package net.onrc.onos.core.topology;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Switch Object stored in In-memory Topology.
 * <p/>
 * TODO REMOVE following design memo: This object itself may hold the DBObject,
 * but this Object itself will not issue any read/write to the DataStore.
 */
public class SwitchImpl extends NetworkGraphObject implements Switch {

    private Long dpid;
    // These needs to be ConcurrentCollecton if allowing Graph to be accessed Concurrently
    private final Map<Long, Port> ports;

    public SwitchImpl(NetworkGraph graph, Long dpid) {
        super(graph);
        this.dpid = dpid;
        ports = new HashMap<Long, Port>();
    }

    @Override
    public Long getDpid() {
        return dpid;
    }

    @Override
    public Collection<Port> getPorts() {
        return Collections.unmodifiableCollection(ports.values());
    }

    @Override
    public Port getPort(Long number) {
        return ports.get(number);
    }

    @Override
    public Iterable<Switch> getNeighbors() {
        Set<Switch> neighbors = new HashSet<>();
        for (Link link : getOutgoingLinks()) {
            neighbors.add(link.getDstSwitch());
        }
        // XXX should incoming considered neighbor?
        for (Link link : getIncomingLinks()) {
            neighbors.add(link.getSrcSwitch());
        }
        return neighbors;
    }

    @Override
    public Link getLinkToNeighbor(Long neighborDpid) {
        for (Link link : getOutgoingLinks()) {
            if (link.getDstSwitch().getDpid().equals(neighborDpid)) {
                return link;
            }
        }
        return null;
    }

    @Override
    public Collection<Device> getDevices() {
        // TODO Should switch also store a list of attached devices to avoid
        // calculating this every time?
        List<Device> devices = new ArrayList<Device>();

        for (Port port : ports.values()) {
            for (Device device : port.getDevices()) {
                devices.add(device);
            }
        }

        return devices;
    }

    public void addPort(Port port) {
        this.ports.put(port.getNumber(), port);
    }

    public Port removePort(Port port) {
        Port p = this.ports.remove(port.getNumber());
        return p;
    }

    public Port addPort(Long portNumber) {
        PortImpl port = new PortImpl(graph, this, portNumber);
        ports.put(port.getNumber(), port);
        return port;
    }

    @Override
    public Iterable<Link> getOutgoingLinks() {
        LinkedList<Link> links = new LinkedList<Link>();
        for (Port port : getPorts()) {
            Link link = port.getOutgoingLink();
            if (link != null) {
                links.add(link);
            }
        }
        return links;
    }

    @Override
    public Iterable<Link> getIncomingLinks() {
        LinkedList<Link> links = new LinkedList<Link>();
        for (Port port : getPorts()) {
            Link link = port.getIncomingLink();
            if (link != null) {
                links.add(link);
            }
        }
        return links;
    }
}