✨ Implement activity enrollment and waiting list

Author: Beelzenef

TaleEngine/TaleEngine.API.Contracts/Dtos/Requests/ActivityEnrollmentRequest.cs

@@ -0,0 +1,18 @@
+namespace TaleEngine.API.Contracts.Dtos.Requests
+{
+    /// <summary>
+    /// Request to enroll in an activity
+    /// </summary>
+    public class ActivityEnrollmentRequest
+    {
+        /// <summary>
+        /// Gets or sets the activity identifier.
+        /// </summary>
+        public int ActivityId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the user identifier.
+        /// </summary>
+        public int UserId { get; set; }
+    }
+}

TaleEngine/TaleEngine.API.Contracts/Dtos/Results/ActivityEnrollmentResult.cs

@@ -0,0 +1,48 @@
+namespace TaleEngine.API.Contracts.Dtos.Results
+{
+    /// <summary>
+    /// Result of an activity enrollment operation
+    /// </summary>
+    public class ActivityEnrollmentResult
+    {
+        /// <summary>
+        /// Gets or sets the activity identifier.
+        /// </summary>
+        public int ActivityId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the user identifier.
+        /// </summary>
+        public int UserId { get; set; }
+
+        /// <summary>
+        /// Gets or sets whether the user was enrolled directly or added to waiting list.
+        /// </summary>
+        public bool IsWaitingList { get; set; }
+
+        /// <summary>
+        /// Gets or sets the position in waiting list (null if enrolled directly).
+        /// </summary>
+        public int? PositionInWaitingList { get; set; }
+
+        /// <summary>
+        /// Gets or sets the number of available places.
+        /// </summary>
+        public int AvailablePlaces { get; set; }
+
+        /// <summary>
+        /// Gets or sets the total places for the activity.
+        /// </summary>
+        public int TotalPlaces { get; set; }
+
+        /// <summary>
+        /// Gets or sets the success message.
+        /// </summary>
+        public string Message { get; set; }
+
+        /// <summary>
+        /// Gets or sets whether the operation was successful.
+        /// </summary>
+        public bool Success { get; set; }
+    }
+}

TaleEngine/TaleEngine.API.Contracts/Dtos/Results/WaitingListResult.cs

@@ -0,0 +1,51 @@
+using System.Collections.Generic;
+
+namespace TaleEngine.API.Contracts.Dtos.Results
+{
+    /// <summary>
+    /// Waiting list for an activity
+    /// </summary>
+    public class WaitingListResult
+    {
+        /// <summary>
+        /// Gets or sets the activity identifier.
+        /// </summary>
+        public int ActivityId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the activity title.
+        /// </summary>
+        public string ActivityTitle { get; set; }
+
+        /// <summary>
+        /// Gets or sets the total number of users in waiting list.
+        /// </summary>
+        public int TotalWaiting { get; set; }
+
+        /// <summary>
+        /// Gets or sets the list of users in waiting list.
+        /// </summary>
+        public List<WaitingListUserDto> UsersInWaitingList { get; set; }
+    }
+
+    /// <summary>
+    /// User in waiting list
+    /// </summary>
+    public class WaitingListUserDto
+    {
+        /// <summary>
+        /// Gets or sets the user identifier.
+        /// </summary>
+        public int UserId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the username.
+        /// </summary>
+        public string Username { get; set; }
+
+        /// <summary>
+        /// Gets or sets the position in waiting list.
+        /// </summary>
+        public int Position { get; set; }
+    }
+}

TaleEngine/TaleEngine.Application.Contracts/IActivityService.cs

@@ -17,5 +17,11 @@ public interface IActivityService
         int CreateActivity(int editionId, Activity activity);
         int UpdateActivity(int id, Activity activity);
 
+        // Waiting List methods
+        bool EnrollUserInActivity(int activityId, int userId);
+        bool RemoveUserFromActivity(int activityId, int userId);
+        List<UserEntity> GetWaitingList(int activityId);
+        int? GetUserPositionInWaitingList(int activityId, int userId);
+        bool PromoteFromWaitingList(int activityId);
     }
 }

TaleEngine/TaleEngine.Application/ActivityService.cs

@@ -241,6 +241,151 @@ private int Update(ActivityEntity activityEntity)
             return 1;
         }
 
+        public bool EnrollUserInActivity(int activityId, int userId)
+        {
+            try
+            {
+                var activity = _unitOfWork.ActivityRepository.GetAllIncludeEnrollments(activityId)
+                    .FirstOrDefault(a => a.Id == activityId);
+                var user = _unitOfWork.UserRepository.GetById(userId);
+
+                if (activity == null || user == null)
+                    return false;
+
+                // Check if user is already enrolled
+                if (activity.UsersPlay != null && activity.UsersPlay.Any(u => u.Id == userId))
+                    return false;
+
+                // Check if user is already in waiting list
+                if (activity.UsersWaitingList != null && activity.UsersWaitingList.Any(u => u.Id == userId))
+                    return false;
+
+                // Check if there are available places
+                if (activity.UsersPlay == null || activity.UsersPlay.Count < activity.Places)
+                {
+                    // Enroll directly
+                    if (activity.UsersPlay == null)
+                        activity.UsersPlay = new List<UserEntity>();
+                    
+                    activity.UsersPlay.Add(user);
+                }
+                else
+                {
+                    // Add to waiting list
+                    if (activity.UsersWaitingList == null)
+                        activity.UsersWaitingList = new List<UserEntity>();
+                    
+                    activity.UsersWaitingList.Add(user);
+                }
+
+                _unitOfWork.ActivityRepository.Update(activity);
+                _unitOfWork.ActivityRepository.Save();
+                return true;
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
+
+        public bool RemoveUserFromActivity(int activityId, int userId)
+        {
+            try
+            {
+                var activity = _unitOfWork.ActivityRepository.GetAllIncludeEnrollments(activityId)
+                    .FirstOrDefault(a => a.Id == activityId);
+                var user = _unitOfWork.UserRepository.GetById(userId);
+
+                if (activity == null || user == null)
+                    return false;
+
+                bool wasEnrolled = false;
+
+                // Remove from enrolled users
+                if (activity.UsersPlay != null && activity.UsersPlay.Any(u => u.Id == userId))
+                {
+                    activity.UsersPlay.Remove(user);
+                    wasEnrolled = true;
+                }
+
+                // Remove from waiting list
+                if (activity.UsersWaitingList != null && activity.UsersWaitingList.Any(u => u.Id == userId))
+                {
+                    activity.UsersWaitingList.Remove(user);
+                }
+
+                _unitOfWork.ActivityRepository.Update(activity);
+                _unitOfWork.ActivityRepository.Save();
+
+                // If user was enrolled, promote from waiting list
+                if (wasEnrolled)
+                {
+                    PromoteFromWaitingList(activityId);
+                }
+
+                return true;
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
+
+        public List<UserEntity> GetWaitingList(int activityId)
+        {
+            var activity = _unitOfWork.ActivityRepository.GetAllIncludeWaitingList(activityId)
+                .FirstOrDefault(a => a.Id == activityId);
+
+            return activity?.UsersWaitingList ?? new List<UserEntity>();
+        }
+
+        public int? GetUserPositionInWaitingList(int activityId, int userId)
+        {
+            var activity = _unitOfWork.ActivityRepository.GetAllIncludeWaitingList(activityId)
+                .FirstOrDefault(a => a.Id == activityId);
+
+            if (activity?.UsersWaitingList == null)
+                return null;
+
+            var position = activity.UsersWaitingList.FindIndex(u => u.Id == userId);
+            return position >= 0 ? position + 1 : (int?)null;
+        }
+
+        public bool PromoteFromWaitingList(int activityId)
+        {
+            try
+            {
+                var activity = _unitOfWork.ActivityRepository.GetAllIncludeEnrollments(activityId)
+                    .FirstOrDefault(a => a.Id == activityId);
+
+                if (activity == null)
+                    return false;
+
+                // Check if there are available places and users in waiting list
+                if (activity.UsersWaitingList != null && activity.UsersWaitingList.Any() &&
+                    (activity.UsersPlay == null || activity.UsersPlay.Count < activity.Places))
+                {
+                    var firstWaitingUser = activity.UsersWaitingList.First();
+                    activity.UsersWaitingList.Remove(firstWaitingUser);
+
+                    if (activity.UsersPlay == null)
+                        activity.UsersPlay = new List<UserEntity>();
+                    
+                    activity.UsersPlay.Add(firstWaitingUser);
+
+                    _unitOfWork.ActivityRepository.Update(activity);
+                    _unitOfWork.ActivityRepository.Save();
+                    return true;
+                }
+
+                return false;
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
+
         #endregion
     }
 }

TaleEngine/TaleEngine.Bussiness/Commands/ActivityCommands.cs

@@ -1,6 +1,9 @@
 using System;
+using System.Linq;
 using TaleEngine.Aggregates.ActivityAggregate;
 using TaleEngine.API.Contracts.Dtos;
+using TaleEngine.API.Contracts.Dtos.Requests;
+using TaleEngine.API.Contracts.Dtos.Results;
 using TaleEngine.CQRS.Contracts;
 using TaleEngine.CQRS.Mappers;
 using TaleEngine.Cross.Enums;
@@ -83,5 +86,59 @@ public void ChangeActivityStatusCommand(int activityId, int statusId)
 
             _activityService.UpdateActivity(activityId, model);
         }
+
+        public ActivityEnrollmentResult EnrollInActivityCommand(ActivityEnrollmentRequest request)
+        {
+            var activity = _activityService.GetById(request.ActivityId);
+            
+            if (activity == null)
+            {
+                return new ActivityEnrollmentResult
+                {
+                    Success = false,
+                    Message = "Activity not found",
+                    ActivityId = request.ActivityId,
+                    UserId = request.UserId
+                };
+            }
+
+            var success = _activityService.EnrollUserInActivity(request.ActivityId, request.UserId);
+            
+            if (!success)
+            {
+                return new ActivityEnrollmentResult
+                {
+                    Success = false,
+                    Message = "Enrollment failed. User may already be enrolled or in waiting list.",
+                    ActivityId = request.ActivityId,
+                    UserId = request.UserId
+                };
+            }
+
+            // Get updated activity to check enrollment status
+            var updatedActivity = _activityService.GetById(request.ActivityId);
+            var enrolledUsers = updatedActivity.UsersPlay?.Count ?? 0;
+            var isWaitingList = enrolledUsers >= activity.Places;
+            var position = isWaitingList ? _activityService.GetUserPositionInWaitingList(request.ActivityId, request.UserId) : null;
+
+            return new ActivityEnrollmentResult
+            {
+                Success = true,
+                ActivityId = request.ActivityId,
+                UserId = request.UserId,
+                IsWaitingList = isWaitingList,
+                PositionInWaitingList = position,
+                AvailablePlaces = activity.Places - enrolledUsers,
+                TotalPlaces = activity.Places,
+                Message = isWaitingList 
+                    ? $"Added to waiting list at position {position}" 
+                    : "Successfully enrolled in activity"
+            };
+        }
+
+        public bool LeaveActivityCommand(ActivityEnrollmentRequest request)
+        {
+            return _activityService.RemoveUserFromActivity(request.ActivityId, request.UserId);
+        }
     }
 }

TaleEngine/TaleEngine.Bussiness/Contracts/IActivityCommands.cs

@@ -1,4 +1,6 @@
 using TaleEngine.API.Contracts.Dtos;
+using TaleEngine.API.Contracts.Dtos.Requests;
+using TaleEngine.API.Contracts.Dtos.Results;
 
 namespace TaleEngine.CQRS.Contracts
 {
@@ -8,5 +10,7 @@ public interface IActivityCommands
         void CreateCommand(int editionId, ActivityDto activityDto);
         void UpdateCommand(ActivityDto activityDto);
         void ChangeActivityStatusCommand(int activityId, int statusId);
+        ActivityEnrollmentResult EnrollInActivityCommand(ActivityEnrollmentRequest request);
+        bool LeaveActivityCommand(ActivityEnrollmentRequest request);
     }
 }

TaleEngine/TaleEngine.Bussiness/Contracts/IActivityQueries.cs

@@ -11,5 +11,7 @@ public interface IActivityQueries
         List<ActivityDto> PendingActivitiesQuery(int editionId);
         ActivityFilteredResult ActiveActivitiesFilteredQuery(ActivityFilterRequest activityFilterRequest, int userId = default);
         List<ActivityDto> LastThreeActivitiesQuery(int editionId);
+        WaitingListResult GetWaitingListQuery(int activityId);
+        int? GetUserPositionInWaitingListQuery(int activityId, int userId);
     }
 }