/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * 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.
   */
  
  package org.apache.commons.jxpath.ri;
  
  import org.apache.commons.jxpath.Pointer;
  import org.apache.commons.jxpath.ri.model.NodePointer;
  import org.apache.commons.jxpath.ri.model.VariablePointer;
  
  /**
   * Type conversions, XPath style.
   */
  public class InfoSetUtil {
  
      private static final Double ZERO = Double.valueOf(0);
      private static final Double ONE = Double.valueOf(1);
      private static final Double NOT_A_NUMBER = Double.valueOf(Double.NaN);
  
      /**
       * Converts the supplied object to boolean.
       *
       * @param object to convert
       * @return boolean
       */
      public static boolean booleanValue(final Object object) {
          if (object instanceof Number) {
              final double value = ((Number) object).doubleValue();
              final int negZero = -0;
              return value != 0 && value != negZero && !Double.isNaN(value);
          }
          if (object instanceof Boolean) {
              return ((Boolean) object).booleanValue();
          }
          if (object instanceof EvalContext) {
              final EvalContext ctx = (EvalContext) object;
              final Pointer ptr = ctx.getSingleNodePointer();
              return ptr != null && booleanValue(ptr);
          }
          if (object instanceof String) {
              return ((String) object).length() != 0;
          }
          if (object instanceof NodePointer) {
              NodePointer pointer = (NodePointer) object;
              if (pointer instanceof VariablePointer) {
                  return booleanValue(pointer.getNode());
              }
              pointer = pointer.getValuePointer();
              return pointer.isActual();
          }
          return object != null;
      }
  
      /**
       * Converts the supplied object to double.
       *
       * @param object to convert
       * @return double
       */
      public static double doubleValue(final Object object) {
          if (object instanceof Number) {
              return ((Number) object).doubleValue();
          }
          if (object instanceof Boolean) {
              return ((Boolean) object).booleanValue() ? 0.0 : 1.0;
          }
          if (object instanceof String) {
              if (object.equals("")) {
                  return 0.0;
              }
              try {
                  return Double.parseDouble((String) object);
              } catch (final NumberFormatException ex) {
                  return Double.NaN;
              }
          }
          if (object instanceof NodePointer) {
              return doubleValue(((NodePointer) object).getValue());
          }
          if (object instanceof EvalContext) {
              final EvalContext ctx = (EvalContext) object;
              final Pointer ptr = ctx.getSingleNodePointer();
              return ptr == null ? Double.NaN : doubleValue(ptr);
          }
          return doubleValue(stringValue(object));
      }
 
     /**
      * Converts the supplied object to Number.
      *
      * @param object to convert
      * @return Number result
      */
     public static Number number(final Object object) {
         if (object instanceof Number) {
             return (Number) object;
         }
         if (object instanceof Boolean) {
             return ((Boolean) object).booleanValue() ? ONE : ZERO;
         }
         if (object instanceof String) {
             try {
                 return Double.valueOf((String) object);
             } catch (final NumberFormatException ex) {
                 return NOT_A_NUMBER;
             }
         }
         if (object instanceof EvalContext) {
             final EvalContext ctx = (EvalContext) object;
             final Pointer ptr = ctx.getSingleNodePointer();
             return ptr == null ? NOT_A_NUMBER : number(ptr);
         }
         if (object instanceof NodePointer) {
             return number(((NodePointer) object).getValue());
         }
         return number(stringValue(object));
     }
 
     /**
      * Converts the supplied object to String.
      *
      * @param object to convert
      * @return String value
      */
     public static String stringValue(final Object object) {
         if (object instanceof String) {
             return (String) object;
         }
         if (object instanceof Number) {
             final double d = ((Number) object).doubleValue();
             final long l = ((Number) object).longValue();
             return d == l ? String.valueOf(l) : String.valueOf(d);
         }
         if (object instanceof Boolean) {
             return ((Boolean) object).booleanValue() ? "true" : "false";
         }
         if (object == null) {
             return "";
         }
         if (object instanceof NodePointer) {
             return stringValue(((NodePointer) object).getValue());
         }
         if (object instanceof EvalContext) {
             final EvalContext ctx = (EvalContext) object;
             final Pointer ptr = ctx.getSingleNodePointer();
             return ptr == null ? "" : stringValue(ptr);
         }
         return String.valueOf(object);
     }
 
     /**
      * Constructs a new instance.
      *
      * @deprecated Will be private in the next major version.
      */
     @Deprecated
     public InfoSetUtil() {
         // empty
     }
 }