feat: changed createGoal method to accept group goals, and added get group method.

src/main/java/no/ntnu/idi/stud/savingsapp/service/GoalService.java

 package no.ntnu.idi.stud.savingsapp.service;
 
+import no.ntnu.idi.stud.savingsapp.dto.goal.GroupUserDTO;
 import no.ntnu.idi.stud.savingsapp.model.goal.Goal;
+import no.ntnu.idi.stud.savingsapp.model.goal.Group;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
@@ -20,7 +22,7 @@ public interface GoalService {
    * @param userId The ID of the user for whom the goal is being created.
    * @return The newly created and persisted Goal object.
    */
-  Goal createGoal(Goal goal, long userId);
+  Goal createGoal(Goal goal, List<GroupUserDTO> GroupUsers, long userId);
 
   /**
    * Retrieves all goals associated with a specific user.
@@ -39,4 +41,12 @@ public interface GoalService {
    * @return A goal object associated with the specified user.
    */
   Goal getGoal(long goalId);
+
+  /**
+   * Retrieves a group associated with a specific goal
+   *
+   * @param goalId the goal that the group contains
+   * @return A group object associated with the specified goal
+   */
+  Group getGroup(Long goalId);
 }

src/main/java/no/ntnu/idi/stud/savingsapp/service/impl/GoalServiceImpl.java

@@ -2,15 +2,20 @@ package no.ntnu.idi.stud.savingsapp.service.impl;
 
 import java.sql.Timestamp;
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 
 import lombok.extern.slf4j.Slf4j;
+import no.ntnu.idi.stud.savingsapp.dto.goal.GroupUserDTO;
 import no.ntnu.idi.stud.savingsapp.exception.goal.GoalNotFoundException;
+import no.ntnu.idi.stud.savingsapp.exception.goal.GroupNotFoundException;
 import no.ntnu.idi.stud.savingsapp.model.goal.Challenge;
 import no.ntnu.idi.stud.savingsapp.model.goal.Goal;
+import no.ntnu.idi.stud.savingsapp.model.goal.Group;
 import no.ntnu.idi.stud.savingsapp.model.user.User;
 import no.ntnu.idi.stud.savingsapp.repository.GoalRepository;
+import no.ntnu.idi.stud.savingsapp.repository.GroupRepository;
 import no.ntnu.idi.stud.savingsapp.service.ChallengeService;
 import no.ntnu.idi.stud.savingsapp.service.GoalService;
 import no.ntnu.idi.stud.savingsapp.service.UserService;
@@ -33,6 +38,9 @@ public class GoalServiceImpl implements GoalService {
   @Autowired
   private ChallengeService challengeService;
 
+  @Autowired
+  private GroupRepository groupRepository;
+
   /**
    * Creates a new goal for a specific user and generates associated challenges.
    *
@@ -41,12 +49,33 @@ public class GoalServiceImpl implements GoalService {
    * @return The newly created Goal, now populated with generated challenges and persisted in the database.
    */
   @Override
-  public Goal createGoal(Goal goal, long userId) {
+  public Goal createGoal(Goal goal, List<GroupUserDTO> GroupUsers, long userId) {
     User user = userService.findById(userId);
     goal.setCreatedAt(Timestamp.from(Instant.now()));
     goal.setUser(user);
     List<Challenge> challenges = challengeService.generateChallenges(goal, user);
     goal.setChallenges(challenges);
+
+    //Create group goal if GroupUsers were added
+    if(GroupUsers != null && !GroupUsers.isEmpty()) {
+      List<Goal> groupGoalList = new ArrayList<>();
+      for (GroupUserDTO groupUserDTO : GroupUsers) {
+        Goal groupGoal = new Goal();
+        User groupUser = userService.findById(groupUserDTO.getUserId());
+        groupGoal.setCreatedAt(Timestamp.from(Instant.now()));
+        groupGoal.setUser(groupUser);
+        List<Challenge> challengeList = challengeService.generateChallenges(groupGoal, groupUser);
+        groupGoal.setChallenges(challengeList);
+        goalRepository.save(groupGoal);
+        groupGoalList.add(groupGoal);
+      }
+
+      Group group = new Group();
+      group.setCreator(user);
+      group.setGoals(groupGoalList);
+      groupRepository.save(group);
+    }
+
     return goalRepository.save(goal);
   }
 
@@ -61,6 +90,12 @@ public class GoalServiceImpl implements GoalService {
     return goalRepository.findByUser_Id(userId);
   }
 
+  /**
+   * Retrieves goal associated with a given goal ID.
+   *
+   * @param goalId The ID of the user whose goals are to be retrieved.
+   * @return The goal associated with the given goal ID.
+   */
   @Override
   public Goal getGoal(long goalId) {
     Optional<Goal> optionalGoal = goalRepository.findById(goalId);
@@ -71,4 +106,21 @@ public class GoalServiceImpl implements GoalService {
       throw new GoalNotFoundException();
     }
   }
+
+  /**
+   *
+   *
+   * @param goalId the goal that the group contains
+   * @return The group containing the goal
+   */
+  @Override
+  public Group getGroup(Long goalId) {
+    Optional<Group> optionalGroup = groupRepository.findBygGoals_Id(goalId);
+    if (optionalGroup.isPresent()) {
+      return optionalGroup.get();
+    } else {
+      log.error("[GoalServiceImpl:getGoal] Group is not found from goal, id: {}", goalId);
+      throw new GroupNotFoundException();
+    }
+  }
 }