package net.onrc.onos.core.flowprogrammer;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.openflow.protocol.OFFlowRemoved;
import org.openflow.protocol.OFMessage;
import org.openflow.protocol.OFType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import net.floodlightcontroller.core.FloodlightContext;
import net.floodlightcontroller.core.IFloodlightProviderService;
import net.floodlightcontroller.core.IOFMessageListener;
import net.floodlightcontroller.core.IOFSwitch;
import net.floodlightcontroller.core.IOFSwitchListener;
import net.floodlightcontroller.core.module.FloodlightModuleContext;
import net.floodlightcontroller.core.module.FloodlightModuleException;
import net.floodlightcontroller.core.module.IFloodlightModule;
import net.floodlightcontroller.core.module.IFloodlightService;
import net.floodlightcontroller.restserver.IRestApiService;
import net.onrc.onos.core.flowprogrammer.web.FlowProgrammerWebRoutable;
import net.onrc.onos.core.util.FlowEntryId;
import net.onrc.onos.registry.controller.IControllerRegistryService;

/**
 * FlowProgrammer is a module responsible to maintain flows installed to switches.
 * FlowProgrammer consists of FlowPusher and FlowSynchronizer.
 * FlowPusher manages the rate of installation, and FlowSynchronizer synchronizes
 * flows between GraphDB and switches.
 * FlowProgrammer also watch the event of addition/deletion of switches to
 * start/stop synchronization. When a switch is added to network, FlowProgrammer
 * immediately kicks synchronization to keep switch's flow table latest state.
 * Adversely, when a switch is removed from network, FlowProgrammer immediately
 * stops synchronization.
 *
 * @author Brian
 */
public class FlowProgrammer implements IFloodlightModule,
        IOFMessageListener,
        IOFSwitchListener {
    // flag to enable FlowSynchronizer
    private static final boolean enableFlowSync = false;
    protected static final Logger log = LoggerFactory.getLogger(FlowProgrammer.class);
    protected volatile IFloodlightProviderService floodlightProvider;
    protected volatile IControllerRegistryService registryService;
    protected volatile IRestApiService restApi;

    protected FlowPusher pusher;
    private static final int NUM_PUSHER_THREAD = 1;

    protected FlowSynchronizer synchronizer;

    public FlowProgrammer() {
        pusher = new FlowPusher(NUM_PUSHER_THREAD);
        if (enableFlowSync) {
            synchronizer = new FlowSynchronizer();
        }
    }

    @Override
    public void init(FloodlightModuleContext context)
            throws FloodlightModuleException {
        floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
        registryService = context.getServiceImpl(IControllerRegistryService.class);
        restApi = context.getServiceImpl(IRestApiService.class);
        pusher.init(null, context, floodlightProvider.getOFMessageFactory(), null);
        if (enableFlowSync) {
            synchronizer.init(pusher);
        }
    }

    @Override
    public void startUp(FloodlightModuleContext context) {
        restApi.addRestletRoutable(new FlowProgrammerWebRoutable());
        pusher.start();
        floodlightProvider.addOFMessageListener(OFType.FLOW_REMOVED, this);
        floodlightProvider.addOFSwitchListener(this);
    }

    @Override
    public Collection<Class<? extends IFloodlightService>> getModuleServices() {
        Collection<Class<? extends IFloodlightService>> l =
                new ArrayList<Class<? extends IFloodlightService>>();
        l.add(IFlowPusherService.class);
        if (enableFlowSync) {
            l.add(IFlowSyncService.class);
        }
        return l;
    }

    @Override
    public Map<Class<? extends IFloodlightService>, IFloodlightService> getServiceImpls() {
        Map<Class<? extends IFloodlightService>,
                IFloodlightService> m =
                new HashMap<Class<? extends IFloodlightService>,
                        IFloodlightService>();
        m.put(IFlowPusherService.class, pusher);
        if (enableFlowSync) {
            m.put(IFlowSyncService.class, synchronizer);
        }
        return m;
    }

    @Override
    public Collection<Class<? extends IFloodlightService>> getModuleDependencies() {
        Collection<Class<? extends IFloodlightService>> l =
                new ArrayList<Class<? extends IFloodlightService>>();
        l.add(IFloodlightProviderService.class);
        l.add(IRestApiService.class);
        return l;
    }

    @Override
    public String getName() {
        // TODO Auto-generated method stub
        return "FlowProgrammer";
    }

    @Override
    public boolean isCallbackOrderingPrereq(OFType type, String name) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean isCallbackOrderingPostreq(OFType type, String name) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public Command receive(IOFSwitch sw, OFMessage msg, FloodlightContext cntx) {
        switch (msg.getType()) {
            case FLOW_REMOVED:
                OFFlowRemoved flowMsg = (OFFlowRemoved) msg;
                FlowEntryId id = new FlowEntryId(flowMsg.getCookie());
                log.debug("Got flow entry removed from {}: {}", sw.getId(), id);
                // TODO: Inform the Forwarding module that a flow has expired
                break;
            default:
                break;
        }

        return Command.CONTINUE;
    }

    @Override
    public void addedSwitch(IOFSwitch sw) {
        log.debug("Switch added: {}", sw.getId());

        if (enableFlowSync) {
            if (registryService.hasControl(sw.getId())) {
                synchronizer.synchronize(sw);
            }
        }
    }

    @Override
    public void removedSwitch(IOFSwitch sw) {
        log.debug("Switch removed: {}", sw.getId());

        if (enableFlowSync) {
            synchronizer.interrupt(sw);
        }
    }

    @Override
    public void switchPortChanged(Long switchId) {
        // TODO Auto-generated method stub
    }

}