/* SPDX-License-Identifier: MIT
 *
 * Multi-path WireGuard Example
 *
 * This example demonstrates how to create a WireGuard device that sends
 * packets through multiple network interfaces simultaneously.
 */

package main

import (
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"

	"golang.zx2c4.com/wireguard/device"
	"golang.zx2c4.com/wireguard/tun"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Printf("Usage: %s <interface1> [interface2] [interface3] ...\n", os.Args[0])
		fmt.Println("Example: sudo ./multipath eth0 wlan0")
		fmt.Println("\nThis will create a WireGuard tunnel that sends packets through both eth0 and wlan0")
		fmt.Println("Available interfaces:")
		
		interfaces, err := device.GetNetworkInterfaceInfo()
		if err != nil {
			log.Fatalf("Failed to get interface info: %v", err)
		}
		
		for _, iface := range interfaces {
			fmt.Printf("  %s\n", iface.String())
		}
		os.Exit(1)
	}

	// Get interface names from command line
	interfaceNames := os.Args[1:]
	
	fmt.Printf("Creating multi-path WireGuard device using interfaces: %v\n", interfaceNames)

	// Create logger
	logger := device.NewLogger(device.LogLevelVerbose, "multipath-example: ")

	// Create TUN device
	tunDevice, err := tun.CreateTUN("wg-multipath", 1420)
	if err != nil {
		log.Fatalf("Failed to create TUN device: %v", err)
	}
	defer tunDevice.Close()

	fmt.Printf("Created TUN device: %s\n", tunDevice.Name())

	// Create multi-path WireGuard device
	wgDevice, err := device.NewMultiPathDeviceByNames(tunDevice, interfaceNames, logger)
	if err != nil {
		log.Fatalf("Failed to create multi-path WireGuard device: %v", err)
	}
	defer wgDevice.Close()

	fmt.Printf("Multi-path WireGuard device created successfully!\n")
	fmt.Printf("Each outbound packet will be sent through ALL %d specified interfaces\n", len(interfaceNames))

	// Configure WireGuard (you would normally load this from a config file)
	// This is just a basic example configuration
	logger.Verbosef("Device ready. You can now configure it using wg(8) commands:")
	logger.Verbosef("  sudo wg set %s private-key <private-key-file>", tunDevice.Name())
	logger.Verbosef("  sudo wg set %s peer <peer-public-key> endpoint <peer-endpoint> allowed-ips <allowed-ips>", tunDevice.Name())
	logger.Verbosef("  sudo ip addr add <your-vpn-ip>/24 dev %s", tunDevice.Name())
	logger.Verbosef("  sudo ip link set %s up", tunDevice.Name())

	// Bring device up
	err = wgDevice.Up()
	if err != nil {
		log.Fatalf("Failed to bring device up: %v", err)
	}

	fmt.Println("WireGuard device is up and running!")
	fmt.Println("Press Ctrl+C to stop...")

	// Wait for interrupt signal
	c := make(chan os.Signal, 1)
	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
	<-c

	fmt.Println("\nShutting down...")
	wgDevice.Down()
}