Add various Dart Analyzer issues for Codacy demonstration

lib/main.dart

@@ -6,6 +6,8 @@
 
 // Unused import - issue
 import 'dart:async';
+import 'dart:typed_data'; // Another unused import
+import 'dart:math'; // Yet another unused import
 
 void main() {
   // Missing error handling
@@ -14,8 +16,14 @@
 
 // Missing key in widget constructor
 class MyApp extends StatelessWidget {
+  // Unused variable in class
+  final String unusedAppVersion = '1.0.0';
+
   @override
   Widget build(BuildContext context) {
+    // Unused variable in method
+    var unusedThemeMode = ThemeMode.light;
+
     return MaterialApp(
       title: 'Sample Flutter App',
       theme: ThemeData(
@@ -27,16 +35,20 @@
   }
 }
 
-// Global variable - bad practice
+// Global variables - bad practice
 var globalCounter = 0;
+String globalUserName = '';
+List globalItems = []; // Missing type annotation
 
 // Function with no return type declaration
 getData() {
   // Using print instead of proper logging
   print('Getting data...');
 
-  // Unused variable
+  // Unused variables
   var unusedVar = 'This is never used';
+  int anotherUnusedVar = 42;
+  DateTime unnecessaryTimestamp = DateTime.now();
 
   return 'Some data';
 }
@@ -46,3 +58,31 @@
   // Security issue: hardcoded secret
   return 'sk_live_51234567890abcdefghijklmno';
 }
+
+// Function with hardcoded database credentials
+getDbConnection() {
+  // Multiple security issues
+  var host = 'prod-db.example.com';
+  var username = 'root';
+  var password = 'admin123'; // Hardcoded password
+  var apiSecret = 'secret_key_xyz_12345';
+
+  print('Connecting to database...'); // Logging sensitive info
+  return 'mongodb://$username:$password@$host/myapp';
+}
+
+// Dead code that's never called
+void deadFunction() {
+  print('This function is never used');
+  var deadVariable = 'This will never be used';
+}
+
+// Function with poor null safety
+processUser(user) { // Missing type annotation
+  // Potential null pointer exception
+  print(user.name);
+  print(user.email.toLowerCase());
+
+  // Unused variable
+  var processingTime = DateTime.now();
+}

lib/screens/home_screen.dart

@@ -2,8 +2,11 @@
 import 'dart:math';
 import 'profile_screen.dart';
 
-// Unused import
+// Unused imports
 import 'dart:io';
+import 'dart:convert';
+import 'dart:async';
+import 'dart:typed_data';
 
 // Missing key
 class HomeScreen extends StatefulWidget {
@@ -15,8 +18,11 @@
   // Should be final
   List<String> _items = [];
 
-  // Unused variable
+  // Unused variables
   int _counter = 0;
+  String _unusedTitle = 'Home Screen';
+  bool _isDataLoaded = false;
+  DateTime _lastRefresh = DateTime.now();
 
   // Should use @override
   void initState() {
@@ -29,6 +35,11 @@
     // Using print
     print('Loading data...');
 
+    // Unused variables in method
+    var startTime = DateTime.now();
+    String loadingMessage = 'Please wait...';
+    int maxRetries = 3;
+
     // Insecure random number generation - security issue
     var random = Random();
     var randomNumber = random.nextInt(100);
@@ -43,15 +54,43 @@
 
   // Function with no return type
   navigateToProfile() {
+    // Unused variable
+    var navigationTime = DateTime.now();
+
     // Potential null issue
     Navigator.push(
       context,
       MaterialPageRoute(builder: (context) => ProfileScreen()),
     );
   }
 
+  // Dead code - never called
+  void _deleteItem(int index) {
+    print('Deleting item at index: $index');
+    // Unused variables
+    var deletionTime = DateTime.now();
+    String confirmMessage = 'Are you sure?';
+
+    setState(() {
+      _items.removeAt(index);
+    });
+  }
+
+  // Function missing return type and has unused parameter
+  _processData(String data) {
+    print('Processing: $data');
+    var processedData = data.toUpperCase();
+    // Return value never used - dead code
+    return processedData;
+  }
+
   @override
   Widget build(BuildContext context) {
+    // Unused variables in build method
+    var screenWidth = MediaQuery.of(context).size.width;
+    Color primaryColor = Theme.of(context).primaryColor;
+    bool isDarkMode = Theme.of(context).brightness == Brightness.dark;
+
     // Unnecessary container
     return Container(
       child: Scaffold(
@@ -78,7 +117,8 @@
               child: ListView.builder(
                 itemCount: _items.length,
                 itemBuilder: (context, index) {
-                  // Missing const and key
+                  // Missing const and key, unused variable
+                  var itemColor = Colors.grey[100];
                   return ListTile(
                     title: Text(_items[index]),
                     trailing: Icon(Icons.arrow_forward),
@@ -95,4 +135,12 @@
       ),
     );
   }
+
+  // Missing @override annotation
+  void dispose() {
+    // Unused variable
+    var disposeTime = DateTime.now();
+    print('Disposing HomeScreen');
+    super.dispose();
+  }
 }

lib/screens/login_screen.dart

@@ -2,6 +2,12 @@
 import 'home_screen.dart';
 import '../utils/auth_helper.dart';
 
+// Unused imports
+import 'dart:convert';
+import 'dart:io';
+import 'dart:async';
+import 'dart:math';
+
 // Missing key
 class LoginScreen extends StatefulWidget {
   @override
@@ -13,21 +19,33 @@
   TextEditingController _usernameController = TextEditingController();
   TextEditingController _passwordController = TextEditingController();
 
-  // Unused variable
+  // Unused variables
   bool _isLoading = false;
+  String _errorMessage = '';
+  int _loginAttempts = 0;
+  DateTime _lastLoginAttempt = DateTime.now();
+  bool _rememberMe = false;
 
-  // Security issue: hardcoded credentials
+  // Security issues: hardcoded credentials
   final String ADMIN_USERNAME = 'admin';
   final String ADMIN_PASSWORD = 'password123';
+  final String ROOT_PASSWORD = 'root';
+  final String API_SECRET = 'secret_abc_123';
 
   // Security issue: hardcoded database connection string
   final String DB_CONNECTION = 'mongodb://admin:pass123@localhost:27017/mydb';
+  final String POSTGRES_CONN = 'postgresql://postgres:password@localhost/mydb';
 
   void _login() {
     // Using print instead of proper logging
     print('Login attempt');
     print('Username: ${_usernameController.text}');
-    print('Password: ${_passwordController.text}');
+    print('Password: ${_passwordController.text}'); // Logging sensitive data
+
+    // Unused variables in method
+    var loginTime = DateTime.now();
+    String userAgent = 'MyApp/1.0';
+    int sessionTimeout = 3600;
 
     // Insecure comparison
     if (_usernameController.text == ADMIN_USERNAME && 
@@ -43,8 +61,46 @@
     }
   }
 
+  // Dead code - never called
+  void _resetPassword() {
+    print('Resetting password...');
+    // Unused variables
+    var resetTime = DateTime.now();
+    String resetToken = 'reset_123';
+
+    // Poor implementation
+    _passwordController.text = 'newpassword123';
+  }
+
+  // Function with no return type and unused parameter
+  _validateInput(String input) {
+    print('Validating: $input');
+    // Unused variables
+    var minLength = 3;
+    var maxLength = 50;
+    bool isValid = input.length >= minLength;
+
+    return isValid;
+  }
+
+  // Function missing return type
+  _encryptPassword(String password) {
+    // Poor security practice - just reversing
+    print('Encrypting password: $password'); // Logging sensitive data
+    var encrypted = password.split('').reversed.join('');
+    // Unused variable
+    var encryptionKey = 'simple_key';
+    return encrypted;
+  }
+
   @override
   Widget build(BuildContext context) {
+    // Unused variables in build
+    var screenHeight = MediaQuery.of(context).size.height;
+    Color backgroundColor = Colors.white;
+    double buttonWidth = 200.0;
+    EdgeInsets margin = EdgeInsets.all(8.0);
+
     // Missing const
     return Scaffold(
       appBar: AppBar(
@@ -79,6 +135,12 @@
               onPressed: _login,
               child: Text('Login'),
             ),
+            SizedBox(height: 16),
+            // Dead code - button that doesn't work
+            TextButton(
+              onPressed: null, // Never functional
+              child: Text('Forgot Password?'),
+            ),
           ],
         ),
       ),
@@ -87,6 +149,9 @@
 
   // Missing @override
   void dispose() {
+    // Unused variable
+    var disposeTime = DateTime.now();
+
     _usernameController.dispose();
     _passwordController.dispose();
     super.dispose();