package cz.cuni.amis.pogamut.sposh.elements;
   
   import cz.cuni.amis.pogamut.shady.ArgString;
   import cz.cuni.amis.pogamut.sposh.executor.ParamInfo;
   import java.lang.reflect.Array;
   import java.util.regex.Matcher;
   import java.util.regex.Pattern;
   
   /**
   * Class representing value and its properties in posh plan. Value in plan can
   * be e.g boolean or string and they have some properties. Methods of this class
   * take an object and perform some test on it (e.g. if you pass {@link Double}
   * with value 0.0 to {@link #isFalse(java.lang.Object) }, it will return true).
   *
   * Most important part of this class are methods {@link #compare(java.lang.Object, java.lang.Object)
   * } and {@link #equal(java.lang.Object, java.lang.Object) }.
   *
   * @author Honza
   */
  public class Result {
  
      /**
       * Is the value false? null is false Boolean false is false Number 0 is
       * false Arrays of size 0 is false, otherwise value is true
       *
       * @see http://docs.python.org/library/stdtypes.html#truth-value-testing
       * @return true if value is null, value convertable to number and 0
       */
      public static boolean isFalse(Object value) {
          if (value == null) {
              return true;
          }
          if (isBoolean(value)) {
              return !getBoolean(value);
          }
          if (isNumber(value)) {
              return getNumber(value).doubleValue() == 0;
          }
          if (value.getClass().isArray()) {
              return Array.getLength(value) == 0;
          }
          return false;
      }
  
      /**
       * Is value true? Basically negate {@link Result#isFalse(java.lang.Object)
       * }.
       *
       * @param value value for which we want the information.
       */
      public static boolean isTrue(Object value) {
          return !isFalse(value);
      }
  
      public static boolean isNumber(Object value) {
          return value instanceof Number;
      }
  
      public static Number getNumber(Object value) {
          assert isNumber(value);
          return (Number) value;
      }
  
      /**
       * Is value instance of {@link Boolean} class?
       *
       * @param value value to be tested
       * @return true if it is instance of {@link Boolean}
       */
      public static boolean isBoolean(Object value) {
          return value instanceof Boolean;
      }
  
      /**
       * Get boolean value from {@link Boolean} class.
       *
       * @param value (value must be instance of {@link Boolean) class.
       * @return value of boolean.
       */
      public static boolean getBoolean(Object value) {
          assert isBoolean(value);
          return ((Boolean) value).booleanValue();
      }
  
      /**
       * Parse string from posh plan and convert it to object. Rules of parsing:
       * "nil" - null "true"/"false" - boolean int number - integer double number
       * - double otherwise string
       *
       * @param valueString string that will be parsed to object NOT NULL.
       * @return created object
       */
      public static Object parseValue(String valueString) throws ParseException {
          // TODO: Maytbe reuse the parser instead of duplicating the code
          assert valueString != null;
  
          if ("nil".equalsIgnoreCase(valueString)) {
              return null;
          }
 
         if (valueString.equalsIgnoreCase(Boolean.TRUE.toString())) {
             return Boolean.TRUE;
         }
 
         if (valueString.equalsIgnoreCase(Boolean.FALSE.toString())) {
             return Boolean.FALSE;
         }
 
         try {
             return Integer.parseInt(valueString);
         } catch (NumberFormatException ex) {
         }
 
         try {
             return Double.parseDouble(valueString);
         } catch (NumberFormatException ex) {
         }
 
         if (valueString.length() >= 2 && valueString.startsWith("\"") && valueString.endsWith("\"")) {
             String unquotedString = valueString.substring(1, valueString.length() - 1);
             try {
                 return ArgString.unescape(unquotedString);
             } catch (cz.cuni.amis.pogamut.shady.ParseException ex) {
                 throw new ParseException(ex.getMessage());
             }
         }
         if (valueString.length() >= 2 && valueString.startsWith("'")) {
             String enumString = valueString.substring(1);
             if (!enumString.matches("[a-zA-Z_]([a-zA-Z_0-9])*(.[a-zA-Z_]([a-zA-Z_0-9])*)*")) {
                 throw new ParseException(enumString + " is not a valid enum name.");
             }
             return new EnumValue(enumString);
         }
         throw new ParseException("No good type from " + valueString);
     }
 
     /**
      * Get numerical representation for object derived from class {@link Number}
      * and from {@link Boolean} (true = 1, false = 0)
      *
      * @param value
      * @return numerical value of value.
      */
     public static double getNumerical(Object value) {
         if (isBoolean(value)) {
             return getBoolean(value) ? 1 : 0;
         }
 
         return getNumber(value).doubleValue();
     }
 
     /**
      * Is value numerical(either number or boolean)?
      *
      * @param value value to check if it is numerical
      */
     public static boolean isNumerical(Object value) {
         return isNumber(value) || isBoolean(value);
     }
 
     /**
      * Are two operands equal? Comparison is based on rules outlines in
      * http://docs.python.org/reference/expressions.html#notin
      *
      * @param operand1
      * @param operand2
      * @return
      */
     public static boolean equal(Object operand1, Object operand2) {
         // I can compare them numericly
         if (isNumerical(operand1) && isNumerical(operand2)) {
             double op1 = getNumerical(operand1);
             double op2 = getNumerical(operand2);
             return op1 == op2;
         }
         // otherwise use standard equals
         return operand1 == null ? operand2 == null : operand1.equals(operand2);
     }
 
     /**
      * What is the comparison of operand1 and operand2?
      *
      * @param operand1
      * @param operand2
      * @return a negative integer, zero, or a positive integer as this object is
      * less than, equal to, or greater than the specified object.
      */
     public static int compare(Object operand1, Object operand2) {
         // I can compare them numericly
         if (isNumerical(operand1) && isNumerical(operand2)) {
             double op1 = getNumerical(operand1);
             double op2 = getNumerical(operand2);
             int sig = (int) Math.signum(op1 - op2);
             return sig;
         }
         // otherwise use comparable
         if (operand1 == null) {
             if (operand2 == null) {
                 return 0;
             }
             // two objects are not equal, but HOW? we have null and something.
             throw new IllegalArgumentException("I can't compare " + operand1 + " with " + operand2);
         }
 
         Comparable op1 = (Comparable) operand1;
         Comparable op2 = (Comparable) operand2;
 
         return op1.compareTo(op2);
     }
 
     /**
      * Get string representation of the value that can be used in the lap plan.
      * Basically opposite of {@link Result#parseValue(java.lang.String) }.
      *
      * @param value value to convret
      * @return string representation that can be used in the plan
      */
     public static String toLap(Object value) {
         if (value == null) {
             return "nil";
         }
         if (value instanceof Character) {
             return "\"" + value.toString() + "\"";
         }
         if (value instanceof String) {
             return "\"" + value.toString() + "\"";
         }
         if (value instanceof EnumValue) {
             return '\'' + ((EnumValue) value).getName();
         }
 
         return value.toString();
     }
     /**
      * Regexp for parameter name be same as <VARIABLE> PoshParser
      */
     public final static String variableNameRegexp = "\\$[a-zA-Z]([_\\-a-zA-Z0-9])*";
 
     /**
      * Check if passed string is variable name. Variable names start with $ and
      * are followed by characters. Should be same as parser <tt>VARIABLE<tt>
      * terminal.
      *
      * @param possibleVariableName Tested string.
      * @return true if passed string is varaible name. False otherwise.
      */
     public static boolean isVariableName(String possibleVariableName) {
         return possibleVariableName.matches(variableNameRegexp);
     }
 }