package org.onlab.onos.provider.of.host.impl;

import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.onlab.onos.net.ConnectPoint;
import org.onlab.onos.net.Host;
import org.onlab.onos.net.HostId;
import org.onlab.onos.net.HostLocation;
import org.onlab.onos.net.host.DefaultHostDescription;
import org.onlab.onos.net.host.HostDescription;
import org.onlab.onos.net.host.HostProvider;
import org.onlab.onos.net.host.HostProviderRegistry;
import org.onlab.onos.net.host.HostProviderService;
import org.onlab.onos.net.provider.AbstractProvider;
import org.onlab.onos.net.provider.ProviderId;
import org.onlab.onos.net.topology.Topology;
import org.onlab.onos.net.topology.TopologyService;
import org.onlab.onos.openflow.controller.Dpid;
import org.onlab.onos.openflow.controller.OpenFlowController;
import org.onlab.onos.openflow.controller.OpenFlowPacketContext;
import org.onlab.onos.openflow.controller.PacketListener;
import org.onlab.packet.ARP;
import org.onlab.packet.Ethernet;
import org.onlab.packet.IPv4;
import org.onlab.packet.IpPrefix;
import org.onlab.packet.VlanId;
import org.slf4j.Logger;

import static org.onlab.onos.net.DeviceId.deviceId;
import static org.onlab.onos.net.PortNumber.portNumber;
import static org.slf4j.LoggerFactory.getLogger;

/**
 * Provider which uses an OpenFlow controller to detect network
 * end-station hosts.
 */
@Component(immediate = true)
public class OpenFlowHostProvider extends AbstractProvider implements HostProvider {

    private final Logger log = getLogger(getClass());

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected HostProviderRegistry providerRegistry;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected OpenFlowController controller;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected TopologyService topologyService;

    private HostProviderService providerService;

    private final InternalHostProvider listener = new InternalHostProvider();

    private boolean ipLearn = true;

    /**
     * Creates an OpenFlow host provider.
     */
    public OpenFlowHostProvider() {
        super(new ProviderId("of", "org.onlab.onos.provider.openflow"));
    }

    @Activate
    public void activate() {
        providerService = providerRegistry.register(this);
        controller.addPacketListener(10, listener);
        log.info("Started");
    }

    @Deactivate
    public void deactivate() {
        providerRegistry.unregister(this);
        controller.removePacketListener(listener);
        providerService = null;
        log.info("Stopped");
    }

    @Override
    public void triggerProbe(Host host) {
        log.info("Triggering probe on device {}", host);
    }

    private class InternalHostProvider implements PacketListener {

        @Override
        public void handlePacket(OpenFlowPacketContext pktCtx) {
            Ethernet eth = pktCtx.parsed();

            VlanId vlan = VlanId.vlanId(eth.getVlanID());
            ConnectPoint heardOn = new ConnectPoint(deviceId(Dpid.uri(pktCtx.dpid())),
                                                    portNumber(pktCtx.inPort()));

            // If this is not an edge port, bail out.
            Topology topology = topologyService.currentTopology();
            if (topologyService.isInfrastructure(topology, heardOn)) {
                return;
            }

            HostLocation hloc = new HostLocation(deviceId(Dpid.uri(pktCtx.dpid())),
                                                 portNumber(pktCtx.inPort()),
                                                 System.currentTimeMillis());

            HostId hid = HostId.hostId(eth.getSourceMAC(), vlan);

            // Potentially a new or moved host
            if (eth.getEtherType() == Ethernet.TYPE_ARP) {
                ARP arp = (ARP) eth.getPayload();
                IpPrefix ip = IpPrefix.valueOf(arp.getSenderProtocolAddress());
                HostDescription hdescr =
                        new DefaultHostDescription(eth.getSourceMAC(), vlan, hloc, ip);
                providerService.hostDetected(hid, hdescr);

            } else if (ipLearn && eth.getEtherType() == Ethernet.TYPE_IPV4) {
                IPv4 pip = (IPv4) eth.getPayload();
                IpPrefix ip = IpPrefix.valueOf(pip.getSourceAddress());
                HostDescription hdescr =
                        new DefaultHostDescription(eth.getSourceMAC(), vlan, hloc, ip);
                providerService.hostDetected(hid, hdescr);

            }

            // TODO: Use DHCP packets as well later...
        }

    }
}