using System;
using System.Text.RegularExpressions;

namespace Gameboard.ShogiUI.Sockets.Models
{
  public class Coords
  {
    private const string BoardNotationRegex = @"(?<file>[A-I])(?<rank>[1-9])";
    private const char A = 'A';
    public int X { get; }
    public int Y { get; }
    public Coords(int x, int y)
    {
      X = x;
      Y = y;
    }

    public string ToBoardNotation()
    {
      var file = (char)(X + A);
      var rank = Y + 1;
      return $"{file}{rank}";
    }

    public static Coords FromBoardNotation(string notation)
    {
      if (string.IsNullOrEmpty(notation))
      {
        if (Regex.IsMatch(notation, BoardNotationRegex))
        {
          var match = Regex.Match(notation, BoardNotationRegex);
          char file = match.Groups["file"].Value[0];
          int rank = int.Parse(match.Groups["rank"].Value);
          return new Coords(file - A, rank);
        }
        throw new ArgumentException("Board notation not recognized."); // TODO: Move this error handling to the service layer.
      }
      return new Coords(-1, -1); // Temporarily this is how I tell Gameboard.API that a piece came from the hand.
    }
  }
}