EasyAuth/src/main/java/org/samo_lego/simpleauth/SimpleAuth.java

package org.samo_lego.simpleauth;

import com.google.gson.JsonObject;
import net.fabricmc.api.DedicatedServerModInitializer;
import net.fabricmc.fabric.api.event.player.*;
import net.fabricmc.fabric.api.event.server.ServerStopCallback;
import net.fabricmc.fabric.api.registry.CommandRegistry;
import net.fabricmc.loader.api.FabricLoader;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.server.MinecraftServer;
import net.minecraft.server.network.ServerPlayerEntity;
import net.minecraft.text.LiteralText;
import net.minecraft.text.Text;
import net.minecraft.world.dimension.DimensionType;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.iq80.leveldb.WriteBatch;
import org.samo_lego.simpleauth.commands.*;
import org.samo_lego.simpleauth.event.AuthEventHandler;
import org.samo_lego.simpleauth.event.entity.player.*;
import org.samo_lego.simpleauth.event.item.DropItemCallback;
import org.samo_lego.simpleauth.event.item.TakeItemCallback;
import org.samo_lego.simpleauth.storage.AuthConfig;
import org.samo_lego.simpleauth.storage.PlayerCache;
import org.samo_lego.simpleauth.storage.SimpleAuthDatabase;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Properties;
import java.util.Timer;
import java.util.TimerTask;

import static org.iq80.leveldb.impl.Iq80DBFactory.bytes;
import static org.samo_lego.simpleauth.utils.CarpetHelper.isPlayerCarpetFake;
import static org.samo_lego.simpleauth.utils.UuidConverter.convertUuid;

public class SimpleAuth implements DedicatedServerModInitializer {
	private static final Logger LOGGER = LogManager.getLogger();

    public static SimpleAuthDatabase db = new SimpleAuthDatabase();

    // HashMap of players that are not authenticated
	// Rather than storing all the authenticated players, we just store ones that are not authenticated
	// It stores some data as well, e.g. login tries and user password
	public static HashMap<String, PlayerCache> deauthenticatedUsers = new HashMap<>();

	// Boolean for easier checking if player is authenticated
	public static boolean isAuthenticated(ServerPlayerEntity player) {
		String uuid = convertUuid(player);
		return !deauthenticatedUsers.containsKey(uuid) || deauthenticatedUsers.get(uuid).wasAuthenticated;
	}

	// Getting game directory
	public static final File gameDirectory = FabricLoader.getInstance().getGameDirectory();

	// Server properties
	public static Properties serverProp = new Properties();

	// Mod config
	public static AuthConfig config;

	@Override
	public void onInitializeServer() {
		// Info I guess :D
		LOGGER.info("[SimpleAuth] SimpleAuth mod by samo_lego.");
		// The support on discord was great! I really appreciate your help.
		LOGGER.info("[SimpleAuth] This mod wouldn't exist without the awesome Fabric Community. TYSM guys!");

		// Creating data directory (database and config files are stored there)
		File file = new File(gameDirectory + "/mods/SimpleAuth/levelDBStore");
		if (!file.exists() && !file.mkdirs())
		    throw new RuntimeException("[SimpleAuth] Error creating directory!");
		// Loading config
		config = AuthConfig.load(new File(gameDirectory + "/mods/SimpleAuth/config.json"));
		// Connecting to db
		db.openConnection();

		try {
			serverProp.load(new FileReader(gameDirectory + "/server.properties"));
		} catch (IOException e) {
			LOGGER.error("[SimpleAuth] Error while reading server properties: " + e.getMessage());
		}


		// Registering the commands
		CommandRegistry.INSTANCE.register(false, dispatcher -> {
			RegisterCommand.registerCommand(dispatcher);
			LoginCommand.registerCommand(dispatcher);
			LogoutCommand.registerCommand(dispatcher);
			ChangepwCommand.registerCommand(dispatcher);
			UnregisterCommand.registerCommand(dispatcher);
			AuthCommand.registerCommand(dispatcher);
		});

		// Registering the events
		PrePlayerJoinCallback.EVENT.register(AuthEventHandler::checkCanPlayerJoinServer);
		PlayerJoinServerCallback.EVENT.register(AuthEventHandler::onPlayerJoin);
		PlayerLeaveServerCallback.EVENT.register(AuthEventHandler::onPlayerLeave);
		DropItemCallback.EVENT.register(AuthEventHandler::onDropItem);
		TakeItemCallback.EVENT.register(AuthEventHandler::onTakeItem);
		ChatCallback.EVENT.register(AuthEventHandler::onPlayerChat);
		PlayerMoveCallback.EVENT.register(AuthEventHandler::onPlayerMove);

		// From Fabric API
		AttackBlockCallback.EVENT.register((playerEntity, world, hand, blockPos, direction) -> AuthEventHandler.onAttackBlock(playerEntity));
        UseBlockCallback.EVENT.register((player, world, hand, blockHitResult) -> AuthEventHandler.onUseBlock(player));
        UseItemCallback.EVENT.register((player, world, hand) -> AuthEventHandler.onUseItem(player));
        AttackEntityCallback.EVENT.register((player, world, hand, entity, entityHitResult) -> AuthEventHandler.onAttackEntity(player));
		UseEntityCallback.EVENT.register((player, world, hand, entity, entityHitResult) -> AuthEventHandler.onUseEntity(player));
		ServerStopCallback.EVENT.register(minecraftServer -> SimpleAuth.onStopServer());
	}

	private static void onStopServer() {
		LOGGER.info("[SimpleAuth] Shutting down SimpleAuth.");

		WriteBatch batch = db.levelDBStore.createWriteBatch();
		// Writing coords of de-authenticated players to database
		deauthenticatedUsers.forEach((uuid, playerCache) -> {
			JsonObject data = new JsonObject();
			data.addProperty("password", playerCache.password);

			JsonObject lastLocation = new JsonObject();
			lastLocation.addProperty("dimId", playerCache.lastDimId);
			lastLocation.addProperty("x", playerCache.lastX);
			lastLocation.addProperty("y", playerCache.lastY);
			lastLocation.addProperty("z", playerCache.lastZ);

			data.addProperty("lastLocation", lastLocation.toString());

			batch.put(bytes("UUID:" + uuid), bytes("data:" + data.toString()));
		});
		try {
			// Writing and closing batch
			db.levelDBStore.write(batch);
			batch.close();
		} catch (IOException e) {
			LOGGER.error("[SimpleAuth] Error saving player data! " + e.getMessage());
		}

		// Closing DB connection
		db.close();
	}

	// Getting some config options
	private static Text notAuthenticated() {
		if(SimpleAuth.config.main.enableGlobalPassword) {
			return new LiteralText(SimpleAuth.config.lang.loginRequired);
		}
		return new LiteralText(SimpleAuth.config.lang.notAuthenticated);
	}

	// Authenticates player and sends the message
	public static void authenticatePlayer(ServerPlayerEntity player, Text msg) {
		// Teleporting player back
		if(config.main.spawnOnJoin)
			teleportPlayer(player, false);

		deauthenticatedUsers.remove(convertUuid(player));

		// Player no longer needs to be invisible and invulnerable
		player.setInvulnerable(false);
		player.setInvisible(false);
		player.sendMessage(msg, false);
	}

	// De-authenticates player
	public static void deauthenticatePlayer(ServerPlayerEntity player) {
		if(db.isClosed())
			return;

		// Marking player as not authenticated, (re)setting login tries to zero
		String uuid = convertUuid(player);
		SimpleAuth.deauthenticatedUsers.put(uuid, new PlayerCache(uuid, player));

		// Teleporting player to spawn to hide its position
		if(config.main.spawnOnJoin)
			teleportPlayer(player, true);

		// Player is now not authenticated
		player.sendMessage(notAuthenticated(), false);
		// Setting the player to be invisible to mobs and also invulnerable
		player.setInvulnerable(SimpleAuth.config.experimental.playerInvulnerable);
		player.setInvisible(SimpleAuth.config.experimental.playerInvisible);
		Timer timer = new Timer();
		timer.schedule(new TimerTask() {
			@Override
			public void run() {
				if(!SimpleAuth.isAuthenticated(player)) // Kicking player if not authenticated
					player.networkHandler.disconnect(new LiteralText(SimpleAuth.config.lang.timeExpired));
			}
		}, SimpleAuth.config.main.delay * 1000);
	}

	// Checking is player is a fake (carpetmod) player
	public static boolean isPlayerFake(PlayerEntity player) {
		// We ask CarpetHelper class since it has the imports needed
		return FabricLoader.getInstance().isModLoaded("carpet") && isPlayerCarpetFake(player);
	}

	// Teleports player to spawn or last location when authenticating
	public static void teleportPlayer(ServerPlayerEntity player, boolean toSpawn) {
		MinecraftServer server = player.getServer();
		if(server == null)
			return;
		if (toSpawn) {
			// Teleports player to spawn
			player.teleport(
					server.getWorld(DimensionType.byRawId(config.worldSpawn.dimensionId)),
					config.worldSpawn.x,
					config.worldSpawn.y,
					config.worldSpawn.z,
					0,
					0
			);
			return;
		}
		PlayerCache cache = deauthenticatedUsers.get(convertUuid(player));
		// Puts player to last cached position
		player.teleport(
				server.getWorld(DimensionType.byRawId(cache.lastDimId)),
				cache.lastX,
				cache.lastY,
				cache.lastZ,
				0,
				0
		);
	}
}