prevent double deletions

lib/philomena/images/image.ex

@@ -214,6 +214,7 @@ defmodule Philomena.Images.Image do
   def hide_changeset(image, attrs, user) do
     image
     |> cast(attrs, [:deletion_reason])
+    |> validate_not_hidden()
     |> put_change(:deleter_id, user.id)
     |> put_change(:hidden_image_key, create_key())
     |> put_change(:hidden_from_users, true)
@@ -228,6 +229,7 @@ defmodule Philomena.Images.Image do
 
   def merge_changeset(image, duplicate_of_image) do
     change(image)
+    |> validate_not_hidden()
     |> put_change(:duplicate_id, duplicate_of_image.id)
     |> put_change(:hidden_image_key, create_key())
     |> put_change(:hidden_from_users, true)
@@ -235,6 +237,7 @@ defmodule Philomena.Images.Image do
 
   def unhide_changeset(image) do
     change(image)
+    |> validate_hidden()
     |> put_change(:deleter_id, nil)
     |> put_change(:hidden_image_key, nil)
     |> put_change(:hidden_from_users, false)
@@ -335,4 +338,18 @@ defmodule Philomena.Images.Image do
   defp create_key do
     Base.encode16(:crypto.strong_rand_bytes(6), case: :lower)
   end
+
+  defp validate_hidden(changeset) do
+    case get_field(changeset, :hidden_from_users) do
+      true -> changeset
+      false -> add_error(changeset, :hidden_from_users, "must be true")
+    end
+  end
+
+  defp validate_not_hidden(changeset) do
+    case get_field(changeset, :hidden_from_users) do
+      true -> add_error(changeset, :hidden_from_users, "must be false")
+      false -> changeset
+    end
+  end
 end

lib/philomena_web/controllers/duplicate_report/accept_controller.ex

@@ -13,14 +13,19 @@ defmodule PhilomenaWeb.DuplicateReport.AcceptController do
     preload: [:image, :duplicate_of_image]
 
   def create(conn, _params) do
-    {:ok, _report} =
-      DuplicateReports.accept_duplicate_report(
-        conn.assigns.duplicate_report,
-        conn.assigns.current_user
-      )
+    report = conn.assigns.duplicate_report
+    user = conn.assigns.current_user
 
-    conn
-    |> put_flash(:info, "Successfully accepted report.")
-    |> redirect(to: Routes.duplicate_report_path(conn, :index))
+    case DuplicateReports.accept_duplicate_report(report, user) do
+      {:ok, _report} ->
+        conn
+        |> put_flash(:info, "Successfully accepted report.")
+        |> redirect(to: Routes.duplicate_report_path(conn, :index))
+
+      _error ->
+        conn
+        |> put_flash(:error, "Failed to accept report! Maybe someone else already accepted it.")
+        |> redirect(to: Routes.duplicate_report_path(conn, :index))
+    end
   end
 end

lib/philomena_web/controllers/duplicate_report/accept_reverse_controller.ex

@@ -13,14 +13,19 @@ defmodule PhilomenaWeb.DuplicateReport.AcceptReverseController do
     preload: [:image, :duplicate_of_image]
 
   def create(conn, _params) do
-    {:ok, _report} =
-      DuplicateReports.accept_reverse_duplicate_report(
-        conn.assigns.duplicate_report,
-        conn.assigns.current_user
-      )
+    report = conn.assigns.duplicate_report
+    user = conn.assigns.current_user
 
-    conn
-    |> put_flash(:info, "Successfully accepted report in reverse.")
-    |> redirect(to: Routes.duplicate_report_path(conn, :index))
+    case DuplicateReports.accept_reverse_duplicate_report(report, user) do
+      {:ok, _report} ->
+        conn
+        |> put_flash(:info, "Successfully accepted report in reverse.")
+        |> redirect(to: Routes.duplicate_report_path(conn, :index))
+
+      _error ->
+        conn
+        |> put_flash(:error, "Failed to accept report! Maybe someone else already accepted it.")
+        |> redirect(to: Routes.duplicate_report_path(conn, :index))
+    end
   end
 end

lib/philomena_web/controllers/image/delete_controller.ex

@@ -21,8 +21,10 @@ defmodule PhilomenaWeb.Image.DeleteController do
         |> put_flash(:info, "Image successfully hidden.")
         |> redirect(to: Routes.image_path(conn, :show, image))
 
-      {:error, :image, changeset, _changes} ->
-        render(conn, "new.html", image: image, changeset: changeset)
+      _error ->
+        conn
+        |> put_flash(:error, "Failed to hide image.")
+        |> redirect(to: Routes.image_path(conn, :show, image))
     end
   end