mchess-client/lib/chess/chess_square.dart

import 'package:flutter/material.dart';
import 'package:mchess/chess/chess_square_outer_dragtarget.dart';
import 'package:mchess/chess_bloc/tap_bloc.dart';
import '../utils/chess_utils.dart';

class ChessSquare extends StatefulWidget {
  final ChessCoordinate coordinate;
  final ChessPiece? containedPiece;
  static const double pieceWidth = 200;
  static const double pieceHeight = 200;

  final Color color;

  const ChessSquare._({
    required this.coordinate,
    required this.containedPiece,
    required this.color,
  });

  factory ChessSquare(ChessCoordinate coord, ChessPiece? piece,
      bool wasPartOfLastMove, bool wasTapped) {
    Color lightSquaresColor =
        wasPartOfLastMove ? Colors.green.shade200 : Colors.brown.shade50;
    Color darkSquaresColor =
        wasPartOfLastMove ? Colors.green.shade300 : Colors.brown.shade400;

    if (wasTapped) {
      lightSquaresColor = Colors.red.shade200;
      darkSquaresColor = Colors.red.shade300;
    }

    Color squareColor;

    if (coord.row % 2 == 0) {
      if (coord.column % 2 == 0) {
        squareColor = darkSquaresColor;
      } else {
        squareColor = lightSquaresColor;
      }
    } else {
      if (coord.column % 2 == 0) {
        squareColor = lightSquaresColor;
      } else {
        squareColor = darkSquaresColor;
      }
    }

    return ChessSquare._(
      coordinate: coord,
      containedPiece: piece,
      color: squareColor,
    );
  }

  @override
  State<ChessSquare> createState() => _ChessSquareState();
}

class _ChessSquareState extends State<ChessSquare> {
  @override
  Widget build(BuildContext context) {
    var dragTarget = Container(
      color: widget.color,
      child: ChessSquareOuterDragTarget(
          coordinate: widget.coordinate,
          containedPiece: widget.containedPiece ?? const ChessPiece.none()),
    );

    if (widget.containedPiece == null) {
      return GestureDetector(
        child: dragTarget,
        onTap: () {
          TapBloc().add(SquareTappedEvent(
              tapped: widget.coordinate, pieceOnSquare: widget.containedPiece));
        },
      );
    } else {
      return dragTarget;
    }
  }
}