/*
 * Copyright 2016-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.opencord.cordvtn.rest;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.onlab.osgi.DefaultServiceDirectory;
import org.onosproject.rest.AbstractWebResource;
import org.opencord.cordvtn.api.CordVtnAdminService;
import org.opencord.cordvtn.api.NetworkId;
import org.openstack4j.core.transport.ObjectMapperSingleton;
import org.openstack4j.model.network.Network;
import org.openstack4j.openstack.networking.domain.NeutronNetwork;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriBuilder;
import javax.ws.rs.core.UriInfo;
import java.io.InputStream;
import java.util.Set;

import static com.fasterxml.jackson.databind.SerializationFeature.INDENT_OUTPUT;
import static javax.ws.rs.core.Response.*;
import static javax.ws.rs.core.Response.Status.NOT_FOUND;

/**
 * Neutron ML2 mechanism driver implementation for the network resource.
 */
@Path("networks")
public class NeutronMl2NetworksWebResource extends AbstractWebResource {
    protected final Logger log = LoggerFactory.getLogger(getClass());

    private static final String MESSAGE = "Received networks %s request";
    private static final String NETWORK  = "network";
    private static final String NETWORKS = "networks";

    private final CordVtnAdminService adminService =
            DefaultServiceDirectory.getService(CordVtnAdminService.class);

    @Context
    private UriInfo uriInfo;

    /**
     * Creates a network from the JSON input stream.
     *
     * @param input network JSON input stream
     * @return 201 CREATED if the JSON is correct, 400 BAD_REQUEST if the JSON
     * is invalid or duplicated network already exists
     */
    @POST
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response createNetwork(InputStream input) {
        log.trace(String.format(MESSAGE, "CREATE"));

        final NeutronNetwork net = readNetwork(input);
        adminService.createNetwork(net);

        UriBuilder locationBuilder = uriInfo.getBaseUriBuilder()
                .path(NETWORKS)
                .path(net.getId());

        return created(locationBuilder.build()).build();
    }

    /**
     * Updates the network with the specified identifier.
     *
     * @param id network identifier
     * @param input network JSON input stream
     * @return 200 OK with the updated network, 400 BAD_REQUEST if the requested
     * network does not exist
     */
    @PUT
    @Path("{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response updateNetwork(@PathParam("id") String id, InputStream input) {
        log.trace(String.format(MESSAGE, "UPDATE " + id));

        final NeutronNetwork net = readNetwork(input);
        adminService.updateNetwork(net);

        ObjectNode result = this.mapper().createObjectNode();
        return ok(result.set(NETWORK, writeNetwork(net))).build();
    }

    /**
     * Returns all networks.
     *
     * @return 200 OK with set of networks
     */
    @GET
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response getNetworks() {
        log.trace(String.format(MESSAGE, "GET"));

        Set<Network> nets = adminService.getNetworks();
        ArrayNode arrayNodes = mapper().createArrayNode();
        nets.stream().forEach(net -> {
            arrayNodes.add(writeNetwork(net));
        });

        ObjectNode result = this.mapper().createObjectNode();
        return ok(result.set(NETWORKS, arrayNodes)).build();
    }

    /**
     * Returns the network with the given network id.
     *
     * @param id network id
     * @return 200 OK with the network, 404 NOT_FOUND if the network does not exist
     */
    @GET
    @Path("{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response getNetwork(@PathParam("id") String id) {
        log.trace(String.format(MESSAGE, "GET " + id));

        Network net = adminService.getNetwork(NetworkId.of(id));
        if (net == null) {
            return status(NOT_FOUND).build();
        }

        ObjectNode result = mapper().createObjectNode();
        return ok(result.set(NETWORK, writeNetwork(net))).build();
    }

    /**
     * Removes the service network.
     *
     * @param id network identifier
     * @return 204 NO_CONTENT, 400 BAD_REQUEST if the network does not exist
     */
    @DELETE
    @Path("{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public Response deleteNetwork(@PathParam("id") String id) {
        log.trace(String.format(MESSAGE, "DELETE " + id));

        adminService.removeNetwork(NetworkId.of(id));
        return noContent().build();
    }

    private NeutronNetwork readNetwork(InputStream input) {
        try {
            JsonNode jsonTree = mapper().enable(INDENT_OUTPUT).readTree(input);
            log.trace(mapper().writeValueAsString(jsonTree));
            return ObjectMapperSingleton.getContext(NeutronNetwork.class)
                    .readerFor(NeutronNetwork.class)
                    .readValue(jsonTree);
        } catch (Exception e) {
            throw new IllegalArgumentException();
        }
    }

    private ObjectNode writeNetwork(Network net) {
        try {
            String strNet = ObjectMapperSingleton.getContext(NeutronNetwork.class)
                    .writerFor(NeutronNetwork.class)
                    .writeValueAsString(net);
            log.trace(strNet);
            return (ObjectNode) mapper().readTree(strNet.getBytes());
        } catch (Exception e) {
            throw new IllegalStateException();
        }
    }
}