/*
 * Copyright 2015 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.flowobjective;

import com.google.common.collect.ImmutableList;
import org.onosproject.core.ApplicationId;
import org.onosproject.net.flow.TrafficTreatment;

import java.util.Collection;
import java.util.List;
import java.util.Optional;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Default implementation of a next objective.
 */
public final class DefaultNextObjective implements NextObjective {

    private final List<TrafficTreatment> treatments;
    private final ApplicationId appId;
    private final Type type;
    private final Integer id;
    private final Operation op;
    private final Optional<ObjectiveContext> context;

    private DefaultNextObjective(Integer id, List<TrafficTreatment> treatments,
                                ApplicationId appId, Type type, Operation op) {
        this.treatments = treatments;
        this.appId = appId;
        this.type = type;
        this.id = id;
        this.op = op;
        this.context = Optional.empty();
    }

    private DefaultNextObjective(Integer id, List<TrafficTreatment> treatments,
                                 ApplicationId appId, ObjectiveContext context,
                                 Type type, Operation op) {
        this.treatments = treatments;
        this.appId = appId;
        this.type = type;
        this.id = id;
        this.op = op;
        this.context = Optional.ofNullable(context);
    }

    @Override
    public Collection<TrafficTreatment> next() {
        return treatments;
    }

    @Override
    public Type type() {
        return type;
    }

    @Override
    public int id() {
        return id;
    }

    @Override
    public int priority() {
        return 0;
    }

    @Override
    public ApplicationId appId() {
        return appId;
    }

    @Override
    public int timeout() {
        return 0;
    }

    @Override
    public boolean permanent() {
        return false;
    }

    @Override
    public Operation op() {
        return op;
    }

    @Override
    public Optional<ObjectiveContext> context() {
        return context;
    }

    /**
     * Returns a new builder.
     *
     * @return new builder
     */
    public static Builder builder() {
        return new Builder();
    }

    public static final class Builder implements NextObjective.Builder {

        private ApplicationId appId;
        private Type type;
        private Integer id;

        private final ImmutableList.Builder<TrafficTreatment> listBuilder
                = ImmutableList.builder();

        @Override
        public NextObjective.Builder withId(int nextId) {
            this.id = nextId;
            return this;
        }

        @Override
        public Builder withType(Type type) {
            this.type = type;
            return this;
        }

        @Override
        public Builder addTreatment(TrafficTreatment treatment) {
            listBuilder.add(treatment);
            return this;
        }

        /**
         * Noop. This method has no effect.
         *
         * @param timeout a timeout
         * @return a next objective builder
         */
        @Override
        public Builder makeTemporary(int timeout) {
            return this;
        }

        /**
         * Noop. This method has no effect.
         *
         * @return a next objective builder
         */
        @Override
        public Builder makePermanent() {
            return this;
        }

        @Override
        public NextObjective.Builder fromApp(ApplicationId appId) {
            this.appId = appId;
            return this;
        }

        /**
         * Noop. This method has no effect.
         *
         * @param priority an integer
         * @return a next objective builder
         */
        @Override
        public Builder withPriority(int priority) {
            return this;
        }

        @Override
        public NextObjective add() {
            List<TrafficTreatment> treatments = listBuilder.build();
            checkNotNull(appId, "Must supply an application id");
            checkNotNull(id, "id cannot be null");
            checkNotNull(type, "The type cannot be null");
            checkArgument(!treatments.isEmpty(), "Must have at least one treatment");

            return new DefaultNextObjective(id, treatments, appId, type, Operation.ADD);
        }

        @Override
        public NextObjective remove() {
            List<TrafficTreatment> treatments = listBuilder.build();
            checkNotNull(appId, "Must supply an application id");
            checkNotNull(id, "id cannot be null");
            checkNotNull(type, "The type cannot be null");
            checkArgument(!treatments.isEmpty(), "Must have at least one treatment");

            return new DefaultNextObjective(id, treatments, appId, type, Operation.REMOVE);
        }

        @Override
        public NextObjective add(ObjectiveContext context) {
            List<TrafficTreatment> treatments = listBuilder.build();
            checkNotNull(appId, "Must supply an application id");
            checkNotNull(id, "id cannot be null");
            checkNotNull(type, "The type cannot be null");
            checkArgument(!treatments.isEmpty(), "Must have at least one treatment");

            return new DefaultNextObjective(id, treatments, appId,
                                            context, type, Operation.ADD);
        }

        @Override
        public NextObjective remove(ObjectiveContext context) {
            List<TrafficTreatment> treatments = listBuilder.build();
            checkNotNull(appId, "Must supply an application id");
            checkNotNull(id, "id cannot be null");
            checkNotNull(type, "The type cannot be null");
            checkArgument(!treatments.isEmpty(), "Must have at least one treatment");

            return new DefaultNextObjective(id, treatments, appId,
                                            context, type, Operation.REMOVE);
        }
    }
}