/**
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.
 * <p>
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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. See accompanying
 * LICENSE file.
 */
package site.ycsb.workloads;

import site.ycsb.Client;
import site.ycsb.WorkloadException;
import site.ycsb.generator.NumberGenerator;

import java.util.Properties;

/**
 * A disk-fragmenting workload.
 * <p>
 * Properties to control the client:
 * </p>
 * <UL>
 * <LI><b>disksize</b>: how many bytes of storage can the disk store? (default 100,000,000)
 * <LI><b>occupancy</b>: what fraction of the available storage should be used? (default 0.9)
 * <LI><b>requestdistribution</b>: what distribution should be used to select the records to operate on - uniform,
 * zipfian or latest (default: histogram)
 * </ul>
 * <p>
 * <p>
 * <p> See also:
 * Russell Sears, Catharine van Ingen.
 * <a href='https://database.cs.wisc.edu/cidr/cidr2007/papers/cidr07p34.pdf'>Fragmentation in Large Object
 * Repositories</a>,
 * CIDR 2006. [<a href='https://database.cs.wisc.edu/cidr/cidr2007/slides/p34-sears.ppt'>Presentation</a>]
 * </p>
 */
public class ConstantOccupancyWorkload extends CoreWorkload {
  private long disksize;
  private long storageages;
  private double occupancy;

  private long objectCount;

  public static final String STORAGE_AGE_PROPERTY = "storageages";
  public static final long STORAGE_AGE_PROPERTY_DEFAULT = 10;

  public static final String DISK_SIZE_PROPERTY = "disksize";
  public static final long DISK_SIZE_PROPERTY_DEFAULT = 100 * 1000 * 1000;

  public static final String OCCUPANCY_PROPERTY = "occupancy";
  public static final double OCCUPANCY_PROPERTY_DEFAULT = 0.9;

  @Override
  public void init(Properties p) throws WorkloadException {
    disksize = Long.parseLong(p.getProperty(DISK_SIZE_PROPERTY, String.valueOf(DISK_SIZE_PROPERTY_DEFAULT)));
    storageages = Long.parseLong(p.getProperty(STORAGE_AGE_PROPERTY, String.valueOf(STORAGE_AGE_PROPERTY_DEFAULT)));
    occupancy = Double.parseDouble(p.getProperty(OCCUPANCY_PROPERTY, String.valueOf(OCCUPANCY_PROPERTY_DEFAULT)));

    if (p.getProperty(Client.RECORD_COUNT_PROPERTY) != null ||
        p.getProperty(Client.INSERT_COUNT_PROPERTY) != null ||
        p.getProperty(Client.OPERATION_COUNT_PROPERTY) != null) {
      System.err.println("Warning: record, insert or operation count was set prior to initting " +
          "ConstantOccupancyWorkload.  Overriding old values.");
    }
    NumberGenerator g = CoreWorkload.getFieldLengthGenerator(p);
    double fieldsize = g.mean();
    int fieldcount = Integer.parseInt(p.getProperty(FIELD_COUNT_PROPERTY, FIELD_COUNT_PROPERTY_DEFAULT));

    objectCount = (long) (occupancy * (disksize / (fieldsize * fieldcount)));
    if (objectCount == 0) {
      throw new IllegalStateException("Object count was zero.  Perhaps disksize is too low?");
    }
    p.setProperty(Client.RECORD_COUNT_PROPERTY, String.valueOf(objectCount));
    p.setProperty(Client.OPERATION_COUNT_PROPERTY, String.valueOf(storageages * objectCount));
    p.setProperty(Client.INSERT_COUNT_PROPERTY, String.valueOf(objectCount));

    super.init(p);
  }

}
