package routingTable

import (
	"fmt"
	"net"
	"net/netip"
	"os"
	"bufio"
)

type Address struct {
	addr netip.Addr;
	prefix netip.Prefix;
}

type Routing struct {
	dest Address;
	cost uint16_t;
	mask netip.Prefix;
}

routingTable := make(map[Address]Routing)

func Initialize(config IpConfig) (error) {
	if len(os.Args) != 2 {
		fmt.Printf("Usage:  %s <configFile>\n", os.Args[0])
		os.Exit(1)
	}
	fileName := os.Args[1]

	lnxConfig, err := lnxconfig.ParseConfig(fileName)
	if err != nil {
		panic(err)
	}

	// populate routing table
	for _, iface := range lnxConfig.Interfaces {
		routingTable[Address{iface.AssignedIP, iface.AssignedPrefix}] = Routing{Address{iface.AssignedIP, iface.AssignedPrefix}, 0, iface.AssignedPrefix}
	}

}

func AddRoute(dest Address, cost uint16_t, mask netip.Prefix) (error) {
	if _, ok := routingTable[dest]; ok {
		return newErrString(ln, "Route already exists")
	}
	routingTable[dest] = Routing{dest, cost, mask}
}

func RemoveRoute(dest Address) (error) {
	if _, ok := routingTable[dest]; !ok {
		return newErrString(ln, "Route does not exist")
	}
	delete(routingTable, dest)
}

func GetRoute(dest Address) (Routing, error) {
	// get the most specific route
	for key, value := range routingTable {
		if key.prefix.Contains(dest.addr) {
			return value, nil
		}
	}
	return nil, newErrString(ln, "Route does not exist")
}

func PrintRoutingTable() {
	for key, value := range routingTable {
		fmt.Printf("%s/%d\t%d\n", key.addr, key.prefix.Bits(), value.cost)
	}
}