/*
    * (c) Copyright 2006-2020 by rapiddweller GmbH & Volker Bergmann. All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, is permitted under the terms of the
    * GNU General Public License.
    *
    * For redistributing this software or a derivative work under a license other
    * than the GPL-compatible Free Software License as defined by the Free
   * Software Foundation or approved by OSI, you must first obtain a commercial
   * license to this software product from rapiddweller GmbH & Volker Bergmann.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
   * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
   * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  package com.rapiddweller.benerator.primitive;
  
  import com.rapiddweller.benerator.GeneratorContext;
  import com.rapiddweller.benerator.InvalidGeneratorSetupException;
  import com.rapiddweller.benerator.NonNullGenerator;
  import com.rapiddweller.benerator.util.AbstractNonNullGenerator;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  /**
   * Combines the output of a 'slow' generator (e.g. a remote hiGenerator)
   * with quickly generated numbers in a range: value = hi * maxLo + local.
   *
   * @author Volker Bergmann
   * @since 0.3.04
   */
  public class HiLoGenerator extends AbstractNonNullGenerator<Long> {
  
    private static final Logger logger = LogManager.getLogger(HiLoGenerator.class);
  
    /**
     * The constant DEFAULT_MAX_LO.
     */
    protected static final int DEFAULT_MAX_LO = 100;
  
    /**
     * The Max lo.
     */
    protected int maxLo;
  
    private int lo;
    private Long hi;
  
    /**
     * The Hi generator.
     */
    protected NonNullGenerator<Long> hiGenerator;
  
    // constructors ----------------------------------------------------------------------------------------------------
  
    /**
     * Instantiates a new Hi lo generator.
     */
    public HiLoGenerator() {
      this(new IncrementGenerator(), DEFAULT_MAX_LO);
    }
  
    /**
     * Instantiates a new Hi lo generator.
     *
     * @param maxLo the max lo
     */
    public HiLoGenerator(int maxLo) {
      this(new IncrementGenerator(), DEFAULT_MAX_LO);
    }
  
    /**
     * Instantiates a new Hi lo generator.
     *
     * @param hiGenerator the hi generator
     * @param maxLo       the max lo
     */
    public HiLoGenerator(NonNullGenerator<Long> hiGenerator, int maxLo) {
      this.hiGenerator = hiGenerator;
      setMaxLo(maxLo);
      resetMembers();
    }
  
    // properties ------------------------------------------------------------------------------------
  
    /**
     * Sets hi generator.
     *
    * @param hiGenerator the hi generator
    */
   public void setHiGenerator(NonNullGenerator<Long> hiGenerator) {
     this.hiGenerator = hiGenerator;
   }
 
   /**
    * Gets max lo.
    *
    * @return the maxLo
    */
   public int getMaxLo() {
     return maxLo;
   }
 
   /**
    * Sets max lo.
    *
    * @param maxLo the maxLo to set
    */
   public void setMaxLo(int maxLo) {
     if (maxLo <= 0) {
       throw new IllegalArgumentException("maxLo must be greater than 0, was: " + maxLo);
     }
     this.maxLo = maxLo;
   }
 
   // Generator interface -------------------------------------------------------------------
 
   @Override
   public Class<Long> getGeneratedType() {
     return Long.class;
   }
 
   @Override
   public synchronized void init(GeneratorContext context) {
     assertNotInitialized();
     if (hiGenerator == null) {
       throw new InvalidGeneratorSetupException("hiGenerator", "is null");
     }
     hiGenerator.init(context);
     resetMembers();
     super.init(context);
   }
 
   @Override
   public synchronized Long generate() {
     assertInitialized();
     if (hi == -1 || lo >= maxLo) {
       hi = hiGenerator.generate();
       if (hi == null) {
         return null;
       }
       logger.debug("fetched new hi value: {}", hi);
       lo = 0;
     } else {
       lo++;
     }
     return hi * (maxLo + 1) + lo;
   }
 
   @Override
   public void reset() {
     hiGenerator.reset();
     resetMembers();
     super.reset();
   }
 
   @Override
   public void close() {
     hiGenerator.close();
     super.close();
   }
 
   @Override
   public boolean isThreadSafe() {
     return hiGenerator.isThreadSafe();
   }
 
   @Override
   public boolean isParallelizable() {
     return hiGenerator.isParallelizable();
   }
 
   @Override
   public String toString() {
     return getClass().getSimpleName() + '[' + maxLo + ',' + hiGenerator + ']';
   }
 
   private void resetMembers() {
     this.lo = -1;
     this.hi = -1L;
   }
 
 }