BlockSeasons/lib/ui/widgets/tray_widget.dart

import 'package:flutter/material.dart';

import '../../game/models/piece.dart';
import 'piece_painter.dart';

/// The 3-slot piece tray. Reports raw pan gestures up; the game screen owns
/// drag state so the lifted piece can float over the board.
class TrayWidget extends StatelessWidget {
  const TrayWidget({
    super.key,
    required this.tray,
    required this.draggingIndex,
    required this.onDragStart,
    required this.onDragUpdate,
    required this.onDragEnd,
  });

  final List<Piece> tray;
  final int? draggingIndex;
  final void Function(int index, Offset globalPosition) onDragStart;
  final void Function(Offset globalPosition) onDragUpdate;
  final void Function() onDragEnd;

  static const double slotCellSize = 16;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      height: 96,
      child: Row(
        children: [
          for (var i = 0; i < 3; i++)
            Expanded(
              child: i < tray.length
                  ? _slot(context, i, tray[i])
                  : const SizedBox.shrink(),
            ),
        ],
      ),
    );
  }

  Widget _slot(BuildContext context, int index, Piece piece) {
    final hidden = index == draggingIndex;
    return GestureDetector(
      behavior: HitTestBehavior.opaque,
      onPanStart: (d) => onDragStart(index, d.globalPosition),
      onPanUpdate: (d) => onDragUpdate(d.globalPosition),
      onPanEnd: (_) => onDragEnd(),
      onPanCancel: onDragEnd,
      child: Center(
        child: Opacity(
          opacity: hidden ? 0.0 : 1.0,
          child: PieceWidget(piece: piece, cellSize: slotCellSize),
        ),
      ),
    );
  }
}