From 9ad0c9b3fdbef933ccf6d0ec050b88a5c7e929d4 Mon Sep 17 00:00:00 2001
From: Ro <ro@ro.social>
Date: Mon, 18 Nov 2024 18:27:25 -0600
Subject: [PATCH] feat: Like and unlike posts

---
 README.md                                     |  4 +-
 lib/postland/activities.ex                    | 37 +++++++++++++++++++
 lib/postland/object.ex                        | 11 ++++++
 .../components/core_components.ex             |  9 +++++
 lib/postland_web/live/timeline_live.ex        | 26 +++++++++++++
 .../20241118235445_add_my_like_id.exs         |  9 +++++
 6 files changed, 94 insertions(+), 2 deletions(-)
 create mode 100644 priv/repo/migrations/20241118235445_add_my_like_id.exs

diff --git a/README.md b/README.md
index 2eafa4d..9ca983a 100644
--- a/README.md
+++ b/README.md
@@ -41,8 +41,8 @@
 - [x] Show the actor avatar and display name
 - [x] Receiving posts w/ images
 - [ ] Receiving posts w/ videos
-- [ ] Liking posts
-- [ ] Unliking posts
+- [x] Liking posts
+- [x] Unliking posts
 - [x] Displaying CW posts behind CW
 - [ ] Displaying polls
 - [ ] Voting in polls
diff --git a/lib/postland/activities.ex b/lib/postland/activities.ex
index b0c758f..a3f2687 100644
--- a/lib/postland/activities.ex
+++ b/lib/postland/activities.ex
@@ -8,6 +8,7 @@ defmodule Postland.Activities do
   alias Postland.Activity
   alias Postland.Repo
   alias Postland.Follows
+  alias Postland.Object
 
   def record_markdown_post(markdown, cw, attachments) do
     id = Ecto.UUID.autogenerate()
@@ -82,6 +83,42 @@ defmodule Postland.Activities do
     |> broadcast_to_followers(activity)
   end
 
+  def like_post(%{id: post_id} = post) do
+    like_id = url(~p"/activities/#{Ecto.UUID.autogenerate()}")
+
+    activity =
+      %{
+        "id" => like_id,
+        "@context" => "https://www.w3.org/ns/activitystreams",
+        "type" => "Like",
+        "actor" => Postland.my_actor_id(),
+        "object" => post_id
+      }
+
+    Multi.new()
+    |> Multi.insert(:activity, Activity.changeset(activity))
+    |> Multi.update(:update_meta_i_liked, Object.like_changeset(post, like_id))
+    |> Repo.transaction()
+    |> broadcast_to_followers(activity)
+  end
+
+  def unlike_post(%{my_like_id: like_id} = post) do
+    activity =
+      %{
+        "id" => url(~p"/activities/#{Ecto.UUID.autogenerate()}"),
+        "@context" => "https://www.w3.org/ns/activitystreams",
+        "type" => "Undo",
+        "actor" => Postland.my_actor_id(),
+        "object" => like_id
+      }
+
+    Multi.new()
+    |> Multi.insert(:activity, Activity.changeset(activity))
+    |> Multi.update(:object, Object.unlike_changeset(post))
+    |> Repo.transaction()
+    |> broadcast_to_followers(activity)
+  end
+
   def broadcast_to_followers({:ok, _} = result, activity) do
     my_actor_id = Postland.my_actor_id()
     private_key = Postland.Accounts.solo_user().private_key
diff --git a/lib/postland/object.ex b/lib/postland/object.ex
index 383301c..c1015bc 100644
--- a/lib/postland/object.ex
+++ b/lib/postland/object.ex
@@ -7,6 +7,7 @@ defmodule Postland.Object do
   schema "objects" do
     field :type, :string
     field :data, :map
+    field :my_like_id, :string
 
     timestamps()
   end
@@ -24,4 +25,14 @@ defmodule Postland.Object do
     |> validate_required(:data)
     |> validate_required(:type)
   end
+
+  def like_changeset(post, like_id) do
+    post
+    |> cast(%{"my_like_id" => like_id}, [:my_like_id])
+  end
+
+  def unlike_changeset(post) do
+    post
+    |> cast(%{"my_like_id" => nil}, [:my_like_id])
+  end
 end
diff --git a/lib/postland_web/components/core_components.ex b/lib/postland_web/components/core_components.ex
index dab06f7..3353dab 100644
--- a/lib/postland_web/components/core_components.ex
+++ b/lib/postland_web/components/core_components.ex
@@ -253,6 +253,15 @@ defmodule PostlandWeb.CoreComponents do
           >
             <.icon name="hero-trash" />
           </a>
+          <a
+            href="#"
+            phx-click={if @post.my_like_id, do: "unlike_post", else: "like_post"}
+            phx-value-post-dom-id={@post_dom_id}
+            phx-value-post-id={@post.id}
+            class={if @post.my_like_id, do: "text-yellow-500", else: "text-gray-500"}
+          >
+            <.icon name="hero-star" />
+          </a>
           <!-- Content goes here -->
               <!-- We use less vertical padding on card footers at all sizes than on headers or body sections -->
         </div>
diff --git a/lib/postland_web/live/timeline_live.ex b/lib/postland_web/live/timeline_live.ex
index 7d96e0f..8795dcd 100644
--- a/lib/postland_web/live/timeline_live.ex
+++ b/lib/postland_web/live/timeline_live.ex
@@ -73,6 +73,32 @@ defmodule PostlandWeb.TimelineLive do
     end
   end
 
+  def handle_event("like_post", %{"post-id" => id, "post-dom-id" => dom_id}, socket) do
+    post = Objects.get_by_id(id)
+
+    case Activities.like_post(post) do
+      {:ok, _} ->
+        post = Objects.get_by_id(id)
+        {:noreply, socket |> stream_insert(:posts, post)}
+
+      _ ->
+        {:noreply, socket |> put_flash(:error, "An unexpected error has occurred.")}
+    end
+  end
+
+  def handle_event("unlike_post", %{"post-id" => id, "post-dom-id" => dom_id}, socket) do
+    post = Objects.get_by_id(id)
+
+    case Activities.unlike_post(post) do
+      {:ok, _} ->
+        post = Objects.get_by_id(id)
+        {:noreply, socket |> stream_insert(:posts, post)}
+
+      _ ->
+        {:noreply, socket |> put_flash(:error, "An unexpected error has occurred.")}
+    end
+  end
+
   def handle_event("change_post", %{"post" => post} = params, socket) do
     cw = Map.get(params, "cw")
     {:noreply, socket |> assign(post: post, cw: cw)}
diff --git a/priv/repo/migrations/20241118235445_add_my_like_id.exs b/priv/repo/migrations/20241118235445_add_my_like_id.exs
new file mode 100644
index 0000000..fd8e4bc
--- /dev/null
+++ b/priv/repo/migrations/20241118235445_add_my_like_id.exs
@@ -0,0 +1,9 @@
+defmodule Postland.Repo.Migrations.AddMyLikeId do
+  use Ecto.Migration
+
+  def change do
+    alter table("objects") do
+      add :my_like_id, :string
+    end
+  end
+end