Restaurant Database Management System

.idea/.gitignore

@@ -0,0 +1,10 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Ignored default folder with query files
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/compiler.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="WS-10-Database" />
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>

.idea/encodings.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding">
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+  </component>
+</project>

.idea/jarRepositories.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://repo.maven.apache.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_25" default="true" project-jdk-name="25" project-jdk-type="JavaSDK" />
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

database.sql

@@ -1,141 +1,96 @@
 -- Restaurant Database Management System
 --
--- Instructions:
--- 1. Create all required tables.
--- 2. Design appropriate PRIMARY KEY and FOREIGN KEY relationships.
--- 3. Add suitable constraints based on the requirements.
--- 4. Insert initial mock data.
--- 5. Insert at least 3 menu items.
--- 6. The script should be executable from start to finish without errors.
+-- This script creates the whole schema from scratch and inserts some
+-- initial data. It can be run from start to finish without errors.
+--
+-- Run with:  psql -U postgres -d restaurant_db -f database.sql
 
 
+-- Drop old tables first so the script is re-runnable.
+-- Order matters because of the foreign keys (drop children before parents).
+DROP TABLE IF EXISTS order_details CASCADE;
+DROP TABLE IF EXISTS orders CASCADE;
+DROP TABLE IF EXISTS menu_items CASCADE;
+DROP TABLE IF EXISTS users CASCADE;
+
 
 -- =======================================================
 -- USER TABLE
 -- =======================================================
---
 -- Represents customers using the system.
---
--- Required information:
--- - Unique identifier
--- - Username
--- - Password
--- - Email (optional)
---
--- Requirements:
--- - Each user must have a unique identifier.
--- - Usernames must be unique.
--- - Username and password are required.
--- - Passwords should not be stored in plain text.
---
--- CREATE TABLE ...
-
+-- Passwords are stored as a hash (never plain text) by the Java app.
+CREATE TABLE users (
+    id       SERIAL       PRIMARY KEY,
+    username VARCHAR(50)  NOT NULL UNIQUE,
+    password VARCHAR(255) NOT NULL,          -- SHA-256 hex hash
+    email    VARCHAR(255)                    -- optional
+);
 
 
 -- =======================================================
 -- MENU ITEM TABLE
 -- =======================================================
---
 -- Represents available food and drink items.
---
--- Required information:
--- - Unique identifier
--- - Name
--- - Description (optional)
--- - Price
--- - Category (optional)
---
--- Requirements:
--- - Each menu item must have a unique identifier.
--- - Name is required.
--- - Price must always be positive.
---
--- CREATE TABLE ...
-
+CREATE TABLE menu_items (
+    id          SERIAL         PRIMARY KEY,
+    name        VARCHAR(100)   NOT NULL,
+    description TEXT,                                 -- optional
+    price       NUMERIC(10, 2) NOT NULL CHECK (price > 0),
+    category    VARCHAR(50)                           -- optional
+);
 
 
 -- =======================================================
--- ORDER TABLE
+-- ORDER TABLE  ("order" is a reserved word, so we use "orders")
 -- =======================================================
---
--- Represents orders placed by customers.
---
--- Required information:
--- - Unique identifier
--- - Reference to customer
--- - Creation date and time
--- - Total price
---
--- Requirements:
--- - Each order must belong to exactly one user.
--- - A user can have multiple orders.
--- - The relationship between User and Order must be implemented.
---
--- Note:
--- Avoid using reserved SQL keywords as table names.
--- Consider using a name such as "orders" or "customer_orders".
---
--- CREATE TABLE ...
-
+-- Each order belongs to exactly one user (One-to-Many: user -> orders).
+CREATE TABLE orders (
+    id          SERIAL         PRIMARY KEY,
+    user_id     INT            NOT NULL REFERENCES users(id),
+    created_at  TIMESTAMP      NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    total_price NUMERIC(10, 2) NOT NULL DEFAULT 0 CHECK (total_price >= 0)
+);
 
 
 -- =======================================================
 -- ORDER DETAIL TABLE
 -- =======================================================
---
--- Represents items inside an order.
---
--- Required information:
--- - Unique identifier
--- - Reference to an order
--- - Reference to a menu item
--- - Quantity
--- - Item price at purchase time
---
--- Requirements:
--- - Each detail record must belong to one order.
--- - Each detail record must reference one menu item.
--- - Quantity must always be greater than zero.
--- - Store the item's price at the moment of purchase.
---
--- CREATE TABLE ...
-
+-- One line inside an order (One-to-Many: order -> order_details).
+-- "price" is the item price at the moment of purchase, so history stays
+-- correct even if the menu price changes later.
+CREATE TABLE order_details (
+    id           SERIAL         PRIMARY KEY,
+    order_id     INT            NOT NULL REFERENCES orders(id) ON DELETE CASCADE,
+    menu_item_id INT            NOT NULL REFERENCES menu_items(id),
+    quantity     INT            NOT NULL CHECK (quantity > 0),
+    price        NUMERIC(10, 2) NOT NULL CHECK (price > 0)
+);
 
 
 -- =======================================================
--- INITIAL MENU DATA
+-- INITIAL MENU DATA (at least 3 items)
 -- =======================================================
---
--- Insert at least 3 food or drink items.
---
--- Example categories:
--- - Pizza
--- - Burger
--- - Pasta
--- - Drink
---
--- INSERT INTO ...
-
+INSERT INTO menu_items (name, description, price, category) VALUES
+    ('Margherita Pizza', 'Classic pizza with tomato, mozzarella and basil', 10.00, 'Pizza'),
+    ('Cheeseburger',     'Beef patty with cheddar, lettuce and tomato',     8.00,  'Burger'),
+    ('Pasta Bolognese',  'Spaghetti with rich beef and tomato sauce',       12.00, 'Pasta'),
+    ('Caesar Salad',     'Romaine, croutons, parmesan and Caesar dressing', 6.50,  'Salad'),
+    ('Coca-Cola',        'Chilled 330ml can',                               2.50,  'Drink');
 
 
 -- =======================================================
 -- OPTIONAL TEST DATA
 -- =======================================================
---
--- You may insert sample users and orders for testing.
--- This section is optional.
---
--- INSERT INTO ...
-
+-- Sample user. The password below is the SHA-256 hash of the text "1234"
+-- so you can log in with username "admin" / password "1234" for testing.
+INSERT INTO users (username, password, email) VALUES
+    ('admin', '03ac674216f3e15c761ee1a5e255f067953623c8b388b4459e13f978d7c846f4', 'admin@pizzeria.com');
 
 
 -- =======================================================
--- VERIFICATION QUERIES
+-- VERIFICATION QUERIES (optional, uncomment to check)
 -- =======================================================
---
--- Uncomment these queries to verify your database.
---
--- SELECT * FROM ...;
--- SELECT * FROM ...;
--- SELECT * FROM ...;
--- SELECT * FROM ...;
+-- SELECT * FROM users;
+-- SELECT * FROM menu_items;
+-- SELECT * FROM orders;
+-- SELECT * FROM order_details;

src/main/java/dev/dao/MenuItemDao.java

@@ -1,25 +1,69 @@
 package dev.dao;
 
+import dev.database.DatabaseConnection;
 import dev.model.MenuItem;
 
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
 import java.util.List;
 
 public class MenuItemDao {
 
     public List<MenuItem> findAll() {
 
-        // TODO:
-        // Retrieve all menu items
+        List<MenuItem> items = new ArrayList<>();
 
-        return null;
+        String sql = "SELECT id, name, description, price, category FROM menu_items ORDER BY id";
+
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql);
+             ResultSet rs = stmt.executeQuery()) {
+
+            while (rs.next()) {
+                items.add(mapRow(rs));
+            }
+
+        } catch (SQLException e) {
+            System.out.println("Error while loading menu: " + e.getMessage());
+        }
+
+        return items;
     }
 
     public MenuItem findById(int id) {
 
-        // TODO:
-        // Find menu item by id
+        String sql = "SELECT id, name, description, price, category FROM menu_items WHERE id = ?";
+
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setInt(1, id);
+
+            try (ResultSet rs = stmt.executeQuery()) {
+                if (rs.next()) {
+                    return mapRow(rs);
+                }
+            }
+
+        } catch (SQLException e) {
+            System.out.println("Error while finding menu item: " + e.getMessage());
+        }
 
         return null;
     }
 
-}
+    /** Turns the current row of a ResultSet into a MenuItem object. */
+    private MenuItem mapRow(ResultSet rs) throws SQLException {
+        return new MenuItem(
+                rs.getInt("id"),
+                rs.getString("name"),
+                rs.getString("description"),
+                rs.getDouble("price"),
+                rs.getString("category")
+        );
+    }
+
+}

src/main/java/dev/dao/OrderDao.java

@@ -1,25 +1,80 @@
 package dev.dao;
 
+import dev.database.DatabaseConnection;
 import dev.model.Order;
 
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Timestamp;
+import java.util.ArrayList;
 import java.util.List;
 
 public class OrderDao {
 
+    /**
+     * Inserts an order and returns the id the database generated for it.
+     * Returns -1 if something went wrong. We let the DB fill in created_at
+     * with its DEFAULT, and only send user_id and total_price.
+     */
     public int save(Order order) {
 
-        // TODO:
-        // Insert order and return generated id
+        String sql = "INSERT INTO orders (user_id, total_price) VALUES (?, ?)";
+
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt =
+                     conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
+
+            stmt.setInt(1, order.getUserId());
+            stmt.setDouble(2, order.getTotalPrice());
+
+            stmt.executeUpdate();
+
+            // Read back the auto-generated id (SERIAL primary key).
+            try (ResultSet keys = stmt.getGeneratedKeys()) {
+                if (keys.next()) {
+                    return keys.getInt(1);
+                }
+            }
+
+        } catch (SQLException e) {
+            System.out.println("Error while saving order: " + e.getMessage());
+        }
 
         return -1;
     }
 
     public List<Order> findByUserId(int userId) {
 
-        // TODO:
-        // Retrieve all orders of a user
+        List<Order> orders = new ArrayList<>();
 
-        return null;
+        String sql = "SELECT id, user_id, created_at, total_price " +
+                "FROM orders WHERE user_id = ? ORDER BY created_at DESC";
+
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setInt(1, userId);
+
+            try (ResultSet rs = stmt.executeQuery()) {
+                while (rs.next()) {
+                    Timestamp ts = rs.getTimestamp("created_at");
+                    orders.add(new Order(
+                            rs.getInt("id"),
+                            rs.getInt("user_id"),
+                            ts.toLocalDateTime(),
+                            rs.getDouble("total_price")
+                    ));
+                }
+            }
+
+        } catch (SQLException e) {
+            System.out.println("Error while loading orders: " + e.getMessage());
+        }
+
+        return orders;
     }
 
-}
+}

src/main/java/dev/dao/OrderDetailDao.java

@@ -1,24 +1,66 @@
 package dev.dao;
 
+import dev.database.DatabaseConnection;
 import dev.model.OrderDetail;
 
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
 import java.util.List;
 
 public class OrderDetailDao {
 
     public void save(OrderDetail detail) {
 
-        // TODO:
-        // Insert order detail
+        String sql = "INSERT INTO order_details (order_id, menu_item_id, quantity, price) " +
+                "VALUES (?, ?, ?, ?)";
 
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setInt(1, detail.getOrderId());
+            stmt.setInt(2, detail.getMenuItemId());
+            stmt.setInt(3, detail.getQuantity());
+            stmt.setDouble(4, detail.getPrice());
+
+            stmt.executeUpdate();
+
+        } catch (SQLException e) {
+            System.out.println("Error while saving order detail: " + e.getMessage());
+        }
     }
 
     public List<OrderDetail> findByOrderId(int orderId) {
 
-        // TODO:
-        // Retrieve order details
+        List<OrderDetail> details = new ArrayList<>();
 
-        return null;
+        String sql = "SELECT id, order_id, menu_item_id, quantity, price " +
+                "FROM order_details WHERE order_id = ? ORDER BY id";
+
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setInt(1, orderId);
+
+            try (ResultSet rs = stmt.executeQuery()) {
+                while (rs.next()) {
+                    details.add(new OrderDetail(
+                            rs.getInt("id"),
+                            rs.getInt("order_id"),
+                            rs.getInt("menu_item_id"),
+                            rs.getInt("quantity"),
+                            rs.getDouble("price")
+                    ));
+                }
+            }
+
+        } catch (SQLException e) {
+            System.out.println("Error while loading order details: " + e.getMessage());
+        }
+
+        return details;
     }
 
-}
+}

src/main/java/dev/dao/UserDao.java

@@ -1,23 +1,68 @@
 package dev.dao;
 
+import dev.database.DatabaseConnection;
 import dev.model.User;
 
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
 public class UserDao {
 
+    /**
+     * Inserts a new user. The password passed in here is expected to already
+     * be hashed by the service layer. Returns true if the insert worked.
+     */
     public boolean save(User user) {
 
-        // TODO:
-        // Insert user into database
+        String sql = "INSERT INTO users (username, password, email) VALUES (?, ?, ?)";
 
-        return false;
+        // try-with-resources closes the connection and statement automatically.
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setString(1, user.getUsername());
+            stmt.setString(2, user.getPassword());
+            stmt.setString(3, user.getEmail());
+
+            int rows = stmt.executeUpdate();
+            return rows > 0;
+
+        } catch (SQLException e) {
+            System.out.println("Error while saving user: " + e.getMessage());
+            return false;
+        }
     }
 
+    /**
+     * Looks up a user by username. Returns null if nobody matches.
+     */
     public User findByUsername(String username) {
 
-        // TODO:
-        // Find a user by username
+        String sql = "SELECT id, username, password, email FROM users WHERE username = ?";
+
+        try (Connection conn = DatabaseConnection.getConnection();
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setString(1, username);
+
+            try (ResultSet rs = stmt.executeQuery()) {
+                if (rs.next()) {
+                    return new User(
+                            rs.getInt("id"),
+                            rs.getString("username"),
+                            rs.getString("password"),
+                            rs.getString("email")
+                    );
+                }
+            }
+
+        } catch (SQLException e) {
+            System.out.println("Error while finding user: " + e.getMessage());
+        }
 
         return null;
     }
 
-}
+}

src/main/java/dev/database/DatabaseConnection.java

@@ -1,8 +1,13 @@
 package dev.database;
 
 import java.sql.Connection;
+import java.sql.DriverManager;
 import java.sql.SQLException;
 
+/**
+ * Small helper that hands out PostgreSQL connections.
+ * Every DAO calls getConnection() when it needs to talk to the database.
+ */
 public class DatabaseConnection {
 
     private static final String URL = "jdbc:postgresql://localhost:5432/restaurant_db"; // DB Server
@@ -18,10 +23,10 @@ public class DatabaseConnection {
     public static Connection getConnection()
             throws SQLException {
 
-        // TODO:
-        // Return a valid PostgreSQL connection
-
-        return null;
+        // DriverManager opens a fresh TCP connection to PostgreSQL using the
+        // JDBC URL and credentials above. The postgresql driver on the
+        // classpath registers itself automatically, so no Class.forName needed.
+        return DriverManager.getConnection(URL, USER, PASSWORD);
     }
 
-}
+}

src/main/java/dev/model/MenuItem.java

@@ -12,4 +12,55 @@ public class MenuItem {
 
     private String category;
 
-}
+    public MenuItem() {
+    }
+
+    public MenuItem(int id, String name, String description, double price, String category) {
+        this.id = id;
+        this.name = name;
+        this.description = description;
+        this.price = price;
+        this.category = category;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public String getCategory() {
+        return category;
+    }
+
+    public void setCategory(String category) {
+        this.category = category;
+    }
+
+}

src/main/java/dev/model/Order.java

@@ -12,4 +12,46 @@ public class Order {
 
     private double totalPrice;
 
-}
+    public Order() {
+    }
+
+    public Order(int id, int userId, LocalDateTime createdAt, double totalPrice) {
+        this.id = id;
+        this.userId = userId;
+        this.createdAt = createdAt;
+        this.totalPrice = totalPrice;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public int getUserId() {
+        return userId;
+    }
+
+    public void setUserId(int userId) {
+        this.userId = userId;
+    }
+
+    public LocalDateTime getCreatedAt() {
+        return createdAt;
+    }
+
+    public void setCreatedAt(LocalDateTime createdAt) {
+        this.createdAt = createdAt;
+    }
+
+    public double getTotalPrice() {
+        return totalPrice;
+    }
+
+    public void setTotalPrice(double totalPrice) {
+        this.totalPrice = totalPrice;
+    }
+
+}

src/main/java/dev/model/OrderDetail.java

@@ -12,4 +12,60 @@ public class OrderDetail {
 
     private double price;
 
-}
+    public OrderDetail() {
+    }
+
+    public OrderDetail(int id, int orderId, int menuItemId, int quantity, double price) {
+        this.id = id;
+        this.orderId = orderId;
+        this.menuItemId = menuItemId;
+        this.quantity = quantity;
+        this.price = price;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public int getOrderId() {
+        return orderId;
+    }
+
+    public void setOrderId(int orderId) {
+        this.orderId = orderId;
+    }
+
+    public int getMenuItemId() {
+        return menuItemId;
+    }
+
+    public void setMenuItemId(int menuItemId) {
+        this.menuItemId = menuItemId;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(int quantity) {
+        this.quantity = quantity;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    /** Convenience: price for this line = unit price * quantity. */
+    public double getSubtotal() {
+        return price * quantity;
+    }
+
+}

src/main/java/dev/model/User.java

@@ -10,4 +10,46 @@ public class User {
 
     private String email;
 
+    public User() {
+    }
+
+    public User(int id, String username, String password, String email) {
+        this.id = id;
+        this.username = username;
+        this.password = password;
+        this.email = email;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
 }

src/main/java/dev/service/AuthService.java

@@ -1,23 +1,79 @@
 package dev.service;
 
+import dev.dao.UserDao;
 import dev.model.User;
 
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
 public class AuthService {
 
+    private final UserDao userDao = new UserDao();
+
+    /**
+     * Registers a new user. Checks the username is free and that the fields
+     * are not empty, then stores the password as a SHA-256 hash.
+     * Returns true only if the account was actually created.
+     */
     public boolean register(String username, String password, String email) {
 
-        // TODO:
-        // Validate and register user
+        if (username == null || username.isBlank()
+                || password == null || password.isBlank()) {
+            System.out.println("Username and password are required.");
+            return false;
+        }
 
-        return false;
+        // Username must be unique.
+        if (userDao.findByUsername(username) != null) {
+            System.out.println("That username is already taken.");
+            return false;
+        }
+
+        User user = new User();
+        user.setUsername(username);
+        user.setPassword(hash(password));      // never store plain text
+        user.setEmail(email == null || email.isBlank() ? null : email);
+
+        return userDao.save(user);
     }
 
+    /**
+     * Checks the given credentials against the database.
+     * Returns the User on success, or null if the username does not exist
+     * or the password is wrong.
+     */
     public User login(String username, String password) {
 
-        // TODO:
-        // Authenticate user
+        User user = userDao.findByUsername(username);
+        if (user == null) {
+            return null;   // no such username
+        }
 
-        return null;
+        // Hash the entered password and compare with the stored hash.
+        if (user.getPassword().equals(hash(password))) {
+            return user;
+        }
+
+        return null;       // wrong password
     }
 
-}
+    /** Hashes text with SHA-256 and returns it as a lowercase hex string. */
+    private String hash(String text) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            byte[] bytes = digest.digest(text.getBytes(StandardCharsets.UTF_8));
+
+            StringBuilder sb = new StringBuilder();
+            for (byte b : bytes) {
+                sb.append(String.format("%02x", b));
+            }
+            return sb.toString();
+
+        } catch (NoSuchAlgorithmException e) {
+            // SHA-256 is always available, so this should never happen.
+            throw new RuntimeException("SHA-256 not available", e);
+        }
+    }
+
+}

src/main/java/dev/service/MenuService.java

@@ -1,12 +1,40 @@
 package dev.service;
 
+import dev.dao.MenuItemDao;
+import dev.model.MenuItem;
+
+import java.util.List;
+
 public class MenuService {
 
-    public void showMenu() {
-
-        // TODO:
-        // Display menu items
+    private final MenuItemDao menuItemDao = new MenuItemDao();
 
+    /** Loads every menu item so other parts of the app can use them. */
+    public List<MenuItem> getMenu() {
+        return menuItemDao.findAll();
     }
 
-}
+    /** Prints the whole menu to the console in a simple table. */
+    public void showMenu() {
+
+        List<MenuItem> items = menuItemDao.findAll();
+
+        if (items.isEmpty()) {
+            System.out.println("The menu is empty.");
+            return;
+        }
+
+        System.out.println("---------------------------------------------");
+        System.out.printf("%-4s %-20s %-10s %-10s%n", "ID", "Name", "Price", "Category");
+        System.out.println("---------------------------------------------");
+
+        for (MenuItem item : items) {
+            String category = item.getCategory() == null ? "-" : item.getCategory();
+            System.out.printf("%-4d %-20s $%-9.2f %-10s%n",
+                    item.getId(), item.getName(), item.getPrice(), category);
+        }
+
+        System.out.println("---------------------------------------------");
+    }
+
+}

src/main/java/dev/service/OrderService.java

@@ -1,26 +1,168 @@
 package dev.service;
 
+import dev.dao.MenuItemDao;
+import dev.dao.OrderDao;
+import dev.dao.OrderDetailDao;
+import dev.model.MenuItem;
+import dev.model.Order;
+import dev.model.OrderDetail;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
 public class OrderService {
 
+    private final MenuItemDao menuItemDao = new MenuItemDao();
+    private final OrderDao orderDao = new OrderDao();
+    private final OrderDetailDao orderDetailDao = new OrderDetailDao();
+
+    private final Scanner scanner;
+
+    /** The Scanner is shared with the console UI so input stays consistent. */
+    public OrderService(Scanner scanner) {
+        this.scanner = scanner;
+    }
+
+    /**
+     * Lets the logged-in user build an order item by item, then stores the
+     * Order and its OrderDetail rows in the database and prints a receipt.
+     */
     public void placeOrder(int userId) {
 
-        // TODO:
-        // Create order
+        List<MenuItem> menu = menuItemDao.findAll();
+        if (menu.isEmpty()) {
+            System.out.println("Sorry, there is nothing on the menu right now.");
+            return;
+        }
 
+        System.out.println("\nAvailable Items:");
+        for (MenuItem item : menu) {
+            System.out.printf("%d. %s - $%.2f%n", item.getId(), item.getName(), item.getPrice());
+        }
+
+        // The "cart": order lines the user has chosen so far.
+        List<OrderDetail> cart = new ArrayList<>();
+
+        while (true) {
+            System.out.print("\nEnter the ID of the item to add (or 0 to finish): ");
+            int itemId = readInt();
+
+            if (itemId == 0) {
+                break;
+            }
+
+            MenuItem item = menuItemDao.findById(itemId);
+            if (item == null) {
+                System.out.println("No item with that ID. Try again.");
+                continue;
+            }
+
+            System.out.print("Enter quantity: ");
+            int quantity = readInt();
+            if (quantity <= 0) {
+                System.out.println("Quantity must be at least 1.");
+                continue;
+            }
+
+            // Store the current price so the receipt stays correct later.
+            OrderDetail line = new OrderDetail();
+            line.setMenuItemId(item.getId());
+            line.setQuantity(quantity);
+            line.setPrice(item.getPrice());
+            cart.add(line);
+
+            System.out.printf("Added %dx %s to your cart.%n", quantity, item.getName());
+        }
+
+        if (cart.isEmpty()) {
+            System.out.println("Your cart is empty, order cancelled.");
+            return;
+        }
+
+        // Work out the grand total.
+        double total = 0;
+        for (OrderDetail line : cart) {
+            total += line.getSubtotal();
+        }
+
+        // Save the order first so we get its generated id.
+        Order order = new Order();
+        order.setUserId(userId);
+        order.setTotalPrice(total);
+
+        int orderId = orderDao.save(order);
+        if (orderId == -1) {
+            System.out.println("Could not save the order. Please try again.");
+            return;
+        }
+
+        // Now save each line with the order id we just got back.
+        for (OrderDetail line : cart) {
+            line.setOrderId(orderId);
+            orderDetailDao.save(line);
+        }
+
+        printReceipt(orderId);
+        System.out.println("Order saved successfully!");
     }
 
+    /**
+     * Reads an order back from the database and prints a detailed receipt:
+     * item names, quantities, unit prices, subtotals and the grand total.
+     */
     public void printReceipt(int orderId) {
 
-        // TODO:
-        // Print order receipt
+        List<OrderDetail> details = orderDetailDao.findByOrderId(orderId);
+        if (details.isEmpty()) {
+            System.out.println("No details found for order #" + orderId);
+            return;
+        }
 
+        System.out.println("\n[Order Summary / Receipt]");
+        System.out.println("---------------------------------------------");
+        System.out.printf("%-18s %-6s %-9s %-9s%n", "Item", "Qty", "Unit", "Total");
+        System.out.println("---------------------------------------------");
+
+        double grandTotal = 0;
+        for (OrderDetail line : details) {
+            MenuItem item = menuItemDao.findById(line.getMenuItemId());
+            String name = (item == null) ? "(removed item)" : item.getName();
+
+            System.out.printf("%-18s %-6d $%-8.2f $%-8.2f%n",
+                    name, line.getQuantity(), line.getPrice(), line.getSubtotal());
+
+            grandTotal += line.getSubtotal();
+        }
+
+        System.out.println("---------------------------------------------");
+        System.out.printf("Final Total: $%.2f%n", grandTotal);
     }
 
+    /** Shows every past order of a user together with what each one cost. */
     public void showOrderHistory(int userId) {
 
-        // TODO:
-        // Display user's order history
+        List<Order> orders = orderDao.findByUserId(userId);
 
+        if (orders.isEmpty()) {
+            System.out.println("You have not placed any orders yet.");
+            return;
+        }
+
+        System.out.println("\n===== ORDER HISTORY =====");
+        for (Order order : orders) {
+            System.out.printf("Order #%d  |  %s  |  Total: $%.2f%n",
+                    order.getId(), order.getCreatedAt(), order.getTotalPrice());
+        }
     }
 
-}
+    /** Reads an int safely so bad input does not crash the program. */
+    private int readInt() {
+        while (!scanner.hasNextInt()) {
+            System.out.print("Please enter a number: ");
+            scanner.next();  // throw away the bad token
+        }
+        return scanner.nextInt();
+    }
+
+}

src/main/java/dev/ui/ConsoleMenu.java

@@ -1,5 +1,10 @@
 package dev.ui;
 
+import dev.model.User;
+import dev.service.AuthService;
+import dev.service.MenuService;
+import dev.service.OrderService;
+
 import java.util.Scanner;
 
 public class ConsoleMenu {
@@ -7,8 +12,16 @@ public class ConsoleMenu {
     private final Scanner scanner =
             new Scanner(System.in);
 
+    private final AuthService authService = new AuthService();
+    private final MenuService menuService = new MenuService();
+    private final OrderService orderService = new OrderService(scanner);
+
     public void start() {
 
+        System.out.println("=======================================");
+        System.out.println("      🍕 WELCOME TO JAVA PIZZERIA 🍕");
+        System.out.println("=======================================");
+
         while (true) {
 
             System.out.println();
@@ -16,20 +29,22 @@ public class ConsoleMenu {
             System.out.println("1. Login");
             System.out.println("2. Register");
             System.out.println("3. Exit");
+            System.out.print("Choose an option: ");
 
-            int choice = scanner.nextInt();
+            int choice = readInt();
 
             switch (choice) {
 
                 case 1:
-                    // TODO
+                    handleLogin();
                     break;
 
                 case 2:
-                    // TODO
+                    handleRegister();
                     break;
 
                 case 3:
+                    System.out.println("Goodbye!");
                     return;
 
                 default:
@@ -41,4 +56,95 @@ public class ConsoleMenu {
 
     }
 
-}
+    private void handleLogin() {
+
+        System.out.print("Enter username: ");
+        String username = scanner.next();
+        System.out.print("Enter password: ");
+        String password = scanner.next();
+
+        User user = authService.login(username, password);
+
+        if (user == null) {
+            System.out.println("Login failed: wrong username or password.");
+            return;
+        }
+
+        System.out.println("Welcome back, " + user.getUsername() + "!");
+        showMainMenu(user);
+    }
+
+    private void handleRegister() {
+
+        System.out.print("Choose a username: ");
+        String username = scanner.next();
+        System.out.print("Choose a password: ");
+        String password = scanner.next();
+        System.out.print("Email (optional, or '-' to skip): ");
+        String email = scanner.next();
+        if (email.equals("-")) {
+            email = null;
+        }
+
+        boolean ok = authService.register(username, password, email);
+        if (ok) {
+            System.out.println("Account created! You can log in now.");
+        } else {
+            System.out.println("Registration failed. Please try again.");
+        }
+    }
+
+    /** The menu shown after a successful login. */
+    private void showMainMenu(User user) {
+
+        while (true) {
+
+            System.out.println();
+            System.out.println("=======================================");
+            System.out.println("          🍽️ MAIN MENU 🍽️");
+            System.out.println("=======================================");
+            System.out.println("1. View Menu");
+            System.out.println("2. Place a New Order");
+            System.out.println("3. View Order History");
+            System.out.println("4. Logout");
+            System.out.print("Choose an option: ");
+
+            int choice = readInt();
+
+            switch (choice) {
+
+                case 1:
+                    menuService.showMenu();
+                    break;
+
+                case 2:
+                    orderService.placeOrder(user.getId());
+                    break;
+
+                case 3:
+                    orderService.showOrderHistory(user.getId());
+                    break;
+
+                case 4:
+                    System.out.println("Logged out.");
+                    return;
+
+                default:
+                    System.out.println("Invalid choice");
+
+            }
+
+        }
+
+    }
+
+    /** Reads an int without crashing on bad input. */
+    private int readInt() {
+        while (!scanner.hasNextInt()) {
+            System.out.print("Please enter a number: ");
+            scanner.next();
+        }
+        return scanner.nextInt();
+    }
+
+}