/*
 * Copyright 2014 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.rest;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.onlab.util.ItemNotFoundException;
import org.onosproject.codec.impl.FlowEntryCodec;
import org.onosproject.net.Device;
import org.onosproject.net.DeviceId;
import org.onosproject.net.device.DeviceService;
import org.onosproject.net.flow.FlowEntry;
import org.onosproject.net.flow.FlowRuleService;

import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;

/**
 * REST resource for interacting with the inventory of flows.
 */

@Path("flows")
public class FlowsWebResource extends AbstractWebResource {
    public static final String DEVICE_NOT_FOUND = "Device is not found";

    final FlowRuleService service = get(FlowRuleService.class);
    final ObjectNode root = mapper().createObjectNode();
    final ArrayNode flowsNode = root.putArray("flows");
    final FlowEntryCodec flowEntryCodec = new FlowEntryCodec();

    /**
     * Gets an array containing all the intents in the system.
     *
     * @return array of all the intents in the system
     */
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response getFlows() {

        final Iterable<Device> devices = get(DeviceService.class).getDevices();
        for (final Device device : devices) {
            final Iterable<FlowEntry> deviceEntries = service.getFlowEntries(device.id());
            if (deviceEntries != null) {
                for (final FlowEntry entry : deviceEntries) {
                    flowsNode.add(flowEntryCodec.encode(entry, this));
                }
            }
        }

        return ok(root.toString()).build();
    }

    /**
     * Gets the flows for a device, where the device is specified by Id.
     *
     * @param deviceId Id of device to look up
     * @return flow data as an array
     */
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    @Path("{deviceId}")
    public Response getFlowByDeviceId(@PathParam("deviceId") String deviceId) {
        final Iterable<FlowEntry> deviceEntries =
                service.getFlowEntries(DeviceId.deviceId(deviceId));

        if (!deviceEntries.iterator().hasNext()) {
            throw new ItemNotFoundException(DEVICE_NOT_FOUND);
        }
        for (final FlowEntry entry : deviceEntries) {
            flowsNode.add(flowEntryCodec.encode(entry, this));
        }
        return ok(root.toString()).build();
    }

    /**
     * Gets the flows for a device, where the device is specified by Id.
     *
     * @param deviceId Id of device to look up
     * @param flowId Id of flow to look up
     * @return flow data as an array
     */
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    @Path("{deviceId}/{flowId}")
    public Response getFlowByDeviceIdAndFlowId(@PathParam("deviceId") String deviceId,
                                               @PathParam("flowId") long flowId) {
        final Iterable<FlowEntry> deviceEntries =
                service.getFlowEntries(DeviceId.deviceId(deviceId));

        if (!deviceEntries.iterator().hasNext()) {
            throw new ItemNotFoundException(DEVICE_NOT_FOUND);
        }
        for (final FlowEntry entry : deviceEntries) {
            if (entry.id().value() == flowId) {
                flowsNode.add(flowEntryCodec.encode(entry, this));
            }
        }
        return ok(root.toString()).build();
    }
}