using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DotnetStreams
{
	public class StdInTextSource : ITextSource
	{
		protected bool isEof;

		public virtual void Open()
		{
			isEof = false;
		}

		public virtual IEnumerable<string> ReadAll()
		{
			string? s = Console.ReadLine();
			while (s != null)
			{
				yield return s;
				s = Console.ReadLine();
			}
			isEof = true;
		}

		public virtual string Read()
		{
			string? s = Console.ReadLine();
			if (s == null)
			{
				isEof = true;
				return string.Empty;
			}
			else
				return s;
		}

		public virtual bool Eof() => isEof;

		public virtual void Close()
		{
		}
	}
}