/**
    * Copyright (c) 2011, University of Konstanz, Distributed Systems Group
    * All rights reserved.
    * 
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions are met:
    * * Redistributions of source code must retain the above copyright
    * notice, this list of conditions and the following disclaimer.
    * * Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   * * Neither the name of the University of Konstanz nor the
   * names of its contributors may be used to endorse or promote products
   * derived from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> 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 org.treetank.service.xml.xpath.operators;
  
  import org.treetank.api.INodeReadTrx;
  import org.treetank.axis.AbsAxis;
  import org.treetank.exception.TTXPathException;
  import org.treetank.node.AtomicValue;
  import org.treetank.node.Type;
  import org.treetank.service.xml.xpath.EXPathError;
  import org.treetank.utils.NamePageHash;
  import org.treetank.utils.TypedValue;
  
  /**
   * <h1>AddOpAxis</h1>
   * <p>
   * Performs an arithmetic addition on two input operators.
   * </p>
   */
  public class AddOpAxis extends AbsObAxis {
  
      /**
       * Constructor. Initializes the internal state.
       * 
       * @param rtx
       *            Exclusive (immutable) trx to iterate with.
       * @param mOp1
       *            First value of the operation
       * @param mOp2
       *            Second value of the operation
       */
      public AddOpAxis(final INodeReadTrx rtx, final AbsAxis mOp1, final AbsAxis mOp2) {
  
          super(rtx, mOp1, mOp2);
      }
  
      /**
       * {@inheritDoc}
       * 
       */
      @Override
      public AtomicValue operate(final AtomicValue mOperand1, final AtomicValue mOperand2)
          throws TTXPathException {
  
          final Type returnType = getReturnType(mOperand1.getTypeKey(), mOperand2.getTypeKey());
          final int typeKey = NamePageHash.generateHashForString(returnType.getStringRepr());
  
          final byte[] value;
  
          switch (returnType) {
          case DOUBLE:
          case FLOAT:
          case DECIMAL:
          case INTEGER:
              final double dOp1 = Double.parseDouble(new String(mOperand1.getRawValue()));
              final double dOp2 = Double.parseDouble(new String(mOperand2.getRawValue()));
              value = TypedValue.getBytes(dOp1 + dOp2);
              break;
          case DATE:
          case TIME:
          case DATE_TIME:
          case YEAR_MONTH_DURATION:
          case DAY_TIME_DURATION:
              throw new IllegalStateException("Add operator is not implemented for the type "
                  + returnType.getStringRepr() + " yet.");
          default:
              throw EXPathError.XPTY0004.getEncapsulatedException();
  
          }
  
          return new AtomicValue(value, typeKey);
  
      }
  
     /**
      * {@inheritDoc}
      * 
      */
     @Override
     protected Type getReturnType(final int mOp1, final int mOp2) throws TTXPathException {
 
         final Type mType1 = Type.getType(mOp1).getPrimitiveBaseType();
         final Type mType2 = Type.getType(mOp2).getPrimitiveBaseType();
 
         if (mType1.isNumericType() && mType2.isNumericType()) {
 
             // if both have the same numeric type, return it
             if (mType1 == mType2) {
                 return mType1;
             } else if (mType1 == Type.DOUBLE || mType2 == Type.DOUBLE) {
                 return Type.DOUBLE;
             } else if (mType1 == Type.FLOAT || mType2 == Type.FLOAT) {
                 return Type.FLOAT;
             } else {
                 assert (mType1 == Type.DECIMAL || mType2 == Type.DECIMAL);
                 return Type.DECIMAL;
             }
 
         } else {
 
             switch (mType1) {
             case DATE:
                 if (mType2 == Type.YEAR_MONTH_DURATION || mType2 == Type.DAY_TIME_DURATION) {
                     return mType1;
                 }
                 break;
             case TIME:
                 if (mType2 == Type.DAY_TIME_DURATION) {
                     return mType1;
                 }
                 break;
             case DATE_TIME:
                 if (mType2 == Type.YEAR_MONTH_DURATION || mType2 == Type.DAY_TIME_DURATION) {
                     return mType1;
                 }
                 break;
             case YEAR_MONTH_DURATION:
                 if (mType2 == Type.DATE || mType2 == Type.DATE_TIME || mType2 == Type.YEAR_MONTH_DURATION) {
                     return mType2;
                 }
                 break;
             case DAY_TIME_DURATION:
                 if (mType2 == Type.DATE || mType2 == Type.TIME || mType2 == Type.DATE_TIME
                     || mType2 == Type.DAY_TIME_DURATION) {
                     return mType2;
                 }
                 break;
             default:
                 throw EXPathError.XPTY0004.getEncapsulatedException();
             }
             throw EXPathError.XPTY0004.getEncapsulatedException();
         }
     }
 
 }