/*
 * Copyright 2014 Open Networking Laboratory
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.onosproject.net.intent.impl;

import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

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.onosproject.core.ApplicationId;
import org.onosproject.core.CoreService;
import org.onosproject.net.ConnectPoint;
import org.onosproject.net.DeviceId;
import org.onosproject.net.Link;
import org.onosproject.net.PortNumber;
import org.onosproject.net.flow.DefaultFlowRule;
import org.onosproject.net.flow.DefaultTrafficSelector;
import org.onosproject.net.flow.DefaultTrafficTreatment;
import org.onosproject.net.flow.FlowRule;
import org.onosproject.net.flow.FlowRuleBatchEntry;
import org.onosproject.net.flow.FlowRuleBatchEntry.FlowRuleOperation;
import org.onosproject.net.flow.FlowRuleBatchOperation;
import org.onosproject.net.flow.TrafficSelector;
import org.onosproject.net.flow.TrafficTreatment;
import org.onosproject.net.intent.IntentExtensionService;
import org.onosproject.net.intent.IntentInstaller;
import org.onosproject.net.intent.LinkCollectionIntent;
import org.onosproject.net.intent.PathIntent;

import com.google.common.collect.Lists;

/**
 * Installer for {@link org.onosproject.net.intent.LinkCollectionIntent} path
 * segment intents.
 */
@Component(immediate = true)
public class LinkCollectionIntentInstaller
        implements IntentInstaller<LinkCollectionIntent> {

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

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

    private ApplicationId appId;

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

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

    @Override
    public List<FlowRuleBatchOperation> install(LinkCollectionIntent intent) {
        Map<DeviceId, Set<PortNumber>> inputMap = new HashMap<DeviceId, Set<PortNumber>>();
        Map<DeviceId, Set<PortNumber>> outputMap = new HashMap<DeviceId, Set<PortNumber>>();
        List<FlowRuleBatchEntry> rules = Lists.newLinkedList();

        for (Link link : intent.links()) {
            if (inputMap.get(link.dst().deviceId()) == null) {
                inputMap.put(link.dst().deviceId(), new HashSet<PortNumber>());
            }
            inputMap.get(link.dst().deviceId()).add(link.dst().port());

            if (outputMap.get(link.src().deviceId()) == null) {
                outputMap.put(link.src().deviceId(), new HashSet<PortNumber>());
            }
            outputMap.get(link.src().deviceId()).add(link.src().port());

        }

        for (ConnectPoint ingressPoint : intent.ingressPoints()) {
            if (inputMap.get(ingressPoint.deviceId()) == null) {
                inputMap
                        .put(ingressPoint.deviceId(), new HashSet<PortNumber>());
            }
            inputMap.get(ingressPoint.deviceId()).add(ingressPoint.port());

        }

        for (ConnectPoint egressPoint : intent.egressPoints()) {
            if (outputMap.get(egressPoint.deviceId()) == null) {
                outputMap
                        .put(egressPoint.deviceId(), new HashSet<PortNumber>());
            }
            outputMap.get(egressPoint.deviceId()).add(egressPoint.port());

        }

        for (Entry<DeviceId, Set<PortNumber>> entry : outputMap.entrySet()) {
            Set<PortNumber> ingressPoints = inputMap.get(entry.getKey());
            rules.addAll(createBatchEntries(FlowRuleOperation.ADD, intent,
                                            entry.getKey(),
                                            ingressPoints,
                                            entry.getValue()));
        }

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

    @Override
    public List<FlowRuleBatchOperation> uninstall(LinkCollectionIntent intent) {
        Map<DeviceId, Set<PortNumber>> inputMap = new HashMap<DeviceId, Set<PortNumber>>();
        Map<DeviceId, Set<PortNumber>> outputMap = new HashMap<DeviceId, Set<PortNumber>>();
        List<FlowRuleBatchEntry> rules = Lists.newLinkedList();

        for (Link link : intent.links()) {
            if (inputMap.get(link.dst().deviceId()) == null) {
                inputMap.put(link.dst().deviceId(), new HashSet<PortNumber>());
            }
            inputMap.get(link.dst().deviceId()).add(link.dst().port());

            if (outputMap.get(link.src().deviceId()) == null) {
                outputMap.put(link.src().deviceId(), new HashSet<PortNumber>());
            }
            outputMap.get(link.src().deviceId()).add(link.src().port());
        }

        for (ConnectPoint ingressPoint : intent.ingressPoints()) {
            if (inputMap.get(ingressPoint.deviceId()) == null) {
                inputMap
                        .put(ingressPoint.deviceId(), new HashSet<PortNumber>());
            }
            inputMap.get(ingressPoint.deviceId()).add(ingressPoint.port());

        }

        for (ConnectPoint egressPoint : intent.egressPoints()) {
            if (outputMap.get(egressPoint.deviceId()) == null) {
                outputMap
                        .put(egressPoint.deviceId(), new HashSet<PortNumber>());
            }
            outputMap.get(egressPoint.deviceId()).add(egressPoint.port());
        }

        for (Entry<DeviceId, Set<PortNumber>> entry : outputMap.entrySet()) {
            Set<PortNumber> ingressPoints = inputMap.get(entry.getKey());
            rules.addAll(createBatchEntries(FlowRuleOperation.REMOVE, intent,
                                            entry.getKey(),
                                            ingressPoints,
                                            entry.getValue()));
        }

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

    @Override
    public List<FlowRuleBatchOperation> replace(LinkCollectionIntent oldIntent,
                                                LinkCollectionIntent newIntent) {
        List<FlowRuleBatchOperation> batches = Lists.newArrayList();
        batches.addAll(uninstall(oldIntent));
        batches.addAll(install(newIntent));
        return batches;
    }

    /**
     * Creates a collection of FlowRuleBatchEntry based on the provided
     * parameters.
     *
     * @param operation the FlowRuleOperation to use
     * @param intent the link collection intent
     * @param deviceId the device ID for the flow rule
     * @param inPorts the logical input ports of the flow rule
     * @param outPorts the output ports of the flow rule
     * @return a collection with the new flow rule batch entries
     */
    private Collection<FlowRuleBatchEntry> createBatchEntries(
                                FlowRuleOperation operation,
                                LinkCollectionIntent intent,
                                DeviceId deviceId,
                                Set<PortNumber> inPorts,
                                Set<PortNumber> outPorts) {
        Collection<FlowRuleBatchEntry> result = Lists.newLinkedList();
        Set<PortNumber> ingressPorts = new HashSet<PortNumber>();

        //
        // Collect all ingress ports for this device.
        // The intent treatment is applied only on those ports.
        //
        for (ConnectPoint cp : intent.ingressPoints()) {
            if (cp.deviceId().equals(deviceId)) {
                ingressPorts.add(cp.port());
            }
        }

        //
        // Create two treatments: one for setting the output ports,
        // and a second one that applies the intent treatment and sets the
        // output ports.
        // NOTE: The second one is created only if there are ingress ports.
        //
        TrafficTreatment.Builder defaultTreatmentBuilder =
            DefaultTrafficTreatment.builder();
        for (PortNumber outPort : outPorts) {
            defaultTreatmentBuilder.setOutput(outPort);
        }
        TrafficTreatment defaultTreatment = defaultTreatmentBuilder.build();
        TrafficTreatment intentTreatment = null;
        if (!ingressPorts.isEmpty()) {
            TrafficTreatment.Builder intentTreatmentBuilder =
                DefaultTrafficTreatment.builder(intent.treatment());
            for (PortNumber outPort : outPorts) {
                intentTreatmentBuilder.setOutput(outPort);
            }
            intentTreatment = intentTreatmentBuilder.build();
        }

        for (PortNumber inPort : inPorts) {
            TrafficSelector selector = DefaultTrafficSelector
                .builder(intent.selector()).matchInport(inPort).build();
            TrafficTreatment treatment = defaultTreatment;
            if (ingressPorts.contains(inPort)) {
                // Use the intent treatment if this is ingress port
                treatment = intentTreatment;
            }
            FlowRule rule = new DefaultFlowRule(deviceId,
                selector, treatment, 123,
                appId, (short) (intent.id().fingerprint() &  0xffff), 0, true);
            result.add(new FlowRuleBatchEntry(operation, rule));
        }

        return result;
    }
}