/*
    * 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;
  
  
  /**
   * Week.
   *
   * Not DSGVO relevant.
   *
   * TODO Constructor with year
   * TODO Listener
   * TODO daysWithin = 7
   * TODO min, max
   */
  public final class Week implements Comparable<Week>, IValueObject
   {
    /**
     * Overflow constant.
     */
    private static final String OVERFLOW = "Overflow"; //$NON-NLS-1$
  
    /**
     * Underflow constant.
     */
    private static final String UNDERFLOW = "Underflow"; //$NON-NLS-1$
  
    /* *
     * Cache for singletons.
     */
    // private static final Map<Integer, Week> CACHE = new WeakHashMap<>();
  
    /**
     * Week.
     */
    private final int week;
  
  
    /**
     * Constructor.
     *
     * @param week Week 1-53
     * @throws IndexOutOfBoundsException When the week is less than 1 or greater than 53
     */
    private Week(final int week)
     {
      super();
      if ((week < 1) || (week > 53))
       {
        throw new IndexOutOfBoundsException("Week number out of range (1-53)!"); //$NON-NLS-1$
       }
      this.week = week;
     }
  
  
    /**
     * Week factory.
     *
     * @param week Week 1-53
     * @return Week object
     */
    public static Week of(final int week)
     {
      /*
      synchronized (Week.class)
       {
        Week obj = Week.CACHE.get(week);
        if (obj != null)
         {
          return obj;
         }
        obj = new Week(week);
        Week.CACHE.put(Integer.valueOf(week), obj);
        return obj;
       }
      */
      return new Week(week);
     }
  
  
    /**
     * Week factory.
     *
     * @param value Week 1-53 string
     * @return Week object
     */
    public static Week of(final String value)
     {
      return of(Integer.parseInt(value));
     }
  
  
    /**
    * Returns the value of this Week as an int.
    *
    * @return The numeric value represented by this object after conversion to type int.
    */
   public int intValue()
    {
     return this.week;
    }
 
 
   /**
    * Returns the value of this Week as an String.
    *
    * @return The numeric value represented by this object after conversion to type String.
    */
   @Override
   public String stringValue()
    {
     return String.valueOf(this.week);
    }
 
 
   /**
    * Calculate hash code.
    *
    * @return Hash
    * @see java.lang.Object#hashCode()
    */
   @Override
   public int hashCode()
    {
     return Integer.hashCode(this.week);
    }
 
 
   /**
    * 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 Week))
      {
       return false;
      }
     final Week other = (Week)obj;
     return this.week == other.week;
    }
 
 
   /**
    * Returns the string representation of this Week.
    *
    * The exact details of this representation are unspecified and subject to change, but the following may be regarded as typical:
    *
    * "Week[week=1]"
    *
    * @return String representation of this Week
    * @see java.lang.Object#toString()
    */
   @Override
   public String toString()
    {
     final var builder = new StringBuilder();
     builder.append("Week[week=").append(this.week).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 Week obj)
    {
     Objects.requireNonNull(obj, "obj"); //$NON-NLS-1$
     return Integer.compare(this.week, obj.week);
    }
 
 
   /**
    * Add weeks to this week.
    *
    * @param weeks Weeks to add to this week
    * @return New week after adding the weeks to this week
    * @throws ArithmeticException In case of an overflow
    */
   public Week add(final Weeks weeks)
    {
     final int newWeek = Math.toIntExact(Math.addExact(this.week, weeks.longValue()));
     if (newWeek > 53) // TODO 52 depends on year
      {
       // TODO Listener
       throw new ArithmeticException(Week.OVERFLOW);
      }
     return Week.of(newWeek);
    }
 
 
   /**
    * Subtract weeks from this week.
    *
    * @param weeks Weeks to subtract from this week
    * @return New week after subtracting weeks from this week
    * @throws ArithmeticException In case of an underflow
    */
   public Week subtract(final Weeks weeks)
    {
     final int newWeek = Math.toIntExact(Math.subtractExact(this.week, weeks.longValue()));
     if (newWeek <= 0)
      {
       // TODO Listener
       throw new ArithmeticException(Week.UNDERFLOW);
      }
     return Week.of(newWeek);
    }
 
 
   /**
    * Increment this week.
    *
    * @return New week after incrementing this week
    * @throws ArithmeticException In case of an overflow
    */
   public Week increment()
    {
     final int newWeek = Math.incrementExact(this.week);
     if (newWeek == 54) // TODO 53 depending on year
      {
       // TODO Listener
       throw new ArithmeticException(Week.OVERFLOW);
      }
     return Week.of(newWeek);
    }
 
 
   /**
    * Decrement this week.
    *
    * @return New week after decrement this week
    * @throws ArithmeticException In case of an overflow
    */
   public Week decrement()
    {
     final int newWeek = Math.decrementExact(this.week);
     if (newWeek == 0)
      {
       // TODO Listener
       throw new ArithmeticException(Week.UNDERFLOW);
      }
     return Week.of(newWeek);
    }
 
  }