/*
 * Copyright 2015-present 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.compiler;

import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.SetMultimap;
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.util.Identifier;
import org.onosproject.core.ApplicationId;
import org.onosproject.core.CoreService;
import org.onosproject.net.ConnectPoint;
import org.onosproject.net.DeviceId;
import org.onosproject.net.PortNumber;
import org.onosproject.net.flow.DefaultFlowRule;
import org.onosproject.net.flow.FlowRule;
import org.onosproject.net.intent.FlowRuleIntent;
import org.onosproject.net.intent.Intent;
import org.onosproject.net.intent.IntentCompiler;
import org.onosproject.net.intent.LinkCollectionIntent;
import org.onosproject.net.intent.constraint.EncapsulationConstraint;
import org.onosproject.net.resource.ResourceService;
import org.onosproject.net.resource.impl.LabelAllocator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;

/**
 * Compiler to produce flow rules from link collections.
 */
@Component(immediate = true)
public class LinkCollectionIntentCompiler
        extends LinkCollectionCompiler<FlowRule>
        implements IntentCompiler<LinkCollectionIntent> {

    private static Logger log = LoggerFactory.getLogger(LinkCollectionIntentCompiler.class);


    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected IntentConfigurableRegistrator registrator;

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

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

    private ApplicationId appId;

    @Activate
    public void activate() {
        appId = coreService.registerApplication("org.onosproject.net.intent");
        registrator.registerCompiler(LinkCollectionIntent.class, this, false);
        if (labelAllocator == null) {
            labelAllocator = new LabelAllocator(resourceService);
        }
    }

    @Deactivate
    public void deactivate() {
        registrator.unregisterCompiler(LinkCollectionIntent.class, false);
    }

    @Override
    public List<Intent> compile(LinkCollectionIntent intent, List<Intent> installable) {

        SetMultimap<DeviceId, PortNumber> inputPorts = HashMultimap.create();
        SetMultimap<DeviceId, PortNumber> outputPorts = HashMultimap.create();
        Map<ConnectPoint, Identifier<?>> labels = ImmutableMap.of();

        Optional<EncapsulationConstraint> encapConstraint = this.getIntentEncapConstraint(intent);

        computePorts(intent, inputPorts, outputPorts);

        if (encapConstraint.isPresent()) {
            labels = labelAllocator.assignLabelToPorts(intent.links(),
                                                       intent.id(),
                                                       encapConstraint.get().encapType());
        }

        List<FlowRule> rules = new ArrayList<>();
        for (DeviceId deviceId: outputPorts.keySet()) {
            rules.addAll(createRules(
                    intent,
                    deviceId,
                    inputPorts.get(deviceId),
                    outputPorts.get(deviceId),
                    labels)
            );
        }
        return Collections.singletonList(new FlowRuleIntent(appId, rules, intent.resources()));
    }

    @Override
    protected List<FlowRule> createRules(LinkCollectionIntent intent,
                                         DeviceId deviceId,
                                         Set<PortNumber> inPorts,
                                         Set<PortNumber> outPorts,
                                         Map<ConnectPoint, Identifier<?>> labels) {

        List<FlowRule> rules = new ArrayList<>(inPorts.size());
        /*
         * Looking for the encapsulation constraint
         */
        Optional<EncapsulationConstraint> encapConstraint = this.getIntentEncapConstraint(intent);

        inPorts.forEach(inport -> {

                ForwardingInstructions instructions = this.createForwardingInstruction(
                        encapConstraint,
                        intent,
                        inport,
                        outPorts,
                        deviceId,
                        labels
                );

                FlowRule rule = DefaultFlowRule.builder()
                        .forDevice(deviceId)
                        .withSelector(instructions.selector())
                        .withTreatment(instructions.treatment())
                        .withPriority(intent.priority())
                        .fromApp(appId)
                        .makePermanent()
                        .build();
                rules.add(rule);
            }
        );

        return rules;
    }
}