7 files changed, 571 insertions, 37 deletions

diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index 65dd251f3..1e2cc2e2b 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -322,6 +322,32 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end
   end
 
+  def react_with_emoji(user, object, emoji, options \\ []) do
+    with local <- Keyword.get(options, :local, true),
+         activity_id <- Keyword.get(options, :activity_id, nil),
+         Pleroma.Emoji.is_unicode_emoji?(emoji),
+         reaction_data <- make_emoji_reaction_data(user, object, emoji, activity_id),
+         {:ok, activity} <- insert(reaction_data, local),
+         {:ok, object} <- add_emoji_reaction_to_object(activity, object),
+         :ok <- maybe_federate(activity) do
+      {:ok, activity, object}
+    end
+  end
+
+  def unreact_with_emoji(user, reaction_id, options \\ []) do
+    with local <- Keyword.get(options, :local, true),
+         activity_id <- Keyword.get(options, :activity_id, nil),
+         user_ap_id <- user.ap_id,
+         %Activity{actor: ^user_ap_id} = reaction_activity <- Activity.get_by_ap_id(reaction_id),
+         object <- Object.normalize(reaction_activity),
+         unreact_data <- make_undo_data(user, reaction_activity, activity_id),
+         {:ok, activity} <- insert(unreact_data, local),
+         {:ok, object} <- remove_emoji_reaction_from_object(reaction_activity, object),
+         :ok <- maybe_federate(activity) do
+      {:ok, activity, object}
+    end
+  end
+
   # TODO: This is weird, maybe we shouldn't check here if we can make the activity.
   def like(
         %User{ap_id: ap_id} = user,
@@ -430,17 +456,18 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     user = User.get_cached_by_ap_id(actor)
     to = (object.data["to"] || []) ++ (object.data["cc"] || [])
 
-    with {:ok, object, activity} <- Object.delete(object),
+    with create_activity <- Activity.get_create_by_object_ap_id(id),
          data <-
            %{
              "type" => "Delete",
              "actor" => actor,
              "object" => id,
              "to" => to,
-             "deleted_activity_id" => activity && activity.id
+             "deleted_activity_id" => create_activity && create_activity.id
            }
            |> maybe_put("id", activity_id),
          {:ok, activity} <- insert(data, local, false),
+         {:ok, object, _create_activity} <- Object.delete(object),
          stream_out_participations(object, user),
          _ <- decrease_replies_count_if_reply(object),
          {:ok, _actor} <- decrease_note_count_if_public(user, object),
@@ -515,6 +542,30 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end
   end
 
+  def move(%User{} = origin, %User{} = target, local \\ true) do
+    params = %{
+      "type" => "Move",
+      "actor" => origin.ap_id,
+      "object" => origin.ap_id,
+      "target" => target.ap_id
+    }
+
+    with true <- origin.ap_id in target.also_known_as,
+         {:ok, activity} <- insert(params, local) do
+      maybe_federate(activity)
+
+      BackgroundWorker.enqueue("move_following", %{
+        "origin_id" => origin.id,
+        "target_id" => target.id
+      })
+
+      {:ok, activity}
+    else
+      false -> {:error, "Target account must have the origin in `alsoKnownAs`"}
+      err -> err
+    end
+  end
+
   defp fetch_activities_for_context_query(context, opts) do
     public = [Pleroma.Constants.as_public()]
 
@@ -698,6 +749,15 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
       |> Map.put("whole_db", true)
       |> Map.put("pinned_activity_ids", user.pinned_activities)
 
+    params =
+      if User.blocks?(reading_user, user) do
+        params
+      else
+        params
+        |> Map.put("blocking_user", reading_user)
+        |> Map.put("muting_user", reading_user)
+      end
+
     recipients =
       user_activities_recipients(%{
         "godmode" => params["godmode"],
@@ -708,6 +768,17 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     |> Enum.reverse()
   end
 
+  def fetch_instance_activities(params) do
+    params =
+      params
+      |> Map.put("type", ["Create", "Announce"])
+      |> Map.put("instance", params["instance"])
+      |> Map.put("whole_db", true)
+
+    fetch_activities([Pleroma.Constants.as_public()], params, :offset)
+    |> Enum.reverse()
+  end
+
   defp user_activities_recipients(%{"godmode" => true}) do
     []
   end
@@ -858,7 +929,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
   defp restrict_muted(query, %{"with_muted" => val}) when val in [true, "true", "1"], do: query
 
   defp restrict_muted(query, %{"muting_user" => %User{} = user} = opts) do
-    mutes = user.mutes
+    mutes = opts["muted_users_ap_ids"] || User.muted_users_ap_ids(user)
 
     query =
       from([activity] in query,
@@ -875,8 +946,8 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
   defp restrict_muted(query, _), do: query
 
-  defp restrict_blocked(query, %{"blocking_user" => %User{} = user}) do
-    blocks = user.blocks || []
+  defp restrict_blocked(query, %{"blocking_user" => %User{} = user} = opts) do
+    blocked_ap_ids = opts["blocked_users_ap_ids"] || User.blocked_users_ap_ids(user)
     domain_blocks = user.domain_blocks || []
 
     query =
@@ -884,14 +955,14 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
     from(
       [activity, object: o] in query,
-      where: fragment("not (? = ANY(?))", activity.actor, ^blocks),
-      where: fragment("not (? && ?)", activity.recipients, ^blocks),
+      where: fragment("not (? = ANY(?))", activity.actor, ^blocked_ap_ids),
+      where: fragment("not (? && ?)", activity.recipients, ^blocked_ap_ids),
       where:
         fragment(
           "not (?->>'type' = 'Announce' and ?->'to' \\?| ?)",
           activity.data,
           activity.data,
-          ^blocks
+          ^blocked_ap_ids
         ),
       where: fragment("not (split_part(?, '/', 3) = ANY(?))", activity.actor, ^domain_blocks),
       where: fragment("not (split_part(?->>'actor', '/', 3) = ANY(?))", o.data, ^domain_blocks)
@@ -918,8 +989,8 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
   defp restrict_pinned(query, _), do: query
 
-  defp restrict_muted_reblogs(query, %{"muting_user" => %User{} = user}) do
-    muted_reblogs = user.muted_reblogs || []
+  defp restrict_muted_reblogs(query, %{"muting_user" => %User{} = user} = opts) do
+    muted_reblogs = opts["reblog_muted_users_ap_ids"] || User.reblog_muted_users_ap_ids(user)
 
     from(
       activity in query,
@@ -935,6 +1006,20 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
   defp restrict_muted_reblogs(query, _), do: query
 
+  defp restrict_instance(query, %{"instance" => instance}) do
+    users =
+      from(
+        u in User,
+        select: u.ap_id,
+        where: fragment("? LIKE ?", u.nickname, ^"%@#{instance}")
+      )
+      |> Repo.all()
+
+    from(activity in query, where: activity.actor in ^users)
+  end
+
+  defp restrict_instance(query, _), do: query
+
   defp exclude_poll_votes(query, %{"include_poll_votes" => true}), do: query
 
   defp exclude_poll_votes(query, _) do
@@ -986,7 +1071,33 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
   defp maybe_order(query, _), do: query
 
+  defp fetch_activities_query_ap_ids_ops(opts) do
+    source_user = opts["muting_user"]
+    ap_id_relations = if source_user, do: [:mute, :reblog_mute], else: []
+
+    ap_id_relations =
+      ap_id_relations ++
+        if opts["blocking_user"] && opts["blocking_user"] == source_user do
+          [:block]
+        else
+          []
+        end
+
+    preloaded_ap_ids = User.outgoing_relations_ap_ids(source_user, ap_id_relations)
+
+    restrict_blocked_opts = Map.merge(%{"blocked_users_ap_ids" => preloaded_ap_ids[:block]}, opts)
+    restrict_muted_opts = Map.merge(%{"muted_users_ap_ids" => preloaded_ap_ids[:mute]}, opts)
+
+    restrict_muted_reblogs_opts =
+      Map.merge(%{"reblog_muted_users_ap_ids" => preloaded_ap_ids[:reblog_mute]}, opts)
+
+    {restrict_blocked_opts, restrict_muted_opts, restrict_muted_reblogs_opts}
+  end
+
   def fetch_activities_query(recipients, opts \\ %{}) do
+    {restrict_blocked_opts, restrict_muted_opts, restrict_muted_reblogs_opts} =
+      fetch_activities_query_ap_ids_ops(opts)
+
     config = %{
       skip_thread_containment: Config.get([:instance, :skip_thread_containment])
     }
@@ -1006,15 +1117,16 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     |> restrict_type(opts)
     |> restrict_state(opts)
     |> restrict_favorited_by(opts)
-    |> restrict_blocked(opts)
-    |> restrict_muted(opts)
+    |> restrict_blocked(restrict_blocked_opts)
+    |> restrict_muted(restrict_muted_opts)
     |> restrict_media(opts)
     |> restrict_visibility(opts)
     |> restrict_thread_visibility(opts, config)
     |> restrict_replies(opts)
     |> restrict_reblogs(opts)
     |> restrict_pinned(opts)
-    |> restrict_muted_reblogs(opts)
+    |> restrict_muted_reblogs(restrict_muted_reblogs_opts)
+    |> restrict_instance(opts)
     |> Activity.restrict_deactivated_users()
     |> exclude_poll_votes(opts)
     |> exclude_visibility(opts)
@@ -1119,7 +1231,8 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
       name: data["name"],
       follower_address: data["followers"],
       following_address: data["following"],
-      bio: data["summary"]
+      bio: data["summary"],
+      also_known_as: Map.get(data, "alsoKnownAs", [])
     }
 
     # nickname can be nil because of virtual actors
@@ -1181,13 +1294,13 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end
   end
 
-  defp collection_private(data) do
-    if is_map(data["first"]) and
-         data["first"]["type"] in ["CollectionPage", "OrderedCollectionPage"] do
+  defp collection_private(%{"first" => first}) do
+    if is_map(first) and
+         first["type"] in ["CollectionPage", "OrderedCollectionPage"] do
       {:ok, false}
     else
       with {:ok, %{"type" => type}} when type in ["CollectionPage", "OrderedCollectionPage"] <-
-             Fetcher.fetch_and_contain_remote_object_from_id(data["first"]) do
+             Fetcher.fetch_and_contain_remote_object_from_id(first) do
         {:ok, false}
       else
         {:error, {:ok, %{status: code}}} when code in [401, 403] ->
@@ -1202,6 +1315,8 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end
   end
 
+  defp collection_private(_data), do: {:ok, true}
+
   def user_data_from_user_object(data) do
     with {:ok, data} <- MRF.filter(data),
          {:ok, data} <- object_to_user_data(data) do
diff --git a/lib/pleroma/web/activity_pub/activity_pub_controller.ex b/lib/pleroma/web/activity_pub/activity_pub_controller.ex
index b2cd965fe..dec5da0d3 100644
--- a/lib/pleroma/web/activity_pub/activity_pub_controller.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub_controller.ex
@@ -45,7 +45,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubController do
   end
 
   def user(conn, %{"nickname" => nickname}) do
-    with %User{} = user <- User.get_cached_by_nickname(nickname),
+    with %User{local: true} = user <- User.get_cached_by_nickname(nickname),
          {:ok, user} <- User.ensure_keys_present(user) do
       conn
       |> put_resp_content_type("application/activity+json")
@@ -53,6 +53,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubController do
       |> render("user.json", %{user: user})
     else
       nil -> {:error, :not_found}
+      %{local: false} -> {:error, :not_found}
     end
   end
 
diff --git a/lib/pleroma/web/activity_pub/mrf/object_age_policy.ex b/lib/pleroma/web/activity_pub/mrf/object_age_policy.ex
new file mode 100644
index 000000000..8b36c1021
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/mrf/object_age_policy.ex
@@ -0,0 +1,101 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.ObjectAgePolicy do
+  alias Pleroma.Config
+  alias Pleroma.User
+  alias Pleroma.Web.ActivityPub.MRF
+
+  require Pleroma.Constants
+
+  @moduledoc "Filter activities depending on their age"
+  @behaviour MRF
+
+  defp check_date(%{"published" => published} = message) do
+    with %DateTime{} = now <- DateTime.utc_now(),
+         {:ok, %DateTime{} = then, _} <- DateTime.from_iso8601(published),
+         max_ttl <- Config.get([:mrf_object_age, :threshold]),
+         {:ttl, false} <- {:ttl, DateTime.diff(now, then) > max_ttl} do
+      {:ok, message}
+    else
+      {:ttl, true} ->
+        {:reject, nil}
+
+      e ->
+        {:error, e}
+    end
+  end
+
+  defp check_reject(message, actions) do
+    if :reject in actions do
+      {:reject, nil}
+    else
+      {:ok, message}
+    end
+  end
+
+  defp check_delist(message, actions) do
+    if :delist in actions do
+      with %User{} = user <- User.get_cached_by_ap_id(message["actor"]) do
+        to = List.delete(message["to"], Pleroma.Constants.as_public()) ++ [user.follower_address]
+        cc = List.delete(message["cc"], user.follower_address) ++ [Pleroma.Constants.as_public()]
+
+        message =
+          message
+          |> Map.put("to", to)
+          |> Map.put("cc", cc)
+
+        {:ok, message}
+      else
+        # Unhandleable error: somebody is messing around, just drop the message.
+        _e ->
+          {:reject, nil}
+      end
+    else
+      {:ok, message}
+    end
+  end
+
+  defp check_strip_followers(message, actions) do
+    if :strip_followers in actions do
+      with %User{} = user <- User.get_cached_by_ap_id(message["actor"]) do
+        to = List.delete(message["to"], user.follower_address)
+        cc = List.delete(message["cc"], user.follower_address)
+
+        message =
+          message
+          |> Map.put("to", to)
+          |> Map.put("cc", cc)
+
+        {:ok, message}
+      else
+        # Unhandleable error: somebody is messing around, just drop the message.
+        _e ->
+          {:reject, nil}
+      end
+    else
+      {:ok, message}
+    end
+  end
+
+  @impl true
+  def filter(%{"type" => "Create", "published" => _} = message) do
+    with actions <- Config.get([:mrf_object_age, :actions]),
+         {:reject, _} <- check_date(message),
+         {:ok, message} <- check_reject(message, actions),
+         {:ok, message} <- check_delist(message, actions),
+         {:ok, message} <- check_strip_followers(message, actions) do
+      {:ok, message}
+    else
+      # check_date() is allowed to short-circuit the pipeline
+      e -> e
+    end
+  end
+
+  @impl true
+  def filter(message), do: {:ok, message}
+
+  @impl true
+  def describe, do: {:ok, %{}}
+end
diff --git a/lib/pleroma/web/activity_pub/relay.ex b/lib/pleroma/web/activity_pub/relay.ex
index fc2619680..99a804568 100644
--- a/lib/pleroma/web/activity_pub/relay.ex
+++ b/lib/pleroma/web/activity_pub/relay.ex
@@ -14,7 +14,6 @@ defmodule Pleroma.Web.ActivityPub.Relay do
       relay_ap_id()
       |> User.get_or_create_service_actor_by_ap_id()
 
-    {:ok, actor} = User.set_invisible(actor, true)
     actor
   end
 
diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 91a164eff..ecba27bef 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -387,7 +387,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def handle_incoming(%{"id" => nil}, _options), do: :error
   def handle_incoming(%{"id" => ""}, _options), do: :error
   # length of https:// = 8, should validate better, but good enough for now.
-  def handle_incoming(%{"id" => id}, _options) when not (is_binary(id) and length(id) > 8),
+  def handle_incoming(%{"id" => id}, _options) when is_binary(id) and byte_size(id) < 8,
     do: :error
 
   # TODO: validate those with a Ecto scheme
@@ -566,6 +566,34 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
+  @misskey_reactions %{
+    "like" => "👍",
+    "love" => "❤️",
+    "laugh" => "😆",
+    "hmm" => "🤔",
+    "surprise" => "😮",
+    "congrats" => "🎉",
+    "angry" => "💢",
+    "confused" => "😥",
+    "rip" => "😇",
+    "pudding" => "🍮",
+    "star" => "⭐"
+  }
+
+  @doc "Rewrite misskey likes into EmojiReactions"
+  def handle_incoming(
+        %{
+          "type" => "Like",
+          "_misskey_reaction" => reaction
+        } = data,
+        options
+      ) do
+    data
+    |> Map.put("type", "EmojiReaction")
+    |> Map.put("content", @misskey_reactions[reaction] || reaction)
+    |> handle_incoming(options)
+  end
+
   def handle_incoming(
         %{"type" => "Like", "object" => object_id, "actor" => _actor, "id" => id} = data,
         _options
@@ -581,6 +609,27 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   end
 
   def handle_incoming(
+        %{
+          "type" => "EmojiReaction",
+          "object" => object_id,
+          "actor" => _actor,
+          "id" => id,
+          "content" => emoji
+        } = data,
+        _options
+      ) do
+    with actor <- Containment.get_actor(data),
+         {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
+         {:ok, object} <- get_obj_helper(object_id),
+         {:ok, activity, _object} <-
+           ActivityPub.react_with_emoji(actor, object, emoji, activity_id: id, local: false) do
+      {:ok, activity}
+    else
+      _e -> :error
+    end
+  end
+
+  def handle_incoming(
         %{"type" => "Announce", "object" => object_id, "actor" => _actor, "id" => id} = data,
         _options
       ) do
@@ -620,7 +669,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
 
       update_data =
         new_user_data
-        |> Map.take([:avatar, :banner, :bio, :name])
+        |> Map.take([:avatar, :banner, :bio, :name, :also_known_as])
         |> Map.put(:fields, fields)
         |> Map.put(:locked, locked)
         |> Map.put(:invisible, invisible)
@@ -718,6 +767,28 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def handle_incoming(
         %{
           "type" => "Undo",
+          "object" => %{"type" => "EmojiReaction", "id" => reaction_activity_id},
+          "actor" => _actor,
+          "id" => id
+        } = data,
+        _options
+      ) do
+    with actor <- Containment.get_actor(data),
+         {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
+         {:ok, activity, _} <-
+           ActivityPub.unreact_with_emoji(actor, reaction_activity_id,
+             activity_id: id,
+             local: false
+           ) do
+      {:ok, activity}
+    else
+      _e -> :error
+    end
+  end
+
+  def handle_incoming(
+        %{
+          "type" => "Undo",
           "object" => %{"type" => "Block", "object" => blocked},
           "actor" => blocker,
           "id" => id
@@ -786,6 +857,24 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
+  def handle_incoming(
+        %{
+          "type" => "Move",
+          "actor" => origin_actor,
+          "object" => origin_actor,
+          "target" => target_actor
+        },
+        _options
+      ) do
+    with %User{} = origin_user <- User.get_cached_by_ap_id(origin_actor),
+         {:ok, %User{} = target_user} <- User.get_or_fetch_by_ap_id(target_actor),
+         true <- origin_actor in target_user.also_known_as do
+      ActivityPub.move(origin_user, target_user, false)
+    else
+      _e -> :error
+    end
+  end
+
   def handle_incoming(_, _), do: :error
 
   @spec get_obj_helper(String.t(), Keyword.t()) :: {:ok, Object.t()} | nil
@@ -1048,7 +1137,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     Map.put(object, "attachment", attachments)
   end
 
-  defp strip_internal_fields(object) do
+  def strip_internal_fields(object) do
     object
     |> Map.drop(Pleroma.Constants.object_internal_fields())
   end
diff --git a/lib/pleroma/web/activity_pub/utils.ex b/lib/pleroma/web/activity_pub/utils.ex
index d812fd734..2ca805c09 100644
--- a/lib/pleroma/web/activity_pub/utils.ex
+++ b/lib/pleroma/web/activity_pub/utils.ex
@@ -11,6 +11,7 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   alias Pleroma.Repo
   alias Pleroma.User
   alias Pleroma.Web
+  alias Pleroma.Web.ActivityPub.ActivityPub
   alias Pleroma.Web.ActivityPub.Visibility
   alias Pleroma.Web.AdminAPI.AccountView
   alias Pleroma.Web.Endpoint
@@ -255,6 +256,16 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> Repo.one()
   end
 
+  @doc """
+  Returns like activities targeting an object
+  """
+  def get_object_likes(%{data: %{"id" => id}}) do
+    id
+    |> Activity.Queries.by_object_id()
+    |> Activity.Queries.by_type("Like")
+    |> Repo.all()
+  end
+
   @spec make_like_data(User.t(), map(), String.t()) :: map()
   def make_like_data(
         %User{ap_id: ap_id} = actor,
@@ -286,13 +297,30 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> maybe_put("id", activity_id)
   end
 
+  def make_emoji_reaction_data(user, object, emoji, activity_id) do
+    make_like_data(user, object, activity_id)
+    |> Map.put("type", "EmojiReaction")
+    |> Map.put("content", emoji)
+  end
+
   @spec update_element_in_object(String.t(), list(any), Object.t()) ::
           {:ok, Object.t()} | {:error, Ecto.Changeset.t()}
   def update_element_in_object(property, element, object) do
+    length =
+      if is_map(element) do
+        element
+        |> Map.values()
+        |> List.flatten()
+        |> length()
+      else
+        element
+        |> length()
+      end
+
     data =
       Map.merge(
         object.data,
-        %{"#{property}_count" => length(element), "#{property}s" => element}
+        %{"#{property}_count" => length, "#{property}s" => element}
       )
 
     object
@@ -300,6 +328,38 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> Object.update_and_set_cache()
   end
 
+  @spec add_emoji_reaction_to_object(Activity.t(), Object.t()) ::
+          {:ok, Object.t()} | {:error, Ecto.Changeset.t()}
+
+  def add_emoji_reaction_to_object(
+        %Activity{data: %{"content" => emoji, "actor" => actor}},
+        object
+      ) do
+    reactions = object.data["reactions"] || %{}
+    emoji_actors = reactions[emoji] || []
+    new_emoji_actors = [actor | emoji_actors] |> Enum.uniq()
+    new_reactions = Map.put(reactions, emoji, new_emoji_actors)
+    update_element_in_object("reaction", new_reactions, object)
+  end
+
+  def remove_emoji_reaction_from_object(
+        %Activity{data: %{"content" => emoji, "actor" => actor}},
+        object
+      ) do
+    reactions = object.data["reactions"] || %{}
+    emoji_actors = reactions[emoji] || []
+    new_emoji_actors = List.delete(emoji_actors, actor)
+
+    new_reactions =
+      if new_emoji_actors == [] do
+        Map.delete(reactions, emoji)
+      else
+        Map.put(reactions, emoji, new_emoji_actors)
+      end
+
+    update_element_in_object("reaction", new_reactions, object)
+  end
+
   @spec add_like_to_object(Activity.t(), Object.t()) ::
           {:ok, Object.t()} | {:error, Ecto.Changeset.t()}
   def add_like_to_object(%Activity{data: %{"actor" => actor}}, object) do
@@ -397,6 +457,19 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> Repo.one()
   end
 
+  def get_latest_reaction(internal_activity_id, %{ap_id: ap_id}, emoji) do
+    %{data: %{"object" => object_ap_id}} = Activity.get_by_id(internal_activity_id)
+
+    "EmojiReaction"
+    |> Activity.Queries.by_type()
+    |> where(actor: ^ap_id)
+    |> where([activity], fragment("?->>'content' = ?", activity.data, ^emoji))
+    |> Activity.Queries.by_object_id(object_ap_id)
+    |> order_by([activity], fragment("? desc nulls last", activity.id))
+    |> limit(1)
+    |> Repo.one()
+  end
+
   #### Announce-related helpers
 
   @doc """
@@ -489,6 +562,25 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> maybe_put("id", activity_id)
   end
 
+  def make_undo_data(
+        %User{ap_id: actor, follower_address: follower_address},
+        %Activity{
+          data: %{"id" => undone_activity_id, "context" => context},
+          actor: undone_activity_actor
+        },
+        activity_id \\ nil
+      ) do
+    %{
+      "type" => "Undo",
+      "actor" => actor,
+      "object" => undone_activity_id,
+      "to" => [follower_address, undone_activity_actor],
+      "cc" => [Pleroma.Constants.as_public()],
+      "context" => context
+    }
+    |> maybe_put("id", activity_id)
+  end
+
   @spec add_announce_to_object(Activity.t(), Object.t()) ::
           {:ok, Object.t()} | {:error, Ecto.Changeset.t()}
   def add_announce_to_object(
@@ -615,26 +707,37 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   def make_flag_data(_, _), do: %{}
 
   defp build_flag_object(%{account: account, statuses: statuses} = _) do
-    [account.ap_id] ++
-      Enum.map(statuses || [], fn act ->
-        id =
-          case act do
-            %Activity{} = act -> act.data["id"]
-            act when is_map(act) -> act["id"]
-            act when is_binary(act) -> act
-          end
+    [account.ap_id] ++ build_flag_object(%{statuses: statuses})
+  end
 
-        activity = Activity.get_by_ap_id_with_object(id)
-        actor = User.get_by_ap_id(activity.object.data["actor"])
+  defp build_flag_object(%{statuses: statuses}) do
+    Enum.map(statuses || [], &build_flag_object/1)
+  end
+
+  defp build_flag_object(act) when is_map(act) or is_binary(act) do
+    id =
+      case act do
+        %Activity{} = act -> act.data["id"]
+        act when is_map(act) -> act["id"]
+        act when is_binary(act) -> act
+      end
 
+    case Activity.get_by_ap_id_with_object(id) do
+      %Activity{} = activity ->
         %{
           "type" => "Note",
           "id" => activity.data["id"],
           "content" => activity.object.data["content"],
           "published" => activity.object.data["published"],
-          "actor" => AccountView.render("show.json", %{user: actor})
+          "actor" =>
+            AccountView.render("show.json", %{
+              user: User.get_by_ap_id(activity.object.data["actor"])
+            })
         }
-      end)
+
+      _ ->
+        %{"id" => id, "deleted" => true}
+    end
   end
 
   defp build_flag_object(_), do: []
@@ -679,6 +782,113 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   end
 
   #### Report-related helpers
+  def get_reports(params, page, page_size) do
+    params =
+      params
+      |> Map.put("type", "Flag")
+      |> Map.put("skip_preload", true)
+      |> Map.put("total", true)
+      |> Map.put("limit", page_size)
+      |> Map.put("offset", (page - 1) * page_size)
+
+    ActivityPub.fetch_activities([], params, :offset)
+  end
+
+  def parse_report_group(activity) do
+    reports = get_reports_by_status_id(activity["id"])
+    max_date = Enum.max_by(reports, &NaiveDateTime.from_iso8601!(&1.data["published"]))
+    actors = Enum.map(reports, & &1.user_actor)
+    [%{data: %{"object" => [account_id | _]}} | _] = reports
+
+    account =
+      AccountView.render("show.json", %{
+        user: User.get_by_ap_id(account_id)
+      })
+
+    status = get_status_data(activity)
+
+    %{
+      date: max_date.data["published"],
+      account: account,
+      status: status,
+      actors: Enum.uniq(actors),
+      reports: reports
+    }
+  end
+
+  defp get_status_data(status) do
+    case status["deleted"] do
+      true ->
+        %{
+          "id" => status["id"],
+          "deleted" => true
+        }
+
+      _ ->
+        Activity.get_by_ap_id(status["id"])
+    end
+  end
+
+  def get_reports_by_status_id(ap_id) do
+    from(a in Activity,
+      where: fragment("(?)->>'type' = 'Flag'", a.data),
+      where: fragment("(?)->'object' @> ?", a.data, ^[%{id: ap_id}]),
+      or_where: fragment("(?)->'object' @> ?", a.data, ^[ap_id])
+    )
+    |> Activity.with_preloaded_user_actor()
+    |> Repo.all()
+  end
+
+  @spec get_reports_grouped_by_status([String.t()]) :: %{
+          required(:groups) => [
+            %{
+              required(:date) => String.t(),
+              required(:account) => %{},
+              required(:status) => %{},
+              required(:actors) => [%User{}],
+              required(:reports) => [%Activity{}]
+            }
+          ]
+        }
+  def get_reports_grouped_by_status(activity_ids) do
+    parsed_groups =
+      activity_ids
+      |> Enum.map(fn id ->
+        id
+        |> build_flag_object()
+        |> parse_report_group()
+      end)
+
+    %{
+      groups: parsed_groups
+    }
+  end
+
+  @spec get_reported_activities() :: [
+          %{
+            required(:activity) => String.t(),
+            required(:date) => String.t()
+          }
+        ]
+  def get_reported_activities do
+    reported_activities_query =
+      from(a in Activity,
+        where: fragment("(?)->>'type' = 'Flag'", a.data),
+        select: %{
+          activity: fragment("jsonb_array_elements((? #- '{object,0}')->'object')", a.data)
+        },
+        group_by: fragment("activity")
+      )
+
+    from(a in subquery(reported_activities_query),
+      distinct: true,
+      select: %{
+        id: fragment("COALESCE(?->>'id'::text, ? #>> '{}')", a.activity, a.activity)
+      }
+    )
+    |> Repo.all()
+    |> Enum.map(& &1.id)
+  end
 
   def update_report_state(%Activity{} = activity, state)
       when state in @strip_status_report_states do
@@ -702,11 +912,29 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> Repo.update()
   end
 
+  def update_report_state(activity_ids, state) when state in @supported_report_states do
+    activities_num = length(activity_ids)
+
+    from(a in Activity, where: a.id in ^activity_ids)
+    |> update(set: [data: fragment("jsonb_set(data, '{state}', ?)", ^state)])
+    |> Repo.update_all([])
+    |> case do
+      {^activities_num, _} -> :ok
+      _ -> {:error, activity_ids}
+    end
+  end
+
   def update_report_state(_, _), do: {:error, "Unsupported state"}
 
   def strip_report_status_data(activity) do
     [actor | reported_activities] = activity.data["object"]
-    stripped_activities = Enum.map(reported_activities, & &1["id"])
+
+    stripped_activities =
+      Enum.map(reported_activities, fn
+        act when is_map(act) -> act["id"]
+        act when is_binary(act) -> act
+      end)
+
     new_data = put_in(activity.data, ["object"], [actor | stripped_activities])
 
     {:ok, %{activity | data: new_data}}
diff --git a/lib/pleroma/web/activity_pub/visibility.ex b/lib/pleroma/web/activity_pub/visibility.ex
index cd4097493..e172f6d3f 100644
--- a/lib/pleroma/web/activity_pub/visibility.ex
+++ b/lib/pleroma/web/activity_pub/visibility.ex
@@ -14,6 +14,7 @@ defmodule Pleroma.Web.ActivityPub.Visibility do
   @spec is_public?(Object.t() | Activity.t() | map()) :: boolean()
   def is_public?(%Object{data: %{"type" => "Tombstone"}}), do: false
   def is_public?(%Object{data: data}), do: is_public?(data)
+  def is_public?(%Activity{data: %{"type" => "Move"}}), do: true
   def is_public?(%Activity{data: data}), do: is_public?(data)
   def is_public?(%{"directMessage" => true}), do: false
   def is_public?(data), do: Utils.label_in_message?(Pleroma.Constants.as_public(), data)