package net.onrc.onos.apps.segmentrouting;

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

import net.floodlightcontroller.core.IFloodlightProviderService;
import net.floodlightcontroller.core.IOFSwitch;
import net.floodlightcontroller.core.module.FloodlightModuleContext;
import net.floodlightcontroller.util.MACAddress;
import net.onrc.onos.core.flowprogrammer.IFlowPusherService;
import net.onrc.onos.core.packet.Ethernet;
import net.onrc.onos.core.packet.IPv4;
import net.onrc.onos.core.topology.ITopologyService;
import net.onrc.onos.core.topology.MutableTopology;
import net.onrc.onos.core.topology.Port;
import net.onrc.onos.core.topology.Switch;

import org.projectfloodlight.openflow.protocol.OFFactory;
import org.projectfloodlight.openflow.protocol.OFMatchV3;
import org.projectfloodlight.openflow.protocol.OFMessage;
import org.projectfloodlight.openflow.protocol.OFOxmList;
import org.projectfloodlight.openflow.protocol.action.OFAction;
import org.projectfloodlight.openflow.protocol.instruction.OFInstruction;
import org.projectfloodlight.openflow.protocol.oxm.OFOxmEthDst;
import org.projectfloodlight.openflow.protocol.oxm.OFOxmEthSrc;
import org.projectfloodlight.openflow.protocol.oxm.OFOxmEthType;
import org.projectfloodlight.openflow.protocol.oxm.OFOxmIpv4DstMasked;
import org.projectfloodlight.openflow.types.EthType;
import org.projectfloodlight.openflow.types.IPv4Address;
import org.projectfloodlight.openflow.types.MacAddress;
import org.projectfloodlight.openflow.types.OFBufferId;
import org.projectfloodlight.openflow.types.OFPort;
import org.projectfloodlight.openflow.types.TableId;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class GenericIpHandler {

    private MutableTopology mutableTopology;
    private ITopologyService topologyService;
    private IFloodlightProviderService floodlightProvider;
    private IFlowPusherService flowPusher;
    private SegmentRoutingManager srManager;

    private static final Logger log = LoggerFactory
            .getLogger(GenericIpHandler.class);

    private static final int TABLE_VLAN = 0;
    private static final int TABLE_TMAC = 1;
    private static final int TABLE_IPv4_UNICAST = 2;
    private static final int TABLE_MPLS = 3;
    private static final int TABLE_META = 4;
    private static final int TABLE_ACL = 5;

    private static final short MAX_PRIORITY = (short) 0xffff;
    private static final short SLASH_24_PRIORITY = (short) 0xfff0;
    private static final short SLASH_16_PRIORITY = (short) 0xff00;
    private static final short SLASH_8_PRIORITY = (short) 0xf000;
    private static final short MIN_PRIORITY = 0x0;

    public GenericIpHandler(FloodlightModuleContext context, SegmentRoutingManager sr) {
        this.floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
        this.topologyService = context.getServiceImpl(ITopologyService.class);
        this.mutableTopology = topologyService.getTopology();
        this.flowPusher = context.getServiceImpl(IFlowPusherService.class);
        this.srManager = sr;

    }

    public void processPacketIn(Switch sw, Port inPort, Ethernet payload) {
        // TODO Auto-generated method stub
        log.debug("GenericIPHandler: Received a IP packet {} from sw {} ",
                payload.toString(), sw.getDpid());
        IPv4 ipv4 = (IPv4)payload.getPayload();
        int destinationAddress = ipv4.getDestinationAddress();

        // Check if the destination is any host known to TopologyService
        for (net.onrc.onos.core.topology.Host host: mutableTopology.getHosts()) {
            IPv4Address hostIpAddress = IPv4Address.of(host.getIpAddress());
            if (hostIpAddress != null && hostIpAddress.getInt() == destinationAddress) {
                byte[] destinationMacAddress = host.getMacAddress().toBytes();
                addRouteToHost(sw, destinationAddress, destinationMacAddress);
                return;
            }
        }

        // Check if the destination is within subnets of the swtich
        if (isWithinSubnets(sw, IPv4Address.of(destinationAddress).toString())) {
            srManager.sendArpRequest(sw, destinationAddress, inPort);
        }
    }

    private boolean isWithinSubnets(Switch sw, String ipAddress) {

        return true;
    }


    /**
     * Add routing rules to forward packets to known hosts
     *
     * @param sw Switch
     * @param hostIp Host IP address to forwards packets to
     */
    public void addRouteToHost(Switch sw, int destinationAddress, byte[] destinationMacAddress) {

        IOFSwitch ofSwitch = floodlightProvider.getMasterSwitch(sw.getDpid().value());
        OFFactory factory = ofSwitch.getFactory();


        OFOxmEthType ethTypeIp = factory.oxms()
                .ethType(EthType.IPv4);
        OFOxmIpv4DstMasked ipPrefix = factory.oxms()
                .ipv4DstMasked(
                        IPv4Address.of(destinationAddress),
                        IPv4Address.NO_MASK); // host addr should be /32
        OFOxmList oxmListSlash32 = OFOxmList.of(ethTypeIp, ipPrefix);
        OFMatchV3 match = factory.buildMatchV3()
                .setOxmList(oxmListSlash32).build();
        OFAction setDmac = null;
        OFOxmEthDst dmac = factory.oxms()
                .ethDst(MacAddress.of(destinationMacAddress));
        setDmac = factory.actions().buildSetField()
                .setField(dmac).build();

        OFAction decTtl = factory.actions().decNwTtl();

        // Set the source MAC address with the switch MAC address
        String switchMacAddress = sw.getStringAttribute("routerMac");
        OFOxmEthSrc srcAddr = factory.oxms().ethSrc(MacAddress.of(switchMacAddress));
        OFAction setSA = factory.actions().buildSetField()
                .setField(srcAddr).build();

        List<OFAction> actionList = new ArrayList<OFAction>();
        actionList.add(setDmac);
        actionList.add(decTtl);
        actionList.add(setSA);


        /* TODO : need to check the config file for all packets
        String subnets = sw.getStringAttribute("subnets");
        try {
            JSONArray arry = new JSONArray(subnets);
            for (int i = 0; i < arry.length(); i++) {
                String subnetIp = (String) arry.getJSONObject(i).get("subnetIp");
                int portNo = (int) arry.getJSONObject(i).get("portNo");

                if (netMatch(subnetIp, IPv4Address.of(hostIp.getDestinationAddress()).toString())) {
                    OFAction out = factory.actions().buildOutput()
                            .setPort(OFPort.of(portNo)).build();
                    actionList.add(out);
                }
            }
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        */

        // Set output port
        net.onrc.onos.core.topology.Host host = mutableTopology.getHostByMac(MACAddress.valueOf(destinationMacAddress));
        if (host != null) {
            for (Port port: host.getAttachmentPoints()) {
                OFAction out = factory.actions().buildOutput()
                                .setPort(OFPort.of(port.getPortNumber().shortValue())).build();
                actionList.add(out);
            }
        }

        OFInstruction writeInstr = factory.instructions().buildWriteActions()
                .setActions(actionList).build();

        List<OFInstruction> instructions = new ArrayList<OFInstruction>();
        instructions.add(writeInstr);

        OFMessage myIpEntry = factory.buildFlowAdd()
                .setTableId(TableId.of(TABLE_IPv4_UNICAST))
                .setMatch(match)
                .setInstructions(instructions)
                .setPriority(MAX_PRIORITY)
                .setBufferId(OFBufferId.NO_BUFFER)
                .setIdleTimeout(0)
                .setHardTimeout(0)
                //.setXid(getNextTransactionId())
                .build();

        log.debug("Sending 'Routing information' OF message to the switch {}.", sw.getDpid().toString());

        flowPusher.add(sw.getDpid(), myIpEntry);

    }


}