tag change mass reversion

lib/philomena/tag_changes.ex

@@ -7,18 +7,90 @@ defmodule Philomena.TagChanges do
   alias Philomena.Repo
 
   alias Philomena.TagChanges.TagChange
+  alias Philomena.Images.Tagging
+  alias Philomena.Tags.Tag
+  alias Philomena.Images
 
-  @doc """
-  Returns the list of tag_changes.
+  # TODO: this is substantially similar to Images.batch_update/4.
+  # Perhaps it should be extracted.
+  def mass_revert(ids, attributes) do
+    now = NaiveDateTime.utc_now() |> NaiveDateTime.truncate(:second)
+    tag_change_attributes = Map.merge(attributes, %{created_at: now, updated_at: now})
+    tag_attributes = %{name: "", slug: "", created_at: now, updated_at: now}
 
-  ## Examples
+    tag_changes =
+      TagChange
+      |> join(:inner, [tc], _ in assoc(tc, :image))
+      |> where([tc, i], tc.id in ^ids and i.hidden_from_users == false)
+      |> order_by(desc: :created_at)
+      |> Repo.all()
+      |> Enum.reject(&is_nil(&1.tag_id))
+      |> Enum.uniq_by(&{&1.image_id, &1.tag_id})
 
-      iex> list_tag_changes()
-      [%TagChange{}, ...]
+    {added, removed} = Enum.split_with(tag_changes, & &1.added)
 
-  """
-  def list_tag_changes do
-    Repo.all(TagChange)
+    image_ids =
+      tag_changes
+      |> Enum.map(& &1.image_id)
+      |> Enum.uniq()
+
+    to_remove =
+      added
+      |> Enum.map(&{&1.image_id, &1.tag_id})
+      |> Enum.reduce(Tagging, fn {image_id, tag_id}, q ->
+        or_where(q, image_id: ^image_id, tag_id: ^tag_id)
+      end)
+      |> select([t], [t.image_id, t.tag_id])
+
+    to_add =
+      Enum.map(removed, &%{image_id: &1.image_id, tag_id: &1.tag_id})
+
+    Repo.transaction(fn ->
+      {_count, inserted} = Repo.insert_all(Tagging, to_add, on_conflict: :nothing, returning: [:image_id, :tag_id])
+      {_count, deleted} = Repo.delete_all(to_remove)
+
+      inserted = Enum.map(inserted, &[&1.image_id, &1.tag_id])
+
+      added_changes = Enum.map(inserted, fn [image_id, tag_id] ->
+        Map.merge(tag_change_attributes, %{image_id: image_id, tag_id: tag_id, added: true})
+      end)
+
+      removed_changes = Enum.map(deleted, fn [image_id, tag_id] ->
+        Map.merge(tag_change_attributes, %{image_id: image_id, tag_id: tag_id, added: false})
+      end)
+
+      Repo.insert_all(TagChange, added_changes ++ removed_changes)
+
+      # In order to merge into the existing tables here in one go, insert_all
+      # is used with a query that is guaranteed to conflict on every row by
+      # using the primary key.
+
+      added_upserts =
+        inserted
+        |> Enum.group_by(fn [_image_id, tag_id] -> tag_id end)
+        |> Enum.map(fn {tag_id, instances} -> Map.merge(tag_attributes, %{id: tag_id, images_count: length(instances)}) end)
+
+      removed_upserts =
+        deleted
+        |> Enum.group_by(fn [_image_id, tag_id] -> tag_id end)
+        |> Enum.map(fn {tag_id, instances} -> Map.merge(tag_attributes, %{id: tag_id, images_count: -length(instances)}) end)
+
+      update_query =
+        update(Tag, inc: [images_count: fragment("EXCLUDED.images_count")])
+
+      upserts = added_upserts ++ removed_upserts
+
+      Repo.insert_all(Tag, upserts, on_conflict: update_query, conflict_target: [:id])
+    end)
+    |> case do
+      {:ok, _result} ->
+        Images.reindex_images(image_ids)
+
+        {:ok, tag_changes}
+
+      error ->
+        error
+    end
   end
 
   @doc """

lib/philomena_web/controllers/tag_change/revert_controller.ex

@@ -0,0 +1,39 @@
+defmodule PhilomenaWeb.TagChange.RevertController do
+  use PhilomenaWeb, :controller
+
+  alias Philomena.TagChanges.TagChange
+  alias Philomena.TagChanges
+
+  plug :verify_authorized
+  plug PhilomenaWeb.UserAttributionPlug
+
+  def create(conn, %{"ids" => ids}) when is_list(ids) do
+    attributes = conn.assigns.attributes
+    attributes = %{
+      ip: attributes[:ip],
+      fingerprint: attributes[:fingerprint],
+      referrer: attributes[:referrer],
+      user_agent: attributes[:referrer],
+      user_id: attributes[:user].id
+    }
+
+    case TagChanges.mass_revert(ids, attributes) do
+      {:ok, tag_changes} ->
+        conn
+        |> put_flash(:info, "Successfully reverted #{length(tag_changes)} tag changes.")
+        |> redirect(external: conn.assigns.referrer)
+
+      _error ->
+        conn
+        |> put_flash(:error, "Couldn't revert those tag changes!")
+        |> redirect(external: conn.assigns.referrer)
+    end
+  end
+
+  defp verify_authorized(conn, _params) do
+    case Canada.Can.can?(conn.assigns.current_user, :revert, TagChange) do
+      true   -> conn
+      _false -> PhilomenaWeb.NotAuthorizedPlug.call(conn)
+    end
+  end
+end

lib/philomena_web/router.ex

@@ -260,6 +260,8 @@ defmodule PhilomenaWeb.Router do
       resources "/reindex", Tag.ReindexController, only: [:create], singleton: true
     end
 
+    resources "/tag_changes/revert", TagChange.RevertController, as: :tag_change_revert, only: [:create], singleton: true
+
     resources "/pages", PageController, only: [:index, :new, :create, :edit, :update]
     resources "/channels", ChannelController, only: [:new, :create, :edit, :update]
   end

lib/philomena_web/templates/tag_change/index.html.slime

@@ -1,52 +1,62 @@
 .block__header
   = @pagination
 
-.block__content
-  table.table
-    thead
-      tr
-        th colspan=2 Image
-        th Tag
-        th Action
-        th Timestamp
-        th User
-
-    tbody
-      = for tag_change <- @tag_changes do
+= form_for :tag_changes, Routes.tag_change_revert_path(@conn, :create), fn _f ->
+  .block__content
+    table.table
+      thead
         tr
-          td.center
-            = link tag_change.image_id, to: Routes.image_path(@conn, :show, tag_change.image)
-          td.center
-            = render PhilomenaWeb.ImageView, "_image_container.html", image: tag_change.image, size: :thumb_tiny, conn: @conn
+          = if reverts_tag_changes?(@conn) do
+            th Revert?
+          th colspan=2 Image
+          th Tag
+          th Action
+          th Timestamp
+          th User
 
-          td
-            = if tag_change.tag do
-              = render PhilomenaWeb.TagView, "_tag.html", tag: tag_change.tag, conn: @conn
+      tbody
+        = for tag_change <- @tag_changes do
+          tr
+            = if reverts_tag_changes?(@conn) do
+              td.center
+                input type="checkbox" name="ids[]" value=tag_change.id
+
+            td.center
+              = link tag_change.image_id, to: Routes.image_path(@conn, :show, tag_change.image)
+            td.center
+              = render PhilomenaWeb.ImageView, "_image_container.html", image: tag_change.image, size: :thumb_tiny, conn: @conn
+
+            td
+              = if tag_change.tag do
+                = render PhilomenaWeb.TagView, "_tag.html", tag: tag_change.tag, conn: @conn
+              - else
+                = tag_change.tag_name_cache || "Unknown tag"
+
+            = if tag_change.added do
+              td.success Added
             - else
-              = tag_change.tag_name_cache || "Unknown tag"
-          
-          = if tag_change.added do
-            td.success Added
-          - else
-            td.danger Removed
-          
-          td
-            = pretty_time(tag_change.created_at)
+              td.danger Removed
 
-          td class=user_column_class(tag_change)
-            => render PhilomenaWeb.UserAttributionView, "_anon_user.html", object: tag_change, conn: @conn
+            td
+              = pretty_time(tag_change.created_at)
 
-            = if can?(@conn, :show, :ip_address) do
-              => link_to_ip @conn, tag_change.ip
-              => link_to_fingerprint @conn, tag_change.fingerprint
+            td class=user_column_class(tag_change)
+              => render PhilomenaWeb.UserAttributionView, "_anon_user.html", object: tag_change, conn: @conn
 
-            = if staff?(tag_change) do
-              br
-              small
-                strong> Stop!
-                ' This user is a staff member.
+              = if can?(@conn, :show, :ip_address) do
+                => link_to_ip @conn, tag_change.ip
+                => link_to_fingerprint @conn, tag_change.fingerprint
+
+              = if staff?(tag_change) do
                 br
-                ' Ask them before reverting their changes.
+                small
+                  strong> Stop!
+                  ' This user is a staff member.
+                  br
+                  ' Ask them before reverting their changes.
 
-.block__header
-  = @pagination
+  .block__header
+    = @pagination
+
+  = if reverts_tag_changes?(@conn) do
+    = submit "Revert selected", class: "button", data: [confirm: "Are you really, really sure?"]

lib/philomena_web/views/tag_change_view.ex

@@ -10,4 +10,7 @@ defmodule PhilomenaWeb.TagChangeView do
       false -> nil
     end
   end
+
+  def reverts_tag_changes?(conn),
+    do: can?(conn, :revert, Philomena.TagChanges.TagChange)
 end