using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Net;

namespace SharedLibrary
{
    public class IFile
    {
        public IFile(String fileName)
        {
            Name = fileName;
            Handle = new StreamReader(new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite));
            sze = Handle.BaseStream.Length;
        }

        public long Length()
        {
            sze = Handle.BaseStream.Length;
            return sze;
        }

        public void Close()
        {
            Handle?.Close();
        }

        public String[] ReadAllLines()
        {
            return Handle?.ReadToEnd().Split(new char[] { '\n' }, StringSplitOptions.RemoveEmptyEntries);
        }

        public String GetText()
        {
            return Handle?.ReadToEnd();
        }

        public String[] Tail(int lineCount)
        {
            var buffer = new List<string>(lineCount);
            string line;
            for (int i = 0; i < lineCount; i++)
            {
                line = Handle.ReadLine();
                if (line == null) return buffer.ToArray();
                buffer.Add(line);
            }

            int lastLine = lineCount - 1;           //The index of the last line read from the buffer.  Everything > this index was read earlier than everything <= this indes

            while (null != (line = Handle.ReadLine()))
            {
                lastLine++;
                if (lastLine == lineCount) lastLine = 0;
                buffer[lastLine] = line;
            }

            if (lastLine == lineCount - 1) return buffer.ToArray();
            var retVal = new string[lineCount];
            buffer.CopyTo(lastLine + 1, retVal, 0, lineCount - lastLine - 1);
            buffer.CopyTo(0, retVal, lineCount - lastLine - 1, lastLine + 1);
            return retVal;
        }
        //END

        private long sze;
        private String Name;
        private StreamReader Handle;
    }
}