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)
				}
			}
			continue
		}
	}
}