using PathFinding;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;

namespace Gameboard.ShogiUI.BoardState.Pieces
{
  public class Bishop : Piece
  {
    private static readonly List<Path> MoveSet = new List<Path>(4)
    {
      new Path(Direction.UpLeft, Distance.MultiStep),
      new Path(Direction.UpRight, Distance.MultiStep),
      new Path(Direction.DownLeft, Distance.MultiStep),
      new Path(Direction.DownRight, Distance.MultiStep)
    };
    private static readonly List<Path> PromotedMoveSet = new List<Path>(8)
    {
      new Path(Direction.Up),
      new Path(Direction.Left),
      new Path(Direction.Right),
      new Path(Direction.Down),
      new Path(Direction.UpLeft, Distance.MultiStep),
      new Path(Direction.UpRight, Distance.MultiStep),
      new Path(Direction.DownLeft, Distance.MultiStep),
      new Path(Direction.DownRight, Distance.MultiStep)
    };
    public Bishop(WhichPlayer owner) : base(WhichPiece.Bishop, owner)
    {
      // TODO: If this strat works out, we can do away with the Direction class entirely.
      PromotedMoveSet.AddRange(MoveSet);
    }

    public override Piece DeepClone()
    {
      var clone = new Bishop(Owner);
      if (IsPromoted) clone.Promote();
      return clone;
    }

    public override ICollection<Path> GetPaths()
    {
      var moveSet = IsPromoted ? PromotedMoveSet : MoveSet;
      return Owner == WhichPlayer.Player1 ? moveSet : moveSet.Select(_ => new Path(Vector2.Negate(_.Direction), _.Distance)).ToList();
    }
  }
}