[Parked – do not merge] UPI Scan & Pay (not production-ready)

README.md

@@ -35,7 +35,7 @@ We have exciting features planned for the future:
   - [ ] Ask AI: "Where am I spending the most?"
   - [ ] Multi-Expense Entry: Add multiple expenses in one go.
   - [ ] Dynamic Stats UI: AI-powered insights.
-- [ ] **UPI Scanner**: Scan QR, select app, and auto-log expense.
+- [X] **UPI Scanner**: Scan QR, select app, and auto-log expense.
 - [ ] **Custom Themes**: Create and share your own chat themes.
 - [ ] **Darker Logo**: A sleek new look.
 

android/app/src/main/AndroidManifest.xml

@@ -1,4 +1,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Required for scanning UPI QR codes with the device camera -->
+    <uses-permission android:name="android.permission.CAMERA" />
+
     <application
         android:label="Clean Expense"
         android:name="${applicationName}"
@@ -49,5 +52,12 @@
             <action android:name="android.intent.action.PROCESS_TEXT"/>
             <data android:mimeType="text/plain"/>
         </intent>
+        <!-- Required (Android 11+) so upi_intent can discover installed UPI
+             apps. No host filter — many UPI apps register the `upi` scheme
+             without host="pay", and restricting it hides them. -->
+        <intent>
+            <action android:name="android.intent.action.VIEW" />
+            <data android:scheme="upi" />
+        </intent>
     </queries>
 </manifest>

ios/Runner/Info.plist

@@ -45,10 +45,23 @@
 	<true/>
 	<key>UIApplicationSupportsIndirectInputEvents</key>
 	<true/>
+	<key>NSCameraUsageDescription</key>
+	<string>Camera access is needed to scan UPI QR codes for payments.</string>
 	<key>LSApplicationQueriesSchemes</key>
 	<array>
 		<string>https</string>
 		<string>mailto</string>
+		<!-- UPI apps, so upi_pay can detect and launch them -->
+		<string>upi</string>
+		<string>tez</string>
+		<string>gpay</string>
+		<string>phonepe</string>
+		<string>paytmmp</string>
+		<string>paytm</string>
+		<string>bhim</string>
+		<string>credpay</string>
+		<string>ybl</string>
+		<string>imobileapp</string>
 	</array>
 </dict>
 </plist>

lib/data/utils/upi_uri.dart

@@ -0,0 +1,54 @@
+/// Lightweight parser for UPI deep-link QR codes.
+///
+/// A UPI QR encodes a string like:
+///   upi://pay?pa=merchant@bank&pn=Merchant%20Name&am=100.00&cu=INR&tn=Order
+///
+/// We only need the payee address (`pa`), an optional display name (`pn`)
+/// and an optional pre-filled amount (`am`). Everything else is ignored — we
+/// rebuild a fresh intent at pay time with the user-entered amount.
+class UpiQrData {
+  /// Payee VPA / UPI ID (the `pa` parameter). Always present.
+  final String vpa;
+
+  /// Payee display name (the `pn` parameter), if the QR provided one.
+  final String? name;
+
+  /// Pre-filled amount (the `am` parameter), if the QR provided one.
+  final double? amount;
+
+  const UpiQrData({required this.vpa, this.name, this.amount});
+
+  /// Parse a scanned string into [UpiQrData].
+  ///
+  /// Returns `null` when the string is not a usable UPI QR — i.e. it isn't a
+  /// `upi://` link or it lacks a payee address. Callers should treat `null`
+  /// as "not a UPI QR" and let the user rescan.
+  static UpiQrData? tryParse(String? raw) {
+    if (raw == null) return null;
+    final trimmed = raw.trim();
+    if (trimmed.isEmpty) return null;
+
+    final uri = Uri.tryParse(trimmed);
+    if (uri == null) return null;
+    if (uri.scheme.toLowerCase() != 'upi') return null;
+
+    final params = uri.queryParameters;
+    final pa = params['pa']?.trim();
+    if (pa == null || pa.isEmpty) return null;
+
+    final pn = params['pn']?.trim();
+
+    double? amount;
+    final am = params['am']?.trim();
+    if (am != null && am.isNotEmpty) {
+      final parsed = double.tryParse(am);
+      if (parsed != null && parsed > 0) amount = parsed;
+    }
+
+    return UpiQrData(
+      vpa: pa,
+      name: (pn != null && pn.isNotEmpty) ? pn : null,
+      amount: amount,
+    );
+  }
+}

lib/screens/home/components/home_app_bar.dart

@@ -5,6 +5,7 @@ import 'package:provider/provider.dart';
 import '../../../data/bloc/app_bloc.dart';
 import '../../settings/settings_screen.dart';
 import '../../transactions/transactions_screen.dart';
+import '../../upi/upi_scan_screen.dart';
 
 import '../../../theme.dart';
 
@@ -66,6 +67,16 @@ class HomeAppBar extends StatelessWidget implements PreferredSizeWidget {
         ),
       ),
       actions: [
+        // Scan UPI QR & Pay Button
+        IconButton(
+          onPressed: () => Navigator.push(
+            context,
+            MaterialPageRoute(builder: (context) => const UpiScanScreen()),
+          ),
+          icon: const Icon(Icons.qr_code_scanner_rounded),
+          color: AppTheme.primaryNavy,
+        ),
+
         // Transaction Button
         IconButton(
           onPressed: () => Navigator.push(

lib/screens/upi/components/category_chip.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+
+import '../../../theme.dart';
+
+/// A selectable, pill-shaped category chip shared by the payment screen and the
+/// category picker sheet.
+class CategoryChip extends StatelessWidget {
+  final String label;
+  final bool selected;
+  final VoidCallback onTap;
+
+  const CategoryChip({
+    super.key,
+    required this.label,
+    required this.selected,
+    required this.onTap,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return ChoiceChip(
+      label: Text(label),
+      selected: selected,
+      onSelected: (_) => onTap(),
+      showCheckmark: false,
+      backgroundColor: AppTheme.inputFill,
+      selectedColor: AppTheme.primaryNavy,
+      labelStyle: TextStyle(
+        color: selected ? AppTheme.textWhite : AppTheme.tagText,
+        fontWeight: FontWeight.w500,
+      ),
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(10),
+        side: BorderSide.none,
+      ),
+    );
+  }
+}

lib/screens/upi/components/category_picker_sheet.dart

@@ -0,0 +1,197 @@
+import 'package:flutter/material.dart';
+import 'package:google_fonts/google_fonts.dart';
+
+import '../../../data/command/commands.dart';
+import '../../../data/data/expense/expense.dart';
+import '../../../theme.dart';
+import 'category_chip.dart';
+
+/// Bottom sheet for picking an expense category.
+///
+/// Shows a search field, a "Most used" row (categories the user actually uses,
+/// ordered by frequency) and the full alphabetical list. Returns the chosen
+/// category string via [Navigator.pop].
+class CategoryPickerSheet extends StatefulWidget {
+  final String? selected;
+  const CategoryPickerSheet({super.key, this.selected});
+
+  /// Opens the sheet and resolves to the chosen category, or `null` if dismissed.
+  static Future<String?> show(BuildContext context, {String? selected}) {
+    return showModalBottomSheet<String>(
+      context: context,
+      isScrollControlled: true,
+      backgroundColor: AppTheme.cardBackground,
+      shape: const RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(24)),
+      ),
+      builder: (_) => CategoryPickerSheet(selected: selected),
+    );
+  }
+
+  @override
+  State<CategoryPickerSheet> createState() => _CategoryPickerSheetState();
+}
+
+class _CategoryPickerSheetState extends State<CategoryPickerSheet> {
+  final TextEditingController _search = TextEditingController();
+
+  // Sorted by usage (most-used first), then defaults alphabetically.
+  late final List<String> _all =
+      BaseAppCommand.blocExpense.getSuggestionsForType(
+    TransactionType.outgoing,
+  );
+  late final Set<String> _used =
+      BaseAppCommand.blocExpense.usedCategories.toSet();
+
+  String _query = '';
+
+  @override
+  void initState() {
+    super.initState();
+    _search.addListener(
+      () => setState(() => _query = _search.text.trim().toLowerCase()),
+    );
+  }
+
+  @override
+  void dispose() {
+    _search.dispose();
+    super.dispose();
+  }
+
+  List<String> get _mostUsed =>
+      _all.where(_used.contains).take(8).toList(growable: false);
+
+  List<String> get _filtered => _query.isEmpty
+      ? _all
+      : _all.where((c) => c.contains(_query)).toList(growable: false);
+
+  void _pick(String category) => Navigator.of(context).pop(category);
+
+  @override
+  Widget build(BuildContext context) {
+    final insets = MediaQuery.viewInsetsOf(context).bottom;
+    final mostUsed = _mostUsed;
+    final filtered = _filtered;
+
+    return Padding(
+      padding: EdgeInsets.only(bottom: insets),
+      child: DraggableScrollableSheet(
+        expand: false,
+        initialChildSize: 0.7,
+        maxChildSize: 0.92,
+        minChildSize: 0.5,
+        builder: (context, scrollController) {
+          return Column(
+            children: [
+              const SizedBox(height: 12),
+              Container(
+                width: 40,
+                height: 4,
+                decoration: BoxDecoration(
+                  color: AppTheme.dividerColor,
+                  borderRadius: BorderRadius.circular(2),
+                ),
+              ),
+              Padding(
+                padding: const EdgeInsets.fromLTRB(20, 16, 20, 8),
+                child: Row(
+                  children: [
+                    Text(
+                      'Select category',
+                      style: GoogleFonts.outfit(
+                        fontSize: 18,
+                        fontWeight: FontWeight.bold,
+                        color: AppTheme.primaryNavy,
+                      ),
+                    ),
+                  ],
+                ),
+              ),
+
+              // Search.
+              Padding(
+                padding: const EdgeInsets.symmetric(horizontal: 20),
+                child: TextField(
+                  controller: _search,
+                  autofocus: false,
+                  decoration: const InputDecoration(
+                    hintText: 'Search categories',
+                    prefixIcon: Icon(Icons.search_rounded),
+                  ),
+                ),
+              ),
+
+              Expanded(
+                child: ListView(
+                  controller: scrollController,
+                  padding: const EdgeInsets.fromLTRB(20, 16, 20, 24),
+                  children: [
+                    if (_query.isEmpty && mostUsed.isNotEmpty) ...[
+                      const _SectionLabel('Most used'),
+                      const SizedBox(height: 8),
+                      Wrap(
+                        spacing: 8,
+                        runSpacing: 8,
+                        children: [
+                          for (final c in mostUsed)
+                            CategoryChip(
+                              label: c,
+                              selected: c == widget.selected,
+                              onTap: () => _pick(c),
+                            ),
+                        ],
+                      ),
+                      const SizedBox(height: 20),
+                      const _SectionLabel('All categories'),
+                      const SizedBox(height: 8),
+                    ],
+                    Wrap(
+                      spacing: 8,
+                      runSpacing: 8,
+                      children: [
+                        for (final c in filtered)
+                          CategoryChip(
+                            label: c,
+                            selected: c == widget.selected,
+                            onTap: () => _pick(c),
+                          ),
+                      ],
+                    ),
+                    if (filtered.isEmpty)
+                      const Padding(
+                        padding: EdgeInsets.only(top: 24),
+                        child: Text(
+                          'No matching categories.',
+                          style: TextStyle(color: AppTheme.textSecondary),
+                        ),
+                      ),
+                  ],
+                ),
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+
+}
+
+/// Small muted section heading used inside the category sheet.
+class _SectionLabel extends StatelessWidget {
+  final String text;
+  const _SectionLabel(this.text);
+
+  @override
+  Widget build(BuildContext context) {
+    return Text(
+      text,
+      style: GoogleFonts.outfit(
+        fontSize: 13,
+        fontWeight: FontWeight.w600,
+        color: AppTheme.textSecondary,
+      ),
+    );
+  }
+}