chore: improvements

lib/safira/activities.ex

@@ -422,12 +422,33 @@ defmodule Safira.Activities do
     |> Repo.all()
   end
 
+  @doc """
+  Returns the list of enrolments of an attendee.
+
+  ## Examples
+
+      iex> get_attendee_enrolments(attendee_id)
+      [%Enrolment{}, ...]
+
+  """
   def get_attendee_enrolments(attendee_id) do
     Enrolment
     |> where([e], e.attendee_id == ^attendee_id)
+    |> preload(:activity)
     |> Repo.all()
   end
 
+  @doc """
+  Enrols an attendee in an activity
+
+  ## Examples
+
+      iex> enrol(attendee_id, activity_id)
+      {:ok, %{enrolment: %Enrolment{}, activity: %Activity{}, new_activity: %Activity{}}}
+
+      iex> enrol(attendee_id, activity_id)
+      {:error, :struct, %Ecto.Changeset{}, %{}}
+  """
   def enrol(attendee_id, activity_id) do
     Ecto.Multi.new()
     # We need to read the activity before updating the enrolment count to avoid
@@ -450,10 +471,42 @@ defmodule Safira.Activities do
     |> Repo.transaction()
   end
 
-  def delete_enrolment(%Enrolment{} = enrolment) do
-    Repo.delete(enrolment)
+  @doc """
+  Deletes an enrolment
+
+  ## Examples
+
+      iex> unenrol(attendee_id, activity_id)
+      {:ok, %{enrolment: %Enrolment{}, activity: %Activity{}, new_activity: %Activity{}}}
+
+      iex> unenrol(attendee_id, activity_id)
+      {:error, :struct, %Ecto.Changeset{}, %{}}
+  """
+  def unenrol(enrolment) do
+    Ecto.Multi.new()
+    # We need to read the activity before updating the enrolment count to avoid
+    # a race condition where the enrolment count changes after the activity was last
+    # read from the database, and before this transaction began
+    |> Ecto.Multi.one(:activity, Activity |> where([a], a.id == ^enrolment.activity_id))
+    |> Ecto.Multi.delete(
+      :enrolment,
+      enrolment
+    )
+    |> Ecto.Multi.update(:new_activity, fn %{activity: act} ->
+      Activity.changeset(act, %{enrolment_count: act.enrolment_count - 1})
+    end)
+    |> Repo.transaction()
   end
 
+  @doc """
+  Returns an `%Ecto.Changeset{}` for tracking enrolment changes.
+
+  ## Examples
+
+      iex> change_enrolment(enrolment)
+      %Ecto.Changeset{data: %Enrolment{}}
+
+  """
   def change_enrolment(%Enrolment{} = enrolment, attrs \\ %{}) do
     Enrolment.changeset(enrolment, attrs)
   end

lib/safira/activities/activity.ex

@@ -54,6 +54,10 @@ defmodule Safira.Activities.Activity do
     |> validate_required(@required_fields)
     |> validate_activity_date()
     |> validate_activity_times()
+    |> check_constraint(:max_enrolments,
+      name: :activity_not_overbooked,
+      message: "Activity overbooked"
+    )
   end
 
   @doc false

lib/safira_web/live/backoffice/schedule_live/enrolment_live/form_component.ex

@@ -48,7 +48,7 @@ defmodule SafiraWeb.Backoffice.ScheduleLive.EnrolmentLive.FormComponent do
                     </div>
                   </.simple_form>
                 <% else %>
-                  <div class="grid space-x-2 grid-cols-9 pl-1 mb-6">
+                  <div class="grid space-x-2 grid-cols-9 pl-1 my-3">
                     <p class="col-span-8"><%= enrolment.attendee.user.name %></p>
                     <.link
                       phx-click={JS.push("delete-enrolment", value: %{id: id})}
@@ -89,8 +89,8 @@ defmodule SafiraWeb.Backoffice.ScheduleLive.EnrolmentLive.FormComponent do
 
     {:ok,
      socket
+     |> assign(assigns)
      |> assign(:enrolments, enrolments)
-     |> assign(:activity, assigns.activity)
      |> assign(:attendees, Accounts.list_attendees())}
   end
 
@@ -157,7 +157,7 @@ defmodule SafiraWeb.Backoffice.ScheduleLive.EnrolmentLive.FormComponent do
 
     # If the enrolment has an id, delete it from the database
     if enrolment.id != nil do
-      Activities.delete_enrolment(enrolment)
+      Activities.unenrol(enrolment)
     end
 
     # Remove the enrolment from the list
@@ -181,8 +181,8 @@ defmodule SafiraWeb.Backoffice.ScheduleLive.EnrolmentLive.FormComponent do
 
     if valid_enrolments do
       # For each enrolment, update or create it
-      Enum.each(enrolments, fn {_, _, _enrolment, form} ->
-        Activities.enrol(form.params.attendee_id, form.params.activity_id)
+      Enum.each(enrolments, fn {_, new, _enrolment, form} ->
+        if new, do: Activities.enrol(form.params["attendee_id"], form.params["activity_id"])
       end)
 
       {:noreply,

lib/safira_web/live/landing/components/schedule.ex

@@ -169,6 +169,13 @@ defmodule SafiraWeb.Landing.Components.Schedule do
               >
                 <%= gettext("Enrol") %>
               </p>
+              <p
+                :if={already_enrolled(@activity, @enrolments)}
+                class="relative -mr-3 font-iregular text-lg text-accent sm:mr-1"
+                phx-value-activity_id={@activity.id}
+              >
+                <%= gettext("Enrolled") %>
+              </p>
             </div>
             <!-- Expand -->
             <button
@@ -389,11 +396,21 @@ defmodule SafiraWeb.Landing.Components.Schedule do
     Activities.list_activity_categories()
   end
 
+  defp already_enrolled(activity, enrolments) do
+    Enum.member?(Enum.map(enrolments, & &1.activity_id), activity.id)
+  end
+
   defp enrolments_enabled(activity, user_role, enrolments) do
     not_full = activity.max_enrolments > activity.enrolment_count
-    already_enrolled = Enum.member?(enrolments, activity)
     is_staff = user_role == :staff
 
-    not_full and activity.has_enrolments and not already_enrolled and not is_staff
+    enrolled_at_same_time =
+      Enum.any?(enrolments, fn e ->
+        Time.compare(e.activity.time_start, activity.time_end) == :lt and
+          Time.compare(e.activity.time_end, activity.time_start) == :gt and
+          e.activity.date == activity.date
+      end)
+
+    not_full and activity.has_enrolments and not enrolled_at_same_time and not is_staff
   end
 end