import 'package:appflowy/plugins/database_view/application/field/field_controller.dart';
import 'package:appflowy/plugins/database_view/application/view/view_cache.dart';
import 'package:appflowy_backend/log.dart';
import 'package:appflowy_backend/protobuf/flowy-database/calendar_entities.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-database/field_entities.pbenum.dart';
import 'package:appflowy_backend/protobuf/flowy-database/group.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-database/group_changeset.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-database/row_entities.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-database/setting_entities.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
import 'package:collection/collection.dart';
import 'dart:async';
import 'package:dartz/dartz.dart';
import 'database_service.dart';
import 'defines.dart';
import 'layout/layout_setting_listener.dart';
import 'row/row_cache.dart';
import 'group/group_listener.dart';

typedef OnRowsChanged = void Function(
  List<RowInfo> rowInfos,
  RowsChangedReason,
);

typedef OnGroupByField = void Function(List<GroupPB>);
typedef OnUpdateGroup = void Function(List<GroupPB>);
typedef OnDeleteGroup = void Function(List<String>);
typedef OnInsertGroup = void Function(InsertedGroupPB);

class GroupCallbacks {
  final OnGroupByField? onGroupByField;
  final OnUpdateGroup? onUpdateGroup;
  final OnDeleteGroup? onDeleteGroup;
  final OnInsertGroup? onInsertGroup;

  GroupCallbacks({
    this.onGroupByField,
    this.onUpdateGroup,
    this.onDeleteGroup,
    this.onInsertGroup,
  });
}

class LayoutCallbacks {
  final void Function(LayoutSettingPB) onLayoutChanged;
  final void Function(LayoutSettingPB) onLoadLayout;

  LayoutCallbacks({
    required this.onLayoutChanged,
    required this.onLoadLayout,
  });
}

class DatabaseCallbacks {
  OnDatabaseChanged? onDatabaseChanged;
  OnRowsChanged? onRowsChanged;
  OnFieldsChanged? onFieldsChanged;
  OnFiltersChanged? onFiltersChanged;
  DatabaseCallbacks({
    this.onDatabaseChanged,
    this.onRowsChanged,
    this.onFieldsChanged,
    this.onFiltersChanged,
  });
}

class DatabaseController {
  final String viewId;
  final DatabaseBackendService _databaseBackendSvc;
  final FieldController fieldController;
  late DatabaseViewCache _viewCache;
  final LayoutTypePB layoutType;

  // Callbacks
  DatabaseCallbacks? _databaseCallbacks;
  GroupCallbacks? _groupCallbacks;
  LayoutCallbacks? _layoutCallbacks;

  // Getters
  List<RowInfo> get rowInfos => _viewCache.rowInfos;
  RowCache get rowCache => _viewCache.rowCache;

  // Listener
  final DatabaseGroupListener groupListener;
  final DatabaseLayoutListener layoutListener;

  DatabaseController({required ViewPB view, required this.layoutType})
      : viewId = view.id,
        _databaseBackendSvc = DatabaseBackendService(viewId: view.id),
        fieldController = FieldController(viewId: view.id),
        groupListener = DatabaseGroupListener(view.id),
        layoutListener = DatabaseLayoutListener(view.id) {
    _viewCache = DatabaseViewCache(
      viewId: viewId,
      fieldController: fieldController,
    );
    _listenOnRowsChanged();
    _listenOnFieldsChanged();
    _listenOnGroupChanged();
    _listenOnLayoutChanged();
  }

  void addListener({
    DatabaseCallbacks? onDatabaseChanged,
    LayoutCallbacks? onLayoutChanged,
    GroupCallbacks? onGroupChanged,
  }) {
    _layoutCallbacks = onLayoutChanged;
    _databaseCallbacks = onDatabaseChanged;
    _groupCallbacks = onGroupChanged;
  }

  Future<Either<Unit, FlowyError>> open() async {
    return _databaseBackendSvc.openGrid().then((result) {
      return result.fold(
        (database) async {
          _databaseCallbacks?.onDatabaseChanged?.call(database);
          _viewCache.rowCache.setInitialRows(database.rows);
          return await fieldController
              .loadFields(
            fieldIds: database.fields,
          )
              .then(
            (result) {
              return result.fold(
                (l) => Future(() async {
                  await _loadGroups();
                  await _loadLayoutSetting();
                  return left(l);
                }),
                (err) => right(err),
              );
            },
          );
        },
        (err) => right(err),
      );
    });
  }

  Future<Either<RowPB, FlowyError>> createRow({
    String? startRowId,
    String? groupId,
    void Function(RowDataBuilder builder)? withCells,
  }) {
    Map<String, String>? cellDataByFieldId;

    if (withCells != null) {
      final rowBuilder = RowDataBuilder();
      withCells(rowBuilder);
      cellDataByFieldId = rowBuilder.build();
    }

    return _databaseBackendSvc.createRow(
      startRowId: startRowId,
      groupId: groupId,
      cellDataByFieldId: cellDataByFieldId,
    );
  }

  Future<Either<Unit, FlowyError>> moveRow(RowPB fromRow,
      {RowPB? toRow, String? groupId}) {
    return _databaseBackendSvc.moveRow(
      fromRowId: fromRow.id,
      toGroupId: groupId,
      toRowId: toRow?.id,
    );
  }

  Future<Either<Unit, FlowyError>> moveGroup(
      {required String fromGroupId, required String toGroupId}) {
    return _databaseBackendSvc.moveGroup(
      fromGroupId: fromGroupId,
      toGroupId: toGroupId,
    );
  }

  Future<void> updateCalenderLayoutSetting(
      CalendarLayoutSettingsPB layoutSetting) async {
    await _databaseBackendSvc
        .updateLayoutSetting(calendarLayoutSetting: layoutSetting)
        .then((result) {
      result.fold((l) => null, (r) => Log.error(r));
    });
  }

  Future<void> dispose() async {
    await _databaseBackendSvc.closeView();
    await fieldController.dispose();
    await groupListener.stop();
  }

  Future<void> _loadGroups() async {
    final result = await _databaseBackendSvc.loadGroups();
    return Future(
      () => result.fold(
        (groups) {
          _groupCallbacks?.onGroupByField?.call(groups.items);
        },
        (err) => Log.error(err),
      ),
    );
  }

  Future<void> _loadLayoutSetting() async {
    _databaseBackendSvc.getLayoutSetting(layoutType).then((result) {
      result.fold(
        (l) {
          _layoutCallbacks?.onLoadLayout(l);
        },
        (r) => Log.error(r),
      );
    });
  }

  void _listenOnRowsChanged() {
    _viewCache.addListener(onRowsChanged: (reason) {
      _databaseCallbacks?.onRowsChanged?.call(rowInfos, reason);
    });
  }

  void _listenOnFieldsChanged() {
    fieldController.addListener(
      onReceiveFields: (fields) {
        _databaseCallbacks?.onFieldsChanged?.call(UnmodifiableListView(fields));
      },
      onFilters: (filters) {
        _databaseCallbacks?.onFiltersChanged?.call(filters);
      },
    );
  }

  void _listenOnGroupChanged() {
    groupListener.start(
      onNumOfGroupsChanged: (result) {
        result.fold((changeset) {
          if (changeset.updateGroups.isNotEmpty) {
            _groupCallbacks?.onUpdateGroup?.call(changeset.updateGroups);
          }

          if (changeset.deletedGroups.isNotEmpty) {
            _groupCallbacks?.onDeleteGroup?.call(changeset.deletedGroups);
          }

          for (final insertedGroup in changeset.insertedGroups) {
            _groupCallbacks?.onInsertGroup?.call(insertedGroup);
          }
        }, (r) => Log.error(r));
      },
      onGroupByNewField: (result) {
        result.fold((groups) {
          _groupCallbacks?.onGroupByField?.call(groups);
        }, (r) => Log.error(r));
      },
    );
  }

  void _listenOnLayoutChanged() {
    layoutListener.start(onLayoutChanged: (result) {
      result.fold((l) {
        _layoutCallbacks?.onLayoutChanged(l);
      }, (r) => Log.error(r));
    });
  }
}

class RowDataBuilder {
  final _cellDataByFieldId = <String, String>{};

  void insertText(FieldInfo fieldInfo, String text) {
    assert(fieldInfo.fieldType == FieldType.RichText);
    _cellDataByFieldId[fieldInfo.field.id] = text;
  }

  void insertNumber(FieldInfo fieldInfo, int num) {
    assert(fieldInfo.fieldType == FieldType.Number);
    _cellDataByFieldId[fieldInfo.field.id] = num.toString();
  }

  void insertDate(FieldInfo fieldInfo, DateTime date) {
    assert(fieldInfo.fieldType == FieldType.DateTime);
    final timestamp = (date.millisecondsSinceEpoch ~/ 1000);
    _cellDataByFieldId[fieldInfo.field.id] = timestamp.toString();
  }

  Map<String, String> build() {
    return _cellDataByFieldId;
  }
}