Notification System

// Create a notification for a single user within the current tenant
await _notificationService.CreateAsync(
    userId: targetUserId,
    tenantId: tenantId,
    type: NotificationType.MemberInvited,
    title: "Invitation sent",
    message: $"You invited {invitedEmail} to join {tenantName}.",
    actionUrl: "/settings/members"
);

// Create a notification for all members of the current tenant
await _notificationService.CreateForAllTenantMembersAsync(
    tenantId: tenantId,
    type: NotificationType.MemberJoined,
    title: "New member joined",
    message: $"{newMemberName} joined {tenantName}.",
    actionUrl: "/settings/members"
);

Cache key: "notifications:unread:{userId}:{tenantId}"
TTL: 30 seconds

// 1. Add to the NotificationType enum in Domain
public enum NotificationType
{
    // existing values...
    MemberInvited,
    MemberJoined,
    // add your new type:
    ProjectCreated,
}

// 2. Call INotificationService in the relevant command handler
public class CreateProjectCommandHandler : IRequestHandler<CreateProjectCommand, Result<ProjectDto>>
{
    private readonly IApplicationDbContext _context;
    private readonly INotificationService _notificationService;

    public async Task<Result<ProjectDto>> Handle(
        CreateProjectCommand request,
        CancellationToken cancellationToken)
    {
        var project = Project.Create(request.Name, request.Description, request.TenantId);
        _context.Projects.Add(project);
        await _context.SaveChangesAsync(cancellationToken);

        // Notify all tenant members about the new project
        await _notificationService.CreateForAllTenantMembersAsync(
            tenantId: request.TenantId,
            type: NotificationType.ProjectCreated,
            title: "New project created",
            message: $"Project \"{project.Name}\" was created.",
            actionUrl: $"/projects/{project.Id}"
        );

        return Result.Success(_mapper.Map<ProjectDto>(project));
    }
}

builder.Entity<Notification>()
    .HasQueryFilter(n =>
        n.TenantId == _tenantContext.CurrentTenantId &&
        n.UserId == _currentUserService.UserId);