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mc_gallery
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live local search 

todos

improve local search
This commit is contained in:
Mguy13 2022-12-23 20:45:30 +01:00
parent 4ade7f1682
commit a0ed894016
9 changed files with 151 additions and 42 deletions
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8
lib/features/core/data/constants/const_sorters.dart Normal file
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@ -0,0 +1,8 @@
import 'package:string_similarity/string_similarity.dart';
abstract class ConstSorters {
/// Uses Dice's Coefficient as a similarity metric, for a 2-way comparison, between a [targetWord]
/// and given words.
static int stringsSimilarityTarget(String a, String b, {required String targetWord}) =>
a.similarityTo(targetWord).compareTo(b.similarityTo(targetWord));
}

3
lib/features/core/data/extensions/map_extensions.dart
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@ -1,3 +1,6 @@
extension MapExtensions<A, B> on Map<A, B> {
Map<A, B> get deepCopy => {...this};
/// Returns the values of a [Map] at given [keys] indices.
Iterable<B> valuesByKeys({required Iterable<A> keys}) => keys.map((final key) => this[key]!);
}

8
lib/features/core/data/extensions/object_extensions.dart Normal file
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@ -0,0 +1,8 @@
extension ObjectExtensions on Object? {
E asType<E>() => this as E;
E? asNullableType<E>() => this as E?;
}
extension AsCallback<T extends Object> on T {
T Function() get asCallback => () => this;
}

14
lib/features/core/data/extensions/string_extensions.dart Normal file
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@ -0,0 +1,14 @@
extension StringExtensions on String {
/// Returns true if given word contains atleast all the characters in [targetChars], and `false` otherwise
///
/// Very efficient `O(n)` instead of naive `O(n*m)`
bool containsAllCharacters({required String targetChars}) {
final Set<String> characterSet = Set.from(targetChars.split(''));
for (final testChar in split('')) {
characterSet.remove(testChar);
if (characterSet.isEmpty) return true;
}
return false;
}
}

39
lib/features/home/services/images_service.dart
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@ -1,12 +1,16 @@
import 'dart:async';
import 'package:mc_gallery/features/core/data/extensions/string_extensions.dart';
import '/features/core/data/constants/const_sorters.dart';
import '/features/core/data/extensions/iterable_extensions.dart';
import '/features/core/data/extensions/map_extensions.dart';
import '/features/core/services/logging_service.dart';
import '/features/core/utils/mutex.dart';
import '/features/home/data/models/image_model.dart';
import '/locator.dart';
import '../abstracts/images_api.dart';
import '../data/enums/search_option.dart';
import '../data/models/image_model.dart';
/// Handles fetching and storing of Images.
///
@ -24,8 +28,9 @@ class ImagesService {
final ImagesApi _imagesApi;
final LoggingService _loggingService;
late final Iterable<ImageModel> _imageModels;
Iterable<ImageModel> get imageModels => _imageModels.deepCopy;
late final Map<String, ImageModel> _imageModels;
Iterable<ImageModel> get imageModels => _imageModels.values.deepCopy;
final Mutex _searchMutex = Mutex();
/// Manual initialization triggering
@ -36,7 +41,10 @@ class ImagesService {
Future<void> _init() async {
_loggingService.info('Fetching and creating image models...');
_imageModels = await _imagesApi.fetchImageUri(token: '');
_imageModels = {
for (final imageModel in await _imagesApi.fetchImageUri(token: ''))
imageModel.imageName: imageModel
};
_imageModels.isNotEmpty
? _loggingService.good("Created ${_imageModels.length} images' models")
@ -49,19 +57,38 @@ class ImagesService {
int get lastAvailableImageIndex => _imageModels.length - 1;
int get numberOfImages => _imageModels.length;
ImageModel imageModelAt({required int index}) => _imageModels.elementAt(index);
ImageModel imageModelAt({required int index}) => _imageModels.values.elementAt(index);
Future<void> get lastQueryIsCompleted => _searchMutex.lastOperationCompletionAwaiter;
/// Performs searching on images, both locally and by a Web API endpoint.
///
/// For now, a simple mechanism is used for handling async calls between (posssible) API fetches ->
/// just 'pile-up'. A mechanism can be made to 'cancel' a fetch if a newer search request comes in,
/// but that may be more complicated, and not the point of the assignment I think.
/// There are lots of optimizations possible for new inputs, for example reducing search frontier
/// by using set-cover/subsetting optimizations on backspace, and so on, but again, not the point,
/// I think.
Future<List<ImageModel>> searchImages({
required SearchOption searchOption,
required String imageNamePart,
bool treatAsInSequence = false,
}) async {
return await _searchMutex.lockAndRun(run: (final unlock) async {
try {
switch (searchOption) {
case SearchOption.local:
return [];
final rankedKeys = _imageModels.keys
// Reduce number of results by atleast occurring
.where((final imageName) => treatAsInSequence
? imageName.contains(imageNamePart)
: imageName.containsAllCharacters(targetChars: imageNamePart))
.toList(growable: false)
// Sorting by the highest similarity first
..sort((final a, final b) =>
ConstSorters.stringsSimilarityTarget(targetWord: imageNamePart, a, b))
..reversed;
return _imageModels.valuesByKeys(keys: rankedKeys).toList(growable: false);
case SearchOption.web:
return await _imagesApi.searchImages(
searchStr: imageNamePart,

40
lib/features/home/views/gallery/gallery_view_model.dart
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@ -7,12 +7,12 @@ import 'package:flutter_cache_manager/flutter_cache_manager.dart';
import '/features/core/abstracts/base_view_model.dart';
import '/features/core/services/logging_service.dart';
import '/features/core/services/navigation_service.dart';
import '/features/home/data/models/image_model.dart';
import '/features/home/services/image_cache_manager_service.dart';
import '/features/home/services/images_service.dart';
import '/features/home/views/image_carousel/image_carousel_view.dart';
import '/locator.dart';
import '../../data/enums/search_option.dart';
import '../../data/models/image_model.dart';
import '../../services/image_cache_manager_service.dart';
import '../../services/images_service.dart';
import '../image_carousel/image_carousel_view.dart';
class GalleryViewModel extends BaseViewModel {
GalleryViewModel({
@ -54,17 +54,20 @@ class GalleryViewModel extends BaseViewModel {
// If empty-string (from backspacing) -> reset state.
if (searchTerm.isEmpty) {
_imageSearchResultsNotifier.value = [];
_loggingService.info('Clearing results on search string removal');
return;
}
// Detached call to prevent UI blocking
unawaited(_imagesService
.searchImages(
imageNamePart: searchTerm,
searchOption: searchOptionListenable.value,
)
.then(
(final fetchedImageModels) => _imageSearchResultsNotifier.value = fetchedImageModels));
unawaited(
_imagesService
.searchImages(
imageNamePart: searchTerm,
searchOption: searchOptionListenable.value,
)
.then(
(final fetchedImageModels) => _imageSearchResultsNotifier.value = fetchedImageModels),
);
// Force-update to trigger listening to `lastQueryResultDone()`.
_imageSearchResultsNotifier.notifyListeners();
@ -72,14 +75,25 @@ class GalleryViewModel extends BaseViewModel {
void searchPressed() {
// If transitioning from 'Searching', clear previous results immediately
if (_isSearchingNotifier.value) _imageSearchResultsNotifier.value = [];
if (_isSearchingNotifier.value) {
_imageSearchResultsNotifier.value = [];
_loggingService.info('Clearing of results on view mode change');
}
_isSearchingNotifier.value = !_isSearchingNotifier.value;
}
Future<void> get lastQueryResultDone => _imagesService.lastQueryIsCompleted;
void onSearchOptionChanged(SearchOption? option) => _searchOptionNotifier.value = option!;
void onSearchOptionChanged(SearchOption? option) {
_searchOptionNotifier.value = option!;
_loggingService.info('Switched over to $option search');
_imageSearchResultsNotifier.value = [];
_loggingService.info('Cleared resultsw from view');
//todo(mehul): Either redo search or force user to type in by clearing field
}
void onPromptPressed() => _isDisplayingPressingPrompt.value = false;

73
lib/features/home/views/gallery/search_gallery_view.dart
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@ -24,29 +24,56 @@ class _SearchGalleryView extends StatelessWidget {
displayedWidget = const CircularProgressIndicator();
break;
case ConnectionState.done:
displayedWidget = Wrap(
runSpacing: 24,
spacing: 8,
alignment: WrapAlignment.center,
runAlignment: WrapAlignment.center,
crossAxisAlignment: WrapCrossAlignment.center,
children: [
for (final imageResult in resultsImageModels)
Image.network(
imageResult.uri.toString(),
loadingBuilder: (context, final child, final loadingProgress) =>
loadingProgress == null
? child
: Center(
child: CircularProgressIndicator(
value: loadingProgress.expectedTotalBytes != null
? loadingProgress.cumulativeBytesLoaded /
loadingProgress.expectedTotalBytes!
: null,
),
),
),
],
displayedWidget = ValueListenableBuilder<SearchOption>(
valueListenable: galleryViewModel.searchOptionListenable,
builder: (context, final searchOption, child) {
switch (searchOption) {
case SearchOption.local:
return Wrap(
runSpacing: 24,
spacing: 8,
alignment: WrapAlignment.center,
runAlignment: WrapAlignment.center,
crossAxisAlignment: WrapCrossAlignment.center,
children: [
for (final resultsImageModel in resultsImageModels)
CachedNetworkImage(
imageUrl: resultsImageModel.uri.toString(),
cacheKey: resultsImageModel.imageIndex.toString(),
progressIndicatorBuilder: (_, __, final progress) =>
CircularProgressIndicator(
value: galleryViewModel.downloadProgressValue(progress: progress),
),
),
],
);
case SearchOption.web:
return Wrap(
runSpacing: 24,
spacing: 8,
alignment: WrapAlignment.center,
runAlignment: WrapAlignment.center,
crossAxisAlignment: WrapCrossAlignment.center,
children: [
for (final imageResult in resultsImageModels)
Image.network(
imageResult.uri.toString(),
loadingBuilder: (context, final child, final loadingProgress) =>
loadingProgress == null
? child
: Center(
child: CircularProgressIndicator(
value: loadingProgress.expectedTotalBytes != null
? loadingProgress.cumulativeBytesLoaded /
loadingProgress.expectedTotalBytes!
: null,
),
),
),
],
);
}
},
);
}

7
pubspec.lock
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@ -546,6 +546,13 @@ packages:
url: "https://pub.dartlang.org"
source: hosted
version: "1.1.1"
string_similarity:
dependency: "direct main"
description:
name: string_similarity
url: "https://pub.dartlang.org"
source: hosted
version: "2.0.0"
synchronized:
dependency: transitive
description:

1
pubspec.yaml
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@ -29,6 +29,7 @@ dependencies:
intl_utils: ^2.8.1
connectivity_plus: ^3.0.2
internet_connection_checker: ^1.0.0+1
string_similarity: ^2.0.0
# Util frontend
flutter_markdown: ^0.6.13