mchess-client/lib/chess/chess_board.dart

import 'dart:developer';
import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:mchess/chess_bloc/chess_bloc.dart';

import 'chess_square.dart';
import '../utils/chess_utils.dart';

class ChessBoard extends StatelessWidget {
  final ChessBoardState bState;
  final List<ChessSquare> squares;

  const ChessBoard._({required this.bState, required this.squares});

  factory ChessBoard(
      {required ChessBoardState boardState, ChessCoordinate? tappedSquare}) {
    List<ChessSquare> squares = List.empty(growable: true);
    for (int i = 0; i < 64; i++) {
      var column = (i % 8) + 1;
      var row = (i ~/ 8) + 1;

      final piece = boardState.position[ChessCoordinate(column, row)];

      bool squareWasPartOfLastMove = false;
      if ((boardState.lastMove.to == ChessCoordinate(column, row) ||
              boardState.lastMove.from == ChessCoordinate(column, row)) &&
          boardState.colorLastMove) {
        squareWasPartOfLastMove = true;
      }

      squares.add(
        ChessSquare(
            ChessCoordinate(column, row),
            piece,
            squareWasPartOfLastMove,
            tappedSquare == ChessCoordinate(column, row)),
      );
    }

    return ChessBoard._(bState: boardState, squares: squares);
  }

  @override
  Widget build(BuildContext context) {
    log("ChessBoard's build()");

    return LayoutBuilder(builder: (context, constraints) {
      /*We calculate the margins manually, because otherwise we would have 
      lines that are 1 pixel wide between the squares (which is ugly)*/
      int smallerSize =
          math.min(constraints.maxWidth.toInt(), constraints.maxHeight.toInt());
      int desiredSize = smallerSize - smallerSize % 8;
      int verticalMargin = constraints.maxHeight.toInt() - desiredSize;
      int verticalMarginTop = verticalMargin ~/ 2;
      int verticalMarginBottom = verticalMargin - verticalMarginTop;
      int horizontalMargin = constraints.maxWidth.toInt() - desiredSize;
      int horizontalMarginLeft = horizontalMargin ~/ 2;
      int horizontalMarginRight = horizontalMargin - horizontalMarginLeft;
      return Container(
        margin: EdgeInsets.only(
          left: horizontalMarginLeft.toDouble(),
          right: horizontalMarginRight.toDouble(),
          top: verticalMarginTop.toDouble(),
          bottom: verticalMarginBottom.toDouble(),
        ),
        child: FittedBox(
          fit: BoxFit.contain,
          child: Container(
            decoration: const BoxDecoration(boxShadow: [
              BoxShadow(color: Colors.black, offset: Offset(10, 10))
            ]),
            child: _buildBoard(bState.bottomColor == ChessColor.black),
          ),
        ),
      );
    });
  }

  Row _buildChessRow(int rowNo, bool flipped) {
    if (!flipped) {
      return Row(
        children: [
          for (int i = 8 * rowNo - 8; i < 8 * rowNo; i++) squares.elementAt(i)
        ],
      );
    } else {
      return Row(
        children: [
          for (int i = 8 * rowNo - 1; i >= 8 * rowNo - 8; i--)
            squares.elementAt(i)
        ],
      );
    }
  }

  Column _buildBoard(bool flipped) {
    List<Row> chessBoard = <Row>[];

    if (!flipped) {
      for (int row = 8; row > 0; row--) {
        chessBoard.add(_buildChessRow(row, flipped));
      }
    } else {
      for (int row = 1; row <= 8; row++) {
        chessBoard.add(_buildChessRow(row, flipped));
      }
    }

    return Column(children: [...chessBoard]);
  }

  ChessSquare getSquareAtCoordinate(ChessCoordinate coord) {
    /* Calculate index in squares[] from column and row */
    int index = (coord.row - 1) * 8 + (coord.column - 1);

    log("getSquareAtCoordinates: index calculated to $index");

    return squares.elementAt(index);
  }
}