using System;
using System.Text;

namespace Org.BouncyCastle.Utilities
{
    /// <summary> General string utilities.</summary>
    public abstract class Strings
    {

        public static string ToUpperCase(string original)
        {
            bool changed = false;
            char[] chars = original.ToCharArray();

            for (int i = 0; i != chars.Length; i++)
            {
                char ch = chars[i];
                if ('a' <= ch && 'z' >= ch)
                {
                    changed = true;
                    chars[i] = (char)(ch - 'a' + 'A');
                }
            }

            if (changed)
            {
                return new string(chars);
            }

            return original;
        }


        internal static bool IsOneOf(string s, params string[] candidates)
        {
            foreach (string candidate in candidates)
            {
                if (s == candidate)
                    return true;
            }
            return false;
        }

        public static string FromByteArray(
            byte[] bs)
        {
            char[] cs = new char[bs.Length];
            for (int i = 0; i < cs.Length; ++i)
            {
                cs[i] = Convert.ToChar(bs[i]);
            }
            return new string(cs);
        }

        public static byte[] ToByteArray(
            char[] cs)
        {
            byte[] bs = new byte[cs.Length];
            for (int i = 0; i < bs.Length; ++i)
            {
                bs[i] = Convert.ToByte(cs[i]);
            }
            return bs;
        }

        public static byte[] ToByteArray(
            string s)
        {
            byte[] bs = new byte[s.Length];
            for (int i = 0; i < bs.Length; ++i)
            {
                bs[i] = Convert.ToByte(s[i]);
            }
            return bs;
        }

        public static string FromAsciiByteArray(
            byte[] bytes)
        {
#if PORTABLE
            // TODO Check for non-ASCII bytes in input?
            return Encoding.UTF8.GetString(bytes, 0, bytes.Length);
#else
            return Encoding.ASCII.GetString(bytes, 0, bytes.Length);
#endif
        }

        public static byte[] ToAsciiByteArray(
            char[] cs)
        {
#if PORTABLE
            // TODO Check for non-ASCII characters in input?
            return Encoding.UTF8.GetBytes(cs);
#else
            return Encoding.ASCII.GetBytes(cs);
#endif
        }

        public static byte[] ToAsciiByteArray(
            string s)
        {
#if PORTABLE
            // TODO Check for non-ASCII characters in input?
            return Encoding.UTF8.GetBytes(s);
#else
            return Encoding.ASCII.GetBytes(s);
#endif
        }

        public static string FromUtf8ByteArray(
            byte[] bytes)
        {
            return Encoding.UTF8.GetString(bytes, 0, bytes.Length);
        }

        public static byte[] ToUtf8ByteArray(
            char[] cs)
        {
            return Encoding.UTF8.GetBytes(cs);
        }

        public static byte[] ToUtf8ByteArray(
            string s)
        {
            return Encoding.UTF8.GetBytes(s);
        }
    }
}