Main.java

package com.example;

import java.sql.*;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.List;
import java.util.Scanner;

public class Main {

    private final Scanner scanner = new Scanner(System.in);
    private AccountRepository accountRepository;
    private MoonMissionRepository moonMissionRepository;
    private DataSource dataSource; /**
     * Starts the application: initializes a development database when dev mode is detected and runs the interactive Main flow.
     *
     * Uses system properties, environment variables, and command-line arguments to determine dev mode before constructing and running the Main instance.
     */

    public static void main(String[] args) {
        if (isDevMode(args)) {
            DevDatabaseInitializer.start();
        }
        new Main().run();
    }

    /**
     * Initializes application resources, verifies database configuration and connectivity, then starts the interactive login and main menu flow.
     *
     * <p>Specifically, this method resolves JDBC configuration, initializes the data source and repositories, tests a database connection, and proceeds to prompt for user login. If login succeeds it enters the main menu loop; otherwise it handles an invalid login. If required configuration is missing the method prints an error and exits early.</p>
     */
    public void run() {

        String JDBC_URL = resolveConfig("APP_JDBC_URL", "APP_JDBC_URL");
        String DB_USER = resolveConfig("APP_DB_USER", "APP_DB_USER");
        String DB_PASS = resolveConfig("APP_DB_PASS", "APP_DB_PASS");

        if (JDBC_URL == null || DB_USER == null || DB_PASS == null) {
            System.err.println("Database configuration environment variables not set.");
            return;
        }

        // --- Konfigurera Repository Pattern ---
        dataSource = new SimpleDriverManagerDataSource(JDBC_URL, DB_USER, DB_PASS);
        accountRepository = new JdbcAccountRepository(dataSource);
        moonMissionRepository = new JdbcMoonMissionRepository(dataSource);
        // --- Slut Konfiguration ---

        System.out.println("Application initialized.");

        try {
            // Vi använder dataSource.getConnection() här för att testa uppkopplingen
            // och bekräfta att den fungerar.
            try (Connection testConnection = dataSource.getConnection()) {
                System.out.println("Database connection established.");
            }

            if (login()) {
                mainMenu();
            } else {
                handleInvalidLogin();
            }
        } catch (SQLException e) {
            System.err.println("Database error: " + e.getMessage());
        }
        // Vi behöver inte stänga en global 'connection' längre,
        // eftersom varje Repository-metod hanterar sin egen Connection.
    }

    /**
     * Prompts the user for a username and password and authenticates them using the account repository.
     *
     * @return `true` if authentication succeeds, `false` otherwise.
     * @throws SQLException if a database access error occurs while validating credentials.
     */

    private boolean login() throws SQLException {
        System.out.print("Username: ");
        String username = scanner.nextLine();
        System.out.print("Password: ");
        String password = scanner.nextLine();

        // Använder AccountRepository
        return accountRepository.findByNameAndPassword(username, password);
    }


    /**
     * Shows an invalid-credentials message and waits for the user to confirm exit by entering "0".
     *
     * Prints a prompt and consumes input lines until the user types exactly "0".
     */
    private void handleInvalidLogin() {
        System.out.println("Invalid username or password. Press 0 to exit.");
        while (true) {
            System.out.print("Choice: ");
            String choice = scanner.nextLine().trim();
            if ("0".equals(choice)) {
                break;
            }
        }
    }

    /**
     * Present the interactive main menu, read user choices, and invoke the corresponding actions.
     *
     * Repeatedly displays the menu and processes selections until the user chooses 0 to exit.
     * Supported choices:
     * 1 — list moon missions; 2 — get moon mission by ID; 3 — count missions by year;
     * 4 — create an account; 5 — update an account password; 6 — delete an account.
     * Handles non-numeric input by prompting the user and reports database operation errors to stderr.
     */

    private void mainMenu() {
        // ... (mainMenu och printMenu förblir oförändrade, förutom anropen nedan) ...
        int choice = -1;
        while (choice != 0) {
            printMenu();
            try {
                System.out.print("Choice: ");
                choice = scanner.nextInt();
                scanner.nextLine();

                switch (choice) {
                    case 1:
                        listMoonMissions();
                        break;
                    case 2:
                        getMoonMissionById();
                        break;
                    case 3:
                        countMissionsByYear();
                        break;
                    case 4:
                        createAccount();
                        break;
                    case 5:
                        updateAccountPassword();
                        break;
                    case 6:
                        deleteAccount();
                        break;
                    case 0:
                        System.out.println("Exiting application.");
                        break;
                    default:
                        System.out.println("Invalid choice. Try again.");
                }
            } catch (InputMismatchException e) {
                System.out.println("Invalid input. Please enter a number.");
                scanner.nextLine();
            } catch (SQLException e) {
                System.err.println("Database operation failed: " + e.getMessage());
            }
        }
    }

    /**
     * Displays the main interactive menu options to the user.
     *
     * The menu lists available numeric commands used by the application's main loop.
     */
    private void printMenu() {
        System.out.println("\n--- Menu ---");
        System.out.println("1) List moon missions (spacecraft names)");
        System.out.println("2) Get a moon mission by mission_id (details)");
        System.out.println("3) Count missions for a given year");
        System.out.println("4) Create an account (first name, last name, ssn, password)");
        System.out.println("5) Update an account password (user_id, new password)");
        System.out.println("6) Delete an account (user_id)");
        System.out.println("0) Exit");
        System.out.println("------------");
    }


    /**
     * Prints the spacecraft names of all moon missions to standard output.
     *
     * Prints a header line ("--- Moon Missions ---") followed by each spacecraft name
     * on its own line, prefixed with " - ".
     *
     * @throws SQLException if a database access error occurs while retrieving missions
     */
    private void listMoonMissions() throws SQLException {
        // Använder MoonMissionRepository
        List<String> spacecrafts = moonMissionRepository.findAllSpacecraftNames();
        System.out.println("--- Moon Missions ---");
        for (String name : spacecrafts) {
            System.out.println(" - " + name);
        }
    }

    /**
     * Prompts the user for a mission ID and displays that mission's details if a record exists.
     *
     * If the entered mission ID is not a valid number, the method prints a warning and returns
     * without querying the database.
     *
     * @throws SQLException if a database access error occurs while retrieving the mission
     */
    private void getMoonMissionById() throws SQLException {
        System.out.print("Enter mission_id: ");
        long missionId;
        try {
            missionId = scanner.nextLong();
            scanner.nextLine();
        }catch (InputMismatchException e){
            System.out.println("Please enter a number");
            return;
        }

        try (Connection connection = dataSource.getConnection();
             ResultSet rs = moonMissionRepository.findMissionById(missionId, connection)) {

            if (rs.next()) {
                System.out.println("--- Mission Details (ID: " + missionId + ") ---");
                System.out.println("Spacecraft: " + rs.getString("spacecraft"));
                System.out.println("Launch Date: " + rs.getDate("launch_date"));
                System.out.println("Outcome: " + rs.getString("outcome"));
            } else {
                System.out.println("Mission with ID " + missionId + " not found.");
            }
        }
    }

    /**
     * Prompts for a year, queries the repository for the number of moon missions launched that year, and prints the result.
     *
     * @throws SQLException if a database error occurs while counting missions
     */
    private void countMissionsByYear() throws SQLException {
        System.out.print("Enter year: ");
        int year = scanner.nextInt();
        scanner.nextLine();

        // Använder MoonMissionRepository
        int count = moonMissionRepository.countMissionsByYear(year);
        System.out.println("Found " + count + " missions launched in " + year + ".");
    }

    /**
     * Creates a new account by prompting the user for first name, last name, SSN and password,
     * generates a username from up to the first three characters of the first and last names,
     * and persists the account via the AccountRepository.
     *
     * If the generated username is empty (both names empty) the method prints an error and returns
     * without creating an account.
     *
     * @throws SQLException if the repository fails to perform the database operation
     */
    private void createAccount() throws SQLException {
        System.out.print("Enter first name: ");
        String firstName = scanner.nextLine();
        System.out.print("Enter last name: ");
        String lastName = scanner.nextLine();
        System.out.print("Enter ssn: ");
        String ssn = scanner.nextLine();
        System.out.print("Enter password: ");
        String password = scanner.nextLine();

        String username = firstName.substring(0, Math.min(firstName.length(), 3))
                + lastName.substring(0, Math.min(lastName.length(), 3));

        if (username.isEmpty()) {
            System.out.println("Cannot create account: first name and last name cannot both be empty.");
            return;
            }

        // Använder AccountRepository
        int rowsAffected = accountRepository.create(firstName, lastName, ssn, password, username);

        if (rowsAffected > 0) {
            System.out.println("Account created successfully. Username is " + username + ".");
        } else {
            System.out.println("Failed to create account.");
        }
    }

    /**
     * Prompts for a user ID and a new password, updates that account's password, and reports success or absence.
     *
     * @throws SQLException if the database update fails
     */
    private void updateAccountPassword() throws SQLException {
        System.out.print("Enter user_id to update: ");
        long userId = scanner.nextLong();
        scanner.nextLine();
        System.out.print("Enter new password: ");
        String newPassword = scanner.nextLine();

        // Använder AccountRepository
        int rowsAffected = accountRepository.updatePassword(userId, newPassword);
        if (rowsAffected > 0) {
            System.out.println("Account password updated successfully for user_id " + userId + ".");
        } else {
            System.out.println("No account found with user_id " + userId + " to update.");
        }
    }

    /**
     * Prompts for a user ID, deletes the corresponding account via the account repository,
     * and prints whether the deletion succeeded or no matching account was found.
     *
     * @throws SQLException if a database access error occurs during the delete operation
     */
    private void deleteAccount() throws SQLException {
        System.out.print("Enter user_id to delete: ");
        long userId = scanner.nextLong();
        scanner.nextLine();

        // Använder AccountRepository
        int rowsAffected = accountRepository.delete(userId);

        if (rowsAffected > 0) {
            System.out.println("Account deleted successfully for user_id " + userId + ".");
        } else {
            System.out.println("No account found with user_id " + userId + " to delete.");
        }
    }


    /**
     * Detects whether the application should run in development mode.
     *
     * @param args the command-line arguments; the presence of the `--dev` flag enables dev mode
     * @return `true` if development mode is enabled via the `devMode` JVM system property (e.g. `-DdevMode=true`),
     *         the `DEV_MODE` environment variable (case-insensitive), or the `--dev` command-line flag;
     *         `false` otherwise
     */
    private static boolean isDevMode(String[] args) {
        if (Boolean.getBoolean("devMode"))  //Add VM option -DdevMode=true
            return true;
        if ("true".equalsIgnoreCase(System.getenv("DEV_MODE")))  //Environment variable DEV_MODE=true
            return true;
        return Arrays.asList(args).contains("--dev"); //Argument --dev
    }

    /**
     * Reads configuration with precedence: Java system property first, then environment variable.
     * Returns trimmed value or null if neither source provides a non-empty value.
     */
    private static String resolveConfig(String propertyKey, String envKey) {
        String v = System.getProperty(propertyKey);
        if (v == null || v.trim().isEmpty()) {
            v = System.getenv(envKey);
        }
        return (v == null || v.trim().isEmpty()) ? null : v.trim();
    }
}