add deletion check for containers

lib/cannery/containers.ex

@@ -3,8 +3,9 @@ defmodule Cannery.Containers do
   The Containers context.
   """
 
+  import CanneryWeb.Gettext
   import Ecto.Query, warn: false
-  alias Cannery.{Accounts.User, Repo, Tags.Tag}
+  alias Cannery.{Accounts.User, Ammo.AmmoGroup, Repo, Tags.Tag}
   alias Cannery.Containers.{Container, ContainerTag}
   alias Ecto.Changeset
 
@@ -88,7 +89,36 @@ defmodule Cannery.Containers do
   """
   @spec delete_container(Container.t()) ::
           {:ok, Container.t()} | {:error, Changeset.t(Container.t())}
-  def delete_container(container), do: container |> Repo.delete()
+  def delete_container(container) do
+    Repo.one(
+      from ag in AmmoGroup,
+        where: ag.container_id == ^container.id,
+        select: count(ag.id)
+    )
+    |> case do
+      0 ->
+        container |> Repo.delete()
+
+      amount ->
+        error_string =
+          dngettext(
+            "errors",
+            "There is still %{amount} ammo group in this container!",
+            "There are still %{amount} ammo groups in this container!",
+            amount
+          )
+
+        container
+        |> change_container()
+        |> Changeset.add_error(
+          :ammo_groups,
+          error_string,
+          amount: amount,
+          count: amount
+        )
+        |> Changeset.apply_action(:delete)
+    end
+  end
 
   @doc """
   Deletes a container.
@@ -100,7 +130,10 @@ defmodule Cannery.Containers do
 
   """
   @spec delete_container!(Container.t()) :: Container.t()
-  def delete_container!(container), do: container |> Repo.delete!()
+  def delete_container!(container) do
+    {:ok, container} = container |> delete_container()
+    container
+  end
 
   @doc """
   Returns an `%Changeset{}` for tracking container changes.

lib/cannery_web/live/container_live/index.ex

@@ -5,8 +5,7 @@ defmodule CanneryWeb.ContainerLive.Index do
 
   use CanneryWeb, :live_view
   import CanneryWeb.ContainerLive.ContainerCard
-  alias Cannery.Containers
-  alias Cannery.Containers.Container
+  alias Cannery.{Containers, Containers.Container}
 
   @impl true
   def mount(_params, session, socket) do
@@ -38,8 +37,32 @@ defmodule CanneryWeb.ContainerLive.Index do
 
   @impl true
   def handle_event("delete", %{"id" => id}, socket) do
-    Containers.get_container!(id) |> Containers.delete_container!()
-    {:noreply, socket |> display_containers()}
+    socket =
+      socket.assigns.containers
+      |> Enum.find(fn %{id: container_id} -> id == container_id end)
+      |> case do
+        nil ->
+          socket |> put_flash(:error, "Could not find that container")
+
+        container ->
+          container
+          |> Containers.delete_container()
+          |> case do
+            {:ok, container} ->
+              socket
+              |> put_flash(:info, "#{container.name} has been deleted")
+              |> display_containers()
+
+            {:error, %{action: :delete, errors: [ammo_groups: _error], valid?: false} = changeset} ->
+              ammo_groups_error = changeset |> changeset_errors(:ammo_groups) |> Enum.join(", ")
+              socket |> put_flash(:error, "Could not delete container: #{ammo_groups_error}")
+
+            {:error, changeset} ->
+              socket |> put_flash(:error, changeset |> changeset_errors())
+          end
+      end
+
+    {:noreply, socket}
   end
 
   defp display_containers(%{assigns: %{current_user: current_user}} = socket) do

lib/cannery_web/live/container_live/show.ex

@@ -26,8 +26,24 @@ defmodule CanneryWeb.ContainerLive.Show do
 
   @impl true
   def handle_event("delete", _, socket) do
-    socket.assigns.container |> Containers.delete_container!()
-    {:noreply, socket |> push_redirect(to: Routes.container_index_path(socket, :index))}
+    socket =
+      socket.assigns.container
+      |> Containers.delete_container()
+      |> case do
+        {:ok, container} ->
+          socket
+          |> put_flash(:info, "#{container.name} has been deleted")
+          |> push_redirect(to: Routes.container_index_path(socket, :index))
+
+        {:error, %{action: :delete, errors: [ammo_groups: _error], valid?: false} = changeset} ->
+          ammo_groups_error = changeset |> changeset_errors(:ammo_groups) |> Enum.join(", ")
+          socket |> put_flash(:error, "Could not delete container: #{ammo_groups_error}")
+
+        {:error, changeset} ->
+          socket |> put_flash(:error, changeset |> changeset_errors())
+      end
+
+    {:noreply, socket}
   end
 
   defp page_title(:show), do: "Show Container"

lib/cannery_web/views/error_helpers.ex

@@ -55,9 +55,10 @@ defmodule CanneryWeb.ErrorHelpers do
   end
 
   @doc """
-  Displays all errors from a changeset
+  Displays all errors from a changeset, or just for a single key
   """
   @spec changeset_errors(Changeset.t()) :: String.t()
+  @spec changeset_errors(Changeset.t(), key :: atom()) :: [String.t()] | nil
   def changeset_errors(changeset) do
     changeset
     |> changeset_error_map()
@@ -66,6 +67,10 @@ defmodule CanneryWeb.ErrorHelpers do
     end)
   end
 
+  def changeset_errors(changeset, key) do
+    changeset |> changeset_error_map() |> Map.get(key)
+  end
+
   @doc """
   Displays all errors from a changeset in a key value map
   """