// Runs a story of sends to addresses ARP cannot resolve on arp-routed's
// network in Java FILIUS (ScenarioNetwork) and records every frame each card
// saw and when each call started and ended.
//
//   ArpRun <scenario.json> <story> <milliseconds> <out.json>
//
// 10.0.0.2 sits behind a switch on the router's 10.0.0.1; 20.0.0.2 on the
// router's 20.0.0.1. No card has 10.0.0.9 or 20.0.0.9. The stories:
//   pingLan     10.0.0.2 pings 10.0.0.9 (ICMP.sendProbe, as the ping command)
//   pingRouted  10.0.0.2 pings 20.0.0.9: the router's ARP fails
//   udpTwice    10.0.0.2 sends two UDP datagrams to 10.0.0.9 at once
//   udpBehind   10.0.0.2 sends a UDP datagram to 10.0.0.9, then one to 20.0.0.2
//   routedUdpBehind      10.0.0.2 sends a UDP datagram to 20.0.0.9, then one
//                        to 20.0.0.2: the router forwards both
//   routedPingBesideUdp  a ping to 20.0.0.2 (the router learns it), a UDP
//                        datagram to 20.0.0.9, 100 ms later (the UDP thread
//                        sends first) a ping to 20.0.0.2 again: only
//                        one thread waits for ARP at a time. Two would meet
//                        ARP's notify, which wakes one waiter, not the one
//                        whose answer came (a Java bug the core does not take)
//   routedPingBehindPing an echo request to 20.0.0.9 (sent, not waited for),
//                        then a ping to 20.0.0.2

import filius.software.transportschicht.UDPSocket;
import filius.software.vermittlungsschicht.ICMP;
import filius.software.vermittlungsschicht.IcmpPaket;

import java.util.ArrayList;
import java.util.List;

public class ArpRun {
    static final String HOST = "00000000-0000-0000-0000-000000000301";

    static ScenarioNetwork network;
    static final List<Object[]> events = new ArrayList<>();

    interface Call {
        String run() throws Exception;
    }

    static synchronized void event(String what) {
        events.add(new Object[] { System.currentTimeMillis() - network.start, what });
    }

    static void call(String label, Call call) {
        event(label + " called");
        try {
            event(label + " returned " + call.run());
        } catch (Exception e) {
            event(label + " failed " + e.getClass().getSimpleName());
        }
    }

    static String icmp(IcmpPaket packet) {
        return packet == null ? "null" : "ICMP " + packet.getIcmpType() + "/" + packet.getIcmpCode() + " from " + packet.getSender();
    }

    static void send(String target, String payload) throws Exception {
        UDPSocket socket = new UDPSocket(network.system(HOST), target, 9);
        socket.verbinden();
        socket.senden(payload);
    }

    public static void main(String[] args) throws Exception {
        network = ScenarioNetwork.read(args[0]);
        String story = args[1];
        long end = Long.parseLong(args[2]);
        network.start();
        Thread.sleep(500);
        switch (story) {
            case "pingLan":
                call("sendProbe 10.0.0.9", () -> icmp(network.system(HOST).holeICMP().sendProbe("10.0.0.9", 64, 1, 1)));
                break;
            case "pingRouted":
                call("sendProbe 20.0.0.9", () -> icmp(network.system(HOST).holeICMP().sendProbe("20.0.0.9", 64, 1, 1)));
                break;
            case "udpTwice":
                call("senden eins", () -> {
                    send("10.0.0.9", "eins");
                    return "";
                });
                call("senden zwei", () -> {
                    send("10.0.0.9", "zwei");
                    return "";
                });
                break;
            case "udpBehind":
                call("senden verloren", () -> {
                    send("10.0.0.9", "verloren");
                    return "";
                });
                call("senden dahinter", () -> {
                    send("20.0.0.2", "dahinter");
                    return "";
                });
                break;
            case "routedUdpBehind":
                call("senden verloren", () -> {
                    send("20.0.0.9", "verloren");
                    return "";
                });
                call("senden dahinter", () -> {
                    send("20.0.0.2", "dahinter");
                    return "";
                });
                break;
            case "routedPingBesideUdp":
                call("sendProbe 20.0.0.2", () -> icmp(network.system(HOST).holeICMP().sendProbe("20.0.0.2", 64, 1, 1)));
                call("senden verloren", () -> {
                    send("20.0.0.9", "verloren");
                    return "";
                });
                Thread.sleep(100);
                call("sendProbe 20.0.0.2", () -> icmp(network.system(HOST).holeICMP().sendProbe("20.0.0.2", 64, 1, 2)));
                break;
            case "routedPingBehindPing":
                call("sendeICMP 20.0.0.9", () -> {
                    network.system(HOST).holeICMP().sendeICMP(ICMP.TYPE_ECHO_REQUEST, ICMP.CODE_ECHO, 2, 2, null, "20.0.0.9");
                    return "";
                });
                call("sendProbe 20.0.0.2", () -> icmp(network.system(HOST).holeICMP().sendProbe("20.0.0.2", 64, 1, 1)));
                break;
            default:
                throw new IllegalArgumentException("unknown story " + story);
        }
        long rest = network.start + end - System.currentTimeMillis();
        if (rest > 0) Thread.sleep(rest);

        ScenarioNetwork.Json out = new ScenarioNetwork.Json();
        out.open('{');
        network.writeFrames(out);
        synchronized (ArpRun.class) {
            out.key("events").open('[');
            for (Object[] each : events) out.open('[').number((Long) each[0]).string((String) each[1]).close(']');
            out.close(']');
        }
        out.close('}');
        network.stop();
        ScenarioNetwork.write(args[3], out);
        System.exit(0);
    }
}