package net.onrc.onos.core.intent;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;

import net.onrc.onos.core.topology.Link;
import net.onrc.onos.core.topology.LinkEvent;
import net.onrc.onos.core.topology.PortEvent.SwitchPort;

/**
 * @author Toshio Koide (t-koide@onlab.us)
 */
public class PathIntentMap extends IntentMap {
    private HashMap<Long, HashMap<Long, HashSet<PathIntent>>> intents;

    public PathIntentMap() {
        intents = new HashMap<>();
    }

    private HashSet<PathIntent> get(SwitchPort swPort) {
        Long dpid = swPort.getDpid();
        Long port = swPort.getNumber();
        HashMap<Long, HashSet<PathIntent>> portToIntents = intents.get(dpid);
        if (portToIntents == null) {
            portToIntents = new HashMap<>();
            intents.put(dpid, portToIntents);
        }
        HashSet<PathIntent> targetIntents = portToIntents.get(port);
        if (targetIntents == null) {
            targetIntents = new HashSet<>();
            portToIntents.put(port, targetIntents);
        }
        return targetIntents;
    }

    private void put(SwitchPort swPort, PathIntent intent) {
        get(swPort).add(intent);
    }

    @Override
    protected void putIntent(Intent intent) {
        if (!(intent instanceof PathIntent)) {
            return; // TODO throw exception
        }
        super.putIntent(intent);

        PathIntent pathIntent = (PathIntent) intent;
        for (LinkEvent linkEvent : pathIntent.getPath()) {
            put(linkEvent.getSrc(), (PathIntent) intent);
            put(linkEvent.getDst(), (PathIntent) intent);
        }
    }

    @Override
    protected void removeIntent(String intentId) {
        PathIntent intent = (PathIntent) getIntent(intentId);
        for (LinkEvent linkEvent : intent.getPath()) {
            get(linkEvent.getSrc()).remove(intent);
            get(linkEvent.getDst()).remove(intent);
        }
        super.removeIntent(intentId);
    }

    public Collection<PathIntent> getIntentsByLink(LinkEvent linkEvent) {
        return getIntentsByPort(
                linkEvent.getSrc().getDpid(),
                linkEvent.getSrc().getNumber());
    }

    public Collection<PathIntent> getIntentsByPort(Long dpid, Long port) {
        HashMap<Long, HashSet<PathIntent>> portToIntents = intents.get(dpid);
        if (portToIntents != null) {
            HashSet<PathIntent> targetIntents = portToIntents.get(port);
            if (targetIntents != null) {
                return Collections.unmodifiableCollection(targetIntents);
            }
        }
        return new HashSet<>();
    }

    public Collection<PathIntent> getIntentsByDpid(Long dpid) {
        HashSet<PathIntent> result = new HashSet<>();
        HashMap<Long, HashSet<PathIntent>> portToIntents = intents.get(dpid);
        if (portToIntents != null) {
            for (HashSet<PathIntent> targetIntents : portToIntents.values()) {
                result.addAll(targetIntents);
            }
        }
        return result;
    }

    /**
     * calculate available bandwidth of specified link.
     *
     * @param link
     * @return
     */
    public Double getAvailableBandwidth(Link link) {
        if (link == null) {
            return null;
        }
        Double bandwidth = link.getCapacity();
        LinkEvent linkEvent = new LinkEvent(link);
        if (!bandwidth.isInfinite()) {
            for (PathIntent intent : getIntentsByLink(linkEvent)) {
                Double intentBandwidth = intent.getBandwidth();
                if (intentBandwidth == null || intentBandwidth.isInfinite() || intentBandwidth.isNaN()) {
                    continue;
                }
                bandwidth -= intentBandwidth;
            }
        }
        return bandwidth;
    }
}