package peer

import (
	"fmt"
	"log"
	"runtime/debug"
)

func (peer *Peer) ifReader() {
	defer func() {
		if r := recover(); r != nil {
			fmt.Println("stacktrace from panic: \n" + string(debug.Stack()))
		}
	}()

	var (
		sender   = newConnSender(peer.conn, peer.ip, STREAM_DATA)
		n        int
		destIP   byte
		router   = peer.router
		viaRoute *route
		route    *route
		iface    = peer.iface
		err      error
		packet   = make([]byte, BUFFER_SIZE)
		version  byte
	)

	for {
		n, err = iface.Read(packet[:BUFFER_SIZE])
		if err != nil {
			log.Fatalf("Failed to read from interface: %v", err)
		}

		if n < 20 {
			log.Printf("Dropping small packet: %d", n)
			continue
		}

		packet = packet[:n]
		version = packet[0] >> 4

		switch version {
		case 4:
			destIP = packet[19]
		case 6:
			destIP = packet[39]
		default:
			log.Printf("Dropping packet with IP version: %d", version)
		}

		route = router.GetRoute(destIP)
		if route == nil || !route.Up {
			log.Printf("Dropping packet for non-existent IP: %d", destIP)
			continue
		}

		if route.useMediator {
			viaRoute = router.GetMediator()
			if viaRoute == nil || !viaRoute.Up {
				log.Printf("Dropping packet due to no mediator: %d", destIP)
				continue
			}
		} else {
			viaRoute = nil
		}

		sender.send(PACKET_TYPE_DATA, packet, route, viaRoute)
	}
}