11 files changed, 397 insertions, 4 deletions

diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index 1c21d78af..697ace488 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -126,7 +126,14 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
   def increase_poll_votes_if_vote(_create_data), do: :noop
 
+  @object_types ["ChatMessage"]
   @spec persist(map(), keyword()) :: {:ok, Activity.t() | Object.t()}
+  def persist(%{"type" => type} = object, meta) when type in @object_types do
+    with {:ok, object} <- Object.create(object) do
+      {:ok, object, meta}
+    end
+  end
+
   def persist(object, meta) do
     with local <- Keyword.fetch!(meta, :local),
          {recipients, _, _} <- get_recipients(object),
@@ -1218,6 +1225,18 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end
   end
 
+  defp exclude_chat_messages(query, %{"include_chat_messages" => true}), do: query
+
+  defp exclude_chat_messages(query, _) do
+    if has_named_binding?(query, :object) do
+      from([activity, object: o] in query,
+        where: fragment("not(?->>'type' = ?)", o.data, "ChatMessage")
+      )
+    else
+      query
+    end
+  end
+
   defp exclude_id(query, %{"exclude_id" => id}) when is_binary(id) do
     from(activity in query, where: activity.id != ^id)
   end
@@ -1323,6 +1342,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     |> restrict_instance(opts)
     |> Activity.restrict_deactivated_users()
     |> exclude_poll_votes(opts)
+    |> exclude_chat_messages(opts)
     |> exclude_visibility(opts)
   end
 
diff --git a/lib/pleroma/web/activity_pub/builder.ex b/lib/pleroma/web/activity_pub/builder.ex
index 429a510b8..7f9c071b3 100644
--- a/lib/pleroma/web/activity_pub/builder.ex
+++ b/lib/pleroma/web/activity_pub/builder.ex
@@ -5,11 +5,37 @@ defmodule Pleroma.Web.ActivityPub.Builder do
   This module encodes our addressing policies and general shape of our objects.
   """
 
+  alias Pleroma.Emoji
   alias Pleroma.Object
   alias Pleroma.User
   alias Pleroma.Web.ActivityPub.Utils
   alias Pleroma.Web.ActivityPub.Visibility
 
+  def create(actor, object, recipients) do
+    {:ok,
+     %{
+       "id" => Utils.generate_activity_id(),
+       "actor" => actor.ap_id,
+       "to" => recipients,
+       "object" => object,
+       "type" => "Create",
+       "published" => DateTime.utc_now() |> DateTime.to_iso8601()
+     }, []}
+  end
+
+  def chat_message(actor, recipient, content) do
+    {:ok,
+     %{
+       "id" => Utils.generate_object_id(),
+       "actor" => actor.ap_id,
+       "type" => "ChatMessage",
+       "to" => [recipient],
+       "content" => content,
+       "published" => DateTime.utc_now() |> DateTime.to_iso8601(),
+       "emoji" => Emoji.Formatter.get_emoji_map(content)
+     }, []}
+  end
+
   @spec like(User.t(), Object.t()) :: {:ok, map(), keyword()}
   def like(actor, object) do
     object_actor = User.get_cached_by_ap_id(object.data["actor"])
diff --git a/lib/pleroma/web/activity_pub/object_validator.ex b/lib/pleroma/web/activity_pub/object_validator.ex
index dc4bce059..20c7cceb6 100644
--- a/lib/pleroma/web/activity_pub/object_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validator.ex
@@ -11,26 +11,71 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
 
   alias Pleroma.Object
   alias Pleroma.User
+  alias Pleroma.Web.ActivityPub.ObjectValidators.ChatMessageValidator
+  alias Pleroma.Web.ActivityPub.ObjectValidators.CreateChatMessageValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.LikeValidator
+  alias Pleroma.Web.ActivityPub.ObjectValidators.Types
 
   @spec validate(map(), keyword()) :: {:ok, map(), keyword()} | {:error, any()}
   def validate(object, meta)
 
   def validate(%{"type" => "Like"} = object, meta) do
     with {:ok, object} <-
-           object |> LikeValidator.cast_and_validate() |> Ecto.Changeset.apply_action(:insert) do
-      object = stringify_keys(object |> Map.from_struct())
+           object
+           |> LikeValidator.cast_and_validate()
+           |> Ecto.Changeset.apply_action(:insert) do
+      object = stringify_keys(object)
       {:ok, object, meta}
     end
   end
 
+  def validate(%{"type" => "ChatMessage"} = object, meta) do
+    with {:ok, object} <-
+           object
+           |> ChatMessageValidator.cast_and_validate()
+           |> Ecto.Changeset.apply_action(:insert) do
+      object = stringify_keys(object)
+      {:ok, object, meta}
+    end
+  end
+
+  def validate(%{"type" => "Create", "object" => object} = create_activity, meta) do
+    with {:ok, object_data} <- cast_and_apply(object),
+         meta = Keyword.put(meta, :object_data, object_data |> stringify_keys),
+         {:ok, create_activity} <-
+           create_activity
+           |> CreateChatMessageValidator.cast_and_validate(meta)
+           |> Ecto.Changeset.apply_action(:insert) do
+      create_activity = stringify_keys(create_activity)
+      {:ok, create_activity, meta}
+    end
+  end
+
+  def cast_and_apply(%{"type" => "ChatMessage"} = object) do
+    ChatMessageValidator.cast_and_apply(object)
+  end
+
+  def cast_and_apply(o), do: {:error, {:validator_not_set, o}}
+
+  def stringify_keys(%{__struct__: _} = object) do
+    object
+    |> Map.from_struct()
+    |> stringify_keys
+  end
+
   def stringify_keys(object) do
     object
     |> Map.new(fn {key, val} -> {to_string(key), val} end)
   end
 
+  def fetch_actor(object) do
+    with {:ok, actor} <- Types.ObjectID.cast(object["actor"]) do
+      User.get_or_fetch_by_ap_id(actor)
+    end
+  end
+
   def fetch_actor_and_object(object) do
-    User.get_or_fetch_by_ap_id(object["actor"])
+    fetch_actor(object)
     Object.normalize(object["object"])
     :ok
   end
diff --git a/lib/pleroma/web/activity_pub/object_validators/chat_message_validator.ex b/lib/pleroma/web/activity_pub/object_validators/chat_message_validator.ex
new file mode 100644
index 000000000..e87c1ac2e
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/object_validators/chat_message_validator.ex
@@ -0,0 +1,98 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.ChatMessageValidator do
+  use Ecto.Schema
+
+  alias Pleroma.User
+  alias Pleroma.Web.ActivityPub.ObjectValidators.Types
+
+  import Ecto.Changeset
+  import Pleroma.Web.ActivityPub.Transmogrifier, only: [fix_emoji: 1]
+
+  @primary_key false
+  @derive Jason.Encoder
+
+  embedded_schema do
+    field(:id, Types.ObjectID, primary_key: true)
+    field(:to, Types.Recipients, default: [])
+    field(:type, :string)
+    field(:content, Types.SafeText)
+    field(:actor, Types.ObjectID)
+    field(:published, Types.DateTime)
+    field(:emoji, :map, default: %{})
+  end
+
+  def cast_and_apply(data) do
+    data
+    |> cast_data
+    |> apply_action(:insert)
+  end
+
+  def cast_and_validate(data) do
+    data
+    |> cast_data()
+    |> validate_data()
+  end
+
+  def cast_data(data) do
+    %__MODULE__{}
+    |> changeset(data)
+  end
+
+  def fix(data) do
+    data
+    |> fix_emoji()
+    |> Map.put_new("actor", data["attributedTo"])
+  end
+
+  def changeset(struct, data) do
+    data = fix(data)
+
+    struct
+    |> cast(data, __schema__(:fields))
+  end
+
+  def validate_data(data_cng) do
+    data_cng
+    |> validate_inclusion(:type, ["ChatMessage"])
+    |> validate_required([:id, :actor, :to, :type, :content, :published])
+    |> validate_length(:to, is: 1)
+    |> validate_length(:content, max: Pleroma.Config.get([:instance, :remote_limit]))
+    |> validate_local_concern()
+  end
+
+  @doc """
+  Validates the following
+  - If both users are in our system
+  - If at least one of the users in this ChatMessage is a local user
+  - If the recipient is not blocking the actor
+  """
+  def validate_local_concern(cng) do
+    with actor_ap <- get_field(cng, :actor),
+         {_, %User{} = actor} <- {:find_actor, User.get_cached_by_ap_id(actor_ap)},
+         {_, %User{} = recipient} <-
+           {:find_recipient, User.get_cached_by_ap_id(get_field(cng, :to) |> hd())},
+         {_, false} <- {:blocking_actor?, User.blocks?(recipient, actor)},
+         {_, true} <- {:local?, Enum.any?([actor, recipient], & &1.local)} do
+      cng
+    else
+      {:blocking_actor?, true} ->
+        cng
+        |> add_error(:actor, "actor is blocked by recipient")
+
+      {:local?, false} ->
+        cng
+        |> add_error(:actor, "actor and recipient are both remote")
+
+      {:find_actor, _} ->
+        cng
+        |> add_error(:actor, "can't find user")
+
+      {:find_recipient, _} ->
+        cng
+        |> add_error(:to, "can't find user")
+    end
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/object_validators/common_validations.ex b/lib/pleroma/web/activity_pub/object_validators/common_validations.ex
index b479c3918..02f3a6438 100644
--- a/lib/pleroma/web/activity_pub/object_validators/common_validations.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/common_validations.ex
@@ -8,7 +8,11 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
   alias Pleroma.Object
   alias Pleroma.User
 
-  def validate_actor_presence(cng, field_name \\ :actor) do
+  def validate_actor_presence(cng) do
+    validate_user_presence(cng, :actor)
+  end
+
+  def validate_user_presence(cng, field_name) do
     cng
     |> validate_change(field_name, fn field_name, actor ->
       if User.get_cached_by_ap_id(actor) do
diff --git a/lib/pleroma/web/activity_pub/object_validators/create_chat_message_validator.ex b/lib/pleroma/web/activity_pub/object_validators/create_chat_message_validator.ex
new file mode 100644
index 000000000..fc582400b
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/object_validators/create_chat_message_validator.ex
@@ -0,0 +1,91 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+# NOTES
+# - Can probably be a generic create validator
+# - doesn't embed, will only get the object id
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.CreateChatMessageValidator do
+  use Ecto.Schema
+
+  alias Pleroma.Object
+  alias Pleroma.Web.ActivityPub.ObjectValidators.Types
+
+  import Ecto.Changeset
+  import Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations
+
+  @primary_key false
+
+  embedded_schema do
+    field(:id, Types.ObjectID, primary_key: true)
+    field(:actor, Types.ObjectID)
+    field(:type, :string)
+    field(:to, Types.Recipients, default: [])
+    field(:object, Types.ObjectID)
+  end
+
+  def cast_and_apply(data) do
+    data
+    |> cast_data
+    |> apply_action(:insert)
+  end
+
+  def cast_data(data) do
+    cast(%__MODULE__{}, data, __schema__(:fields))
+  end
+
+  def cast_and_validate(data, meta \\ []) do
+    cast_data(data)
+    |> validate_data(meta)
+  end
+
+  def validate_data(cng, meta \\ []) do
+    cng
+    |> validate_required([:id, :actor, :to, :type, :object])
+    |> validate_inclusion(:type, ["Create"])
+    |> validate_actor_presence()
+    |> validate_recipients_match(meta)
+    |> validate_actors_match(meta)
+    |> validate_object_nonexistence()
+  end
+
+  def validate_object_nonexistence(cng) do
+    cng
+    |> validate_change(:object, fn :object, object_id ->
+      if Object.get_cached_by_ap_id(object_id) do
+        [{:object, "The object to create already exists"}]
+      else
+        []
+      end
+    end)
+  end
+
+  def validate_actors_match(cng, meta) do
+    object_actor = meta[:object_data]["actor"]
+
+    cng
+    |> validate_change(:actor, fn :actor, actor ->
+      if actor == object_actor do
+        []
+      else
+        [{:actor, "Actor doesn't match with object actor"}]
+      end
+    end)
+  end
+
+  def validate_recipients_match(cng, meta) do
+    object_recipients = meta[:object_data]["to"] || []
+
+    cng
+    |> validate_change(:to, fn :to, recipients ->
+      activity_set = MapSet.new(recipients)
+      object_set = MapSet.new(object_recipients)
+
+      if MapSet.equal?(activity_set, object_set) do
+        []
+      else
+        [{:to, "Recipients don't match with object recipients"}]
+      end
+    end)
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/object_validators/create_validator.ex b/lib/pleroma/web/activity_pub/object_validators/create_note_validator.ex
index 926804ce7..926804ce7 100644
--- a/lib/pleroma/web/activity_pub/object_validators/create_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/create_note_validator.ex
diff --git a/lib/pleroma/web/activity_pub/object_validators/types/recipients.ex b/lib/pleroma/web/activity_pub/object_validators/types/recipients.ex
new file mode 100644
index 000000000..408e0f6ee
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/object_validators/types/recipients.ex
@@ -0,0 +1,36 @@
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.Types.Recipients do
+  use Ecto.Type
+
+  alias Pleroma.Web.ActivityPub.ObjectValidators.Types.ObjectID
+
+  def type, do: {:array, ObjectID}
+
+  def cast(object) when is_binary(object) do
+    cast([object])
+  end
+
+  def cast(data) when is_list(data) do
+    data
+    |> Enum.reduce_while({:ok, []}, fn element, {:ok, list} ->
+      case ObjectID.cast(element) do
+        {:ok, id} ->
+          {:cont, {:ok, [id | list]}}
+
+        _ ->
+          {:halt, :error}
+      end
+    end)
+  end
+
+  def cast(_) do
+    :error
+  end
+
+  def dump(data) do
+    {:ok, data}
+  end
+
+  def load(data) do
+    {:ok, data}
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/object_validators/types/safe_text.ex b/lib/pleroma/web/activity_pub/object_validators/types/safe_text.ex
new file mode 100644
index 000000000..822e8d2c1
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/object_validators/types/safe_text.ex
@@ -0,0 +1,25 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.Types.SafeText do
+  use Ecto.Type
+
+  alias Pleroma.HTML
+
+  def type, do: :string
+
+  def cast(str) when is_binary(str) do
+    {:ok, HTML.strip_tags(str)}
+  end
+
+  def cast(_), do: :error
+
+  def dump(data) do
+    {:ok, data}
+  end
+
+  def load(data) do
+    {:ok, data}
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/side_effects.ex b/lib/pleroma/web/activity_pub/side_effects.ex
index 6a8f1af96..e394c75d7 100644
--- a/lib/pleroma/web/activity_pub/side_effects.ex
+++ b/lib/pleroma/web/activity_pub/side_effects.ex
@@ -5,8 +5,12 @@ defmodule Pleroma.Web.ActivityPub.SideEffects do
   liked object, a `Follow` activity will add the user to the follower
   collection, and so on.
   """
+  alias Pleroma.Chat
   alias Pleroma.Notification
   alias Pleroma.Object
+  alias Pleroma.Repo
+  alias Pleroma.User
+  alias Pleroma.Web.ActivityPub.Pipeline
   alias Pleroma.Web.ActivityPub.Utils
 
   def handle(object, meta \\ [])
@@ -23,8 +27,42 @@ defmodule Pleroma.Web.ActivityPub.SideEffects do
     {:ok, object, meta}
   end
 
+  # Tasks this handles
+  # - Actually create object
+  # - Rollback if we couldn't create it
+  # - Set up notifications
+  def handle(%{data: %{"type" => "Create"}} = activity, meta) do
+    with {:ok, _object, _meta} <- handle_object_creation(meta[:object_data], meta) do
+      Notification.create_notifications(activity)
+      {:ok, activity, meta}
+    else
+      e -> Repo.rollback(e)
+    end
+  end
+
   # Nothing to do
   def handle(object, meta) do
     {:ok, object, meta}
   end
+
+  def handle_object_creation(%{"type" => "ChatMessage"} = object, meta) do
+    with {:ok, object, meta} <- Pipeline.common_pipeline(object, meta) do
+      actor = User.get_cached_by_ap_id(object.data["actor"])
+      recipient = User.get_cached_by_ap_id(hd(object.data["to"]))
+
+      [[actor, recipient], [recipient, actor]]
+      |> Enum.each(fn [user, other_user] ->
+        if user.local do
+          Chat.bump_or_create(user.id, other_user.ap_id)
+        end
+      end)
+
+      {:ok, object, meta}
+    end
+  end
+
+  # Nothing to do
+  def handle_object_creation(object) do
+    {:ok, object}
+  end
 end
diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 3a4d364e7..40a505b91 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -656,6 +656,16 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     |> handle_incoming(options)
   end
 
+  def handle_incoming(
+        %{"type" => "Create", "object" => %{"type" => "ChatMessage"}} = data,
+        _options
+      ) do
+    with {:ok, %User{}} <- ObjectValidator.fetch_actor(data),
+         {:ok, activity, _} <- Pipeline.common_pipeline(data, local: false) do
+      {:ok, activity}
+    end
+  end
+
   def handle_incoming(%{"type" => "Like"} = data, _options) do
     with :ok <- ObjectValidator.fetch_actor_and_object(data),
          {:ok, activity, _meta} <-