/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.workflow.conditionparser;
  
  import java.util.Objects;
  
  /**
   * Represents a "value" in the condition language, so a string or a number, with corresponding comparison functions
   */
  public final class Atom implements Comparable<Atom> {
    private final Double number;
    private final String string;
  
    private Atom(Double number, String string) {
      this.number = number;
      this.string = string;
    }
  
    @Override
    public String toString() {
      if (number != null) {
        final String s = String.valueOf(number);
        // This is a simple little hack to support something like 3+'4' to be converted to '34' instead of '3.04'. It's
        // dirty, but you maybe shouldn't be doing 3+'4' anyways.
        if (s.endsWith(".0")) {
          return s.substring(0, s.length() - 2);
        }
        return s;
      }
      return string;
    }
  
    private static Atom fromNumber(double number) {
      return new Atom(number, null);
    }
  
    static Atom fromString(String string) {
      return new Atom(null, string);
    }
  
    static Atom parseNumber(String text) {
      return new Atom(Double.parseDouble(text), null);
    }
  
    static Atom parseString(String text) {
      return new Atom(null, text);
    }
  
    Atom reduce(Atom atom, NumericalOperator op) {
      switch (op) {
        case ADD:
          if (number != null && atom.number != null) {
            return Atom.fromNumber(number + atom.number);
          }
          return Atom.fromString(toString() + atom.toString());
        case SUBTRACT:
          if (number != null) {
            return Atom.fromNumber(number - atom.number);
          }
          throw new IllegalArgumentException("Tried to subtract from string '" + string + "'");
        case MULTIPLY:
          if (number != null) {
            return Atom.fromNumber(number * atom.number);
          }
          throw new IllegalArgumentException("Tried to multiply with string '" + string + "'");
        default:
          if (number != null) {
            return Atom.fromNumber(number / atom.number);
          }
          throw new IllegalArgumentException("Tried to divide from string '" + string + "'");
      }
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
     Atom atom = (Atom) o;
     return Objects.equals(number, atom.number) && Objects.equals(string, atom.string);
   }
 
   @Override
   public int hashCode() {
     return Objects.hash(number, string);
   }
 
   @Override
   public int compareTo(Atom o) {
     if (number != null) {
       if (o.number == null) {
         return toString().compareTo(o.string);
       }
       return number.compareTo(o.number);
     }
     if (o.string == null) {
       return string.compareTo(o.toString());
     }
     return string.compareTo(o.string);
   }
 }