using System.Numerics;

namespace Gameboard.ShogiUI.BoardState
{
  /// <summary>
  /// Provides normalized Vector2s relative to player. 
  /// "Up" for player 1 is "Down" for player 2; that sort of thing.
  /// </summary>
  public class Direction
  {
    private static readonly Vector2 PositiveX = new Vector2(1, 0);
    private static readonly Vector2 NegativeX = new Vector2(-1, 0);
    private static readonly Vector2 PositiveY = new Vector2(0, 1);
    private static readonly Vector2 NegativeY = new Vector2(0, -1);
    private static readonly Vector2 PositiveYX = new Vector2(1, 1);
    private static readonly Vector2 NegativeYX = new Vector2(-1, -1);
    private static readonly Vector2 NegativeYPositiveX = new Vector2(1, -1);
    private static readonly Vector2 PositiveYNegativeX = new Vector2(-1, 1);

    private readonly WhichPlayer whichPlayer;
    public Direction(WhichPlayer whichPlayer)
    {
      this.whichPlayer = whichPlayer;
    }

    public Vector2 Up => whichPlayer == WhichPlayer.Player1 ? PositiveY : NegativeY;
    public Vector2 Down => whichPlayer == WhichPlayer.Player1 ? NegativeY : PositiveY;
    public Vector2 Left => whichPlayer == WhichPlayer.Player1 ? NegativeX : PositiveX;
    public Vector2 Right => whichPlayer == WhichPlayer.Player1 ? PositiveX : NegativeX;
    public Vector2 UpLeft => whichPlayer == WhichPlayer.Player1 ? PositiveYNegativeX : NegativeYPositiveX;
    public Vector2 UpRight => whichPlayer == WhichPlayer.Player1 ? PositiveYX : NegativeYX;
    public Vector2 DownLeft => whichPlayer == WhichPlayer.Player1 ? NegativeYX : PositiveYX;
    public Vector2 DownRight => whichPlayer == WhichPlayer.Player1 ? NegativeYPositiveX : PositiveYNegativeX;
    public Vector2 KnightLeft => whichPlayer == WhichPlayer.Player1 ? new Vector2(-1, 2) : new Vector2(1, -2);
    public Vector2 KnightRight => whichPlayer == WhichPlayer.Player1 ? new Vector2(1, 2) : new Vector2(-1, -2);
  }
}