import "package:meta/meta.dart";

@immutable
class Piece {
  // Private constructor to prevent instantiation.
  Piece._();

  static const emptySquare = 0;
  static const whiteKing   = 1;
  static const whiteQueen  = 2;
  static const whiteRook   = 3;
  static const whiteBishop = 4;
  static const whiteKnight = 5;
  static const whitePawn   = 6;
  static const blackKing   = 7;
  static const blackQueen  = 8;
  static const blackRook   = 9;
  static const blackBishop = 10;
  static const blackKnight = 11;
  static const blackPawn   = 12;

  static const Map<String, int> pieceByFenCharacter = {
    "k": blackKing,
    "q": blackQueen,
    "r": blackRook,
    "b": blackBishop,
    "n": blackKnight,
    "p": blackPawn,
    "K": whiteKing,
    "Q": whiteQueen,
    "R": whiteRook,
    "B": whiteBishop,
    "N": whiteKnight,
    "P": whitePawn,
  };

  static const Map<int, String> fenCharacterByPiece = <int, String>{
    Piece.emptySquare: " ",
    Piece.blackKing  : "k",
    Piece.blackQueen : "q",
    Piece.blackRook  : "r",
    Piece.blackBishop: "b",
    Piece.blackKnight: "n",
    Piece.blackPawn  : "p",
    Piece.whiteKing  : "K",
    Piece.whiteQueen : "Q",
    Piece.whiteRook  : "R",
    Piece.whiteBishop: "B",
    Piece.whiteKnight: "N",
    Piece.whitePawn  : "P",
  };

  static bool isWhite(int piece) => piece >= whiteKing && piece <= whitePawn;
  static bool isBlack(int piece) => piece >= blackKing && piece <= blackPawn;
}