using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

// A spot for immutable helpers

namespace imm
{
	public record class Versioned<T>
		where T : Versioned<T>
	{
		public uint Version { get; protected set; } = 0;
		public string Reason { get; protected set; } = "";

		public T Process( Func<T, T> fn, string reason = "" )
		{
			var newT = fn( ( T )this );

			return newT with
			{
				Version = newT.Version + 1,
				Reason = reason,
			};
		}
	}

	public record class Recorded<T> : Versioned<T>
		where T : Recorded<T>
	{
		public T? Old { get; protected set; }
		public string Expression { get; protected set; } = "";
		public string MemberName { get; protected set; } = "";
		public string FilePath { get; protected set; } = "";
		public int LineNumber { get; protected set; } = -1;

		public T Record( string reason = "",
														[CallerMemberName] string memberName = "",
														[CallerFilePath] string filePath = "",
														[CallerLineNumber] int lineNumber = 0 )
		{
			var orig = ( T )this;

			var newT = base.Process( ( old ) => old with
			{
				Old = orig,
				MemberName = memberName,
				FilePath = filePath,
				LineNumber = lineNumber,
			}, reason );

			return newT;
		}

		public T Process( Func<T, T> fn, string reason = "",
														[CallerMemberName] string memberName = "",
														[CallerFilePath] string filePath = "",
														[CallerLineNumber] int lineNumber = 0,
														[CallerArgumentExpression("fn")]
														string expression = default )
		{
			var orig = ( T )this;

			return ( T )this with
			{
				//Do the Versioned code here
				Version = orig.Version + 1,

				//Recorded
				Old = orig,
				Expression = expression,
				MemberName = memberName,
				FilePath = filePath,
				LineNumber = lineNumber,
			};
		}
	}


	public record class Timed<T> : Recorded<T>
		where T : Timed<T>
	{
		public readonly DateTime CreatedAt = DateTime.Now;
		public DateTime TouchedAt { get; set; } = DateTime.Now;

		public T Process( Func<T, T> fn, string reason = "",
														[CallerMemberName] string memberName = "",
														[CallerFilePath] string filePath = "",
														[CallerLineNumber] int lineNumber = 0,
														[CallerArgumentExpression("fn")]
														string expression = default )
		{
			var orig = ( T )this;

			return ( T )this with
			{
				//Versioned
				Version = orig.Version + 1,

				//Recorded
				Old = orig,
				Expression = expression,
				MemberName = memberName,
				FilePath = filePath,
				LineNumber = lineNumber,

				TouchedAt = DateTime.Now,
			};
		}
	}


	public static class Util
	{



	}

}