use more correct way of propagating user through models

lib/philomena/comments.ex

@@ -40,10 +40,10 @@ defmodule Philomena.Comments do
       {:error, %Ecto.Changeset{}}
 
   """
-  def create_comment(image, user, attributes, params \\ %{}) do
+  def create_comment(image, attribution, params \\ %{}) do
     comment =
-      struct(Comment, [image_id: image.id] ++ attributes)
-      |> Comment.creation_changeset(user, params)
+      Ecto.build_assoc(image, :comments)
+      |> Comment.creation_changeset(params, attribution)
 
     image_query =
       Image
@@ -53,7 +53,7 @@ defmodule Philomena.Comments do
     |> Multi.insert(:comment, comment)
     |> Multi.update_all(:image, image_query, inc: [comments_count: 1])
     |> Multi.run(:subscribe, fn _repo, _changes ->
-      Images.create_subscription(image, user)
+      Images.create_subscription(image, attribution[:user])
     end)
     |> Repo.transaction()
   end

lib/philomena/comments/comment.ex

@@ -31,12 +31,13 @@ defmodule Philomena.Comments.Comment do
   end
 
   @doc false
-  def creation_changeset(comment, user, attrs) do
+  def creation_changeset(comment, attrs, attribution) do
     comment
     |> cast(attrs, [:body, :anonymous])
-    |> set_name_at_post_time(user)
     |> validate_required([:body])
     |> validate_length(:body, min: 1, max: 300_000, count: :bytes)
+    |> change(attribution)
+    |> put_name_at_post_time()
   end
 
   def changeset(comment, attrs) do
@@ -47,8 +48,8 @@ defmodule Philomena.Comments.Comment do
     |> validate_length(:edit_reason, max: 70, count: :bytes)
   end
 
-  def set_name_at_post_time(changeset, nil), do: changeset
-  def set_name_at_post_time(changeset, %{name: name}) do
-    change(changeset, name_at_post_time: name)
-  end
+  defp put_name_at_post_time(%{changes: %{user: %{data: %{name: name}}}} = changeset),
+    do: change(changeset, name_at_post_time: name)
+  defp put_name_at_post_time(changeset),
+    do: changeset
 end

lib/philomena/images/image.ex

@@ -15,10 +15,12 @@ defmodule Philomena.Images.Image do
   alias Philomena.Users.User
   alias Philomena.Images.Tagging
   alias Philomena.Galleries
+  alias Philomena.Comments.Comment
 
   schema "images" do
     belongs_to :user, User
     belongs_to :deleter, User, source: :deleted_by_id
+    has_many :comments, Comment
     has_many :upvotes, ImageVote, where: [up: true]
     has_many :downvotes, ImageVote, where: [up: false]
     has_many :faves, ImageFave

lib/philomena/posts.ex

@@ -41,7 +41,7 @@ defmodule Philomena.Posts do
       {:error, %Ecto.Changeset{}}
 
   """
-  def create_post(topic, user, attributes, params \\ %{}) do
+  def create_post(topic, attributes, params \\ %{}) do
     topic_query =
       Topic
       |> where(id: ^topic.id)
@@ -61,7 +61,7 @@ defmodule Philomena.Posts do
         |> repo.one()
 
       Ecto.build_assoc(topic, :posts, [topic_position: (last_position || -1) + 1] ++ attributes)
-      |> Post.creation_changeset(params, user)
+      |> Post.creation_changeset(params, attributes)
       |> repo.insert()
     end)
     |> Multi.run(:update_topic, fn repo, %{post: %{id: post_id}} ->
@@ -77,7 +77,7 @@ defmodule Philomena.Posts do
       {:ok, count}
     end)
     |> Multi.run(:subscribe, fn _repo, _changes ->
-      Topics.create_subscription(topic, user)
+      Topics.create_subscription(topic, attributes[:user])
     end)
     |> Repo.isolated_transaction(:serializable)
   end

lib/philomena/posts/post.ex

@@ -40,16 +40,17 @@ defmodule Philomena.Posts.Post do
   end
 
   @doc false
-  def creation_changeset(post, attrs, user) do
+  def creation_changeset(post, attrs, attribution) do
     post
     |> cast(attrs, [:body, :anonymous])
-    |> set_name_at_post_time(user)
     |> validate_required([:body])
     |> validate_length(:body, min: 1, max: 300_000, count: :bytes)
+    |> change(attribution)
+    |> put_name_at_post_time()
   end
 
-  def set_name_at_post_time(changeset, nil), do: changeset
-  def set_name_at_post_time(changeset, %{name: name}) do
-    change(changeset, name_at_post_time: name)
-  end
+  defp put_name_at_post_time(%{changes: %{user: %{data: %{name: name}}}} = changeset),
+    do: change(changeset, name_at_post_time: name)
+  defp put_name_at_post_time(changeset),
+    do: changeset
 end

lib/philomena_web/controllers/image/comment_controller.ex

@@ -63,9 +63,8 @@ defmodule PhilomenaWeb.Image.CommentController do
   def create(conn, %{"comment" => comment_params}) do
     attributes = conn.assigns.attributes
     image = conn.assigns.image
-    user = conn.assigns.current_user
 
-    case Comments.create_comment(image, user, attributes, comment_params) do
+    case Comments.create_comment(image, attributes, comment_params) do
       {:ok, %{comment: comment}} ->
         Comments.notify_comment(comment)
         Comments.reindex_comment(comment)

lib/philomena_web/controllers/topic/post_controller.ex

@@ -14,9 +14,8 @@ defmodule PhilomenaWeb.Topic.PostController do
     attributes = conn.assigns.attributes
     forum = conn.assigns.forum
     topic = conn.assigns.topic
-    user = conn.assigns.current_user
 
-    case Posts.create_post(topic, user, attributes, post_params) do
+    case Posts.create_post(topic, attributes, post_params) do
       {:ok, %{post: post}} ->
         Posts.notify_post(post)
         Posts.reindex_post(post)

lib/philomena_web/plugs/user_attribution_plug.ex

@@ -19,13 +19,15 @@ defmodule PhilomenaWeb.UserAttributionPlug do
   def call(conn, _opts) do
     {:ok, remote_ip} = EctoNetwork.INET.cast(conn.remote_ip)
     conn = Conn.fetch_cookies(conn)
+    user = Pow.Plug.current_user(conn)
+
     attributes =
       [
         ip:          remote_ip,
         fingerprint: conn.cookies["_ses"],
         referrer:    conn.assigns.referrer,
-        user_agent:  user_agent(conn),
-        user_id:     user_id(conn)
+        user:        user,
+        user_agent:  user_agent(conn)
       ]
 
     conn
@@ -38,13 +40,4 @@ defmodule PhilomenaWeb.UserAttributionPlug do
       _    -> nil
     end
   end
-
-  defp user_id(conn) do
-    user = Pow.Plug.current_user(conn)
-
-    case user do
-      %{id: id} -> id
-      _         -> nil
-    end
-  end
 end