package nic

import (
	"log"
	"net"
	"strings"

	omm "git.loafle.net/overflow/model/meta"
	omn "git.loafle.net/overflow/model/net"
	oun "git.loafle.net/overflow/util-go/net"
	oung "git.loafle.net/overflow/util-go/net/gateway"

	"github.com/google/gopacket/pcap"
)

func DiscoverGateway() (net.IP, string, error) {
	return oung.DiscoverGateway()
}

func DiscoverInterfaces() ([]*omn.Interface, error) {
	gwIP, gwIface, err := DiscoverGateway()
	if nil != err {
		return nil, err
	}

	netIfaces, err := net.Interfaces()
	if err != nil {
		return nil, err
	}

	ifaces := make([]*omn.Interface, 0)

	for _, netIface := range netIfaces {
		if netIface.Flags&net.FlagLoopback != 0 || netIface.Flags&net.FlagUp == 0 {
			continue
		}

		iface := &omn.Interface{}
		ifaces = append(ifaces, iface)

		iface.FriendlyName = netIface.Name
		iface.Mac = netIface.HardwareAddr.String()
		iface.Addresses = make([]*omn.InterfaceAddress, 0)

		netAddrs, err := netIface.Addrs()
		if nil != err {
			continue
		}

	LOOP_ADDR:
		for _, netAddr := range netAddrs {
			_, ipNet, err := oun.ParseCIDR(netAddr.String())
			if nil != err {
				continue
			}

			var ip net.IP
			switch v := netAddr.(type) {
			case *net.IPNet:
				ip = v.IP
			case *net.IPAddr:
				ip = v.IP
			default:
				log.Print("Addr is not *net.IPNet or *net.IPAddr", netAddr)
			}

			addr := &omn.InterfaceAddress{}
			iface.Addresses = append(iface.Addresses, addr)
			addr.Address = ip.String()
			addr.Netmask = ipNet.Mask.String()
			addr.Network = ipNet.Network().String()

			if gwIface == ip.String() {
				addr.Gateway = gwIP.String()
			}

			switch ipNet.Version() {
			case 4:
				addr.MetaIPType = omm.ToMetaIPType(omm.MetaIPTypeEnumV4)
			case 6:
				addr.MetaIPType = omm.ToMetaIPType(omm.MetaIPTypeEnumV6)
			default:
				continue LOOP_ADDR
			}
			iface.Iface = ifaceName(ip.String())
		}

	}

	return ifaces, nil
}

func ifaceName(ip string) string {
	devices, err := pcap.FindAllDevs()
	if err != nil {
		return ""
	}
	for _, d := range devices {
		for _, address := range d.Addresses {
			if strings.Compare(address.IP.String(), ip) == 0 {
				return d.Name
			}
		}
	}
	return ""
}