/*
 * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */

package org.opendaylight.controller.topology.northbound;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentMap;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
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.SecurityContext;
import javax.xml.bind.JAXBElement;

import org.codehaus.enunciate.jaxrs.ResponseCode;
import org.codehaus.enunciate.jaxrs.StatusCodes;
import org.codehaus.enunciate.jaxrs.TypeHint;
import org.opendaylight.controller.northbound.commons.RestMessages;
import org.opendaylight.controller.northbound.commons.exception.InternalServerErrorException;
import org.opendaylight.controller.northbound.commons.exception.ResourceNotFoundException;
import org.opendaylight.controller.northbound.commons.exception.UnauthorizedException;
import org.opendaylight.controller.northbound.commons.utils.NorthboundUtils;
import org.opendaylight.controller.sal.authorization.Privilege;
import org.opendaylight.controller.sal.core.Edge;
import org.opendaylight.controller.sal.core.Property;
import org.opendaylight.controller.sal.utils.ServiceHelper;
import org.opendaylight.controller.sal.utils.Status;
import org.opendaylight.controller.topologymanager.ITopologyManager;
import org.opendaylight.controller.topologymanager.TopologyUserLinkConfig;

/**
 * Topology Northbound REST API
 *
 * <br>
 * <br>
 * Authentication scheme : <b>HTTP Basic</b><br>
 * Authentication realm : <b>opendaylight</b><br>
 * Transport : <b>HTTP and HTTPS</b><br>
 * <br>
 * HTTPS Authentication is disabled by default. Administrator can enable it in
 * tomcat-server.xml after adding a proper keystore / SSL certificate from a
 * trusted authority.<br>
 * More info :
 * http://tomcat.apache.org/tomcat-7.0-doc/ssl-howto.html#Configuration
 */

@Path("/")
public class TopologyNorthboundJAXRS {

    private String username;

    @Context
    public void setSecurityContext(SecurityContext context) {
        username = context.getUserPrincipal().getName();
    }

    protected String getUserName() {
        return username;
    }

    /**
     *
     * Retrieve the Topology
     *
     * @param containerName
     *            The container for which we want to retrieve the topology
     *
     * @return A List of EdgeProps each EdgeProp represent an Edge of the grap
     *         with the corresponding properties attached to it.
     */
    @Path("/{containerName}")
    @GET
    @Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
    @TypeHint(Topology.class)
    @StatusCodes({ @ResponseCode(code = 404, condition = "The Container Name passed was not found") })
    public Topology getTopology(@PathParam("containerName") String containerName) {

        if (!NorthboundUtils.isAuthorized(
                getUserName(), containerName, Privilege.READ, this)) {
            throw new UnauthorizedException(
                    "User is not authorized to perform this operation on container "
                            + containerName);
        }
        ITopologyManager topologyManager = (ITopologyManager) ServiceHelper
                .getInstance(ITopologyManager.class, containerName, this);
        if (topologyManager == null) {
            throw new ResourceNotFoundException(
                    RestMessages.NOCONTAINER.toString());
        }

        Map<Edge, Set<Property>> topo = topologyManager.getEdges();
        if (topo != null) {
            List<EdgeProperties> res = new ArrayList<EdgeProperties>();
            for (Map.Entry<Edge, Set<Property>> entry : topo.entrySet()) {
                EdgeProperties el = new EdgeProperties(entry.getKey(),
                        entry.getValue());
                res.add(el);
            }
            return new Topology(res);
        }

        return null;
    }

    /**
     * Retrieve the user configured links
     *
     * @param containerName
     *            The container for which we want to retrieve the user links
     *
     * @return A List of user configured links
     */
    @Path("/{containerName}/userLink")
    @GET
    @Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
    @TypeHint(TopologyUserLinks.class)
    @StatusCodes({ @ResponseCode(code = 404, condition = "The Container Name passed was not found") })
    public TopologyUserLinks getUserLinks(
            @PathParam("containerName") String containerName) {

        if (!NorthboundUtils.isAuthorized(
                getUserName(), containerName, Privilege.READ, this)) {
            throw new UnauthorizedException(
                    "User is not authorized to perform this operation on container "
                            + containerName);
        }
        ITopologyManager topologyManager = (ITopologyManager) ServiceHelper
                .getInstance(ITopologyManager.class, containerName, this);
        if (topologyManager == null) {
            throw new ResourceNotFoundException(
                    RestMessages.NOCONTAINER.toString());
        }

        ConcurrentMap<String, TopologyUserLinkConfig> userLinks = topologyManager
                .getUserLinks();
        if ((userLinks != null) && (userLinks.values() != null)) {
            List<TopologyUserLinkConfig> res = new ArrayList<TopologyUserLinkConfig>(
                    userLinks.values());
            return new TopologyUserLinks(res);
        }

        return null;
    }

    /**
     * Add an User Link
     *
     * @param containerName
     *            Name of the Container. The base Container is "default".
     * @param TopologyUserLinkConfig
     *            in JSON or XML format
     * @return Response as dictated by the HTTP Response Status code
     */

    @Path("/{containerName}/userLink")
    @POST
    @Consumes({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
    @StatusCodes({
            @ResponseCode(code = 201, condition = "User Link added successfully"),
            @ResponseCode(code = 404, condition = "The Container Name passed was not found"),
            @ResponseCode(code = 409, condition = "Failed to add User Link due to Conflicting Name"),
            @ResponseCode(code = 500, condition = "Failed to add User Link. Failure Reason included in HTTP Error response"),
            @ResponseCode(code = 503, condition = "One or more of Controller services are unavailable") })
    public Response addUserLink(
            @PathParam(value = "containerName") String containerName,
            @TypeHint(TopologyUserLinkConfig.class) JAXBElement<TopologyUserLinkConfig> userLinkConfig) {

        if (!NorthboundUtils.isAuthorized(
                getUserName(), containerName, Privilege.WRITE, this)) {
            throw new UnauthorizedException(
                    "User is not authorized to perform this operation on container "
                            + containerName);
        }
        ITopologyManager topologyManager = (ITopologyManager) ServiceHelper
                .getInstance(ITopologyManager.class, containerName, this);
        if (topologyManager == null) {
            throw new ResourceNotFoundException(
                    RestMessages.NOCONTAINER.toString());
        }

        Status status = topologyManager.addUserLink(userLinkConfig.getValue());
        if (status.isSuccess()) {
            return Response.status(Response.Status.CREATED).build();
        }
        throw new InternalServerErrorException(status.getDescription());
    }

    /**
     * Delete an User Link
     *
     * @param containerName
     *            Name of the Container. The base Container is "default".
     * @param name
     *            Name of the Link Configuration
     * @return Response as dictated by the HTTP Response Status code
     */

    @Path("/{containerName}/userLink/{name}")
    @DELETE
    @Consumes({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
    @StatusCodes({
            @ResponseCode(code = 200, condition = "Operation successful"),
            @ResponseCode(code = 404, condition = "The Container Name or Link Configuration Name was not found"),
            @ResponseCode(code = 503, condition = "One or more of Controller services are unavailable") })
    public Response deleteUserLink(
            @PathParam("containerName") String containerName,
            @PathParam("name") String name) {

        if (!NorthboundUtils.isAuthorized(
                getUserName(), containerName, Privilege.WRITE, this)) {
            throw new UnauthorizedException(
                    "User is not authorized to perform this operation on container "
                            + containerName);
        }
        ITopologyManager topologyManager = (ITopologyManager) ServiceHelper
                .getInstance(ITopologyManager.class, containerName, this);
        if (topologyManager == null) {
            throw new ResourceNotFoundException(
                    RestMessages.NOCONTAINER.toString());
        }

        Status ret = topologyManager.deleteUserLink(name);
        if (ret.isSuccess()) {
            return Response.ok().build();
        }
        throw new ResourceNotFoundException(ret.getDescription());
    }

}