[Feature] Add utility extensions (#11)

* feat: implement date time picker utils and extensions

* feat: use file picker utils on the contact us

* chore: resolve merge conflicts from develop branch

* ref: refactor utils

* chore: resolve merge conflicts from develop

* chore: resolve merge conflicts from develop

* chore: resolve merge conflicts from develop

* feat: add file size and type validation for photo, image, video and files

* feat: add permission util class

* [Refactor] Add constant in particular feture const file and add doc comments on mime constants

* [Refactor] Move constants to dedicated directory

* [Refactor] Rename folder from feature to constant

* [Refactor] Applied suggested PR changes and sorted localization keys alphabetically

* [Feature] Add unit tests for datetime extensions utilities

* [Fix] Ignore cacheoptions in mock Dio get requests and fix test failures

* [Refactor] Applied ai suggested improvements in applicable areas of code

* [Refactor] Applied suggested changes from PR comments

* [Refactor] Rename file extension constants with dot prefix

* [Refactor] Add clarity missing import

* refactor: remove unused import from login bloc

---------

Co-authored-by: vishaltsolguruz <vishalt@solguruz.com>

Author: GaneshSolGuruz

integration_test/presentation/login/login_screen_test.dart

@@ -21,7 +21,12 @@ void main() {
 
     when(() => mockResponse.statusCode).thenReturn(200);
     when(() => mockResponse.data).thenReturn(productsResponse);
-    when(() => mockDio.get(any())).thenAnswer((_) async => mockResponse);
+    when(
+      () => mockDio.get(
+        any(),
+        options: any(named: 'options'), // ignore the CacheOptions in test
+      ),
+    ).thenAnswer((_) async => mockResponse);
     when(() => mockDio.interceptors).thenReturn(Interceptors());
   });
 

lib/constants/constants.dart

@@ -2,10 +2,51 @@ const String kLogFileName = 'app.log';
 
 const kMimeTypeVideo = 'video/';
 const kMimeTypeImage = 'image/';
-const kSVGExtension = '.svg';
-const kPNGExtension = '.png';
+const kSVGWithDot = '.svg';
+const kPNGWithDot = '.png';
 
-// Firebase auth exceptions
+const  kPdf = 'pdf';
+const  kText = 'txt';
+const  kDoc = 'doc';
+const  kMp4 = 'mp4';
+
+/// MIME types for identifying PDF, TXT, Word DOC, and MP4 files
+const kPdfMimeType = 'application/pdf';
+const kTextMimeType = 'text/plain';
+const kDocMimeType = 'application/msword';
+const kVideoMimeType = 'video/mp4';
+
+/// PDF files start with "%PDF-" as a magic number to identify real PDFs, and
+/// MP4/ISO media files contain "ftyp" near the header to verify valid media format
+const String kPdfFileSignature = '%PDF-';
+const String kFileTypeBoxSignature = 'ftyp';
+
+/// Signature bytes that identify a Microsoft OLE Compound File (used by legacy
+/// Microsoft Office formats such as `.doc`, `.xls`, `.ppt`).
+/// We use this constant for file type detection/validation — e.g., to check
+/// whether a given file is a valid legacy Office document before processing.
+const List<int> kDocOleFileSignature = [
+  0xD0,
+  0xCF,
+  0x11,
+  0xE0,
+  0xA1,
+  0xB1,
+  0x1A,
+  0xE1,
+];
+
+const String kSomethingWentWrong = 'Oops! Something went wrong';
+
+// Chat messaging constants
+const String kHeroAnimationPrefix = 'fullscreen_image_0';
+
+// Regex patterns
+final kEmailRegex = RegExp(
+  r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$',
+);
+
+// Firebase Auth exception codes
 const kFirebaseAuthWeakPasswordException = 'weak-password';
 const kFirebaseAuthUserNotFoundException = 'user-not-found';
 const kFirebaseAuthWrongPasswordException = 'wrong-password';
@@ -15,17 +56,12 @@ const kFirebaseAuthSessionExpiredException = 'session-expired';
 const kFirebaseAuthSessionEmailAlreadyInUse = 'email-already-in-use';
 const kFirebaseAuthRequiresRecentLogin = 'requires-recent-login';
 
-const String kSomethingWentWrong = 'Oops! Something went wrong';
-
-// Chat messaging constants
-const String kHereAnimationPrefix = 'fullscreen_image_0';
-
-// Contact us constants
-final kEmailRegex = RegExp(r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$');
-final kAllowedFileExtensions = ['pdf'];
-
 // Network/SSL pinning constants
 const String kConnectionIsNotSecureError = 'Connection is not secure';
 
 // Cache Api Response
 const String kApiCache = 'api_cache';
+
+// Date formats
+const String kDefaultDateFormat = 'dd-MM-yyyy';
+const String kDefaultTimeFormat12Hour = 'hh:mm a';