Created the UserManager.java

src/main/java/de/gnmyt/mcdash/api/UserManager.java

@@ -0,0 +1,109 @@
+package de.gnmyt.mcdash.api;
+
+import at.favre.lib.crypto.bcrypt.BCrypt;
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+import de.gnmyt.mcdash.MCDashWrapper;
+import de.gnmyt.mcdash.entities.User;
+import org.apache.commons.io.FileUtils;
+
+import java.io.File;
+import java.util.ArrayList;
+
+public class UserManager {
+
+    private static final Logger LOG = new Logger(UserManager.class);
+    private static final File USERS_FILE = MCDashWrapper.getDataSource("users.json");
+
+    private ArrayList<User> users = new ArrayList<>();
+    private final Gson gson = new Gson();
+
+    public UserManager() {
+        if (!USERS_FILE.exists()) {
+            try {
+                USERS_FILE.createNewFile();
+                FileUtils.writeStringToFile(USERS_FILE, "[]", "UTF-8");
+            } catch (Exception e) {
+                LOG.error("An error occurred while creating the users file: {}", e.getMessage());
+            }
+        }
+
+        readUsers();
+    }
+
+    /**
+     * Checks if the server is in setup mode
+     *
+     * @return <code>true</code> if the server is in setup mode
+     */
+    public boolean isSetupMode() {
+        return users.isEmpty();
+    }
+
+    /**
+     * Adds a new user to the user list
+     *
+     * @param username The username of the user
+     * @param password The password of the user. It will be hashed with BCrypt
+     */
+    public void addUser(String username, String password) {
+        users.add(new User(username, BCrypt.withDefaults().hashToString(12, password.toCharArray())));
+        saveUsers();
+    }
+
+    /**
+     * Removes a user from the user list
+     *
+     * @param username The username of the user
+     */
+    public void removeUser(String username) {
+        users.removeIf(user -> user.getUsername().equals(username));
+        saveUsers();
+    }
+
+    /**
+     * Checks if a user exists
+     *
+     * @param username The username of the user
+     * @return <code>true</code> if the user exists
+     */
+    public boolean userExists(String username) {
+        return users.stream().anyMatch(user -> user.getUsername().equals(username));
+    }
+
+    /**
+     * Checks if the password of a user is correct
+     *
+     * @param username The username of the user
+     * @param password The password of the user
+     * @return <code>true</code> if the password is correct
+     */
+    public boolean isPasswordCorrect(String username, String password) {
+        return users.stream().anyMatch(user -> user.getUsername().equals(username) && BCrypt.verifyer().verify(password.toCharArray(), user.getPassword()).verified);
+    }
+
+    /**
+     * Reads the users from the users file
+     */
+    public void readUsers() {
+        try {
+            String json = FileUtils.readFileToString(USERS_FILE, "UTF-8");
+            users = gson.fromJson(json, new TypeToken<ArrayList<User>>() {
+            }.getType());
+        } catch (Exception e) {
+            LOG.error("An error occurred while reading the users: {}", e.getMessage());
+        }
+    }
+
+    /**
+     * Saves the users to the users file
+     */
+    public void saveUsers() {
+        try {
+            String json = gson.toJson(users);
+            FileUtils.writeStringToFile(USERS_FILE, json, "UTF-8");
+        } catch (Exception e) {
+            LOG.error("An error occurred while saving the users: {}", e.getMessage());
+        }
+    }
+}