earthquake_query.dart

// Copyright (c) 2020-2023 Navibyte (https://navibyte.com). All rights reserved.
// Use of this source code is governed by a “BSD-3-Clause”-style license that is
// specified in the LICENSE file.
//
// Docs: https://github.com/navibyte/geospatial_demos

import 'package:equatable/equatable.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import 'earthquake_model.dart';

/// A minimum earthquake magnitude used by an earthquake filter.
enum Magnitude {
  significant,
  m45plus,
  m25plus,
  m10plus,
  all;

  /// An identifier used by the USGS service (not equals with the enum [name]).
  String get code {
    switch (this) {
      case Magnitude.significant:
        return 'significant';
      case Magnitude.m45plus:
        return '4.5';
      case Magnitude.m25plus:
        return '2.5';
      case Magnitude.m10plus:
        return '1.0';
      case Magnitude.all:
        return 'all';
    }
  }
}

/// A time period ("past from now") used by an earthquake filter.
enum Past {
  hour,
  day,
  week,
  month;

  /// An identifier used by the USGS service (equals with the enum [name]).
  String get code => name;
}

/// A query to filter earthquakes when requesting data from a data source.
///
/// This model class extends `Equatable` that implements `==` and `hashCode`.
class EarthquakeQuery extends Equatable {
  /// The selection of the producer for earthquake data.
  final EarthquakeProducer producer;

  /// A minimum earthquake magnitude.
  ///
  /// This is a required parameter at least for the USGS producer.
  final Magnitude magnitude;

  /// A time period ("past from now").
  ///
  /// This is a required parameter at least for the USGS producer.
  final Past past;

  /// A query to filter earthquakes when requesting data from a data source.
  const EarthquakeQuery({
    required this.producer,
    required this.magnitude,
    required this.past,
  });

  /// Copies this query as a new instance with optional parameter values.
  EarthquakeQuery copyWith({
    EarthquakeProducer? producer,
    Magnitude? magnitude,
    Past? past,
  }) =>
      EarthquakeQuery(
        producer: producer ?? this.producer,
        magnitude: magnitude ?? this.magnitude,
        past: past ?? this.past,
      );

  @override
  List<Object?> get props => [producer, magnitude, past];
}

/// The state notifier provider for an query used to filter earthquakes.
///
/// This is used `earthquakeMarkers` to get a filter for earthquakes. Filter
/// parameters can be customized on the settings view.
final earthquakeFilter =
    StateNotifierProvider<EarthquakeFilterNotifier, EarthquakeQuery>(
  (ref) => EarthquakeFilterNotifier(),
);

/// The state notifier class for an query used to filter earthquakes.
class EarthquakeFilterNotifier extends StateNotifier<EarthquakeQuery> {
  EarthquakeFilterNotifier()
      : super(
          // The default query filters earthquakes with a magnitude above 4.5
          // for the past week.
          const EarthquakeQuery(
            producer: EarthquakeProducer.usgs,
            magnitude: Magnitude.m45plus,
            past: Past.week,
          ),
        );

  /// Updates the [producer] selection on this filter.
  void updateProducer(EarthquakeProducer producer) {
    if (producer != state.producer) {
      state = state.copyWith(producer: producer);
    }
  }

  /// Updates the minimum [magnitude] selection on this filter.
  void updateMagnitude(Magnitude magnitude) {
    if (magnitude != state.magnitude) {
      state = state.copyWith(magnitude: magnitude);
    }
  }

  /// Updates the time period or [past] selection on this filter.
  void updatePast(Past past) {
    if (past != state.past) {
      state = state.copyWith(past: past);
    }
  }
}