import 'dart:collection';

import 'package:app_flowy/plugins/grid/application/block/block_cache.dart';
import 'package:app_flowy/plugins/grid/application/field/field_cache.dart';
import 'package:app_flowy/plugins/grid/application/grid_service.dart';
import 'package:app_flowy/plugins/grid/application/row/row_cache.dart';
import 'package:flowy_sdk/protobuf/flowy-error/errors.pb.dart';
import 'package:flowy_sdk/protobuf/flowy-folder/view.pb.dart';
import 'dart:async';
import 'package:dartz/dartz.dart';
import 'package:flowy_sdk/protobuf/flowy-grid/protobuf.dart';

typedef OnFieldsChanged = void Function(UnmodifiableListView<FieldPB>);
typedef OnGridChanged = void Function(GridPB);
typedef DidLoadGroups = void Function(List<GroupPB>);
typedef OnRowsChanged = void Function(
  List<RowInfo>,
  RowsChangedReason,
);
typedef OnError = void Function(FlowyError);

class BoardDataController {
  final String gridId;
  final GridFFIService _gridFFIService;
  final GridFieldCache fieldCache;

  // key: the block id
  final LinkedHashMap<String, GridBlockCache> _blocks;
  LinkedHashMap<String, GridBlockCache> get blocks => _blocks;

  OnFieldsChanged? _onFieldsChanged;
  OnGridChanged? _onGridChanged;
  DidLoadGroups? _didLoadGroup;
  OnRowsChanged? _onRowsChanged;
  OnError? _onError;

  List<RowInfo> get rowInfos {
    final List<RowInfo> rows = [];
    for (var block in _blocks.values) {
      rows.addAll(block.rows);
    }
    return rows;
  }

  BoardDataController({required ViewPB view})
      : gridId = view.id,
        _blocks = LinkedHashMap.new(),
        _gridFFIService = GridFFIService(gridId: view.id),
        fieldCache = GridFieldCache(gridId: view.id);

  void addListener({
    OnGridChanged? onGridChanged,
    OnFieldsChanged? onFieldsChanged,
    DidLoadGroups? didLoadGroups,
    OnRowsChanged? onRowsChanged,
    OnError? onError,
  }) {
    _onGridChanged = onGridChanged;
    _onFieldsChanged = onFieldsChanged;
    _didLoadGroup = didLoadGroups;
    _onRowsChanged = onRowsChanged;
    _onError = onError;

    fieldCache.addListener(onFields: (fields) {
      _onFieldsChanged?.call(UnmodifiableListView(fields));
    });
  }

  Future<Either<Unit, FlowyError>> loadData() async {
    final result = await _gridFFIService.loadGrid();
    return Future(
      () => result.fold(
        (grid) async {
          _onGridChanged?.call(grid);

          return await _loadFields(grid).then((result) {
            return result.fold(
              (l) {
                _loadGroups(grid.blocks);
                return left(l);
              },
              (err) => right(err),
            );
          });
        },
        (err) => right(err),
      ),
    );
  }

  Future<Either<RowPB, FlowyError>> createBoardCard(String groupId) {
    return _gridFFIService.createBoardCard(groupId);
  }

  Future<void> dispose() async {
    await _gridFFIService.closeGrid();
    await fieldCache.dispose();

    for (final blockCache in _blocks.values) {
      blockCache.dispose();
    }
  }

  Future<Either<Unit, FlowyError>> _loadFields(GridPB grid) async {
    final result = await _gridFFIService.getFields(fieldIds: grid.fields);
    return Future(
      () => result.fold(
        (fields) {
          fieldCache.fields = fields.items;
          _onFieldsChanged?.call(UnmodifiableListView(fieldCache.fields));
          return left(unit);
        },
        (err) => right(err),
      ),
    );
  }

  Future<void> _loadGroups(List<BlockPB> blocks) async {
    for (final block in blocks) {
      final cache = GridBlockCache(
        gridId: gridId,
        block: block,
        fieldCache: fieldCache,
      );

      cache.addListener(onRowsChanged: (reason) {
        _onRowsChanged?.call(rowInfos, reason);
      });
      _blocks[block.id] = cache;
    }

    final result = await _gridFFIService.loadGroups();
    return Future(
      () => result.fold(
        (groups) {
          _didLoadGroup?.call(groups.items);
        },
        (err) => _onError?.call(err),
      ),
    );
  }
}