using System;
using System.Collections;
using System.Text;

namespace Org.BouncyCastle.Utilities.Collections
{
    public abstract class CollectionUtilities
    {
        public static void AddRange(IList to, IEnumerable range)
        {
            foreach (object o in range)
            {
                to.Add(o);
            }
        }

        public static bool CheckElementsAreOfType(IEnumerable e, Type t)
        {
            foreach (object o in e)
            {
                if (!t.IsInstanceOfType(o))
                    return false;
            }
            return true;
        }

        public static IDictionary ReadOnly(IDictionary d)
        {
            return new UnmodifiableDictionaryProxy(d);
        }

        public static IList ReadOnly(IList l)
        {
            return new UnmodifiableListProxy(l);
        }

        public static ISet ReadOnly(ISet s)
        {
            return new UnmodifiableSetProxy(s);
        }

        public static object RequireNext(IEnumerator e)
        {
            if (!e.MoveNext())
                throw new InvalidOperationException();

            return e.Current;
        }

        public static string ToString(IEnumerable c)
        {
            IEnumerator e = c.GetEnumerator();
            if (!e.MoveNext())
                return "[]";

            StringBuilder sb = new StringBuilder("[");
            sb.Append(e.Current.ToString());
            while (e.MoveNext())
            {
                sb.Append(", ");
                sb.Append(e.Current.ToString());
            }
            sb.Append(']');
            return sb.ToString();
        }
    }
}
