usability fixes

lib/screens/history/history_screen.dart

@@ -1,6 +1,8 @@
 import 'package:flutter/material.dart';
 import 'package:go_router/go_router.dart';
+import 'package:intl/intl.dart';
 import 'package:provider/provider.dart';
+import 'package:qpay/auth_state.dart';
 import 'package:qpay/models/responsive_policy.dart';
 import 'package:qpay/screens/receipt/receipt_controller.dart';
 import 'package:qpay/screens/transaction_controller.dart';
@@ -251,6 +253,142 @@ class _HistoryScreenState extends State<HistoryScreen>
     );
   }
 
+  /// Shows the report download bottom sheet with start/end date pickers.
+  void _showReportSheet() {
+    DateTime selectedStart = DateTime.now().subtract(const Duration(days: 7));
+    DateTime selectedEnd = DateTime.now();
+
+    showModalBottomSheet(
+      context: context,
+      isScrollControlled: true,
+      shape: const RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
+      ),
+      builder: (ctx) {
+        return StatefulBuilder(
+          builder: (context, setSheetState) {
+            return Padding(
+              padding: EdgeInsets.only(
+                left: 20,
+                right: 20,
+                top: 20,
+                bottom: MediaQuery.of(context).viewInsets.bottom + 20,
+              ),
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: [
+                  const Text(
+                    'Download Report',
+                    style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600),
+                  ),
+                  const SizedBox(height: 20),
+                  _buildDateField(
+                    label: 'Start Date',
+                    date: selectedStart,
+                    onTap: () async {
+                      final picked = await showDatePicker(
+                        context: context,
+                        initialDate: selectedStart,
+                        firstDate: DateTime(2020),
+                        lastDate: selectedEnd,
+                      );
+                      if (picked != null) {
+                        setSheetState(() => selectedStart = picked);
+                      }
+                    },
+                  ),
+                  const SizedBox(height: 16),
+                  _buildDateField(
+                    label: 'End Date',
+                    date: selectedEnd,
+                    onTap: () async {
+                      final picked = await showDatePicker(
+                        context: context,
+                        initialDate: selectedEnd,
+                        firstDate: selectedStart,
+                        lastDate: DateTime.now(),
+                      );
+                      if (picked != null) {
+                        setSheetState(() => selectedEnd = picked);
+                      }
+                    },
+                  ),
+                  const SizedBox(height: 24),
+                  SizedBox(
+                    width: double.infinity,
+                    child: ElevatedButton.icon(
+                      icon: controller.model.isActing
+                          ? const SizedBox(
+                              width: 18,
+                              height: 18,
+                              child: CircularProgressIndicator(
+                                strokeWidth: 2,
+                                color: Colors.white,
+                              ),
+                            )
+                          : const Icon(Icons.download),
+                      label: Text(
+                        controller.model.isActing
+                            ? 'Downloading…'
+                            : 'Download Report',
+                      ),
+                      onPressed: controller.model.isActing
+                          ? null
+                          : () {
+                              Navigator.of(ctx).pop();
+                              final workspaceId =
+                                  prefs.getString("workspaceId") ?? '';
+                              controller.downloadReport(
+                                workspaceId: workspaceId,
+                                startDate: selectedStart,
+                                endDate: selectedEnd,
+                              );
+                            },
+                    ),
+                  ),
+                  const SizedBox(height: 8),
+                ],
+              ),
+            );
+          },
+        );
+      },
+    );
+  }
+
+  /// Builds a tappable date field for the report sheet.
+  Widget _buildDateField({
+    required String label,
+    required DateTime date,
+    required VoidCallback onTap,
+  }) {
+    final df = DateFormat('dd MMM yyyy');
+    return InkWell(
+      onTap: onTap,
+      borderRadius: BorderRadius.circular(12),
+      child: Container(
+        width: double.infinity,
+        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
+        decoration: BoxDecoration(
+          color: Colors.grey.shade100,
+          borderRadius: BorderRadius.circular(12),
+        ),
+        child: Row(
+          children: [
+            Expanded(
+              child: Text(
+                '$label: ${df.format(date)}',
+                style: const TextStyle(fontSize: 15),
+              ),
+            ),
+            Icon(Icons.calendar_today, size: 20, color: Colors.grey.shade600),
+          ],
+        ),
+      ),
+    );
+  }
+
   @override
   void dispose() {
     _searchController.dispose();
@@ -396,6 +534,15 @@ class _HistoryScreenState extends State<HistoryScreen>
           },
         ),
         const SizedBox(width: 8),
+        // Report download — only visible to logged-in users.
+        if (authState.isLoggedIn)
+          _buildIconButton(
+            icon: Icons.description_outlined,
+            tooltip: 'Download report',
+            isActive: false,
+            onPressed: _showReportSheet,
+          ),
+        const SizedBox(width: 8),
         _buildIconButton(
           icon: Icons.add,
           tooltip: 'New payment',
@@ -679,4 +826,4 @@ class _HistoryScreenState extends State<HistoryScreen>
       ),
     );
   }
-}
+}