getChessWeight method

int getChessWeight(ChessPos pos)

Weight of a chess (Experimental nature)

Implementation

int getChessWeight(ChessPos pos) {
  String chess = fen[pos.y][pos.x];
  if (chess == '0') return 0;
  int weight = chessWeight[chess.toLowerCase()]!;

  int chessCount = fen.getAllChr().length;
  ChessPos kPos =
      fen.find(chess.codeUnitAt(0) > ChessFen.colIndexBase ? 'K' : 'k')!;

  // 开局，中局炮价值增加
  if (chess == 'c' || chess == 'C') {
    if (chessCount > 25) {
      weight = (weight * 1.5).toInt();
    }

    // 炮和将一线权重翻倍
    if (kPos.y == pos.y || kPos.x == pos.x) {
      weight = weight * 2;
    }
  }

  // 残局 马价值增加
  if (chess == 'n' || chess == 'N') {
    if (chessCount < 15) {
      weight = (weight * 1.5).toInt();
    }
  }

  // 兵过河价值翻倍，接近9宫3倍，占宫4倍
  if (chess == 'p') {
    if (pos.y < 5) {
      weight *= 2;
      if (pos.y < 4 && pos.x > 1 && pos.x < 8) {
        weight *= 2;
        if (pos.y < 3 && pos.x > 2 && pos.x < 7) {
          weight *= 2;
        }
      }
    }
  } else if (chess == 'P') {
    if (pos.y > 4) {
      weight *= 2;
      if (pos.y > 5 && pos.x > 1 && pos.x < 8) {
        weight *= 2;
        if (pos.y > 6 && pos.x > 2 && pos.x < 7) {
          weight *= 2;
        }
      }
    }
  }

  return weight;
}