package main

import (
	"bufio"
	"fmt"
	"iptcp/pkg/ipstack"
	"net/netip"
	"os"
	"strings"
)

func main() {
	if len(os.Args) == 1 {
		fmt.Printf("Usage:  %s <configFile>\n", os.Args[0])
		os.Exit(1)
	}

	fileName := os.Args[2]

	err := ipstack.Initialize(fileName)
	if err != nil {
		return
	}
	ipstack.RegisterProtocolHandler(ipstack.TEST_PROTOCOL)

	scanner := bufio.NewScanner(os.Stdin)

	for scanner.Scan() {
		line := scanner.Text()
		switch line {
		case "li":
			fmt.Println("Name\tAddr/Prefix\tState")
			fmt.Println(ipstack.SprintInterfaces())
		case "ln":
			fmt.Println("Iface\tVIP\tUDPAddr")
			fmt.Println(ipstack.SprintNeighbors())
		case "lr":
			fmt.Println("T\tPrefix\tNext Hop\tCost")
			fmt.Println(ipstack.SprintRoutingTable())
		case "q":
			ipstack.CleanUp()
			os.Exit(0)
		default:
			if len(line) > 4 {
				if line[:4] == "down" {
					ifaceName := line[5:]
					ipstack.InterfaceDownREPL(ifaceName)
				}

				if line[:4] == "send" {
					// get IP address and message that follows it
					IPAndMessage := strings.Split(line, " ")
					ipAddr := IPAndMessage[1]
					message := IPAndMessage[2:]

					// combine message into one string
					messageToSend := strings.Join(message, " ")
					messageToSendBytes := []byte(messageToSend)

					hop, err := ipstack.LongestPrefix(netip.MustParseAddr(ipAddr))
					if err != nil {
						fmt.Println(err)
						continue
					}
					myAddr := hop.Interface.IpPrefix.Addr()
					for _, neighbor := range ipstack.GetNeighbors()[hop.Interface.Name] {
						// TODO: fix multiple send bug here on static route
						if neighbor.VipAddr == netip.MustParseAddr(ipAddr) ||
							neighbor.VipAddr == hop.VIP && hop.Type == "S" {
							bytesWritten, err := ipstack.SendIP(&myAddr, neighbor, ipstack.TEST_PROTOCOL, messageToSendBytes, ipAddr, nil)
							if err != nil {
								fmt.Println(err)
							} else {
								fmt.Printf("Sent %d bytes to %s\n", bytesWritten, neighbor.VipAddr.String())

							}
						}
					}
				}
			}
			if len(line) > 2 {
				if line[:2] == "up" {
					// get interface name
					ifaceName := line[3:]
					ipstack.InterfaceUpREPL(ifaceName)
				}
			} else {
				fmt.Println("Invalid command: ", line)
				fmt.Println("Commands: ")
				fmt.Println("  exit Terminate this program")
				fmt.Println("    li List interfaces")
				fmt.Println("    lr List routes")
				fmt.Println("    ln List available neighbors")
				fmt.Println("    up Enable an interface")
				fmt.Println("  down Disable an interface")
				fmt.Println("  send Send test packet")
			}
			continue
		}
	}
}