Add comments and vote models; pub/sub voting on posts

lib/aggiedit/accounts/user.ex

@@ -14,6 +14,8 @@ defmodule Aggiedit.Accounts.User do
 
     belongs_to :room, Room, on_replace: :update
     has_many :posts, Aggiedit.Rooms.Post
+    has_many :votes, Aggiedit.Post.Vote
+    has_many :comments, Aggiedit.Post.Comment
 
     timestamps()
   end

lib/aggiedit/roles.ex

@@ -6,7 +6,7 @@ defmodule Aggiedit.Roles do
   def guard?(user, action, object)
   def guard?(%User{role: :admin}, _, _), do: true
   def guard?(%User{room_id: rid}, :index, %Room{id: rid}), do: true
-  def guard?(%User{room_id: rid}, :show, %Post{room_id: rid}), do: true
+  def guard?(%User{room_id: rid}, action, %Post{room_id: rid}) when action in [:show, :vote], do: true
   def guard?(%User{id: id, room_id: rid}, action, %Post{user_id: id, room_id: rid}) when action in [:delete, :edit], do: true
   def guard?(_, _, _), do: false
 

lib/aggiedit/rooms.ex

@@ -6,9 +6,11 @@ defmodule Aggiedit.Rooms do
   import Ecto.Query, warn: false
   alias Aggiedit.Repo
 
-  alias Aggiedit.Accounts
+  alias Aggiedit.Accounts.User
   alias Aggiedit.Rooms.Room
 
+  alias Aggiedit.Post.{Vote, Comment}
+
   alias Phoenix.PubSub
 
   def list_rooms do
@@ -91,6 +93,23 @@ defmodule Aggiedit.Rooms do
     Post.changeset(post, attrs)
   end
 
+  def vote_count(post) do
+    votes = post
+    |> Repo.preload(:votes)
+    |> Map.get(:votes)
+    |> Enum.map(fn vote -> if vote.is_up, do: 1, else: -1 end)
+    |> Enum.sum()
+  end
+
+  def vote_post(%Post{} = post, %User{} = user, direction) do
+    is_up = direction == "upvote"
+    vote = %Vote{is_up: is_up, user: user, post: post}
+    |> Repo.insert(on_conflict: [set: [is_up: is_up]], conflict_target: [:user_id, :post_id])
+    post = change_post(post, %{score: vote_count(post)})
+    |> Repo.update()
+    broadcast_post_over_room(post, :post_voted)
+  end
+
   defp broadcast_post_over_room({:error, _reason}=error, _event), do: error
   defp broadcast_post_over_room({:ok, post}, event) do 
     PubSub.broadcast(Aggiedit.PubSub, "room:#{post.room_id}:posts", {event, post})

lib/aggiedit/rooms/comment.ex

@@ -0,0 +1,20 @@
+defmodule Aggiedit.Post.Comment do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "post_comments" do
+    field :comment, :string
+
+    belongs_to :user, Aggiedit.Accounts.User
+    belongs_to :post, Aggiedit.Rooms.Post
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(comment, attrs) do
+    comment
+    |> cast(attrs, [:comment])
+    |> validate_required([:comment])
+  end
+end

lib/aggiedit/rooms/post.ex

@@ -5,18 +5,22 @@ defmodule Aggiedit.Rooms.Post do
   schema "posts" do
     field :body, :string
     field :title, :string
+    field :score, :integer
     
     belongs_to :room, Aggiedit.Rooms.Room
     belongs_to :user, Aggiedit.Accounts.User
     belongs_to :upload, Aggiedit.Uploads.Upload
 
+    has_many :votes, Aggiedit.Post.Vote
+    has_many :comments, Aggiedit.Post.Comment
+
     timestamps()
   end
 
   @doc false
   def changeset(post, attrs) do
     post
-    |> cast(attrs, [:title, :body])
+    |> cast(attrs, [:title, :body, :score])
     |> validate_required([:title, :body])
   end
 

lib/aggiedit/rooms/vote.ex

@@ -0,0 +1,20 @@
+defmodule Aggiedit.Post.Vote do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "post_votes" do
+    field :is_up, :boolean
+
+    belongs_to :user, Aggiedit.Accounts.User
+    belongs_to :post, Aggiedit.Rooms.Post
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(vote, attrs) do
+    vote
+    |> cast(attrs, [:direction])
+    |> validate_required([:direction])
+  end
+end

lib/aggiedit_web/live/post_live/index.ex

@@ -12,7 +12,14 @@ defmodule AggieditWeb.PostLive.Index do
     case socket.assigns do
       %{:room => room} -> 
         if connected?(socket), do: Rooms.subscribe(socket.assigns.room)
-        {:ok, assign(socket, %{:posts => room |> Repo.preload(posts: [:user, :upload]) |> Map.get(:posts)}), temporary_assigns: [posts: []]}
+        posts = room 
+        |> Repo.preload(posts: [:user, :upload])
+        |> Map.get(:posts)
+        votes = socket.assigns.current_user
+        |> Repo.preload(:votes)
+        |> Map.get(:votes)
+        |> Enum.reduce(%{}, fn v, a -> Map.put(a, v.post_id, v) end)
+        {:ok, assign(socket, %{:posts => posts, :votes => votes}), temporary_assigns: [posts: []]}
       _ -> {:ok, socket}
     end
   end
@@ -50,6 +57,16 @@ defmodule AggieditWeb.PostLive.Index do
     |> assign(:post, nil)
   end
 
+  def handle_event(vote, %{"id" => id}, socket) when vote in ["upvote", "downvote"] do
+    post = Rooms.get_post!(id)
+    if Roles.guard?(socket.assigns.current_user, :vote, post) do
+      Rooms.vote_post(post, socket.assigns.current_user, vote)
+      {:noreply, socket}
+    else
+      {:noreply, socket |> put_flash(:error, "You don't have permission to do that.") |> redirect(to: Routes.post_show_path(socket, :show, socket.assigns.room, post))}
+    end
+  end
+
   @impl true
   def handle_event("delete", %{"id" => id}, socket) do
     post = Rooms.get_post!(id)
@@ -62,7 +79,7 @@ defmodule AggieditWeb.PostLive.Index do
   end
 
   @impl true
-  def handle_info({action, post}, socket) when action in [:post_created, :post_updated, :post_deleted] do
+  def handle_info({action, post}, socket) when action in [:post_created, :post_updated, :post_deleted, :post_voted] do
     {:noreply, update(socket, :posts, fn posts -> 
       [posts | post]
     end)}

lib/aggiedit_web/live/post_live/index.html.heex

@@ -18,13 +18,29 @@
 <div id="posts" phx-update="prepend">
   <%= for post <- @posts do %>
     <div id={"post-#{post.id}"} class="card d-flex flex-row align-items-center p-2 m-2 shadow">
+      <div class="d-flex flex-column m-2">
+        <%= 
+          has_vote = Map.has_key?(@votes, post.id)
+          is_upvote = has_vote && @votes[post.id].is_up
+          ""
+        %>
+        <div class="d-flex">
+          <span><%= link "", to: "#", phx_click: "upvote", phx_value_id: post.id, class: "bi bi-arrow-up-circle#{if has_vote && is_upvote, do: "-fill", else: ""}" %></span>
+        </div>
+        <div class="d-flex">
+          <%= post.score %>
+        </div>
+        <div class="d-flex">
+          <span><%= link "", to: "#", phx_click: "downvote", phx_value_id: post.id, class: "bi bi-arrow-down-circle#{if has_vote && !is_upvote, do: "-fill", else: ""}" %></span>
+        </div>
+      </div>
+      <div class="m-2 card-image d-flex justify-content-center" style="width: 100px">
         <%= if !is_nil(post.upload) do %>
           <%= live_redirect to: Routes.post_show_path(@socket, :show, @room, post) do %>
-          <div class="card-image d-flex justify-content-center" style="width: 100px">
             <img class="fluid-img thumbnail" src={Routes.static_path(@socket, "/uploads/#{post.upload.file}")} />
+          <% end %>
+        <% end %>
       </div>
-        <% end %>
-      <% end %>
       <div class="card-body">
         <%= live_redirect to: Routes.post_show_path(@socket, :show, @room, post) do %>
           <h4 class="card-title"><%= post.title %></h4>

lib/aggiedit_web/templates/layout/root.html.heex

@@ -11,6 +11,7 @@
 
     <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3" crossorigin="anonymous">
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js" integrity="sha384-ka7Sk0Gln4gmtz2MlQnikT1wXgYsOg+OMhuP+IlRH9sENBO0LRn5q+8nbTov4+1p" crossorigin="anonymous"></script>
+    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.8.0/font/bootstrap-icons.css">
   </head>
   <body class="bg-secondary min-vh-100">
     <header>

priv/repo/migrations/20220406185124_create_posts.exs

@@ -5,6 +5,7 @@ defmodule Aggiedit.Repo.Migrations.CreatePosts do
     create table(:posts) do
       add :title, :text
       add :body, :text
+      add :score, :integer, default: 0
       add :user_id, references(:users, on_delete: :nothing)
       add :upload_id, references(:uploads, on_delete: :nothing)
       add :room_id, references(:rooms, on_delete: :nothing)

priv/repo/migrations/20220415015055_create_post_votes.exs

@@ -0,0 +1,15 @@
+defmodule Aggiedit.Repo.Migrations.CreatePostVotes do
+  use Ecto.Migration
+
+  def change do
+    create table(:post_votes) do
+      add :is_up, :boolean
+      add :user_id, references(:users, on_delete: :nothing)
+      add :post_id, references(:posts, on_delete: :delete_all)
+
+      timestamps()
+    end
+
+    create unique_index(:post_votes, [:user_id, :post_id])
+  end
+end

priv/repo/migrations/20220415021530_create_post_comments.exs

@@ -0,0 +1,16 @@
+defmodule Aggiedit.Repo.Migrations.CreatePostComments do
+  use Ecto.Migration
+
+  def change do
+    create table(:post_comments) do
+      add :comment, :text
+      add :user_id, references(:users, on_delete: :delete_all)
+      add :post_id, references(:posts, on_delete: :delete_all)
+
+      timestamps()
+    end
+
+    create index(:post_comments, [:user_id])
+    create index(:post_comments, [:post_id])
+  end
+end