package org.onlab.onos.net.intent.impl;

import static org.onlab.onos.net.flow.DefaultTrafficTreatment.builder;
import static org.slf4j.LoggerFactory.getLogger;

import java.util.List;

import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.onlab.onos.ApplicationId;
import org.onlab.onos.CoreService;
import org.onlab.onos.net.ConnectPoint;
import org.onlab.onos.net.Link;
import org.onlab.onos.net.flow.DefaultFlowRule;
import org.onlab.onos.net.flow.DefaultTrafficSelector;
import org.onlab.onos.net.flow.DefaultTrafficTreatment;
import org.onlab.onos.net.flow.FlowRule;
import org.onlab.onos.net.flow.FlowRuleBatchEntry;
import org.onlab.onos.net.flow.FlowRuleBatchEntry.FlowRuleOperation;
import org.onlab.onos.net.flow.FlowRuleBatchOperation;
import org.onlab.onos.net.flow.FlowRuleService;
import org.onlab.onos.net.flow.TrafficSelector;
import org.onlab.onos.net.flow.TrafficTreatment;
import org.onlab.onos.net.intent.IntentExtensionService;
import org.onlab.onos.net.intent.IntentInstaller;
import org.onlab.onos.net.intent.OpticalPathIntent;
import org.onlab.onos.net.resource.DefaultLinkResourceRequest;
import org.onlab.onos.net.resource.Lambda;
import org.onlab.onos.net.resource.LambdaResourceAllocation;
import org.onlab.onos.net.resource.LinkResourceAllocations;
import org.onlab.onos.net.resource.LinkResourceRequest;
import org.onlab.onos.net.resource.LinkResourceService;
import org.onlab.onos.net.resource.ResourceAllocation;
import org.onlab.onos.net.resource.ResourceType;
import org.onlab.onos.net.topology.TopologyService;
import org.slf4j.Logger;

import com.google.common.collect.Lists;

/**
 * OpticaliIntentInstaller for optical path intents.
 * It essentially generates optical FlowRules and
 * call the flowRule service to execute them.
 */

@Component(immediate = true)
public class OpticalPathIntentInstaller implements IntentInstaller<OpticalPathIntent> {
    private final Logger log = getLogger(getClass());

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected IntentExtensionService intentManager;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected FlowRuleService flowRuleService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected CoreService coreService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected TopologyService topologyService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected LinkResourceService resourceService;

    private ApplicationId appId;

    //final short WAVELENGTH = 80;

    @Activate
    public void activate() {
        appId = coreService.registerApplication("org.onlab.onos.net.intent");
        intentManager.registerInstaller(OpticalPathIntent.class, this);
    }

    @Deactivate
    public void deactivate() {
        intentManager.unregisterInstaller(OpticalPathIntent.class);
    }

    @Override
    public List<FlowRuleBatchOperation> install(OpticalPathIntent intent) {
        LinkResourceAllocations allocations = assignWavelength(intent);

        TrafficSelector.Builder selectorBuilder = DefaultTrafficSelector.builder();
        selectorBuilder.matchInport(intent.src().port());

        List<FlowRuleBatchEntry> rules = Lists.newLinkedList();
        ConnectPoint prev = intent.src();

        //TODO throw exception if the lambda was not assigned successfully
        for (Link link : intent.path().links()) {
            Lambda la = null;
            for (ResourceAllocation allocation : allocations.getResourceAllocation(link)) {
                if (allocation.type() == ResourceType.LAMBDA) {
                    la = ((LambdaResourceAllocation) allocation).lambda();
                    break;
                }
            }

            if (la == null) {
                log.info("Lambda was not assigned successfully");
                return null;
            }

            TrafficTreatment.Builder treatmentBuilder = DefaultTrafficTreatment.builder();
            treatmentBuilder.setOutput(link.src().port());
            treatmentBuilder.setLambda((short) la.toInt());

            FlowRule rule = new DefaultFlowRule(prev.deviceId(),
                    selectorBuilder.build(),
                    treatmentBuilder.build(),
                    100,
                    appId,
                    100,
                    true);
            rules.add(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule));

            prev = link.dst();
            selectorBuilder.matchInport(link.dst().port());
            selectorBuilder.matchLambda((short) la.toInt());
        }

        // build the last T port rule
        TrafficTreatment treatmentLast = builder()
                .setOutput(intent.dst().port()).build();
        FlowRule rule = new DefaultFlowRule(intent.dst().deviceId(),
                selectorBuilder.build(),
                treatmentLast,
                100,
                appId,
                100,
                true);
        rules.add(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule));

        return Lists.newArrayList(new FlowRuleBatchOperation(rules));
    }

    private LinkResourceAllocations assignWavelength(OpticalPathIntent intent) {
        LinkResourceRequest.Builder request = DefaultLinkResourceRequest.builder(intent.id(),
                intent.path().links())
                .addLambdaRequest();
        LinkResourceAllocations retLambda = resourceService.requestResources(request.build());
        return retLambda;
    }

    /*private Lambda assignWavelength(List<Link> links) {
        // TODO More wavelength assignment algorithm
        int wavenum = 0;
        Iterator<Link> itrlink = links.iterator();
        for (int i = 1; i <= WAVELENGTH; i++) {
            wavenum = i;
            boolean found = true;
            while (itrlink.hasNext()) {
                Link link = itrlink.next();
                if (isWavelengthUsed(link, i)) {
                    found = false;
                    break;
                }
            }
            // First-Fit wavelength assignment algorithm
            if (found) {
                break;
            }
        }

        if (wavenum == 0) {
            return null;
        }

        Lambda wave = Lambda.valueOf(wavenum);
        return wave;
    }

    private boolean isWavelengthUsed(Link link, int i) {
        Iterable<LinkResourceAllocations> wave = resourceService.getAllocations(link);
        for (LinkResourceAllocations ir : wave) {
            //if ir.resources().contains(i) {
            //}
        }
        return false;
    }*/

    @Override
    public List<FlowRuleBatchOperation> uninstall(OpticalPathIntent intent) {
        LinkResourceAllocations allocations = resourceService.getAllocations(intent.id());

        TrafficSelector.Builder selectorBuilder = DefaultTrafficSelector.builder();
        selectorBuilder.matchInport(intent.src().port());

        TrafficTreatment.Builder treatmentBuilder = DefaultTrafficTreatment.builder();

        List<FlowRuleBatchEntry> rules = Lists.newLinkedList();
        ConnectPoint prev = intent.src();

        //TODO throw exception if the lambda was not retrieved successfully
        for (Link link : intent.path().links()) {
            Lambda la = null;
            for (ResourceAllocation allocation : allocations.getResourceAllocation(link)) {
                if (allocation.type() == ResourceType.LAMBDA) {
                    la = ((LambdaResourceAllocation) allocation).lambda();
                    break;
                }
            }

            if (la == null) {
                log.info("Lambda was not retrieved successfully");
                return null;
            }

            treatmentBuilder.setOutput(link.src().port());
            treatmentBuilder.setLambda((short) la.toInt());

            FlowRule rule = new DefaultFlowRule(prev.deviceId(),
                    selectorBuilder.build(),
                    treatmentBuilder.build(),
                    100,
                    appId,
                    100,
                    true);
            rules.add(new FlowRuleBatchEntry(FlowRuleOperation.REMOVE, rule));

            prev = link.dst();
            selectorBuilder.matchInport(link.dst().port());
            selectorBuilder.matchLambda((short) la.toInt());
        }

        // build the last T port rule
        TrafficTreatment treatmentLast = builder()
                .setOutput(intent.dst().port()).build();
        FlowRule rule = new DefaultFlowRule(intent.dst().deviceId(),
                selectorBuilder.build(),
                treatmentLast,
                100,
                appId,
                100,
                true);
        rules.add(new FlowRuleBatchEntry(FlowRuleOperation.REMOVE, rule));

        return Lists.newArrayList(new FlowRuleBatchOperation(rules));
    }

}