INSServer/frontend/utils/WebApp.java

package ins.frontend.utils;

import dev.unlegitdqrk.unlegitlibrary.file.ConfigurationManager;
import org.openautonomousconnection.webserver.utils.PasswordHasher;
import org.openautonomousconnection.webserver.utils.Pbkdf2Sha256Hasher;

import java.io.File;
import java.io.IOException;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Objects;

/**
 * Application singleton holding DAO + password hasher.
 */
public final class WebApp {

    private static volatile WebApp INSTANCE;
    private static boolean isInit;
    private static UserDao.DataSourceProvider dsp = null;
    private final UserDao userDao;
    private final RegistrarDao registrarDao;
    private final PasswordHasher passwordHasher;

    private WebApp(UserDao userDao, RegistrarDao registrarDao, PasswordHasher passwordHasher) {
        this.userDao = Objects.requireNonNull(userDao, "userDao");
        this.registrarDao = Objects.requireNonNull(registrarDao, "registrarDao");
        this.passwordHasher = Objects.requireNonNull(passwordHasher, "passwordHasher");
    }

    /**
     * Initializes the singleton (call once at server startup).
     */
    public static void init() {
        if (isInit) return;

        try {
            if (!new File(new File(".").getParent(), "db.properties").exists()) {
                new File(new File(".").getParent(), "db.properties").createNewFile();
            }

            ConfigurationManager config = new ConfigurationManager(new File(new File(".").getParent(), "db.properties"));
            config.loadProperties();

            if (!config.isSet("db.url")) {
                config.set(
                        "db.url",
                        "jdbc:mariadb://localhost:3306/ins?useUnicode=true&characterEncoding=utf8"
                );
                config.saveProperties();
            }

            if (!config.isSet("db.user")) {
                config.set("db.user", "username");
                config.saveProperties();
            }

            if (!config.isSet("db.password")) {
                config.set("db.password", "password");
                config.saveProperties();
            }

            dsp = () -> {
                try {
                    isInit = true;

                    return DriverManager.getConnection(config.getString("db.url"), config.getString("db.user"), config.getString("db.password"));
                } catch (SQLException e) {
                    throw new SQLException("Failed to open DB connection", e);
                }
            };
        } catch (IOException e) {
            throw new RuntimeException("Failed to create config", e);
        }
        UserDao udao = new UserDao(dsp);
        RegistrarDao rdao = new RegistrarDao(dsp);
        PasswordHasher hasher = new Pbkdf2Sha256Hasher(150_000, 16, 32);

        INSTANCE = new WebApp(udao, rdao, hasher);
    }

    /**
     * Returns the initialized instance.
     *
     * @return app
     */
    public static WebApp get() {
        WebApp v = INSTANCE;
        if (v == null) throw new IllegalStateException("Oac2WebApp not initialized. Call Oac2WebApp.init(...) first.");
        return v;
    }

    /**
     * @return user DAO
     */
    public UserDao users() {
        return userDao;
    }

    /**
     * @return registrar DAO
     */
    public RegistrarDao dao() {
        return registrarDao;
    }

    /**
     * @return password hasher
     */
    public PasswordHasher passwordHasher() {
        return passwordHasher;
    }
}