package net.onrc.onos.core.intent.runtime;

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;

import net.floodlightcontroller.util.MACAddress;
import net.onrc.onos.core.intent.FlowEntry;
import net.onrc.onos.core.intent.Intent;
import net.onrc.onos.core.intent.IntentOperation;
import net.onrc.onos.core.intent.IntentOperation.Operator;
import net.onrc.onos.core.intent.IntentOperationList;
import net.onrc.onos.core.intent.PathIntent;
import net.onrc.onos.core.intent.ShortestPathIntent;
import net.onrc.onos.core.topology.LinkEvent;
//import net.onrc.onos.core.topology.NetworkGraph;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 * @author Brian O'Connor <bocon@onlab.us>
 *
 */

public class PlanCalcRuntime {

//    NetworkGraph graph;
    private final static Logger log = LoggerFactory.getLogger(PlanCalcRuntime.class);

    public PlanCalcRuntime(/*NetworkGraph graph*/) {
//	this.graph = graph;
    }

    public List<Set<FlowEntry>> computePlan(IntentOperationList intentOps) {
	long start = System.nanoTime();
	List<Collection<FlowEntry>> flowEntries = computeFlowEntries(intentOps);
	long step1 = System.nanoTime();
	List<Set<FlowEntry>> plan = buildPhases(flowEntries);
	long step2 = System.nanoTime();
	log.error("MEASUREMENT: Compute flow entries: {} ns, Build phases: {} ns", 
		  (step1 - start), (step2 - step1));
	return plan;
    }

    private List<Collection<FlowEntry>> computeFlowEntries(IntentOperationList intentOps) {
	List<Collection<FlowEntry>> flowEntries = new LinkedList<>();
	for(IntentOperation i : intentOps) {
	    if(!(i.intent instanceof PathIntent)) {
		log.warn("Not a path intent: {}", i);
		continue;
	    }
	    PathIntent intent = (PathIntent) i.intent;
	    Intent parent = intent.getParentIntent();
	    long srcPort, dstPort;
	    long lastDstSw = -1, lastDstPort = -1;
	    MACAddress srcMac, dstMac;
	    if(parent instanceof ShortestPathIntent) {
		ShortestPathIntent pathIntent = (ShortestPathIntent) parent;
//		Switch srcSwitch = graph.getSwitch(pathIntent.getSrcSwitchDpid());
//		srcPort = srcSwitch.getPort(pathIntent.getSrcPortNumber());
		srcPort = pathIntent.getSrcPortNumber();
		srcMac = MACAddress.valueOf(pathIntent.getSrcMac());
		dstMac = MACAddress.valueOf(pathIntent.getDstMac());
//		Switch dstSwitch = graph.getSwitch(pathIntent.getDstSwitchDpid());
		lastDstSw = pathIntent.getDstSwitchDpid();
//		lastDstPort = dstSwitch.getPort(pathIntent.getDstPortNumber());
		lastDstPort = pathIntent.getDstPortNumber();
	    }
	    else {
		log.warn("Unsupported Intent: {}", parent);
		continue;
	    }
	    List<FlowEntry> entries = new ArrayList<>();
	    for(LinkEvent linkEvent : intent.getPath()) {
//		Link link = graph.getLink(linkEvent.getSrc().getDpid(),
//			  linkEvent.getSrc().getNumber(),
//			  linkEvent.getDst().getDpid(),
//			  linkEvent.getDst().getNumber());
//		Switch sw = link.getSrcSwitch();
		long sw = linkEvent.getSrc().getDpid();
//		dstPort = link.getSrcPort();
		dstPort = linkEvent.getSrc().getNumber();
		FlowEntry fe = new FlowEntry(sw, srcPort, dstPort, srcMac, dstMac, i.operator);
		entries.add(fe);
//		srcPort = link.getDstPort();
		srcPort = linkEvent.getDst().getNumber();
	    }
	    if(lastDstSw >= 0 && lastDstPort >= 0) {
		//Switch sw = lastDstPort.getSwitch();
		long sw = lastDstSw;
		dstPort = lastDstPort;
		FlowEntry fe = new FlowEntry(sw, srcPort, dstPort, srcMac, dstMac, i.operator);
		entries.add(fe);
	    }
	    // install flow entries in reverse order
	    Collections.reverse(entries);
	    flowEntries.add(entries);
	}
	return flowEntries;
    }

    private List<Set<FlowEntry>> buildPhases(List<Collection<FlowEntry>> flowEntries) {
	Map<FlowEntry, Integer> map = new HashMap<>();
	List<Set<FlowEntry>> plan = new ArrayList<>();
	for(Collection<FlowEntry> c : flowEntries) {
	    for(FlowEntry e : c) {
		Integer i = map.get(e);
		if(i == null) {
		    i = Integer.valueOf(0);
		}
		switch(e.getOperator()) {
		case ADD:
		    i += 1;
		    break;
		case REMOVE:
		    i -= 1;
		    break;
		default:
		    break;
		}
		map.put(e, i);
		// System.out.println(e + " " + e.getOperator());
	    }
	}

	// really simple first iteration of plan
	//TODO: optimize the map in phases
	Set<FlowEntry> phase = new HashSet<>();
	for(FlowEntry e : map.keySet()) {
	    Integer i = map.get(e);
	    if(i == 0) {
		continue;
	    }
	    else if(i > 0) {
		e.setOperator(Operator.ADD);
	    }
	    else if(i < 0) {
		e.setOperator(Operator.REMOVE);
	    }
	    phase.add(e);
	}
	plan.add(phase);

	return plan;
    }
}