package org.jboss.resteasy.core.request;

import java.math.BigDecimal;
import java.math.MathContext;


/**
 * A individual variant quality bean for the <span title="Remote Variant Selection Algorithm">RVSA</span>.
 *
 * @author Pascal S. de Kloe
 * @see "RFC 2296"
 */
public class VariantQuality
{

   private QualityValue mediaTypeQualityValue = QualityValue.DEFAULT;
   private QualityValue characterSetQualityValue = QualityValue.DEFAULT;
   private QualityValue encodingQualityValue = QualityValue.DEFAULT;
   private QualityValue languageQualityValue = QualityValue.DEFAULT;


   public VariantQuality()
   {
   }


   public void setMediaTypeQualityValue(QualityValue value)
   {
      if (value == null)
         mediaTypeQualityValue = QualityValue.DEFAULT;
      else
         mediaTypeQualityValue = value;
   }


   public void setCharacterSetQualityValue(QualityValue value)
   {
      if (value == null)
         characterSetQualityValue = QualityValue.DEFAULT;
      else
         characterSetQualityValue = value;
   }


   public void setEncodingQualityValue(QualityValue value)
   {
      if (value == null)
         encodingQualityValue = QualityValue.DEFAULT;
      else
         encodingQualityValue = value;
   }


   public void setLanguageQualityValue(QualityValue value)
   {
      if (value == null)
         languageQualityValue = QualityValue.DEFAULT;
      else
         languageQualityValue = value;
   }


   /**
    * @return the quality value between zero and one with five decimal places after the point.
    * @see "3.3 Computing overall quality values"
    */
   public BigDecimal getOverallQuality()
   {
      BigDecimal qt = BigDecimal.valueOf(mediaTypeQualityValue.intValue(), 3);
      BigDecimal qc = BigDecimal.valueOf(characterSetQualityValue.intValue(), 3);
      BigDecimal qe = BigDecimal.valueOf(encodingQualityValue.intValue(), 3);
      BigDecimal ql = BigDecimal.valueOf(languageQualityValue.intValue(), 3);
      assert qt.compareTo(BigDecimal.ZERO) >= 0 && qt.compareTo(BigDecimal.ONE) <= 0;
      assert qc.compareTo(BigDecimal.ZERO) >= 0 && qc.compareTo(BigDecimal.ONE) <= 0;
      assert qe.compareTo(BigDecimal.ZERO) >= 0 && qe.compareTo(BigDecimal.ONE) <= 0;
      assert ql.compareTo(BigDecimal.ZERO) >= 0 && ql.compareTo(BigDecimal.ONE) <= 0;

      BigDecimal result = qt;
      result = result.multiply(qc, MathContext.DECIMAL32);
      result = result.multiply(qe, MathContext.DECIMAL32);
      result = result.multiply(ql, MathContext.DECIMAL32);
      assert result.compareTo(BigDecimal.ZERO) >= 0 && result.compareTo(BigDecimal.ONE) <= 0;

      long round5 = result.scaleByPowerOfTen(5).longValue();
      result = BigDecimal.valueOf(round5, 5);
      assert result.compareTo(BigDecimal.ZERO) >= 0 && result.compareTo(BigDecimal.ONE) <= 0;

      return result;
   }

}
