Fixed structure of UI, Added some logic to Auth

src/main/java/repository/UserRepository.java

@@ -6,6 +6,7 @@ import java.util.Optional;
 
 public interface UserRepository {
     Optional<User> getUser(String username, String password);
+    Boolean userExists(String username);
     Optional<User> saveUser(String username, String email, String password);
     boolean deleteUser(int userId);
 }

src/main/java/repository/UserRepositoryJdbc.java

@@ -27,6 +27,9 @@ public class UserRepositoryJdbc implements UserRepository {
 
             preparedStatement.setString(1, username);
             ResultSet resultSet = preparedStatement.executeQuery();
+            if (!resultSet.next()) {
+                return Optional.empty();
+            }
 
             String passwordFromDB = resultSet.getString("password");
             String emailFromDB = resultSet.getString("email");
@@ -43,6 +46,28 @@ public class UserRepositoryJdbc implements UserRepository {
         }
     }
 
+    @Override
+    public Boolean userExists(String username) {
+        try {
+            PreparedStatement preparedStatement = connection.prepareStatement(
+                    "SELECT * FROM users WHERE name=(?);"
+            );
+
+            preparedStatement.setString(1, username);
+            ResultSet resultSet = preparedStatement.executeQuery();
+
+            if (resultSet.next()) {
+                return true;
+            }
+
+            return false;
+        } catch (SQLException e) {
+            e.printStackTrace();
+            return false;
+        }
+    }
+
+
     @Override
     public Optional<User> saveUser(String username, String email, String password) {
         try {

src/main/java/service/UserService.java

@@ -15,10 +15,7 @@ public class UserService {
 
     public Optional<User> login(String username, String password) {
         try {
-
+            return userRepository.getUser(username, password);
-
-
-            return Optional.empty();
         } catch (Exception e) {
             System.out.println(e.getMessage());
             return Optional.empty();
@@ -27,6 +24,10 @@ public class UserService {
 
     public Optional<User> register(String username, String email, String password) {
         try {
+            if (userRepository.userExists(username)) {
+                return Optional.empty();
+            }
+
             return userRepository.saveUser(username, email, password);
         } catch (Exception e) {
             e.printStackTrace();

src/main/java/ui/AuthPanel.java

@@ -0,0 +1,28 @@
+package ui;
+
+import javax.swing.*;
+import java.awt.*;
+import java.util.function.Consumer;
+
+public class AuthPanel extends BasePanel {
+
+    public AuthPanel(Consumer<String> changePanel) {
+        super(changePanel);
+
+        // Login
+        JButton loginButton = new JButton("Login");
+        loginButton.addActionListener(e -> {
+            changePanel.accept("login");
+        });
+
+        // Registry
+        JButton registryButton = new JButton("Registry");
+        registryButton.addActionListener(e -> {
+            changePanel.accept("registry");
+        });
+
+
+        add(loginButton);
+        add(registryButton);
+    }
+}

src/main/java/ui/BasePanel.java

@@ -0,0 +1,13 @@
+package ui;
+
+import javax.swing.*;
+import java.util.function.Consumer;
+
+public abstract class BasePanel extends JPanel {
+    protected Consumer<String> changePanel;
+
+    public BasePanel(Consumer<String> changePanel) {
+        this.changePanel = changePanel;
+    }
+}
+

src/main/java/ui/HomePanel.java

@@ -0,0 +1,30 @@
+package ui;
+
+import models.User;
+import util.Session;
+
+import javax.swing.*;
+import java.util.function.Consumer;
+
+public class HomePanel extends BasePanel {
+
+    public HomePanel(Consumer<String> changePanel) {
+        super(changePanel);
+
+        User user = Session.getInstance().getUser();
+        if (user == null) {
+            // Log, user is not logged.
+            changePanel.accept("auth");
+        }
+
+
+        JButton logoutButton = new JButton("Logout");
+        logoutButton.addActionListener(e -> {
+            Session.getInstance().logout();
+            changePanel.accept("auth");
+        });
+
+        add(logoutButton);
+    }
+
+}

src/main/java/ui/LoginPanel.java

@@ -8,17 +8,18 @@ import util.Session;
 import javax.swing.*;
 import java.awt.*;
 import java.util.Optional;
+import java.util.function.Consumer;
 
-public class LoginPanel {
+public class LoginPanel extends BasePanel {
 
-    public static JPanel getLoginPanel(){
+    public LoginPanel(Consumer<String> changePanel) {
-        JPanel panel = new JPanel();
+        super(changePanel);
 
         JTextField username = new JTextField("Login");
         JPasswordField password = new JPasswordField("Password");
 
-        panel.add(username, BorderLayout.NORTH);
+        add(username, BorderLayout.NORTH);
-        panel.add(password, BorderLayout.CENTER);
+        add(password, BorderLayout.CENTER);
 
         JButton loginButton = new JButton("Login");
         loginButton.addActionListener(e -> {
@@ -32,18 +33,22 @@ public class LoginPanel {
                 Optional<User> user = service.login(usernameText, passwordText);
                 if (user.isPresent()) {
                     Session.getInstance().setUser(user.get());
+                    changePanel.accept("home");
                 } else {
-                    JOptionPane.showMessageDialog(panel, "User not found");
+                    JOptionPane.showMessageDialog(this, "User not found");
                 }
 
             } catch (Exception ex) {
-                JOptionPane.showMessageDialog(panel, "Error");
+                ex.printStackTrace();
+                JOptionPane.showMessageDialog(this, ex.getMessage());
             }
-
         });
+        add(loginButton, BorderLayout.SOUTH);
 
-        panel.add(loginButton, BorderLayout.SOUTH);
+        JButton returnButton = new JButton("Return");
-
+        returnButton.addActionListener(e -> {
-        return panel;
+            changePanel.accept("auth");
+        });
+        add(returnButton, BorderLayout.EAST);
     }
 }

src/main/java/ui/MyFrame.java

@@ -7,9 +7,18 @@ public class MyFrame extends JFrame {
     JPanel mainPanel = new JPanel(new CardLayout());
 
     public void changePanel(String panel) {
-
+        CardLayout cardLayout = (CardLayout) mainPanel.getLayout();
+        cardLayout.show(mainPanel, panel);
     }
 
+    public void init(JPanel mainPanel) {
+        mainPanel.add(new AuthPanel(this::changePanel), "auth");
+        mainPanel.add(new LoginPanel(this::changePanel), "login");
+        mainPanel.add(new RegistryPanel(this::changePanel), "registry");
+        mainPanel.add(new HomePanel(this::changePanel), "home");
+    }
+
+
     public MyFrame() {
         super("Todo App");
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
@@ -17,26 +26,7 @@ public class MyFrame extends JFrame {
         setLocation(50, 50);
         setLayout(new CardLayout());
 
-        JPanel startPanel = new JPanel();
+        init(mainPanel);
-        JButton loginButton = new JButton("Login");
-        JButton registryButton = new JButton("Registry");
-
-        startPanel.add(loginButton);
-        startPanel.add(registryButton);
-        mainPanel.add(startPanel, "start");
-        mainPanel.add(LoginPanel.getLoginPanel(), "login");
-        mainPanel.add(RegistryPanel.getRegistryPanel(), "registry");
-
-        loginButton.addActionListener(e -> {
-            CardLayout cl = (CardLayout)mainPanel.getLayout();
-            cl.show(mainPanel, "login");
-        });
-
-        registryButton.addActionListener(e -> {
-            CardLayout cl = (CardLayout)mainPanel.getLayout();
-            cl.show(mainPanel, "registry");
-        });
-
         add(mainPanel);
         setVisible(true);
     }

src/main/java/ui/RegistryPanel.java

@@ -8,22 +8,23 @@ import util.Session;
 import javax.swing.*;
 import java.awt.*;
 import java.util.Optional;
+import java.util.function.Consumer;
 
-public class RegistryPanel {
+public class RegistryPanel extends BasePanel {
 
-    public static JPanel getRegistryPanel(){
+    public RegistryPanel(Consumer<String> changePanel){
-        JPanel panel = new JPanel();
+        super(changePanel);
 
         JTextField username = new JTextField("Login");
         JTextField email = new JTextField("email@email.com");
         JPasswordField password = new JPasswordField("Password");
 
-        panel.add(username, BorderLayout.NORTH);
+        add(username, BorderLayout.NORTH);
-        panel.add(email, BorderLayout.NORTH);
+        add(email, BorderLayout.NORTH);
-        panel.add(password, BorderLayout.CENTER);
+        add(password, BorderLayout.CENTER);
 
-        JButton loginButton = new JButton("Registry");
+        JButton registryButton = new JButton("Registry");
-        loginButton.addActionListener(e -> {
+        registryButton.addActionListener(e -> {
             try {
                 String usernameText = username.getText();
                 String emailText = email.getText();
@@ -35,21 +36,24 @@ public class RegistryPanel {
                 Optional<User> user = service.register(usernameText, emailText, passwordText);
                 if (user.isPresent()) {
                     Session.getInstance().setUser(user.get());
+                    changePanel.accept("home");
                 } else {
-                    JOptionPane.showMessageDialog(panel, "User not found");
+                    JOptionPane.showMessageDialog(this, "User not found");
                 }
 
             } catch (Exception ex) {
-                JOptionPane.showMessageDialog(panel, "Error");
+                ex.printStackTrace();
+                JOptionPane.showMessageDialog(this, ex.getMessage());
             }
-
         });
+        add(registryButton, BorderLayout.SOUTH);
 
-        panel.add(loginButton, BorderLayout.SOUTH);
+        JButton returnButton = new JButton("Return");
-
+        returnButton.addActionListener(e -> {
-        return panel;
+            changePanel.accept("auth");
+        });
+        add(returnButton, BorderLayout.SOUTH);
     }
-
-
-
 }
+
+