mchess-client/lib/chess/chess_square_inner_draggable.dart

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

class ChessSquareInnerDraggable extends StatelessWidget {
  const ChessSquareInnerDraggable({
    super.key,
    required this.coordinate,
    required this.containedPiece,
  });

  final ChessCoordinate coordinate;
  final ChessPiece? containedPiece;

  @override
  Widget build(BuildContext context) {
    double windowWidth = MediaQuery.of(context).size.width;
    double windowHeight = MediaQuery.of(context).size.height;
    double draggableFdbSize;

    var canMove = (ChessBloc.turnColor == ChessBloc.myColor) &&
        (containedPiece?.color == ChessBloc.turnColor);
    var maxDrags = kDebugMode ? 1 : (canMove ? 1 : 0);

    if (windowWidth < windowHeight) {
      draggableFdbSize = 0.15 * windowWidth;
    } else {
      draggableFdbSize = 0.15 * windowHeight;
    }

    return SizedBox(
      width: ChessSquare.pieceWidth,
      height: ChessSquare.pieceWidth,
      child: Draggable<PieceDragged>(
        /* We create the move with the startSquare == endSquare. The receiving widget will give the correct value to end square. */
        data: PieceDragged(coordinate, coordinate, containedPiece),
        maxSimultaneousDrags: maxDrags,
        feedback: FractionalTranslation(
          translation: const Offset(-0.5, -0.75),
          child: SizedBox(
              height: draggableFdbSize,
              width: draggableFdbSize,
              child: containedPiece),
        ),
        childWhenDragging: Container(),
        dragAnchorStrategy: pointerDragAnchorStrategy,
        child: containedPiece ?? Container(),
        onDragCompleted: () {},
        onDragStarted: () {
          TapBloc().add(SquareTappedEvent(
              tapped: coordinate, pieceOnSquare: containedPiece));
        },
      ),
    );
  }
}