using System;
using System.Text;

namespace CueSplitter.Helpers
{
    internal static class TextHelper
    {
        static TextHelper()
        {
            try
            {
                Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
            }
            catch
            {
                //EAT ERR
            }
        }

        private static Encoding TestCodePage(Encoding testCode, byte[] byteArray)
        {
            try
            {
                var encoding = Encoding.GetEncoding(testCode.CodePage, EncoderFallback.ExceptionFallback, DecoderFallback.ExceptionFallback);
                var a = encoding.GetCharCount(byteArray);
                return testCode;
            }
            catch (Exception e)
            {
                return null;
            }
        }

        public static Encoding DetectCodePage(byte[] contents)
        {
            if (contents == null || contents.Length == 0)
            {
                return Encoding.Default;
            }

            return TestCodePage(Encoding.UTF8, contents)
                   ?? TestCodePage(Encoding.GetEncoding("SHIFT-JIS"), contents)
                   ?? TestCodePage(Encoding.GetEncoding("GB2312"), contents)
                   ?? TestCodePage(Encoding.GetEncoding("EUC-KR"), contents)
                   ?? TestCodePage(Encoding.Unicode, contents)
                   ?? TestCodePage(Encoding.BigEndianUnicode, contents)
                   ?? TestCodePage(Encoding.ASCII, contents)
                   ;
        }
    }
}