/*
 * 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.onosproject.openstackinterface.impl;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
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.apache.felix.scr.annotations.Service;
import org.onosproject.core.ApplicationId;
import org.onosproject.core.CoreService;
import org.onosproject.net.Port;
import org.onosproject.net.config.ConfigFactory;
import org.onosproject.net.config.NetworkConfigEvent;
import org.onosproject.net.config.NetworkConfigListener;
import org.onosproject.net.config.NetworkConfigRegistry;
import org.onosproject.openstackinterface.OpenstackInterfaceService;
import org.onosproject.openstackinterface.OpenstackNetwork;
import org.onosproject.openstackinterface.OpenstackNetworkingConfig;
import org.onosproject.openstackinterface.OpenstackPort;
import org.onosproject.openstackinterface.OpenstackRouter;
import org.onosproject.openstackinterface.OpenstackSecurityGroup;
import org.onosproject.openstackinterface.OpenstackSubnet;
import org.onosproject.openstackinterface.web.OpenstackNetworkCodec;
import org.onosproject.openstackinterface.web.OpenstackPortCodec;
import org.onosproject.openstackinterface.web.OpenstackRouterCodec;
import org.onosproject.openstackinterface.web.OpenstackSecurityGroupCodec;
import org.onosproject.openstackinterface.web.OpenstackSubnetCodec;
import org.slf4j.Logger;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Entity;
import javax.ws.rs.client.Invocation;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MediaType;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.stream.Collectors;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.net.MediaType.JSON_UTF_8;
import static org.onlab.util.Tools.groupedThreads;
import static org.onosproject.net.config.basics.SubjectFactories.APP_SUBJECT_FACTORY;
import static org.slf4j.LoggerFactory.getLogger;

/**
 * Handles REST Calls to Openstack Neutron.
 *
 */
@Service
@Component(immediate = true)
public class OpenstackInterfaceManager implements OpenstackInterfaceService {

    private static final String URI_NETWORKS = "networks";
    private static final String URI_PORTS = "ports";
    private static final String URI_SUBNETS = "subnets";
    private static final String URI_SECURITY_GROUPS = "security-groups";
    private static final String URI_TOKENS = "tokens";

    private static final String PATH_ROUTERS = "routers";
    private static final String PATH_NETWORKS = "networks";
    private static final String PATH_PORTS = "ports";
    private static final String PATH_SUBNETS = "subnets";
    private static final String PATH_ACCESS = "access";
    private static final String PATH_TOKEN = "token";
    private static final String PATH_ID = "id";

    private static final String HEADER_AUTH_TOKEN = "X-Auth-Token";

    private final Logger log = getLogger(getClass());
    private String neutronUrl;
    private String keystoneUrl;
    private String tokenId;
    private String userName;
    private String pass;

    private static final String PORT_NAME = "portName";

    private ApplicationId appId;

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

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected NetworkConfigRegistry cfgService;

    private InternalConfigListener internalConfigListener = new InternalConfigListener();
    private ExecutorService networkEventExcutorService =
            Executors.newSingleThreadExecutor(groupedThreads("onos/openstackinterface", "config-event"));

    private final Set<ConfigFactory> factories = ImmutableSet.of(
            new ConfigFactory<ApplicationId, OpenstackNetworkingConfig>(APP_SUBJECT_FACTORY,
                    OpenstackNetworkingConfig.class,
                    "openstackinterface") {
                @Override
                public OpenstackNetworkingConfig createConfig() {
                    return new OpenstackNetworkingConfig();
                }
            }
    );


    @Activate
    protected void activate() {
        appId = coreService
                .registerApplication("org.onosproject.openstackinterface");

        factories.forEach(cfgService::registerConfigFactory);
        cfgService.addListener(internalConfigListener);

        log.info("started");
    }

    @Deactivate
    protected void deactivate() {
        cfgService.removeListener(internalConfigListener);
        factories.forEach(cfgService::unregisterConfigFactory);
        log.info("stopped");
    }

    /**
     * Returns network information stored in Neutron.
     *
     * @return List of OpenstackNetwork
     */
    public Collection<OpenstackNetwork> getNetworks() {

        Invocation.Builder builder = getClientBuilder(neutronUrl + URI_NETWORKS);
        String response = builder.accept(MediaType.APPLICATION_JSON_TYPE).
                header(HEADER_AUTH_TOKEN, getToken()).get(String.class);

        log.debug("networks response:" + response);

        ObjectMapper mapper = new ObjectMapper();
        List<OpenstackNetwork> openstackNetworks = Lists.newArrayList();
        try {
            ObjectNode node = (ObjectNode) mapper.readTree(response);
            ArrayNode networkList = (ArrayNode) node.path(PATH_NETWORKS);
            OpenstackNetworkCodec networkCodec = new OpenstackNetworkCodec();
            networkList.forEach(n -> openstackNetworks.add(networkCodec.decode((ObjectNode) n, null)));
        } catch (IOException e) {
            log.warn("getNetworks()", e);
        }

        openstackNetworks.removeAll(Collections.singleton(null));
        openstackNetworks.forEach(n -> log.debug("network ID: {}", n.id()));

        return openstackNetworks;
    }

    /**
     * Returns port information stored in Neutron.
     *
     * @return List of OpenstackPort
     */
    public Collection<OpenstackPort> getPorts() {

        Invocation.Builder builder = getClientBuilder(neutronUrl + URI_PORTS);
        String response = builder.accept(MediaType.APPLICATION_JSON_TYPE).
                header(HEADER_AUTH_TOKEN, getToken()).get(String.class);

        ObjectMapper mapper = new ObjectMapper();
        List<OpenstackPort> openstackPorts = Lists.newArrayList();
        try {
            ObjectNode node = (ObjectNode) mapper.readTree(response);
            ArrayNode portList = (ArrayNode) node.path(PATH_PORTS);
            OpenstackPortCodec portCodec = new OpenstackPortCodec();
            portList.forEach(p -> openstackPorts.add(portCodec.decode((ObjectNode) p, null)));
        } catch (IOException e) {
            log.warn("getPorts()", e);
        }

        log.debug("port response:" + response);
        openstackPorts.forEach(n -> log.debug("port ID: {}", n.id()));

        return openstackPorts;
    }

    public Collection<OpenstackRouter> getRouters() {
        Invocation.Builder builder = getClientBuilder(neutronUrl + PATH_ROUTERS);
        String response = builder.accept(MediaType.APPLICATION_JSON_TYPE).
                header(HEADER_AUTH_TOKEN, getToken()).get(String.class);

        ObjectMapper mapper = new ObjectMapper();
        List<OpenstackRouter> openstackRouters = Lists.newArrayList();

        try {
            ObjectNode node = (ObjectNode) mapper.readTree(response);
            ArrayNode routerList = (ArrayNode) node.path(PATH_ROUTERS);
            OpenstackRouterCodec openstackRouterCodec = new OpenstackRouterCodec();
            routerList.forEach(r -> openstackRouters
                    .add(openstackRouterCodec.decode((ObjectNode) r, null)));
        } catch (IOException e) {
            log.warn("getRouters()", e);
        }

        log.debug("router response:" + response);
        openstackRouters.forEach(r -> log.debug("router ID: {}", r.id()));

        return openstackRouters;
    }

    /**
     * Returns Subnet information in Neutron.
     *
     * @return List of OpenstackSubnet
     */
    public Collection<OpenstackSubnet> getSubnets() {
        Invocation.Builder builder = getClientBuilder(neutronUrl + URI_SUBNETS);
        String response = builder.accept(MediaType.APPLICATION_JSON_TYPE).
                header(HEADER_AUTH_TOKEN, getToken()).get(String.class);

        ObjectMapper mapper = new ObjectMapper();
        List<OpenstackSubnet> subnets = Lists.newArrayList();
        try {
            ObjectNode node = (ObjectNode) mapper.readTree(response);
            ArrayNode subnetList = (ArrayNode) node.path(PATH_SUBNETS);
            OpenstackSubnetCodec subnetCodec = new OpenstackSubnetCodec();
            subnetList.forEach(s -> subnets.add(subnetCodec.decode((ObjectNode) s, null)));
        } catch (IOException e) {
            log.warn("getSubnets()", e);
        }

        log.debug("subnets response:" + response);
        subnets.forEach(s -> log.debug("subnet ID: {}", s.id()));

        return subnets;
    }

    /**
     * Extracts OpenstackSecurityGroup information for the ID.
     *
     * @param id Security Group ID
     * @return OpenstackSecurityGroup object or null if fails
     */
    public OpenstackSecurityGroup getSecurityGroup(String id) {
        Invocation.Builder builder = getClientBuilder(neutronUrl + URI_SECURITY_GROUPS + "/" + id);
        String response = builder.accept(MediaType.APPLICATION_JSON_TYPE).
                header(HEADER_AUTH_TOKEN, getToken()).get(String.class);

        ObjectMapper mapper = new ObjectMapper();
        OpenstackSecurityGroup securityGroup = null;
        try {
            ObjectNode node = (ObjectNode) mapper.readTree(response);
            OpenstackSecurityGroupCodec sgCodec = new OpenstackSecurityGroupCodec();
            securityGroup = sgCodec.decode(node, null);
        } catch (IOException e) {
            log.warn("getSecurityGroup()", e);
        }

        return securityGroup;
    }

    private Invocation.Builder getClientBuilder(String uri) {
        Client client = ClientBuilder.newClient();
        WebTarget wt = client.target(uri);
        return wt.request(JSON_UTF_8.toString());
    }

    private String getToken() {
        if (isTokenInvalid()) {
            String request = "{\"auth\": {\"tenantName\": \"admin\", " +
                    "\"passwordCredentials\":  {\"username\": \"" +
                    userName + "\",\"password\": \"" + pass + "\"}}}";
            Invocation.Builder builder = getClientBuilder(keystoneUrl + URI_TOKENS);
            String response = builder.accept(MediaType.APPLICATION_JSON).post(Entity.json(request), String.class);

            ObjectMapper mapper = new ObjectMapper();
            try {
                ObjectNode node = (ObjectNode) mapper.readTree(response);
                tokenId = node.path(PATH_ACCESS).path(PATH_TOKEN).path(PATH_ID).asText();
            } catch (IOException e) {
                log.warn("getToken()", e);
            }
            log.debug("token response:" + response);
        }

        return tokenId;
    }

    private boolean isTokenInvalid() {
        //TODO: validation check for the existing token
        return true;
    }

    @Override
    public Collection<OpenstackPort> ports(String networkId) {
        return getPorts().stream()
                .filter(port -> port.networkId().equals(networkId))
                .collect(Collectors.toList());
    }

    @Override
    public Collection<OpenstackPort> ports() {
        return getPorts();
    }

    @Override
    public OpenstackPort port(Port port) {
        String uuid = port.annotations().value(PORT_NAME).substring(3);
        return getPorts().stream()
                .filter(p -> p.id().startsWith(uuid))
                .findAny().orElse(null);
    }

    @Override
    public OpenstackPort port(String portId) {
        return getPorts().stream()
                .filter(p -> p.id().equals(portId))
                .findAny().orElse(null);
    }

    @Override
    public OpenstackNetwork network(String networkId) {
        Collection<OpenstackSubnet> subnets = getSubnets().stream()
                .filter(s -> s.networkId().equals(networkId))
                .collect(Collectors.toList());

        OpenstackNetwork openstackNetwork = getNetworks().stream()
                .filter(n -> n.id().equals(networkId))
                .findAny().orElse(null);

        if (openstackNetwork == null) {
            return null;
        }

        return OpenstackNetwork.builder()
                .id(openstackNetwork.id())
                .name(openstackNetwork.name())
                .networkType(openstackNetwork.networkType())
                .segmentId(openstackNetwork.segmentId())
                .tenantId(openstackNetwork.tenantId())
                .subnets(subnets)
                .build();
    }

    @Override
    public Collection<OpenstackNetwork> networks() {
        return getNetworks();
    }

    @Override
    public OpenstackSubnet subnet(String subnetId) {
        return getSubnets().stream()
                .filter(subnet -> subnet.id().equals(subnetId))
                .findAny().orElse(null);
    }

    @Override
    public Collection<OpenstackSubnet> subnets() {
        return getSubnets();
    }

    @Override
    public Collection<OpenstackRouter> routers() {
        return getRouters();
    }

    @Override
    public OpenstackRouter router(String routerId) {
        return getRouters().stream()
                .filter(router -> router.id().equals(routerId))
                .findAny().orElse(null);
    }

    private class InternalConfigListener implements NetworkConfigListener {

        public void configureNetwork() {
            OpenstackNetworkingConfig cfg =
                    cfgService.getConfig(appId, OpenstackNetworkingConfig.class);
            if (cfg == null) {
                log.error("There is no openstack server information in config.");
                return;
            }

            neutronUrl = checkNotNull(cfg.neutronServer());
            keystoneUrl = checkNotNull(cfg.keystoneServer());
            userName = checkNotNull(cfg.userName());
            pass = checkNotNull(cfg.password());
        }

        @Override
        public void event(NetworkConfigEvent event) {
            if (((event.type() == NetworkConfigEvent.Type.CONFIG_ADDED ||
                    event.type() == NetworkConfigEvent.Type.CONFIG_UPDATED)) &&
                    event.configClass().equals(OpenstackNetworkingConfig.class)) {

                log.info("Network configuration changed");
                networkEventExcutorService.execute(this::configureNetwork);
            }
        }
    }
}