Added Dao for User with SQLite

.gitignore

@@ -39,3 +39,4 @@ build/
 .DS_Store
 
 *.log
+*.db

pom.xml

@@ -33,12 +33,19 @@
             <scope>test</scope>
         </dependency>
 
+        <!-- Server -->
         <dependency>
             <groupId>org.xerial</groupId>
             <artifactId>sqlite-jdbc</artifactId>
             <version>3.51.3.0</version>
         </dependency>
 
+        <!-- Client -->
+        <dependency>
+            <groupId>com.googlecode.lanterna</groupId>
+            <artifactId>lanterna</artifactId>
+            <version>3.1.2</version>
+        </dependency>
     </dependencies>
 
 </project>

src/main/java/user/UserController.java

@@ -10,11 +10,17 @@ public class UserController {
         this.service = service;
     }
 
-    public Optional<User> loginIntoUser(
+    public Optional<User> createUser(
             String username,
             String password
     ) {
-        return service.loginIntoUser(username, password);
+        return service.createUser(username, password);
     }
 
+    public Optional<User> getUser(
+            String username,
+            String password
+    ) {
+        return service.getUser(username, password);
+    }
 }

src/main/java/user/UserDao.java

@@ -1,6 +1,103 @@
 package user;
 
+import java.sql.*;
+import java.util.Optional;
+
 public class UserDao {
 
+    public static final String DRIVER = "org.sqlite.JDBC";
+    public static final String DB_URL = "jdbc:sqlite:chat.db";
 
+    private Connection conn;
+    private Statement stat;
+
+    public UserDao() {
+        try {
+            conn = DriverManager.getConnection(DB_URL);
+            stat = conn.createStatement();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+
+        createTables();
+    }
+
+    public boolean createTables() {
+        String createUsers = "CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY AUTOINCREMENT, username VARCHAR(255) UNIQUE, password VARCHAR(255) )";
+        try {
+            stat.execute(createUsers);
+        } catch (SQLException e) {
+            e.printStackTrace();
+            return false;
+        }
+
+        return true;
+    }
+
+    public Boolean checkIfUsernameExists(String username) {
+        try {
+            PreparedStatement preparedStatement = conn.prepareStatement(
+                    "SELECT * FROM users WHERE username=(?);"
+            );
+
+            preparedStatement.setString(1, username);
+            ResultSet result = preparedStatement.executeQuery();
+
+            while (result.next()) {
+                return true;
+            }
+
+            return false;
+        } catch (SQLException e) {
+            e.printStackTrace();
+            return true;
+        }
+    }
+
+
+    public Optional<User> insertUser(String username, String password) {
+        try {
+            PreparedStatement preparedStatement = conn.prepareStatement(
+                    "INSERT INTO users VALUES (NULL, ?, ?);"
+            );
+
+            preparedStatement.setString(1, username);
+            preparedStatement.setString(2, password); // FIXME, later hash or smth..
+            preparedStatement.execute();
+
+            User user = new User(username);
+            return Optional.of(user);
+        } catch (SQLException e) {
+            e.printStackTrace();
+            return Optional.empty();
+        }
+    }
+
+    public Optional<User> getUser(String username, String password) {
+        try {
+            PreparedStatement preparedStatement = conn.prepareStatement(
+                    "SELECT * FROM users WHERE username=(?);"
+            );
+
+            preparedStatement.setString(1, username);
+            ResultSet result = preparedStatement.executeQuery();
+
+            // FIXME: Hasło tu też ogarnąć
+            String passwordFromDB;
+
+            while (result.next()) {
+                passwordFromDB = result.getString("password");
+
+                if (password.equals(passwordFromDB)) {
+                    return Optional.of(new User(username));
+                } else {
+                    return Optional.empty();
+                }
+            }
+            return Optional.empty();
+        } catch (SQLException e) {
+            e.printStackTrace();
+            return Optional.empty();
+        }
+    }
 }

src/main/java/user/UserService.java

@@ -14,12 +14,29 @@ public class UserService {
         this.userDao = userDao;
     }
 
-    public Optional<User> loginIntoUser(
+    public Optional<User> createUser(
             String username,
             String pass
     ) {
         try {
+
+            if (!userDao.checkIfUsernameExists(username)) {
+                return userDao.insertUser(username, pass);
+            }
+
             return Optional.empty();
+        } catch (Exception e) {
+            logger.error("Error creating user: {}", e.toString());
+            return Optional.empty();
+        }
+    }
+
+    public Optional<User> getUser(
+            String username,
+            String pass
+    ) {
+        try {
+            return userDao.getUser(username, pass);
         } catch (Exception e) {
             logger.error("Error while login into user: {}", e.toString());
             return Optional.empty();