Create ImageService (PalisadoesFoundation#2265)

* resolved conflicts

* fetchmore result typecast

* added ImageService and written its tests

* added coverage to missing lines.

* Minor fix

* fixed failing test

* added ImageService and written its tests

* resolved requested changes.

* added changes to locator.dart

* add debug print.

* resolve requested changes.

* resolved requested changes.

lib/locator.dart

@@ -8,6 +8,7 @@ import 'package:talawa/services/comment_service.dart';
 import 'package:talawa/services/database_mutation_functions.dart';
 import 'package:talawa/services/event_service.dart';
 import 'package:talawa/services/graphql_config.dart';
+import 'package:talawa/services/image_service.dart';
 import 'package:talawa/services/navigation_service.dart';
 import 'package:talawa/services/org_service.dart';
 import 'package:talawa/services/post_service.dart';
@@ -70,11 +71,8 @@ final connectivity = locator<Connectivity>();
 ///creating GetIt for OrganizationService.
 final organizationService = locator<OrganizationService>();
 
-///creating GetIt for ImageCropper.
-final imageCropper = locator<ImageCropper>();
-
-///creating GetIt for ImagePicker.
-final imagePicker = locator<ImagePicker>();
+///creating GetIt for ImageService.
+final imageService = locator<ImageService>();
 
 /// This function registers the widgets/objects in "GetIt".
 ///
@@ -104,8 +102,9 @@ void setupLocator() {
   locator.registerLazySingleton(() => MultiMediaPickerService());
   locator.registerLazySingleton(() => Connectivity());
   locator.registerLazySingleton(() => ChatService());
-  locator.registerLazySingleton(() => ImageCropper());
+  locator.registerLazySingleton(() => ImageService());
   locator.registerLazySingleton(() => ImagePicker());
+  locator.registerLazySingleton(() => ImageCropper());
 
   //graphql
   locator.registerSingleton(GraphqlConfig());

lib/services/image_service.dart

@@ -0,0 +1,80 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:image_cropper/image_cropper.dart';
+import 'package:talawa/locator.dart';
+
+/// ImageService class provides different functions as service in the context of Images.
+///
+/// Services include:
+/// * `cropImage`
+/// * `convertToBase64`
+class ImageService {
+  /// Global instance of ImageCropper.
+  final ImageCropper _imageCropper = locator<ImageCropper>();
+
+  /// Crops the image selected by the user.
+  ///
+  /// **params**:
+  /// * `imageFile`: the image file to be cropped.
+  ///
+  /// **returns**:
+  /// * `Future<File?>`: the image after been cropped.
+  ///
+  /// **throws**:
+  /// - `Exception`: If an error occurs during the image cropping process.
+  Future<File?> cropImage({required File imageFile}) async {
+    // try, to crop the image and returns a File with cropped image path.
+    try {
+      final CroppedFile? croppedImage = await _imageCropper.cropImage(
+        sourcePath: imageFile.path,
+        aspectRatioPresets: [
+          CropAspectRatioPreset.square,
+          CropAspectRatioPreset.original,
+        ],
+        uiSettings: [
+          AndroidUiSettings(
+            toolbarTitle: 'Crop Image',
+            toolbarColor: const Color(0xff18191A),
+            toolbarWidgetColor: Colors.white,
+            backgroundColor: Colors.black,
+            cropGridColor: Colors.white,
+            initAspectRatio: CropAspectRatioPreset.original,
+            lockAspectRatio: false,
+          ),
+          IOSUiSettings(
+            minimumAspectRatio: 1.0,
+          ),
+        ],
+      );
+
+      if (croppedImage != null) {
+        return File(croppedImage.path);
+      }
+    } catch (e) {
+      throw Exception(
+        "ImageService : $e.",
+      );
+    }
+
+    return null;
+  }
+
+  /// Converts the image into Base64 format.
+  ///
+  /// **params**:
+  /// * `file`: Image as a File object.
+  ///
+  /// **returns**:
+  /// * `Future<String?>`: image in string format
+  Future<String?> convertToBase64(File file) async {
+    try {
+      final List<int> bytes = await file.readAsBytes();
+      final String base64String = base64Encode(bytes);
+      return base64String;
+    } catch (error) {
+      return null;
+    }
+  }
+}

lib/services/third_party_service/multi_media_pick_service.dart

@@ -6,12 +6,12 @@ Service usage: "add_post_view_model.dart"
 import 'dart:async';
 import 'dart:io';
 
-import 'package:flutter/material.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
-import 'package:image_cropper/image_cropper.dart';
 import 'package:image_picker/image_picker.dart';
 import 'package:permission_handler/permission_handler.dart';
 import 'package:talawa/locator.dart';
+import 'package:talawa/services/image_service.dart';
 import 'package:talawa/services/navigation_service.dart';
 import 'package:talawa/widgets/custom_alert_dialog.dart';
 
@@ -26,15 +26,22 @@ class MultiMediaPickerService {
   MultiMediaPickerService() {
     _picker = locator<ImagePicker>();
     _fileStream = _fileStreamController.stream.asBroadcastStream();
+    _imageService = imageService;
   }
 
-  //Local Variables
+  /// Controller for handling the stream of selected files.
   final StreamController<File> _fileStreamController = StreamController();
+
+  /// Stream of selected files.
   late Stream<File> _fileStream;
+
+  /// [ImagePicker] used for selecting images or videos.
   late ImagePicker _picker;
-  //Getters
 
-  /// This function returns the stream of files.
+  /// [ImageService] for additional image-related operations.
+  late ImageService _imageService;
+
+  /// Provides a stream of selected multimedia files.
   ///
   /// params:
   /// None.
@@ -43,11 +50,10 @@ class MultiMediaPickerService {
   /// * `Stream<dynamic>`: Stream of files.
   Stream get fileStream => _fileStream;
 
-  /// This function is used to pick the image from gallery or to click the image from user's camera.
-  ///
-  /// The function first ask for the permission to access the camera, if denied then returns a message in.
+  /// Picks the image from gallery or to click the image from user's camera.
   ///
-  /// custom Dialog Box. This function returns a File type for which `camera` variable is false by default.
+  /// First ask for the permission to access the camera, if denied then returns a message in.
+  /// custom Dialog Box. Returns a File type for which `camera` variable is false by default.
   ///
   /// **params**:
   /// * `camera`: if true then open camera for image, else open gallery to select image.
@@ -63,73 +69,46 @@ class MultiMediaPickerService {
       );
       // if image is selected or not null, call the cropImage function that provide service to crop the selected image.
       if (image != null) {
-        return await cropImage(imageFile: File(image.path));
+        return await _imageService.cropImage(
+          imageFile: File(image.path),
+        );
       }
     } catch (e) {
       // if the permission denied or error occurs.
       if (e is PlatformException && e.code == 'camera_access_denied') {
         // push the dialog alert with the message.
         locator<NavigationService>().pushDialog(
-          CustomAlertDialog(
-            success: () {
-              locator<NavigationService>().pop();
-              openAppSettings();
-            },
-            dialogTitle: 'Permission Denied',
-            successText: 'SETTINGS',
-            dialogSubTitle:
-                "Camera permission is required, to use this feature, give permission from app settings",
-          ),
+          permissionDeniedDialog(),
         );
       }
-      print(
+      debugPrint(
         "MultiMediaPickerService : Exception occurred while choosing photo from the gallery $e",
       );
     }
+
     return null;
   }
 
-  /// This function is used to crop the image selected by the user.
+  /// Generates a custom alert dialog for permission denial.
   ///
-  /// The function accepts a `File` type image and returns `File` type of cropped image.
+  /// When called, it creates and returns a `CustomAlertDialog` widget with pre-defined settings.
+  /// This dialog prompts the user to grant camera permissions from the app settings.
   ///
   /// **params**:
-  /// * `imageFile`: the image file to be cropped.
+  ///   None
   ///
   /// **returns**:
-  /// * `Future<File?>`: the image after been cropped.
-  Future<File?> cropImage({required File imageFile}) async {
-    // try, to crop the image and returns a File with cropped image path.
-    try {
-      final CroppedFile? croppedImage = await locator<ImageCropper>().cropImage(
-        sourcePath: imageFile.path,
-        aspectRatioPresets: [
-          CropAspectRatioPreset.square,
-          CropAspectRatioPreset.original,
-        ],
-        uiSettings: [
-          AndroidUiSettings(
-            toolbarTitle: 'Crop Image',
-            toolbarColor: const Color(0xff18191A),
-            toolbarWidgetColor: Colors.white,
-            backgroundColor: Colors.black,
-            cropGridColor: Colors.white,
-            initAspectRatio: CropAspectRatioPreset.original,
-            lockAspectRatio: false,
-          ),
-          IOSUiSettings(
-            minimumAspectRatio: 1.0,
-          ),
-        ],
-      );
-      if (croppedImage != null) {
-        return File(croppedImage.path);
-      }
-    } catch (e) {
-      print(
-        "MultiMediaPickerService : Exception occurred while cropping Image",
-      );
-    }
-    return null;
+  /// * `CustomAlertDialog`: Custom Alert Dialog widget.
+  CustomAlertDialog permissionDeniedDialog() {
+    return CustomAlertDialog(
+      success: () {
+        locator<NavigationService>().pop();
+        openAppSettings();
+      },
+      dialogTitle: 'Permission Denied',
+      successText: 'SETTINGS',
+      dialogSubTitle:
+          "Camera permission is required, to use this feature, give permission from app settings",
+    );
   }
 }

lib/view_model/after_auth_view_models/add_post_view_models/add_post_view_model.dart

@@ -1,12 +1,12 @@
 import 'dart:async';
-import 'dart:convert';
 import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:talawa/enums/enums.dart';
 import 'package:talawa/locator.dart';
 import 'package:talawa/models/organization/org_info.dart';
 import 'package:talawa/services/database_mutation_functions.dart';
+import 'package:talawa/services/image_service.dart';
 import 'package:talawa/services/navigation_service.dart';
 import 'package:talawa/services/third_party_service/multi_media_pick_service.dart';
 import 'package:talawa/services/user_config.dart';
@@ -22,6 +22,7 @@ class AddPostViewModel extends BaseModel {
   //Services
   late MultiMediaPickerService _multiMediaPickerService;
   late NavigationService _navigationService;
+  late ImageService _imageService;
 
   // ignore: unused_field
   late File? _imageFile;
@@ -65,7 +66,7 @@ class AddPostViewModel extends BaseModel {
   /// **returns**:
   /// * `Future<void>`: define_the_return
   Future<void> setImageInBase64(File file) async {
-    _imageInBase64 = await convertToBase64(file);
+    _imageInBase64 = await _imageService.convertToBase64(file);
     notifyListeners();
   }
 
@@ -124,33 +125,15 @@ class AddPostViewModel extends BaseModel {
   void initialise() {
     _navigationService = locator<NavigationService>();
     _imageFile = null;
+    _imageInBase64 = null;
     _multiMediaPickerService = locator<MultiMediaPickerService>();
+    _imageService = locator<ImageService>();
     if (!demoMode) {
       _dbFunctions = locator<DataBaseMutationFunctions>();
       _selectedOrg = locator<UserConfig>().currentOrg;
     }
   }
 
-  /// to convert the image in base64.
-  ///
-  ///
-  /// **params**:
-  /// * `file`: file of image clicked.
-  ///
-  /// **returns**:
-  /// * `Future<String>`: Future string containing the base 64 format image
-  Future<String> convertToBase64(File file) async {
-    try {
-      final List<int> bytes = await file.readAsBytes();
-      final String base64String = base64Encode(bytes);
-      print(base64String);
-      _imageInBase64 = base64String;
-      return base64String;
-    } catch (error) {
-      return '';
-    }
-  }
-
   /// This function is used to get the image from gallery.
   ///
   /// The function uses the `_multiMediaPickerService` services.
@@ -167,7 +150,7 @@ class AddPostViewModel extends BaseModel {
     if (image != null) {
       _imageFile = image;
       // convertImageToBase64(image.path);
-      convertToBase64(image);
+      _imageInBase64 = await _imageService.convertToBase64(image);
       // print(_imageInBase64);
       _navigationService.showTalawaErrorSnackBar(
         "Image is added",

test/helpers/test_helpers.dart

@@ -25,6 +25,7 @@ import 'package:talawa/services/comment_service.dart';
 import 'package:talawa/services/database_mutation_functions.dart';
 import 'package:talawa/services/event_service.dart';
 import 'package:talawa/services/graphql_config.dart';
+import 'package:talawa/services/image_service.dart';
 import 'package:talawa/services/navigation_service.dart';
 import 'package:talawa/services/org_service.dart';
 import 'package:talawa/services/post_service.dart';
@@ -53,6 +54,7 @@ import 'package:talawa/view_model/theme_view_model.dart';
 import 'package:talawa/view_model/widgets_view_models/custom_drawer_view_model.dart';
 import 'package:talawa/view_model/widgets_view_models/like_button_view_model.dart';
 import 'package:talawa/view_model/widgets_view_models/progress_dialog_view_model.dart';
+import '../service_tests/image_service_test.dart';
 import '../views/main_screen_test.dart';
 import 'test_helpers.mocks.dart';
 
@@ -429,6 +431,13 @@ ImageCropper getAndRegisterImageCropper() {
   return service;
 }
 
+ImageService getAndRegisterImageService() {
+  _removeRegistrationIfExists<ImageService>();
+  final service = MockImageService();
+  locator.registerLazySingleton<ImageService>(() => service);
+  return service;
+}
+
 ImagePicker getAndRegisterImagePicker() {
   _removeRegistrationIfExists<ImagePicker>();
   final service = MockImagePicker();