/* Copyright (c) 2008-2013, Avian Contributors

   Permission to use, copy, modify, and/or distribute this software
   for any purpose with or without fee is hereby granted, provided
   that the above copyright notice and this permission notice appear
   in all copies.

   There is NO WARRANTY for this software.  See license.txt for
   details. */

package java.util;

public class Arrays {
  private Arrays() { }

  public static String toString(Object[] a) {
    return asList(a).toString();
  }

  public static String toString(byte[] a) {
    if (a == null) {
      return "null";
    } else {
      StringBuilder sb = new StringBuilder();
      sb.append("[");
      for (int i = 0; i < a.length; ++i) {
        sb.append(String.valueOf(a[i]));
        if (i + 1 != a.length) {
          sb.append(", ");
        }
      }
      sb.append("]");
      return sb.toString();
    }
  }

  private static boolean equal(Object a, Object b) {
    return (a == null && b == null) || (a != null && a.equals(b));
  }

  public static void sort(Object[] array) {
    sort(array, new Comparator() {
        public int compare(Object a, Object b) {
          return ((Comparable) a).compareTo(b);
        }
      });
  }

  public static <T> void sort(T[] array, Comparator<? super T> comparator) {
    // insertion sort
    for (int j = 1; j < array.length; ++j) {
      T t = array[j];
      int i = j - 1;
      while (i >= 0 && comparator.compare(array[i], t) > 0) {
        array[i + 1] = array[i];
        i = i - 1;
      }
      array[i + 1] = t;
    }
  }

  public static int hashCode(Object[] array) {
    if(array == null) {
      return 9023;
    }

    int hc = 823347;
    for(Object o : array) {
      hc += o != null ? o.hashCode() : 54267;
      hc *= 3;
    }
    return hc;
  }

  public static boolean equals(Object[] a, Object[] b) {
    if(a == b) {
      return true;
    }
    if(a == null || b == null) {
      return false;
    }
    if(a.length != b.length) {
      return false;
    }
    for(int i = 0; i < a.length; i++) {
      if(!equal(a[i], b[i])) {
        return false;
      }
    }
    return true;
  }

  public static <T> List<T> asList(final T ... array) {
    return new AbstractList<T>() {
      public int size() {
        return array.length;
      }

      public void add(int index, T element) {
        throw new UnsupportedOperationException();
      }
      
      public int indexOf(Object element) {
        for (int i = 0; i < array.length; ++i) {
          if (equal(element, array[i])) {
            return i;
          }
        }
        return -1;
      }

      public int lastIndexOf(Object element) {
        for (int i = array.length - 1; i >= 0; --i) {
          if (equal(element, array[i])) {
            return i;
          }
        }
        return -1;
      }
      
      public T get(int index) {
        return array[index];
      }

      public T set(int index, T value) {
        throw new UnsupportedOperationException();
      }

      public T remove(int index) {
        throw new UnsupportedOperationException();
      }

      public ListIterator<T> listIterator(int index) {
        return new Collections.ArrayListIterator(this, index);
      }
    };
  }

  public static void fill(int[] array, int value) {
    for (int i=0;i<array.length;i++) {
      array[i] = value;
    }
  }

  public static void fill(char[] array, char value) {
    for (int i=0;i<array.length;i++) {
      array[i] = value;
    }
  }
  
  public static <T> void fill(T[] array, T value) {
    for (int i=0;i<array.length;i++) {
      array[i] = value;
    }
  }

}