/*
    * 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;
  
  
  /**
   * Month.
   *
   * Not DSGVO relevant.
   *
   * TODO constructor with year
   * TODO daysWithin() = 31, 30, 29, 28, n (Year specific for february, or october 1582)
   * TODO Listener
   * TODO Translations short/long
   */
  public final class Month implements Comparable<Month>, IValueObject
   {
    /* *
     * Cache for singletons.
     */
    // private static final Map<Integer, Month> CACHE = new WeakHashMap<>();
  
    /**
     * Overflow constant.
     */
    private static final String OVERFLOW = "Overflow"; //$NON-NLS-1$
  
    /**
     * Underflow constant.
     */
    private static final String UNDERFLOW = "Underflow"; //$NON-NLS-1$
  
    /**
     * Month.
     */
    private final int month;
  
  
    /**
     * Constructor.
     *
     * @param month Month 1-12
     * @throws IndexOutOfBoundsException When the month is less than 1 or greater than 12
     */
    private Month(final int month)
     {
      super();
      if ((month < 1) || (month > 12))
       {
        throw new IndexOutOfBoundsException("Month number out of range (1-12)!"); //$NON-NLS-1$
       }
      this.month = month;
     }
  
  
    /**
     * Month factory.
     *
     * @param month Month 1-12
     * @return Month object
     * @throws IndexOutOfBoundsException When the month is less than 1 or greater than 12
     */
    public static Month of(final int month)
     {
      /*
      synchronized (Month.class)
       {
        Month obj = Month.CACHE.get(month);
        if (obj != null)
         {
          return obj;
         }
        obj = new Month(month);
        Month.CACHE.put(Integer.valueOf(month), obj);
        return obj;
       }
      */
      return new Month(month);
     }
  
  
    /**
     * Month factory.
     *
     * @param value Month 1-12 string
     * @return Month object
     * @throws IndexOutOfBoundsException When the month is less than 1 or greater than 12
     */
    public static Month of(final String value)
     {
      return of(Integer.parseInt(value));
     }
  
 
   /**
    * Returns the value of this Month as an int.
    *
    * @return The numeric value represented by this object after conversion to type int.
    */
   public int intValue()
    {
     return this.month;
    }
 
 
   /**
    * Returns the value of this Month as an String.
    *
    * @return The numeric value represented by this object after conversion to type String.
    */
   @Override
   public String stringValue()
    {
     return String.valueOf(this.month);
    }
 
 
   /**
    * Calculate hash code.
    *
    * @return Hash
    * @see java.lang.Object#hashCode()
    */
   @Override
   public int hashCode()
    {
     return Integer.hashCode(this.month);
    }
 
 
   /**
    * 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 Month))
      {
       return false;
      }
     final Month other = (Month)obj;
     return this.month == other.month;
    }
 
 
   /**
    * Returns the string representation of this Month.
    *
    * The exact details of this representation are unspecified and subject to change, but the following may be regarded as typical:
    *
    * "Month[month=1]"
    *
    * @return String representation of this Month
    * @see java.lang.Object#toString()
    */
   @Override
   public String toString()
    {
     final var builder = new StringBuilder();
     builder.append("Month[month=").append(this.month).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 Month obj)
    {
     Objects.requireNonNull(obj, "obj"); //$NON-NLS-1$
     return Integer.compare(this.month, obj.month);
    }
 
 
   /**
    * Add months to this month.
    *
    * @param months Months to add to this month
    * @return New month after adding the months to this month
    * @throws ArithmeticException In case of an overflow
    */
   public Month add(final Months months)
    {
     final long newMonth = Math.toIntExact(Math.addExact(this.month, months.longValue()));
     if (newMonth > 12) // while (newMonth > 12)
      {
       // TODO Listener
       // newMonth -= 12;
       // incrementYear();
       throw new ArithmeticException(Month.OVERFLOW);
      }
     return Month.of(Math.toIntExact(newMonth));
    }
 
 
   /**
    * Subtract months from this month.
    *
    * @param months Months to subtract from this month
    * @return New month after subtracting months from this month
    * @throws ArithmeticException In case of an underflow
    */
   public Month subtract(final Months months)
    {
     final long newMonth = Math.toIntExact(Math.subtractExact(this.month, months.longValue()));
     if (newMonth <= 0) // while (newMonth <= 0)
      {
       // TODO Listener
       // newMonth += 12;
       // decrementYear();
       throw new ArithmeticException(Month.UNDERFLOW);
      }
     return Month.of(Math.toIntExact(newMonth));
    }
 
 
   /**
    * Increment this month.
    *
    * @return New month after incrementing this month
    * @throws ArithmeticException In case of an overflow
    */
   public Month increment()
    {
     final int newMonth = Math.incrementExact(this.month);
     if (newMonth == 13)
      {
       // TODO Listener
       // newMonth = 1;
       // incrementYear();
       throw new ArithmeticException(Month.OVERFLOW);
      }
     return Month.of(newMonth);
    }
 
 
   /**
    * Decrement this month.
    *
    * @return New month after decrement this month
    * @throws ArithmeticException In case of an overflow
    */
   public Month decrement()
    {
     final int newMonth = Math.decrementExact(this.month);
     if (newMonth == 0)
      {
       // TODO Listener
       // newMonth = 12;
       // decrementYear();
       throw new ArithmeticException(Month.UNDERFLOW);
      }
     return Month.of(newMonth);
    }
 
  }