/*
 *   Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 *   WSO2 Inc. licenses this file to you 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.wso2.carbon.mdm.services.android.services.impl;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.wso2.carbon.analytics.datasource.commons.exception.AnalyticsException;
import org.wso2.carbon.device.mgt.analytics.data.publisher.exception.DataPublisherConfigurationException;
import org.wso2.carbon.mdm.services.android.bean.DeviceState;
import org.wso2.carbon.mdm.services.android.bean.ErrorResponse;
import org.wso2.carbon.mdm.services.android.bean.wrapper.EventBeanWrapper;
import org.wso2.carbon.mdm.services.android.exception.BadRequestException;
import org.wso2.carbon.mdm.services.android.exception.NotFoundException;
import org.wso2.carbon.mdm.services.android.exception.UnexpectedServerErrorException;
import org.wso2.carbon.mdm.services.android.services.EventReceiverService;
import org.wso2.carbon.mdm.services.android.util.AndroidAPIUtils;
import org.wso2.carbon.mdm.services.android.util.Message;

import javax.validation.Valid;
import javax.validation.constraints.Size;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Response;
import java.util.List;

@Path("/events")
public class EventReceiverServiceImpl implements EventReceiverService {
    private static final String EVENT_STREAM_DEFINITION = "org.wso2.iot.LocationStream";
    private static final Log log = LogFactory.getLog(EventReceiverServiceImpl.class);
    private Gson gson = new Gson();

    private static final String LONGITUDE = "longitude";
    private static final String LATITUDE = "latitude";
    private static final String TIME_STAMP = "timeStamp";
    private static final String LOCATION_EVENT_TYPE = "location";

    @POST
    @Path("/publish")
    @Override
    public Response publishEvents(@Valid EventBeanWrapper eventBeanWrapper) {
        if (log.isDebugEnabled()) {
            log.debug("Invoking Android device even logging.");
        }
        String eventType = eventBeanWrapper.getType();
        if (!LOCATION_EVENT_TYPE.equals(eventType)) {
            String msg = "Dropping Android " + eventType + " Event.Only Location Event Type is supported.";
            log.warn(msg);
            return Response.status(Response.Status.BAD_REQUEST).entity(msg).build();
        }
        Message message = new Message();
        Object metaData[] = {eventBeanWrapper.getDeviceIdentifier(), eventType};
        String eventPayload = eventBeanWrapper.getPayload();
        JsonObject jsonObject = gson.fromJson(eventPayload, JsonObject.class);
        Object payload[] = {
                jsonObject.get(TIME_STAMP),
                jsonObject.get(LONGITUDE),
                jsonObject.get(LATITUDE)
        };
        try {
            if (AndroidAPIUtils.getEventPublisherService().publishEvent(
                    EVENT_STREAM_DEFINITION, "1.0.0", metaData, new Object[0], payload)) {
                message.setResponseCode("Event is published successfully.");
                return Response.status(Response.Status.CREATED).entity(message).build();
            } else {
                throw new UnexpectedServerErrorException(
                        new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage("Error occurred while " +
                                "publishing the event.").build());
            }
        } catch (DataPublisherConfigurationException e) {
            String msg = "Error occurred while getting the Data publisher Service instance.";
            log.error(msg, e);
            throw new UnexpectedServerErrorException(
                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
        }
    }

    @GET
    @Override
    public Response retrieveAlerts(@QueryParam("id")
                                       @Size(min = 2, max = 45)
                                       String deviceId,
                                   @QueryParam("from") long from,
                                   @QueryParam("to") long to,
                                       @Size(min = 2, max = 45)
                                   @QueryParam("type") String type,
                                   @HeaderParam("If-Modified-Since") String ifModifiedSince) {

        if (from != 0l && to != 0l && deviceId != null) {
            return retrieveAlertFromDate(deviceId, from, to);
        } else if (deviceId != null && type != null) {
            return retrieveAlertByType(deviceId, type);
        } else if (deviceId != null) {
            return retrieveAlert(deviceId);
        } else {
            throw new BadRequestException(
                    new ErrorResponse.ErrorResponseBuilder().setCode(400l).setMessage("Request must contain " +
                            "the device identifier. Optionally, both from and to value should be present to get " +
                            "alerts between times.").build());
        }
    }

    private Response retrieveAlert(String deviceId) {
        if (log.isDebugEnabled()) {
            log.debug("Retrieving events for given device Identifier.");
        }
        String query = "deviceIdentifier:" + deviceId;
        List<DeviceState> deviceStates;
        try {
            deviceStates = AndroidAPIUtils.getAllEventsForDevice(EVENT_STREAM_DEFINITION, query);
            if (deviceStates == null) {
                throw new NotFoundException(
                        new ErrorResponse.ErrorResponseBuilder().setCode(404l).setMessage("No any alerts are " +
                                "published for Device: " + deviceId + ".").build());
            } else {
                return Response.status(Response.Status.OK).entity(deviceStates).build();
            }
        } catch (AnalyticsException e) {
            String msg = "Error occurred while getting published events for specific device: " + deviceId + ".";
            log.error(msg, e);
            throw new UnexpectedServerErrorException(
                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
        }
    }

    private Response retrieveAlertFromDate(String deviceId, long from, long to) {
        String fromDate = String.valueOf(from);
        String toDate = String.valueOf(to);
        if (log.isDebugEnabled()) {
            log.debug("Retrieving events for given device Identifier and time period.");
        }

        String query = "deviceIdentifier:" + deviceId + " AND _timestamp: [" + fromDate + " TO " + toDate + "]";
        List<DeviceState> deviceStates;
        try {
            deviceStates = AndroidAPIUtils.getAllEventsForDevice(EVENT_STREAM_DEFINITION, query);
            if (deviceStates == null) {
                throw new NotFoundException(
                        new ErrorResponse.ErrorResponseBuilder().setCode(404l).setMessage("No any alerts are " +
                                "published on given date for given Device: " + deviceId + ".").build());

            } else {
                return Response.status(Response.Status.OK).entity(deviceStates).build();
            }
        } catch (AnalyticsException e) {
            String msg = "Error occurred while getting published events for specific " +
                    "Device: " + deviceId + " on given Date.";
            log.error(msg, e);
            throw new UnexpectedServerErrorException(
                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
        }
    }

    private Response retrieveAlertByType(String deviceId, String type) {
        if (log.isDebugEnabled()) {
            log.debug("Retrieving events for given device identifier and type.");
        }
        String query = "deviceIdentifier:" + deviceId + " AND type:" + type;
        List<DeviceState> deviceStates;
        try {
            deviceStates = AndroidAPIUtils.getAllEventsForDevice(EVENT_STREAM_DEFINITION, query);
            if (deviceStates == null) {
                throw new NotFoundException(
                        new ErrorResponse.ErrorResponseBuilder().setCode(404l).setMessage("No any alerts are " +
                                "published for given Device: '" + deviceId + "' and given specific Type.").build());

            } else {
                return Response.status(Response.Status.OK).entity(deviceStates).build();
            }
        } catch (AnalyticsException e) {
            String msg = "Error occurred while getting published events for specific " +
                    "Device: " + deviceId + "and given specific Type.";
            log.error(msg, e);
            throw new UnexpectedServerErrorException(
                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
        }
    }

}
