x-control-panel/app/src/main/java/ru/kirillius/XCP/Application.java

package ru.kirillius.XCP;

import lombok.Getter;
import ru.kirillius.XCP.Commons.Config;
import ru.kirillius.XCP.Commons.ConfigManager;
import ru.kirillius.XCP.Commons.Context;
import ru.kirillius.XCP.Commons.Service;
import ru.kirillius.XCP.Logging.Logger;
import ru.kirillius.XCP.Logging.LoggingSystem;
import ru.kirillius.XCP.Logging.LoggingSystemImpl;
import ru.kirillius.XCP.Persistence.RepositoryServiceImpl;
import ru.kirillius.XCP.Security.ConfigManagerImpl;
import ru.kirillius.XCP.Security.SecurityManager;
import ru.kirillius.XCP.Security.SecurityManagerImpl;
import ru.kirillius.XCP.Services.ServiceLoadPriority;
import ru.kirillius.XCP.Services.WebService;
import ru.kirillius.XCP.web.WebServiceImpl;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

@Getter
public class Application implements Context {
    @Getter
    private final SecurityManager securityManager;
    @Getter
    private final LoggingSystem loggingSystem;
    private final Logger log;
    @Getter
    private final List<String> launchArgs;
    @Getter
    private final Config config;
    @Getter
    private final ConfigManager configManager;
    private final Map<Class<? extends Service>, Service> services = new ConcurrentHashMap<>();

    private Config loadConfig() {
        var configFile = configManager.getConfigFile().getAbsolutePath();

        try {
            configFile = configManager.getConfigFile().getCanonicalPath();
        } catch (IOException e) {
            log.warning("Unable to determine real path of file " + configFile);
        }

        Config config;
        if (configManager.isExist()) {
            try {
                config = configManager.load();
                log.info("Loaded config file: " + configFile);
            } catch (IOException e) {
                log.error("Error loading config file " + configFile, e);
                throw new RuntimeException(e);
            }
        } else {
            log.warning("Unable to find config file " + configFile + ". Using default values.");
            config = configManager.create();
            log.info("Saving default config file to " + configFile);
            try {
                configManager.save(config);
            } catch (IOException e) {
                throw new RuntimeException("Unable to save config file", e);
            }
        }
        return config;
    }

    public Application(String[] args) {
        launchArgs = Arrays.stream(args).toList();
        loggingSystem = new LoggingSystemImpl(this);
        log = loggingSystem.createLogger(Application.class);
        configManager = new ConfigManagerImpl(this);
        config = loadConfig();

        securityManager = new SecurityManagerImpl();
        try {
            loadServices();
        } catch (Throwable throwable) {
            log.error(throwable);
            shutdown();
            throw new RuntimeException("Error loading services");
        }
        Runtime.getRuntime().addShutdownHook(new Thread(this::shutdown));

        ((WebServiceImpl) getService(WebService.class)).join();
    }

    private void loadServices() {
        var servicesToLoad = List.of(RepositoryServiceImpl.class, WebServiceImpl.class);

        servicesToLoad.stream().sorted(Comparator.comparingInt(aClass -> {
            var order = aClass.getAnnotation(ServiceLoadPriority.class);
            return order == null ? 100000 : order.value();
        })).forEach(aClass -> {
            @SuppressWarnings("unchecked") var facade = (Class<? extends Service>) Arrays.stream(aClass.getInterfaces())
                    .filter(Service.class::isAssignableFrom)
                    .findFirst().
                    orElseThrow(() -> new ClassCastException("Unable to get service interface from class " + aClass.getSimpleName()));
            log.info("Loading service " + facade.getSimpleName());
            try {
                var constructor = aClass.getConstructor();
                try {
                    var service = constructor.newInstance();
                    try {
                        service.initialize(this);

                        services.put(facade, service);
                    } catch (Throwable e) {
                        try {
                            service.close();
                        } catch (IOException ex) {
                            e.addSuppressed(ex);
                        }
                        throw new RuntimeException("Failed to start " + facade.getSimpleName(), e);
                    }
                } catch (InstantiationException | IllegalAccessException | InvocationTargetException e) {
                    throw new RuntimeException("Failed to instantiate " + facade.getSimpleName(), e);
                }

            } catch (NoSuchMethodException e) {
                throw new RuntimeException("Failed to find default constructor of " + facade.getSimpleName(), e);
            }
        });
    }

    @SuppressWarnings("unchecked")
    @Override
    public <S extends Service> S getService(Class<S> serviceClass) {
        return (S) services.get(serviceClass);
    }

    @Override
    public void shutdown() {
        try {
            services.forEach((serviceClass, service) -> {
                try {
                    log.info("Shutting down service " + serviceClass.getSimpleName());
                    service.close();
                } catch (IOException e) {
                    log.error("Error shutting down service " + serviceClass.getSimpleName(), e);
                }
            });
            loggingSystem.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public boolean isDebuggingEnabled() {
        return launchArgs.contains("--debug");
    }

    public static void main(String[] args) {
        try {
            new Application(args);
        } catch (Throwable e) {
            System.err.println("Error starting application");
            e.printStackTrace(System.err);
            System.exit(1);
        }
    }

}