package envoy.client.ui;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import javafx.scene.image.Image;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;

import envoy.client.data.*;
import envoy.client.net.Client;
import envoy.client.net.WriteProxy;
import envoy.data.Message;
import envoy.data.User;
import envoy.data.User.UserStatus;
import envoy.exception.EnvoyException;
import envoy.util.EnvoyLog;

/**
 * Project: <strong>envoy-client</strong><br>
 * File: <strong>Startup.java</strong><br>
 * Created: <strong>26.03.2020</strong><br>
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Client v0.1-beta
 */
public final class Startup extends Application {

	private LocalDB			localDB;
	private Client			client;
	private WriteProxy		writeProxy;
	private Cache<Message>	cache;

	private FXMLLoader	loader	= new FXMLLoader();
	private Stage		stage;
	private Scene		previousScene;

	private final String[] CSSPaths = { "file://./src/main/resources/fxml/themes/base.css",
			"file://./src/main/resources/fxml/themes/" + (settings.isUsingDefaultTheme() ? settings.getCurrentThemeName() : "custom") + ".css" };

	private static final Settings		settings	= Settings.getInstance();
	private static final ClientConfig	config		= ClientConfig.getInstance();
	private static final Logger			logger		= EnvoyLog.getLogger(Startup.class);

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void start(Stage stage) throws Exception {
		this.stage = stage;
		try {
			// Load the configuration from client.properties first
			Properties properties = new Properties();
			properties.load(Startup.class.getClassLoader().getResourceAsStream("client.properties"));
			config.load(properties);

			// Override configuration values with command line arguments
			String[] args = getParameters().getRaw().toArray(new String[0]);
			if (args.length > 0) config.load(args);

			// Check if all mandatory configuration values have been initialized
			if (!config.isInitialized()) throw new EnvoyException("Configuration is not fully initialized");
		} catch (Exception e) {
			new Alert(AlertType.ERROR, "Error loading configuration values:\n" + e);
			e.printStackTrace();
			System.exit(1);
		}

		// Setup logger for the envoy package
		EnvoyLog.initialize(config);
		EnvoyLog.attach("envoy");
		EnvoyLog.setFileLevelBarrier(config.getFileLevelBarrier());
		EnvoyLog.setConsoleLevelBarrier(config.getConsoleLevelBarrier());

		// Initialize the local database
		if (config.isIgnoreLocalDB()) {
			localDB = new TransientLocalDB();
			new Alert(AlertType.WARNING, "Ignoring local database.\nMessages will not be saved!").showAndWait();
		} else try {
			localDB = new PersistentLocalDB(new File(config.getHomeDirectory(), config.getLocalDB().getPath()));
		} catch (IOException e3) {
			logger.log(Level.SEVERE, "Could not initialize local database", e3);
			new Alert(AlertType.ERROR, "Could not initialize local database!\n" + e3).showAndWait();
			System.exit(1);
			return;
		}

		// Initialize client and unread message cache
		client	= new Client();
		cache	= new Cache<>();

		// Try to connect to the server
		new LoginDialog(client, localDB, cache).showAndWait();

		// Set client user in local database
		localDB.setUser(client.getSender());

		// Initialize chats in local database
		try {
			localDB.initializeUserStorage();
			localDB.loadUserData();
		} catch (FileNotFoundException e) {
			// The local database file has not yet been created, probably first login
		} catch (Exception e) {
			e.printStackTrace();
			new Alert(AlertType.ERROR, "Error while loading local database: " + e + "\nChats will not be stored locally.").showAndWait();
		}

		// Initialize write proxy
		writeProxy = client.createWriteProxy(localDB);

		if (client.isOnline()) {

			// Save all users to the local database and flush cache
			localDB.setUsers(client.getUsers());
			writeProxy.flushCache();
		} else
			// Set all contacts to offline mode
			localDB.getUsers()
				.values()
				.stream()
				.filter(u -> u instanceof User && u != localDB.getUser())
				.map(User.class::cast)
				.forEach(u -> u.setStatus(UserStatus.OFFLINE));

		// Prepare stage and load ChatScene
		changeScene("/fxml/ChatScene.fxml", new GridPane(), false);
		Platform.runLater(() -> { ((ChatSceneController) loader.getController()).initializeData(this, localDB, client, writeProxy); });
		stage.setTitle("Envoy");
		stage.getIcons().add(new Image(getClass().getResourceAsStream("/icons/envoy_logo.png")));

		stage.show();

		// Relay unread messages from cache
		if (cache != null && client.isOnline()) cache.relay();
	}

	/**
	 * Changes the scene of the stage.
	 *
	 * @param <T>          the type of the layout to use
	 * @param fxmlLocation the location of the fxml file
	 * @param layout       the layout to use
	 * @param savePrevious if true, the previous stage will be stored in this
	 *                     instance of Startup, else the variable storing it will
	 *                     be
	 *                     set to null
	 * @since Envoy Client v0.1-beta
	 */
	public <T extends Pane> void changeScene(String fxmlLocation, T layout, boolean savePrevious) {
		Platform.runLater(() -> {
			try {
				// Clearing the loader so that a new Scene can be initialised
				loader = new FXMLLoader();
				var	rootNode	= loader.<T>load(getClass().getResourceAsStream(fxmlLocation));
				var	scene		= new Scene(rootNode);
				previousScene = savePrevious ? stage.getScene() : null;
				// Setting the visual appearance
				scene.getStylesheets().addAll(CSSPaths);
				System.out.println(Paths.get(".").toAbsolutePath().normalize().toString());
				stage.setScene(scene);
				stage.show();
				// return loader.getController();
			} catch (IOException e) {
				new Alert(AlertType.ERROR, "The screen could not be updated due to reasons. (...bad programming...)");
				System.err.println("input: FXMLLocation: " + fxmlLocation + ", CSS paths: " + CSSPaths);
				e.printStackTrace();
				logger.severe("Something happened (while loading the new scene from " + fxmlLocation + ")");
			}
		});
	}

	/**
	 * Changes the visual scene back to the saved value. The currently active scene
	 * can be saved, but must not be.
	 *
	 * @param storeCurrent the old scene to store, if wanted. Can be null
	 * @since Envoy Client v0.1-beta
	 */
	public void restoreScene(boolean storeCurrent) {
		Platform.runLater(() -> {
			if (previousScene == null) throw new IllegalStateException("Someone tried restoring a null scene. (Something happened)");
			else {
				// switching previous and current
				var temp = storeCurrent ? stage.getScene() : null;
				stage.setScene(previousScene);
				previousScene = temp;
				stage.show();
			}
		});
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void stop() throws Exception {
		try {

			// Save Settings and PersistentLocalDB on shutdown
			logger.info("Closing connection...");
			client.close();

			logger.info("Saving local database and settings...");
			localDB.save();
			Settings.getInstance().save();
		} catch (Exception e) {
			logger.log(Level.SEVERE, "Unable to save local files", e);
		}
	}

	@SuppressWarnings("javadoc")
	public static void main(String[] args) { launch(args); }

	/**
	 * @return the controller of the current scene or a {@link NullPointerException}
	 *         if there is none
	 * @since Envoy Client v0.1-beta
	 */
	public Object getCurrentController() {
		if (loader.getController() == null) throw new NullPointerException("Cannot deliver current controller as its undefined (duh!)");
		else return loader.getController();
	}

	/**
	 * @return the CSSPaths
	 * @since Envoy Client v0.1-beta
	 */
	public String[] getCSSPaths() { return CSSPaths; }

	/**
	 * Changes the currently displayed theme
	 *
	 * @since Envoy Client v0.1-beta
	 */
	public void changeTheme() {
		// the base.css file should never be changed during runtime
		CSSPaths[1] = "file://.fxml/themes/" + (settings.isUsingDefaultTheme() ? settings.getCurrentThemeName() : "custom") + ".css";
		var styleSheets = stage.getScene().getStylesheets();
		styleSheets.remove(styleSheets.size() - 1);
		styleSheets.add(CSSPaths[1]);
	}
}