/*
    * Copyright (C) 2020-2023 Dipl.-Inform. Kai Hofmann. All rights reserved!
    */
   package de.powerstat.validation.values;
   
   
   import java.util.Objects;
   
   import de.powerstat.validation.interfaces.IValueObject;
  
  
  /**
   * Hour.
   *
   * Not DSGVO relevant.
   *
   * TODO Listener
   * TODO minutesWithin = 60
   * TODO min, max
   */
  public final class Hour implements Comparable<Hour>, IValueObject
   {
    /**
     * Overflow constant.
     */
    private static final String OVERFLOW = "Overflow"; //$NON-NLS-1$
  
    /**
     * Underflow contant.
     */
    private static final String UNDERFLOW = "Underflow"; //$NON-NLS-1$
  
    /* *
     * Cache for singletons.
     */
    // private static final Map<Integer, Hour> CACHE = new WeakHashMap<>();
  
    /**
     * Hour.
     */
    private final int hour;
  
  
    /**
     * Constructor.
     *
     * @param hour Hour 0-23
     * @throws IndexOutOfBoundsException When the hour is less than 0 or greater than 23
     */
    private Hour(final int hour)
     {
      super();
      if ((hour < 0) || (hour > 23))
       {
        throw new IndexOutOfBoundsException("Hour number out of range (0-23)!"); //$NON-NLS-1$
       }
      this.hour = hour;
     }
  
  
    /**
     * Hour factory.
     *
     * @param hour Hour 0-23
     * @return Hour object
     */
    public static Hour of(final int hour)
     {
      /*
      synchronized (Hour.class)
       {
        Hour obj = Hour.CACHE.get(hour);
        if (obj != null)
         {
          return obj;
         }
        obj = new Hour(hour);
        Hour.CACHE.put(Integer.valueOf(hour), obj);
        return obj;
       }
      */
      return new Hour(hour);
     }
  
  
    /**
     * Hour factory.
     *
     * @param value Hour 0-23 string
     * @return Hour object
     */
    public static Hour of(final String value)
     {
      return of(Integer.parseInt(value));
     }
  
  
    /**
     * Returns the value of this Hour as an int.
    *
    * @return The numeric value represented by this object after conversion to type int.
    */
   public int intValue()
    {
     return this.hour;
    }
 
 
   /**
    * Returns the value of this Hour as a String.
    *
    * @return The numeric value represented by this object after conversion to type String.
    */
   @Override
   public String stringValue()
    {
     return String.valueOf(this.hour);
    }
 
 
   /**
    * Calculate hash code.
    *
    * @return Hash
    * @see java.lang.Object#hashCode()
    */
   @Override
   public int hashCode()
    {
     return Integer.hashCode(this.hour);
    }
 
 
   /**
    * Is equal with another object.
    *
    * @param obj Object
    * @return true when equal, false otherwise
    * @see java.lang.Object#equals(java.lang.Object)
    */
   @Override
   public boolean equals(final Object obj)
    {
     if (this == obj)
      {
       return true;
      }
     if (!(obj instanceof Hour))
      {
       return false;
      }
     final Hour other = (Hour)obj;
     return this.hour == other.hour;
    }
 
 
   /**
    * Returns the string representation of this Hour.
    *
    * The exact details of this representation are unspecified and subject to change, but the following may be regarded as typical:
    *
    * "Hour[hour=1]"
    *
    * @return String representation of this Hour
    * @see java.lang.Object#toString()
    */
   @Override
   public String toString()
    {
     final var builder = new StringBuilder();
     builder.append("Hour[hour=").append(this.hour).append(']'); //$NON-NLS-1$
     return builder.toString();
    }
 
 
   /**
    * Compare with another object.
    *
    * @param obj Object to compare with
    * @return 0: equal; 1: greater; -1: smaller
    * @see java.lang.Comparable#compareTo(java.lang.Object)
    */
   @Override
   public int compareTo(final Hour obj)
    {
     Objects.requireNonNull(obj, "obj"); //$NON-NLS-1$
     return Integer.compare(this.hour, obj.hour);
    }
 
 
   /**
    * Add hours to this hour.
    *
    * @param hours Hours to add to this hour
    * @return New hour after adding the hours to this hour
    * @throws ArithmeticException In case of an overflow
    */
   public Hour add(final Hours hours)
    {
     final int newHour = Math.toIntExact(Math.addExact(this.hour, hours.longValue()));
     if (newHour > 23)
      {
       // TODO Listener
       throw new ArithmeticException(Hour.OVERFLOW);
      }
     return Hour.of(newHour);
    }
 
 
   /**
    * Subtract hours from this hour.
    *
    * @param hours Hours to subtract from this hour
    * @return New hour after subtracting hours from this hour
    * @throws ArithmeticException In case of an underflow
    */
   public Hour subtract(final Hours hours)
    {
     final int newHour = Math.toIntExact(Math.subtractExact(this.hour, hours.longValue()));
     if (newHour < 0)
      {
       // TODO Listener
       throw new ArithmeticException(Hour.UNDERFLOW);
      }
     return Hour.of(newHour);
    }
 
 
   /**
    * Increment this hour.
    *
    * @return New hour after incrementing this hour
    * @throws ArithmeticException In case of an overflow
    */
   public Hour increment()
    {
     final int newHour = Math.incrementExact(this.hour);
     if (newHour == 24)
      {
       // TODO Listener
       throw new ArithmeticException(Hour.OVERFLOW);
      }
     return Hour.of(newHour);
    }
 
 
   /**
    * Decrement this hour.
    *
    * @return New hour after decrement this hour
    * @throws ArithmeticException In case of an overflow
    */
   public Hour decrement()
    {
     final int newHour = Math.decrementExact(this.hour);
     if (newHour == -1)
      {
       // TODO Listener
       throw new ArithmeticException(Hour.UNDERFLOW);
      }
     return Hour.of(newHour);
    }
 
  }