip, Port: 45535}

	return doOnce(ctx, func(context.Context) error {
		conn, err := net.DialUDP("udp", lUdpAddr, rUdpAddr)
		if err != nil {
			return err
		}
		conn.Close()
		return nil
	})
}

func nebulaPmuxProcConfig(
	hostBootstrap bootstrap.Bootstrap,
	daemonConfig daemon.Config,
) (
	pmuxlib.ProcessConfig, error,
) {

	var (
		lighthouseHostIPs []string
		staticHostMap     = map[string][]string{}
	)

	for _, host := range hostBootstrap.Hosts {

		if host.Nebula.PublicAddr == "" {
			continue
		}

		ip := host.IP().String()
		lighthouseHostIPs = append(lighthouseHostIPs, ip)
		staticHostMap[ip] = []string{host.Nebula.PublicAddr}
	}

	config := map[string]interface{}{
		"pki": map[string]string{
			"ca":   hostBootstrap.Nebula.CAPublicCredentials.CertPEM,
			"cert": hostBootstrap.Nebula.HostCredentials.Public.CertPEM,
			"key":  hostBootstrap.Nebula.HostCredentials.PrivateKeyPEM,
		},
		"static_host_map": staticHostMap,
		"punchy": map[string]bool{
			"punch":   true,
			"respond": true,
		},
		"tun": map[string]interface{}{
			"dev": "isle-tun",
		},
		"firewall": daemonConfig.VPN.Firewall,
	}

	if publicAddr := daemonConfig.VPN.PublicAddr; publicAddr == "" {

		config["listen"] = map[string]string{
			"host": "0.0.0.0",
			"port": "0",
		}

		config["lighthouse"] = map[string]interface{}{
			"hosts": lighthouseHostIPs,
		}

	} else {

		_, port, err := net.SplitHostPort(publicAddr)

		if err != nil {
			return pmuxlib.ProcessConfig{}, fmt.Errorf("parsing public address %q: %w", publicAddr, err)
		}

		config["listen"] = map[string]string{
			"host": "0.0.0.0",
			"port": port,
		}

		config["lighthouse"] = map[string]interface{}{
			"hosts":         []string{},
			"am_lighthouse": true,
		}
	}

	nebulaYmlPath := filepath.Join(envRuntimeDirPath, "nebula.yml")

	if err := yamlutil.WriteYamlFile(config, nebulaYmlPath); err != nil {
		return pmuxlib.ProcessConfig{}, fmt.Errorf("writing nebula.yml to %q: %w", nebulaYmlPath, err)
	}

	return pmuxlib.ProcessConfig{
		Name: "nebula",
		Cmd:  binPath("nebula"),
		Args: []string{"-config", nebulaYmlPath},
	}, nil
}