/*
 * Copyright 2018-present Open Networking Foundation
 *
 * 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.
 *
 * This work was partially supported by EC H2020 project METRO-HAUL (761727).
 */
package org.onosproject.drivers.odtn.tapi;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.ImmutableSet;
import org.onosproject.net.Device;
import org.onosproject.net.DeviceId;
import org.onosproject.net.OchSignal;
import org.onosproject.net.Port;
import org.onosproject.net.PortNumber;
import org.onosproject.net.behaviour.LambdaQuery;
import org.onosproject.net.device.DeviceService;
import org.onosproject.net.driver.AbstractHandlerBehaviour;
import org.onosproject.protocol.rest.RestSBController;
import org.slf4j.Logger;

import javax.ws.rs.core.MediaType;
import java.io.IOException;
import java.io.InputStream;
import java.util.Set;

import static com.google.common.base.Preconditions.checkNotNull;
import static org.onosproject.drivers.odtn.tapi.TapiDeviceHelper.MC_POOL;
import static org.onosproject.drivers.odtn.tapi.TapiDeviceHelper.MEDIA_CHANNEL_SERVICE_INTERFACE_POINT_SPEC;
import static org.onosproject.drivers.odtn.tapi.TapiDeviceHelper.SERVICE_INTERFACE_POINT;
import static org.onosproject.drivers.odtn.tapi.TapiDeviceHelper.TAPI_COMMON;
import static org.onosproject.drivers.odtn.tapi.TapiDeviceHelper.UUID;
import static org.slf4j.LoggerFactory.getLogger;


/**
 * Driver behavior of TAPI devices to discover the map of available lambdas of the ports.
 */
public class TapiDeviceLambdaQuery extends AbstractHandlerBehaviour
        implements LambdaQuery {

    private static final Logger log = getLogger(TapiDeviceLambdaQuery.class);
    private static final String SIP_REQUEST_DATA_API = "/restconf/data/tapi-common:context/service-interface-point=";

    /**
     * Get the deviceId for which the methods apply.
     *
     * @return The deviceId as contained in the handler data
     */
    private DeviceId did() {
        return handler().data().deviceId();
    }

    @Override
    public Set<OchSignal> queryLambdas(PortNumber port) {
        RestSBController controller = checkNotNull(handler().get(RestSBController.class));
        DeviceService deviceService = checkNotNull(handler().get(DeviceService.class));
        DeviceId deviceId = did();
        Device dev = deviceService.getDevice(deviceId);
        if (dev == null) {
            log.error("Device {} does not exist", deviceId);
            return ImmutableSet.of();
        }
        Port p = deviceService.getPort(dev.id(), port);
        if (p == null) {
            log.error("Port {} does not exist", port);
            return ImmutableSet.of();
        }
        String uuid = p.annotations().value(UUID);

        try {
            InputStream inputStream = controller.get(deviceId, SIP_REQUEST_DATA_API + uuid,
                    MediaType.APPLICATION_JSON_TYPE);
            log.debug("Service interface point UUID: {}", uuid);
            JsonNode sipAttributes = new ObjectMapper().readTree(inputStream);
            JsonNode mcPool = sipAttributes.get(TAPI_COMMON + ":" + SERVICE_INTERFACE_POINT).get(0)
                    .get(MEDIA_CHANNEL_SERVICE_INTERFACE_POINT_SPEC).get(MC_POOL);

            //This creates a hashset of OChSignals representing the spectrum availability at the target port.
            return TapiDeviceHelper.getOchSignal(mcPool);

        } catch (IOException e) {
            log.error("Exception discoverPortDetails() {}", did(), e);
            return ImmutableSet.of();
        }
    }


}