/*

 *   SONEWS News Server

 *   see AUTHORS for the list of contributors

 *

 *   This program is free software: you can redistribute it and/or modify

 *   it under the terms of the GNU General Public License as published by

 *   the Free Software Foundation, either version 3 of the License, or

 *   (at your option) any later version.

 *

 *   This program is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

package org.sonews.util;

import java.util.Calendar;

import org.sonews.config.Config;

import org.sonews.storage.Channel;

import org.sonews.storage.StorageBackendException;

import org.sonews.storage.StorageManager;

/**

 * Class that capsulates statistical data gathering.

 * @author Christian Lins

 * @since sonews/0.5.0

 */

public final class Stats 

{

  public static final byte CONNECTIONS    = 1;

  public static final byte POSTED_NEWS    = 2;

  public static final byte GATEWAYED_NEWS = 3;

  public static final byte FEEDED_NEWS    = 4;

  public static final byte MLGW_RUNSTART  = 5;

  public static final byte MLGW_RUNEND    = 6;

  private static Stats instance = new Stats();

  public static Stats getInstance()

  {

    return Stats.instance;

  }

  private Stats() {}

  private volatile int connectedClients = 0;

  /**

   * A generic method that writes event data to the storage backend.

   * If event logging is disabled with sonews.eventlog=false this method

   * simply does nothing.

   * @param type

   * @param groupname

   */

  private void addEvent(byte type, String groupname)

  {

    try

    {

      if (Config.inst().get(Config.EVENTLOG, true))

      {

        Channel group = Channel.getByName(groupname);

        if (group != null)

        {

          StorageManager.current().addEvent(

                  System.currentTimeMillis(), type, group.getInternalID());

        }

      } 

      else

      {

        Log.get().info("Group " + groupname + " does not exist.");

      }

    } 

    catch (StorageBackendException ex)

    {

      ex.printStackTrace();

    }

  }

  public void clientConnect()

  {

    this.connectedClients++;

  }

  public void clientDisconnect()

  {

    this.connectedClients--;

  }

  public int connectedClients()

  {

    return this.connectedClients;

  }

  public int getNumberOfGroups()

  {

    try

    {

      return StorageManager.current().countGroups();

    }

    catch(StorageBackendException ex)

    {

      ex.printStackTrace();

      return -1;

    }

  }

  public int getNumberOfNews()

  {

    try

    {

      return StorageManager.current().countArticles();

    }

    catch(StorageBackendException ex)

    {

      ex.printStackTrace();

      return -1;

    }

  }

  public int getYesterdaysEvents(final byte eventType, final int hour,

    final Channel group)

  {

    // Determine the timestamp values for yesterday and the given hour

    Calendar cal = Calendar.getInstance();

    int year  = cal.get(Calendar.YEAR);

    int month = cal.get(Calendar.MONTH);

    int dayom = cal.get(Calendar.DAY_OF_MONTH) - 1; // Yesterday

    cal.set(year, month, dayom, hour, 0, 0);

    long startTimestamp = cal.getTimeInMillis();

    cal.set(year, month, dayom, hour + 1, 0, 0);

    long endTimestamp = cal.getTimeInMillis();

    try

    {

      return StorageManager.current()

        .getEventsCount(eventType, startTimestamp, endTimestamp, group);

    }

    catch(StorageBackendException ex)

    {

      ex.printStackTrace();

      return -1;

    }

  }

  public void mailPosted(String groupname)

  {

    addEvent(POSTED_NEWS, groupname);

  }

  public void mailGatewayed(String groupname)

  {

    addEvent(GATEWAYED_NEWS, groupname);

  }

  public void mailFeeded(String groupname)

  {

    addEvent(FEEDED_NEWS, groupname);

  }

  public void mlgwRunStart()

  {

    addEvent(MLGW_RUNSTART, "control");

  }

  public void mlgwRunEnd()

  {

    addEvent(MLGW_RUNEND, "control");

  }

  private double perHour(int key, long gid)

  {

    try

    {

      return StorageManager.current().getEventsPerHour(key, gid);

    }

    catch(StorageBackendException ex)

    {

      ex.printStackTrace();

      return -1;

    }

  }

  public double postedPerHour(long gid)

  {

    return perHour(POSTED_NEWS, gid);

  }

  public double gatewayedPerHour(long gid)

  {

    return perHour(GATEWAYED_NEWS, gid);

  }

  public double feededPerHour(long gid)

  {

    return perHour(FEEDED_NEWS, gid);

  }

}