mchess-client/lib/chess_bloc/promotion_bloc.dart

import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:mchess/chess_bloc/chess_bloc.dart';
import 'package:mchess/chess_bloc/chess_events.dart';
import 'package:mchess/utils/chess_utils.dart';

class PromotionBloc extends Bloc<PromotionEvent, PromotionState> {
  static final PromotionBloc _instance = PromotionBloc._internal();
  static late ChessMove move;

  PromotionBloc._internal() : super(PromotionState.init()) {
    on<PawnMovedToPromotionField>(promotionMoveHandler);
    on<PieceChosen>(pieceChosenHandler);
  }

  void promotionMoveHandler(
    PawnMovedToPromotionField event,
    Emitter<PromotionState> emit,
  ) {
    switch (event.colorMoved) {
      case ChessColor.white:
        if (event.move.from.row != 7) return;
        break;
      case ChessColor.black:
        if (event.move.from.row != 2) return;
        break;
    }
    move = event.move;
    emit(PromotionState(
        showPromotionDialog: true, colorMoved: event.colorMoved));
  }

  void pieceChosenHandler(
    PieceChosen event,
    Emitter<PromotionState> emit,
  ) {
    ChessBloc.getInstance()
        .add(OwnPromotionPlayed(pieceClass: event.pieceClass, move: move));
    emit(PromotionState(showPromotionDialog: false, colorMoved: event.color));
  }

  factory PromotionBloc.getInstance() {
    return PromotionBloc();
  }

  factory PromotionBloc() {
    return _instance;
  }
}

abstract class PromotionEvent {}

class PawnMovedToPromotionField extends PromotionEvent {
  final ChessMove move;
  final ChessColor colorMoved;

  PawnMovedToPromotionField({required this.move, required this.colorMoved});
}

class PieceChosen extends PromotionEvent {
  final ChessPieceClass pieceClass;
  final ChessColor color;

  PieceChosen({required this.pieceClass, required this.color});
}

class PromotionState {
  final bool showPromotionDialog;
  final ChessColor colorMoved;

  PromotionState({required this.showPromotionDialog, required this.colorMoved});

  factory PromotionState.init() {
    return PromotionState(
        showPromotionDialog: false, colorMoved: ChessColor.white);
  }
}