/*
 * 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.openstacknetworking.web;

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.Lists;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.WebResource;
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.driver.DriverService;
import org.onosproject.openstacknetworking.OpenstackNetwork;
import org.onosproject.openstacknetworking.OpenstackNetworkingService;
import org.onosproject.openstacknetworking.OpenstackPort;
import org.onosproject.openstacknetworking.OpenstackPortInfo;
import org.onosproject.openstacknetworking.OpenstackRouter;
import org.onosproject.openstacknetworking.OpenstackSecurityGroup;
import org.onosproject.openstacknetworking.OpenstackSubnet;
import org.onosproject.openstacknetworking.OpenstackSwitchingService;
import org.slf4j.Logger;
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.Map;
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.slf4j.LoggerFactory.getLogger;

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

    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 DriverService driverService;

    protected OpenstackSwitchingService openstackSwitchingService;

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

        log.info("started");
    }

    @Deactivate
    protected void deactivate() {
        log.info("stopped");
    }

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

        WebResource.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() {

        WebResource.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() {
        WebResource.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() {

        WebResource.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) {
        WebResource.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 WebResource.Builder getClientBuilder(String uri) {
        Client client = Client.create();
        WebResource resource = client.resource(uri);
        return resource.accept(JSON_UTF_8.toString())
                .type(JSON_UTF_8.toString());
    }

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

            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) {
        return getNetworks().stream()
                .filter(n -> n.id().equals(networkId))
                .findAny().orElse(null);
    }

    @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);
    }

    @Override
    public Map<String, OpenstackPortInfo> openstackPortInfo() {
        return openstackSwitchingService.openstackPortInfo();
    }

    @Override
    public void setConfigurations(String neutronUrl, String keystoneUrl, String userName, String pass) {
        this.neutronUrl = checkNotNull(neutronUrl);
        this.keystoneUrl = checkNotNull(keystoneUrl);
        this.userName = checkNotNull(userName);
        this.pass = checkNotNull(pass);
    }
}