[auth] Add hook to share code

auth/lib/l10n/arb/app_en.arb

@@ -118,6 +118,7 @@
   "emailVerificationToggle": "Email verification",
   "emailVerificationEnableWarning": "To avoid getting locked out of your account, be sure to store a copy of your email 2FA outside of Ente Auth before enabling email verification.",
   "authToChangeEmailVerificationSetting": "Please authenticate to change email verification",
+  "authenticateGeneric": "Please authenticate",
   "authToViewYourRecoveryKey": "Please authenticate to view your recovery key",
   "authToChangeYourEmail": "Please authenticate to change your email",
   "authToChangeYourPassword": "Please authenticate to change your password",
@@ -211,6 +212,7 @@
   "scanAQrCode": "Scan a QR code",
   "enterDetailsManually": "Enter details manually",
   "edit": "Edit",
+  "share": "Share",
   "restore": "Restore",
   "copiedToClipboard": "Copied to clipboard",
   "copiedNextToClipboard": "Copied next code to clipboard",

auth/lib/ui/code_widget.dart

@@ -1,5 +1,7 @@
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
+import 'dart:math';
 import 'dart:ui' as ui;
 
 import 'package:auto_size_text/auto_size_text.dart';
@@ -15,6 +17,7 @@ import 'package:ente_auth/services/preference_service.dart';
 import 'package:ente_auth/store/code_store.dart';
 import 'package:ente_auth/theme/ente_theme.dart';
 import 'package:ente_auth/ui/code_timer_progress.dart';
+import 'package:ente_auth/ui/share/code_share.dart';
 import 'package:ente_auth/ui/utils/icon_utils.dart';
 import 'package:ente_auth/utils/dialog_util.dart';
 import 'package:ente_auth/utils/platform_util.dart';
@@ -291,13 +294,13 @@ class _CodeWidgetState extends State<CodeWidget> {
                 if (!widget.code.isTrashed) SizedBox(width: slideSpace),
                 if (!widget.code.isTrashed)
                   SlidableAction(
-                    onPressed: _onShowQrPressed,
+                    onPressed: _onSharePressed,
                     backgroundColor: Colors.grey.withOpacity(0.1),
                     borderRadius: const BorderRadius.all(Radius.circular(8)),
                     foregroundColor:
                         Theme.of(context).colorScheme.inverseBackgroundColor,
-                    icon: Icons.qr_code_2_outlined,
+                    icon: Icons.adaptive.share_outlined,
-                    label: "QR",
+                    label: l10n.share,
                     padding: const EdgeInsets.only(left: 4, right: 0),
                     spacing: 8,
                   ),
@@ -605,6 +608,16 @@ class _CodeWidgetState extends State<CodeWidget> {
     );
   }
 
+  Future<void> _onSharePressed(_) async {
+    bool isAuthSuccessful = await LocalAuthenticationService.instance
+        .requestLocalAuthentication(context, context.l10n.authenticateGeneric);
+    await PlatformUtil.refocusWindows();
+    if (!isAuthSuccessful) {
+      return;
+    }
+    showShareDialog(context, widget.code);
+  }
+
   Future<void> _onPinPressed(_) async {
     bool currentlyPinned = widget.code.isPinned;
     final display = widget.code.display;

auth/lib/ui/share/code_share.dart

@@ -0,0 +1,159 @@
+import 'dart:convert';
+import 'dart:math';
+import 'dart:typed_data';
+
+import 'package:dropdown_button2/dropdown_button2.dart';
+import 'package:ente_auth/l10n/l10n.dart';
+import 'package:ente_auth/models/code.dart';
+import 'package:ente_auth/ui/components/buttons/button_widget.dart';
+import 'package:ente_auth/ui/components/models/button_type.dart';
+import 'package:ente_auth/utils/dialog_util.dart';
+import 'package:ente_auth/utils/share_utils.dart';
+import 'package:ente_auth/utils/totp_util.dart';
+import 'package:ente_crypto_dart/ente_crypto_dart.dart';
+import 'package:flutter/material.dart';
+import 'package:logging/logging.dart';
+
+class ShareCodeDialog extends StatefulWidget {
+  final Code code;
+  const ShareCodeDialog({super.key, required this.code});
+
+  @override
+  State<ShareCodeDialog> createState() => _ShareCodeDialogState();
+}
+
+class _ShareCodeDialogState extends State<ShareCodeDialog> {
+  final Logger logger = Logger('_ShareCodeDialogState');
+  List<int> items = [5, 15, 30, 60];
+
+  String getItemLabel(int min) {
+    if (min == 60) return '1 hour';
+    if (min > 60) {
+      var hour = '${min ~/ 60}';
+      if (min % 60 == 0) return '$hour hour';
+      var minx = '${min % 60}';
+      return '$hour hr $minx min';
+    }
+    return '$min min';
+  }
+
+  int selectedValue = 15;
+
+  @override
+  void initState() {
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const Text('Share codes'),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          const Text(
+            'Select the duration for which you want to share codes.',
+          ),
+          const SizedBox(height: 10),
+          DropdownButtonHideUnderline(
+            child: DropdownButton2(
+              hint: const Text('Select an option'),
+              items: items
+                  .map(
+                    (item) => DropdownMenuItem<int>(
+                      value: item,
+                      child: Align(
+                        alignment: Alignment.centerLeft,
+                        child: Text(getItemLabel(item)),
+                      ),
+                    ),
+                  )
+                  .toList(),
+              value: selectedValue,
+              onChanged: (value) {
+                setState(() {
+                  selectedValue = value ?? 15;
+                });
+              },
+            ),
+          ),
+        ],
+      ),
+      actions: [
+        ButtonWidget(
+          buttonType: ButtonType.primary,
+          buttonSize: ButtonSize.large,
+          labelText: context.l10n.share,
+          onTap: () async {
+            try {
+              await shareCode();
+
+              Navigator.of(context).pop();
+            } catch (e) {
+              logger.warning('Failed to share code: ${e.toString()}');
+              showGenericErrorDialog(context: context, error: e).ignore();
+            }
+          },
+        ),
+        const SizedBox(height: 8),
+        ButtonWidget(
+          buttonType: ButtonType.secondary,
+          buttonSize: ButtonSize.large,
+          labelText: context.l10n.cancel,
+          onTap: () async {
+            Navigator.of(context).pop();
+          },
+        ),
+      ],
+    );
+  }
+
+  Future<void> shareCode() async {
+    final result = generateFutureTotpCodes(widget.code, 30);
+    // show toast with total time taken
+    Map<String, dynamic> data = {
+      'startTime': result.$1,
+      'step': widget.code.period,
+      'codes': result.$2.join(","),
+    };
+    try {
+      // generated 128 bit crypto secure random key
+      final Uint8List key = generate256BitKey();
+      Uint8List input = utf8.encode(jsonEncode(data));
+      final encResult = CryptoUtil.encryptSync(input, key);
+      String url =
+          'https://auth.io/share?data=${uint8ListToUrlSafeBase64(encResult.encryptedData!)}&nonce=${uint8ListToUrlSafeBase64(encResult.nonce!)}#key=${uint8ListToUrlSafeBase64(key)}';
+      logger.info('url: $url');
+      shareText(url, context: context).ignore();
+    } catch (e) {
+      logger.warning('Failed to encrypt data: ${e.toString()}');
+    }
+  }
+
+  String uint8ListToUrlSafeBase64(Uint8List data) {
+    String base64Str = base64UrlEncode(data);
+    return base64Str.replaceAll('=', '');
+  }
+
+  Uint8List generate256BitKey() {
+    final random = Random.secure();
+    final bytes = Uint8List(32); // 32 bytes = 32 * 8 bits = 256 bits
+    for (int i = 0; i < bytes.length; i++) {
+      bytes[i] = random
+          .nextInt(256); // Generates a random number between 0 and 255 (1 byte)
+    }
+    return bytes;
+  }
+}
+
+void showShareDialog(BuildContext context, Code code) {
+  showDialog(
+    context: context,
+    builder: (BuildContext context) {
+      return ShareCodeDialog(
+        code: code,
+      );
+    },
+  );
+}

auth/lib/utils/share_utils.dart

@@ -5,6 +5,8 @@ import 'package:ente_auth/ui/components/buttons/button_widget.dart';
 import 'package:ente_auth/ui/components/dialog_widget.dart';
 import 'package:ente_auth/ui/components/models/button_type.dart';
 import 'package:flutter/material.dart';
+import 'package:logging/logging.dart';
+import 'package:share_plus/share_plus.dart';
 
 Future<void> shareDialog(
   BuildContext context,
@@ -49,3 +51,52 @@ Future<void> shareDialog(
     ],
   );
 }
+
+Rect _sharePosOrigin(BuildContext? context, GlobalKey? key) {
+  late final Rect rect;
+  if (context != null) {
+    rect = shareButtonRect(context, key);
+  } else {
+    rect = const Offset(20.0, 20.0) & const Size(10, 10);
+  }
+  return rect;
+}
+
+/// Returns the rect of button if context and key are not null
+/// If key is null, returned rect will be at the center of the screen
+Rect shareButtonRect(BuildContext context, GlobalKey? shareButtonKey) {
+  Size size = MediaQuery.sizeOf(context);
+  final RenderObject? renderObject =
+      shareButtonKey?.currentContext?.findRenderObject();
+  RenderBox? renderBox;
+  if (renderObject != null && renderObject is RenderBox) {
+    renderBox = renderObject;
+  }
+  if (renderBox == null) {
+    return Rect.fromLTWH(0, 0, size.width, size.height / 2);
+  }
+  size = renderBox.size;
+  final Offset position = renderBox.localToGlobal(Offset.zero);
+  return Rect.fromCenter(
+    center: position + Offset(size.width / 2, size.height / 2),
+    width: size.width,
+    height: size.height,
+  );
+}
+
+Future<ShareResult> shareText(
+  String text, {
+  BuildContext? context,
+  GlobalKey? key,
+}) async {
+  try {
+    final sharePosOrigin = _sharePosOrigin(context, key);
+    return Share.share(
+      text,
+      sharePositionOrigin: sharePosOrigin,
+    );
+  } catch (e, s) {
+    Logger("ShareUtil").severe("failed to share text", e, s);
+    return ShareResult.unavailable;
+  }
+}