upd: completed device service integration

src/main/java/com/backend/glowhouse/controller/DeviceController.java

+package com.backend.glowhouse.controller;
+
+import com.backend.glowhouse.model.Device;
+import com.backend.glowhouse.model.request.DeviceRegistrationRequest;
+import com.backend.glowhouse.model.response.ApiResponse;
+import com.backend.glowhouse.model.response.DeviceIdResponse;
+import com.backend.glowhouse.model.response.DeviceRegistrationResponse;
+import com.backend.glowhouse.repository.device.DeviceRepository;
+import com.backend.glowhouse.repository.user.UserRepository;
+import com.backend.glowhouse.service.DeviceService;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/device")
+public class DeviceController {
+    @Autowired
+    private DeviceService deviceService;
+
+    @PostMapping("/registerDevice")
+    @PreAuthorize("hasRole('USER')")
+    public String registerDevice(@RequestBody DeviceRegistrationRequest deviceRegistrationRequest) throws JsonProcessingException {
+        return deviceService.handleDeviceRegistration(deviceRegistrationRequest);
+    }
+
+    @GetMapping("/getDeviceIdForUser")
+    public String getDeviceIdForUser(@RequestParam(value = "username") String username) throws JsonProcessingException {
+        return deviceService.getDeviceIdForUser(username);
+    }
+}

src/main/java/com/backend/glowhouse/repository/device/DeviceRepositoryCustom.java

@@ -3,5 +3,5 @@ package com.backend.glowhouse.repository.device;
 import com.backend.glowhouse.model.Device;
 
 public interface DeviceRepositoryCustom {
-    Device updateDeviceAssignUserAndSetRegisteredTrue(String deviceId, String username);
+    Device registerUserToDevice(String deviceId, String username);
 }

src/main/java/com/backend/glowhouse/repository/device/DeviceRepositoryImpl.java

@@ -19,7 +19,7 @@ public class DeviceRepositoryImpl implements DeviceRepositoryCustom {
     @Override
     //Method for updating device document when registered
     //Returns
-    public Device updateDeviceAssignUserAndSetRegisteredTrue(String deviceId, String username) {
+    public Device registerUserToDevice(String deviceId, String username) {
         //Query for existing device
         Query query = new Query();
         query.addCriteria(Criteria.where("deviceId").is(deviceId));

src/main/java/com/backend/glowhouse/controller/DeviceDataController.java → src/main/java/com/backend/glowhouse/service/DeviceService.java

-package com.backend.glowhouse.controller;
+package com.backend.glowhouse.service;
 
 import com.backend.glowhouse.model.Device;
-import com.backend.glowhouse.model.DeviceRegistrationRequest;
+import com.backend.glowhouse.model.request.DeviceRegistrationRequest;
+import com.backend.glowhouse.model.response.ApiResponse;
 import com.backend.glowhouse.model.response.DeviceIdResponse;
 import com.backend.glowhouse.model.response.DeviceRegistrationResponse;
 import com.backend.glowhouse.repository.device.DeviceRepository;
-import com.backend.glowhouse.repository.UserRepository;
+import com.backend.glowhouse.repository.user.UserRepository;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.http.ResponseEntity;
-import org.springframework.security.access.prepost.PreAuthorize;
-import org.springframework.web.bind.annotation.*;
+import org.springframework.stereotype.Service;
 
-import java.util.Optional;
-
-@RestController
-@RequestMapping("/api/device")
-public class DeviceDataController {
+@Service
+public class DeviceService {
     private DeviceRepository deviceRepository;
     private UserRepository userRepository;
 
     ObjectMapper mapper = new ObjectMapper();
 
     @Autowired
-    public DeviceDataController(DeviceRepository deviceRepository, UserRepository userRepository) {
+    public DeviceService(DeviceRepository deviceRepository, UserRepository userRepository) {
         this.deviceRepository = deviceRepository;
         this.userRepository = userRepository;
     }
 
-    @PostMapping("/registerDevice")
-    @PreAuthorize("hasRole('USER')")
-    public String registerDevice(@RequestBody DeviceRegistrationRequest deviceRegistrationRequest) throws JsonProcessingException {
+    public String handleDeviceRegistration(DeviceRegistrationRequest deviceRegistrationRequest) throws JsonProcessingException {
         String deviceId = deviceRegistrationRequest.getDeviceId();
         String username = deviceRegistrationRequest.getUsername();
 
-        Device deviceToRegister = deviceRepository.updateDeviceAssignUserAndSetRegisteredTrue(deviceId, username);
+        Device deviceToRegister = deviceRepository.registerUserToDevice(deviceId, username);
+
+        if (deviceToRegister == null) {
+            ApiResponse response = new ApiResponse(false, "The device does not exist");
+
+            return mapper.writeValueAsString(response);
+        }
 
-        userRepository.updateUserAssignDevice(username, deviceToRegister);
+        userRepository.registerDeviceToUser(username, deviceToRegister);
 
         DeviceRegistrationResponse deviceRegistrationResponse = new DeviceRegistrationResponse(deviceToRegister.getDeviceId());
 
         return mapper.writeValueAsString(deviceRegistrationResponse);
     }
 
-    @GetMapping("/getDeviceIdForUser")
-    @PreAuthorize("hasRole('USER')")
-    public String getDeviceIdForUser(@RequestParam(value = "username") String username) throws JsonProcessingException {
+    public String getDeviceIdForUser(String username) throws JsonProcessingException {
         Device device = deviceRepository.findByRegisteredUser(username);
 
         DeviceIdResponse deviceIdResponse = new DeviceIdResponse(device.getDeviceId());
 
-        return mapper.writeValueAsString(deviceIdResponse);
+        if (deviceIdResponse.getDeviceId() != null) {
+            return mapper.writeValueAsString(deviceIdResponse);
+        } else {
+            return null;
+        }
     }
 }