/*
 * ============LICENSE_START========================================================================
 * ONAP : tr-069-adapter
 * =================================================================================================
 * Copyright (C) 2020 CommScope Inc Intellectual Property.
 * =================================================================================================
 * This tr-069-adapter software file is distributed by CommScope Inc 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
 *
 * This file 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.
 * ===============LICENSE_END=======================================================================
 */

package org.commscope.tr069adapter.netconf.rpc;

import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlRootElement;
import org.commscope.tr069adapter.netconf.error.NetconfNotificationException;
import org.opendaylight.netconf.api.NetconfMessage;
import org.opendaylight.netconf.api.xml.XmlElement;
import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
import org.opendaylight.netconf.api.xml.XmlUtil;
import org.opendaylight.netconf.impl.NetconfServerSession;
import org.opendaylight.netconf.impl.mapping.operations.DefaultNetconfOperation;
import org.opendaylight.netconf.util.mapping.AbstractLastNetconfOperation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;

public class CreateSubscription extends AbstractLastNetconfOperation
    implements DefaultNetconfOperation {

  private static final Logger logger = LoggerFactory.getLogger(CreateSubscription.class);
  private final Map<Notification, NetconfMessage> notifications;
  private NetconfServerSession session;
  private ScheduledExecutorService scheduledExecutorService;
  private static Map<String, NetconfServerSession> netconfServerSessionMap = new HashMap<>();
  private String deviceID;
  private String swVersion;
  private String hwVersion;

  public CreateSubscription(final String id, final Optional<File> notificationsFile,
      String deviceID, String swVersion, String hwVersion) {

    super(id);

    logger.debug("CreateSubscription RPC is created with macID {}", deviceID);
    this.deviceID = deviceID;
    this.swVersion = swVersion;
    this.hwVersion = hwVersion;

    final Optional<Notifications> notifs;

    if (notificationsFile.isPresent()) {
      notifs = Optional.of(loadNotifications(notificationsFile.get()));
      scheduledExecutorService = Executors.newScheduledThreadPool(1);
    } else {
      notifs = Optional.empty();
    }

    if (notifs.isPresent()) {
      final Collection<Notification> toCopy = notifs.get().getNotificationList();
      final Map<Notification, NetconfMessage> preparedMessages =
          Maps.newHashMapWithExpectedSize(toCopy.size());
      for (final Notification notification : toCopy) {
        final NetconfMessage parsedNotification =
            parseNetconfNotification(notification.getContent());
        preparedMessages.put(notification, parsedNotification);
      }
      this.notifications = preparedMessages;
    } else {
      this.notifications = Collections.emptyMap();
    }
  }

  private static Notifications loadNotifications(final File file) {
    try {
      final JAXBContext jaxbContext = JAXBContext.newInstance(Notifications.class);
      final Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
      return (Notifications) jaxbUnmarshaller.unmarshal(file);
    } catch (final JAXBException e) {
      throw new IllegalArgumentException("can not parse file " + file + " as a notifications file",
          e);
    }
  }

  @Override
  protected String getOperationName() {
    return "create-subscription";
  }

  @Override
  protected String getOperationNamespace() {
    return "urn:ietf:params:xml:ns:netconf:notification:1.0";
  }
  
  public String getSwVersion() {
    return swVersion;
  }

  public String getHwVersion() {
    return hwVersion;
  }

  @Override
  protected Element handleWithNoSubsequentOperations(final Document document,
      final XmlElement operationElement) {
    long delayAggregator = 0;
    for (final Map.Entry<Notification, NetconfMessage> notification : notifications.entrySet()) {
      for (int i = 0; i <= notification.getKey().getTimes(); i++) {

        delayAggregator += notification.getKey().getDelayInSeconds();

        scheduledExecutorService.schedule(() -> {
          Preconditions.checkState(session != null,
              "Session is not set, cannot process notifications");
          session.sendMessage(notification.getValue());
        }, delayAggregator, TimeUnit.SECONDS);
      }
    }
    return document.createElement(XmlNetconfConstants.OK);
  }

  private static NetconfMessage parseNetconfNotification(String content) {
    final int startEventTime = content.indexOf("<eventTime>") + "<eventTime>".length();
    final int endEventTime = content.indexOf("</eventTime>");
    final String eventTime = content.substring(startEventTime, endEventTime);
    if (eventTime.equals("XXXX")) {
      content = content.replace(eventTime,
          new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX").format(new Date()));
    }

    try {
      return new NetconfMessage(XmlUtil.readXmlToDocument(content));
    } catch (SAXException | IOException e) {
      throw new IllegalArgumentException("Cannot parse notifications", e);
    }
  }

  @Override
  public void setNetconfSession(final NetconfServerSession newSession) {
    logger.debug("Adding netconf session to notification server sessions map : {}", newSession);
    logger.debug("This CreateSubscription is setup to support  macID= {}", deviceID);
    this.session = newSession;
    netconfServerSessionMap.put(deviceID, newSession);
  }

  public static void sendNotification(NetconfMessage netconfMessage, String deviceID)
      throws NetconfNotificationException {
    logger.debug("Request to send notification. NetConfMessage : {}", netconfMessage);
    NetconfServerSession session = netconfServerSessionMap.get(deviceID);
    if (session != null && session.isUp()) {
      try {
        session.sendMessage(netconfMessage);
        logger.debug("Successfully send notification for deviceID: {}", deviceID);
      } catch (Exception e) {
        logger.error("Failed to send notification. while posting got error. {}", e.toString());
        throw new NetconfNotificationException("Exception while posting the netconf message", e);
      }

    } else {
      logger.debug(
          "Failed to send notification. None of valid netconf session is available for {}.",
          deviceID);
      logger.debug("Available netconf sessions : {}", netconfServerSessionMap);
      throw new NetconfNotificationException("NetConf active session deosn't not exist");
    }
  }

  @XmlRootElement(name = "notifications")
  public static final class Notifications {

    @javax.xml.bind.annotation.XmlElement(nillable = false, name = "notification", required = true)
    private List<Notification> notificationList;

    public List<Notification> getNotificationList() {
      return notificationList;
    }

    @Override
    public String toString() {
      final StringBuilder sb = new StringBuilder("Notifications{");
      sb.append("notificationList=").append(notificationList);
      sb.append('}');
      return sb.toString();
    }
  }

  public static final class Notification {

    @javax.xml.bind.annotation.XmlElement(nillable = false, name = "delay")
    private long delayInSeconds;

    @javax.xml.bind.annotation.XmlElement(nillable = false, name = "times")
    private long times;

    @javax.xml.bind.annotation.XmlElement(nillable = false, name = "content", required = true)
    private String content;

    public long getDelayInSeconds() {
      return delayInSeconds;
    }

    public long getTimes() {
      return times;
    }

    public String getContent() {
      return content;
    }

    @Override
    public String toString() {
      final StringBuilder sb = new StringBuilder("Notification{");
      sb.append("delayInSeconds=").append(delayInSeconds);
      sb.append(", times=").append(times);
      sb.append(", content='").append(content).append('\'');
      sb.append('}');
      return sb.toString();
    }
  }
}