Add grouped notifications API

changelog.d/grouped-notifications-api.add

@@ -0,0 +1 @@
+Add Mastodon-compatible grouped notifications API endpoints under `/api/v2/notifications`

lib/pleroma/notification.ex

@@ -62,6 +62,90 @@ defmodule Pleroma.Notification do
     |> Repo.aggregate(:count, :id)
   end
 
+  @groupable_notification_types ~w{favourite follow reblog}
+  @group_bucket_seconds 12 * 60 * 60
+
+  def groupable_notification_types, do: @groupable_notification_types
+
+  def group_notifications(notifications, grouped_types \\ nil) do
+    grouped_types = normalize_grouped_types(grouped_types)
+
+    {group_keys, grouped_notifications} =
+      Enum.reduce(notifications, {[], %{}}, fn notification,
+                                               {group_keys, grouped_notifications} ->
+        group_key = group_key(notification, grouped_types)
+
+        if Map.has_key?(grouped_notifications, group_key) do
+          {group_keys, Map.update!(grouped_notifications, group_key, &[notification | &1])}
+        else
+          {[group_key | group_keys], Map.put(grouped_notifications, group_key, [notification])}
+        end
+      end)
+
+    group_keys
+    |> Enum.reverse()
+    |> Enum.map(fn group_key ->
+      grouped_notifications
+      |> Map.fetch!(group_key)
+      |> Enum.reverse()
+    end)
+  end
+
+  def group_key(notification, grouped_types \\ nil)
+
+  def group_key(%Notification{} = notification, nil) do
+    group_key(notification, @groupable_notification_types)
+  end
+
+  def group_key(%Notification{type: type} = notification, grouped_types) do
+    grouped_types = normalize_grouped_types(grouped_types)
+
+    if type in @groupable_notification_types and type in grouped_types do
+      case group_target_id(notification) do
+        nil -> ungrouped_group_key(notification)
+        target_id -> "#{type}-#{target_id}-#{group_time_bucket(notification)}"
+      end
+    else
+      ungrouped_group_key(notification)
+    end
+  end
+
+  def normalize_grouped_types(nil), do: @groupable_notification_types
+  def normalize_grouped_types(types) when is_list(types), do: types
+  def normalize_grouped_types(type), do: [type]
+
+  defp ungrouped_group_key(%Notification{id: id}), do: "ungrouped-#{id}"
+
+  defp group_time_bucket(%Notification{inserted_at: inserted_at}) do
+    inserted_at
+    |> NaiveDateTime.to_erl()
+    |> :calendar.datetime_to_gregorian_seconds()
+    |> div(@group_bucket_seconds)
+  end
+
+  defp group_target_id(%Notification{type: type, activity: activity})
+       when type in ["favourite", "reblog"] do
+    with object_id when is_binary(object_id) <- object_id_for(activity),
+         %Activity{id: id} <- Activity.get_create_by_object_ap_id(object_id) do
+      to_string(id)
+    else
+      _ -> nil
+    end
+  end
+
+  defp group_target_id(%Notification{type: "follow", activity: %{data: %{"object" => ap_id}}}) do
+    case User.get_cached_by_ap_id(ap_id) do
+      %User{id: id} -> to_string(id)
+      _ -> nil
+    end
+  end
+
+  defp group_target_id(_), do: nil
+
+  defp object_id_for(%{data: %{"object" => %{"id" => id}}}) when is_binary(id), do: id
+  defp object_id_for(%{data: %{"object" => id}}) when is_binary(id), do: id
+  defp object_id_for(_), do: nil
+
   @notification_types ~w{
     favourite
     follow

lib/pleroma/web/api_spec/operations/notification_operation.ex

@@ -91,6 +91,79 @@ defmodule Pleroma.Web.ApiSpec.NotificationOperation do
     }
   end
 
+  def grouped_index_operation do
+    %Operation{
+      tags: ["Notifications"],
+      summary: "Retrieve grouped notifications",
+      description: "Notifications concerning the user, grouped by supported notification types.",
+      operationId: "NotificationController.grouped_index",
+      security: [%{"oAuth" => ["read:notifications"]}],
+      parameters: grouped_notification_params() ++ pagination_params(),
+      responses: %{
+        200 => Operation.response("Grouped notifications", "application/json", grouped_result()),
+        404 => Operation.response("Error", "application/json", ApiError)
+      }
+    }
+  end
+
+  def show_group_operation do
+    %Operation{
+      tags: ["Notifications"],
+      summary: "Retrieve a notification group",
+      operationId: "NotificationController.show_group",
+      security: [%{"oAuth" => ["read:notifications"]}],
+      parameters: [group_key_param()],
+      responses: %{
+        200 => Operation.response("Grouped notifications", "application/json", grouped_result()),
+        404 => Operation.response("Error", "application/json", ApiError)
+      }
+    }
+  end
+
+  def group_accounts_operation do
+    %Operation{
+      tags: ["Notifications"],
+      summary: "Retrieve notification group accounts",
+      operationId: "NotificationController.group_accounts",
+      security: [%{"oAuth" => ["write:notifications"]}],
+      parameters: [group_key_param()],
+      responses: %{
+        200 =>
+          Operation.response("Accounts", "application/json", %Schema{
+            type: :array,
+            items: Account
+          })
+      }
+    }
+  end
+
+  def unread_count_operation do
+    %Operation{
+      tags: ["Notifications"],
+      summary: "Retrieve unread grouped notification count",
+      operationId: "NotificationController.unread_count",
+      security: [%{"oAuth" => ["read:notifications"]}],
+      parameters:
+        grouped_notification_params() ++
+          [
+            Operation.parameter(
+              :limit,
+              :query,
+              %Schema{type: :integer},
+              "Maximum number of notifications to count"
+            )
+          ],
+      responses: %{
+        200 =>
+          Operation.response("Unread notification group count", "application/json", %Schema{
+            type: :object,
+            properties: %{count: %Schema{type: :integer}}
+          }),
+        404 => Operation.response("Error", "application/json", ApiError)
+      }
+    }
+  end
+
   def clear_operation do
     %Operation{
       tags: ["Notifications"],
@@ -114,6 +187,18 @@ defmodule Pleroma.Web.ApiSpec.NotificationOperation do
     }
   end
 
+  def dismiss_group_operation do
+    %Operation{
+      tags: ["Notifications"],
+      summary: "Dismiss a notification group",
+      description: "Clear all notifications in a notification group from the server.",
+      operationId: "NotificationController.dismiss_group",
+      parameters: [group_key_param()],
+      security: [%{"oAuth" => ["write:notifications"]}],
+      responses: %{200 => empty_object_response()}
+    }
+  end
+
   def dismiss_via_body_operation do
     %Operation{
       tags: ["Notifications"],
@@ -194,6 +279,73 @@ defmodule Pleroma.Web.ApiSpec.NotificationOperation do
     }
   end
 
+  defp grouped_result do
+    %Schema{
+      title: "GroupedNotificationsResults",
+      type: :object,
+      properties: %{
+        accounts: %Schema{type: :array, items: Account},
+        statuses: %Schema{type: :array, items: Status},
+        notification_groups: %Schema{type: :array, items: notification_group()}
+      },
+      required: [:accounts, :statuses, :notification_groups]
+    }
+  end
+
+  defp notification_group do
+    %Schema{
+      title: "NotificationGroup",
+      type: :object,
+      properties: %{
+        group_key: %Schema{type: :string},
+        notifications_count: %Schema{type: :integer},
+        type: notification_type(),
+        most_recent_notification_id: %Schema{type: :string},
+        page_min_id: %Schema{type: :string, nullable: true},
+        page_max_id: %Schema{type: :string, nullable: true},
+        latest_page_notification_at: %Schema{type: :string, format: :"date-time", nullable: true},
+        sample_account_ids: %Schema{type: :array, items: %Schema{type: :string}},
+        status_id: %Schema{type: :string, nullable: true}
+      },
+      required: [
+        :group_key,
+        :notifications_count,
+        :type,
+        :most_recent_notification_id,
+        :sample_account_ids
+      ]
+    }
+  end
+
+  defp grouped_notification_params do
+    [
+      Operation.parameter(
+        :exclude_types,
+        :query,
+        %Schema{type: :array, items: notification_type()},
+        "Array of types to exclude"
+      ),
+      Operation.parameter(
+        :account_id,
+        :query,
+        %Schema{type: :string},
+        "Return only notifications received from this account"
+      ),
+      Operation.parameter(
+        :types,
+        :query,
+        %Schema{type: :array, items: notification_type()},
+        "Include the notifications for activities with the given types"
+      ),
+      Operation.parameter(
+        :grouped_types,
+        :query,
+        %Schema{type: :array, items: notification_type()},
+        "Notification types that may be grouped"
+      )
+    ]
+  end
+
   defp notification_type do
     %Schema{
       type: :string,
@@ -239,4 +391,11 @@ defmodule Pleroma.Web.ApiSpec.NotificationOperation do
       required: true
     )
   end
+
+  defp group_key_param do
+    Operation.parameter(:group_key, :path, :string, "Notification group key",
+      example: "favourite-123",
+      required: true
+    )
+  end
 end

lib/pleroma/web/mastodon_api/controllers/notification_controller.ex

@@ -8,10 +8,12 @@ defmodule Pleroma.Web.MastodonAPI.NotificationController do
   import Pleroma.Web.ControllerHelper, only: [add_link_headers: 2]
 
   alias Pleroma.Notification
+  alias Pleroma.User
+  alias Pleroma.Web.MastodonAPI.AccountView
   alias Pleroma.Web.MastodonAPI.MastodonAPI
   alias Pleroma.Web.Plugs.OAuthScopesPlug
 
-  @oauth_read_actions [:show, :index]
+  @oauth_read_actions [:show, :index, :grouped_index, :show_group, :unread_count]
 
   plug(Pleroma.Web.ApiSpec.CastAndValidate, replace_params: false)
 
@@ -39,7 +41,7 @@ defmodule Pleroma.Web.MastodonAPI.NotificationController do
 
   # GET /api/v1/notifications
   def index(%{private: %{open_api_spex: %{params: %{account_id: account_id} = params}}} = conn, _) do
-    case Pleroma.User.get_cached_by_id(account_id) do
+    case User.get_cached_by_id(account_id) do
       %{ap_id: account_ap_id} ->
         params =
           params
@@ -59,10 +61,110 @@ defmodule Pleroma.Web.MastodonAPI.NotificationController do
     do_get_notifications(conn, params)
   end
 
-  defp do_get_notifications(%{assigns: %{user: user}} = conn, params) do
+  # GET /api/v2/notifications
+  def grouped_index(
+        %{private: %{open_api_spex: %{params: %{account_id: account_id} = params}}} = conn,
+        _
+      ) do
+    case User.get_cached_by_id(account_id) do
+      %{ap_id: account_ap_id} ->
         params =
-      Map.new(params, fn {k, v} -> {to_string(k), v} end)
+          params
-      |> Map.put_new("types", Map.get(params, :include_types, @default_notification_types))
+          |> Map.delete(:account_id)
+          |> Map.put(:account_ap_id, account_ap_id)
+
+        do_get_grouped_notifications(conn, params)
+
+      _ ->
+        conn
+        |> put_status(:not_found)
+        |> json(%{"error" => "Account is not found"})
+    end
+  end
+
+  def grouped_index(%{private: %{open_api_spex: %{params: params}}} = conn, _) do
+    do_get_grouped_notifications(conn, params)
+  end
+
+  # GET /api/v2/notifications/:group_key
+  def show_group(
+        %{assigns: %{user: user}, private: %{open_api_spex: %{params: %{group_key: group_key}}}} =
+          conn,
+        _
+      ) do
+    notifications = MastodonAPI.get_notification_group(user, group_key, %{})
+
+    if Enum.empty?(notifications) do
+      conn
+      |> put_status(:not_found)
+      |> json(%{"error" => "Notification group is not found"})
+    else
+      grouped_types = if String.starts_with?(group_key, "ungrouped-"), do: [], else: nil
+
+      render(conn, "grouped_index.json",
+        notification_groups: [notifications],
+        for: user,
+        grouped_types: grouped_types
+      )
+    end
+  end
+
+  # GET /api/v2/notifications/:group_key/accounts
+  def group_accounts(
+        %{assigns: %{user: user}, private: %{open_api_spex: %{params: %{group_key: group_key}}}} =
+          conn,
+        _
+      ) do
+    users =
+      user
+      |> MastodonAPI.get_notification_group(group_key, %{})
+      |> notification_actors()
+
+    json(conn, AccountView.render("index.json", %{users: users, for: user}))
+  end
+
+  # GET /api/v2/notifications/unread_count
+  def unread_count(
+        %{private: %{open_api_spex: %{params: %{account_id: account_id} = params}}} = conn,
+        _
+      ) do
+    case User.get_cached_by_id(account_id) do
+      %{ap_id: account_ap_id} ->
+        params =
+          params
+          |> Map.delete(:account_id)
+          |> Map.put(:account_ap_id, account_ap_id)
+
+        do_get_unread_group_count(conn, params)
+
+      _ ->
+        conn
+        |> put_status(:not_found)
+        |> json(%{"error" => "Account is not found"})
+    end
+  end
+
+  def unread_count(%{private: %{open_api_spex: %{params: params}}} = conn, _) do
+    do_get_unread_group_count(conn, params)
+  end
+
+  # POST /api/v2/notifications/:group_key/dismiss
+  def dismiss_group(
+        %{assigns: %{user: user}, private: %{open_api_spex: %{params: %{group_key: group_key}}}} =
+          conn,
+        _
+      ) do
+    ids =
+      user
+      |> MastodonAPI.get_notification_group(group_key, %{})
+      |> Enum.map(& &1.id)
+
+    Notification.destroy_multiple(user, ids)
+    json(conn, %{})
+  end
+
+  defp do_get_notifications(%{assigns: %{user: user}} = conn, params) do
+    params = normalize_notification_params(params)
 
     notifications = MastodonAPI.get_notifications(user, params)
 
@@ -74,6 +176,40 @@ defmodule Pleroma.Web.MastodonAPI.NotificationController do
     )
   end
 
+  defp do_get_grouped_notifications(%{assigns: %{user: user}} = conn, params) do
+    params = normalize_notification_params(params)
+
+    {notification_groups, page_notifications, notification_group_counts} =
+      MastodonAPI.get_grouped_notification_page(user, params)
+
+    conn
+    |> add_link_headers(page_notifications)
+    |> render("grouped_index.json",
+      notification_groups: notification_groups,
+      notification_group_counts: notification_group_counts,
+      for: user,
+      grouped_types: params["grouped_types"]
+    )
+  end
+
+  defp do_get_unread_group_count(%{assigns: %{user: user}} = conn, params) do
+    params = normalize_notification_params(params)
+    json(conn, %{count: MastodonAPI.unread_notification_group_count(user, params)})
+  end
+
+  defp normalize_notification_params(params) do
+    params
+    |> Map.new(fn {k, v} -> {to_string(k), v} end)
+    |> Map.put_new("types", Map.get(params, :include_types, @default_notification_types))
+  end
+
+  defp notification_actors(notifications) do
+    notifications
+    |> Enum.map(&User.get_cached_by_ap_id(&1.activity.data["actor"]))
+    |> Enum.filter(& &1)
+    |> Enum.uniq_by(& &1.id)
+  end
+
   # GET /api/v1/notifications/:id
   def show(%{assigns: %{user: user}, private: %{open_api_spex: %{params: %{id: id}}}} = conn, _) do
     with {:ok, notification} <- Notification.get(user, id) do

lib/pleroma/web/mastodon_api/mastodon_api.ex

@@ -8,6 +8,7 @@ defmodule Pleroma.Web.MastodonAPI.MastodonAPI do
 
   alias Pleroma.Notification
   alias Pleroma.Pagination
+  alias Pleroma.Repo
   alias Pleroma.ScheduledActivity
   alias Pleroma.User
   alias Pleroma.Web.CommonAPI
@@ -61,10 +62,145 @@ defmodule Pleroma.Web.MastodonAPI.MastodonAPI do
   end
 
   def get_notifications(user, params \\ %{}) do
-    options =
+    user
-      cast_params(params) |> Map.update(:include_types, [], fn include_types -> include_types end)
+    |> notifications_query(params)
+    |> Pagination.fetch_paginated(params)
+  end
 
+  def get_grouped_notification_page(user, params \\ %{}) do
+    grouped_types = Map.get(params, "grouped_types", Map.get(params, :grouped_types))
+    {query, order} = group_pagination_query(notifications_query(user, params), params)
+
+    notifications =
+      query
+      |> order_by([n], [{^order, n.id}])
+      |> Repo.all()
+
+    notification_group_counts =
+      Enum.frequencies_by(notifications, &Notification.group_key(&1, grouped_types))
+
+    page_notifications =
+      notifications
+      |> take_grouped_page_notifications(grouped_types, grouped_limit(params))
+
+    page_notifications =
+      if order == :asc, do: Enum.reverse(page_notifications), else: page_notifications
+
+    {
+      Notification.group_notifications(page_notifications, grouped_types),
+      page_notifications,
+      notification_group_counts
+    }
+  end
+
+  def get_grouped_notification_groups(user, params \\ %{}) do
+    {groups, _notifications, _notification_group_counts} =
+      get_grouped_notification_page(user, params)
+
+    groups
+  end
+
+  def get_notification_group(user, group_key, params \\ %{})
+
+  def get_notification_group(user, "ungrouped-" <> notification_id, _params) do
+    case Notification.get(user, notification_id) do
+      {:ok, notification} -> [notification]
+      _ -> []
+    end
+  end
+
+  def get_notification_group(user, group_key, params) do
+    grouped_types = Map.get(params, "grouped_types", Map.get(params, :grouped_types))
+
+    user
+    |> notifications_query(params)
+    |> order_by([n], desc: n.id)
+    |> Repo.all()
+    |> Enum.filter(&(Notification.group_key(&1, grouped_types) == group_key))
+  end
+
+  defp group_pagination_query(query, params) do
+    cond do
+      min_id = Map.get(params, "min_id", Map.get(params, :min_id)) ->
+        query = where(query, [n], n.id > ^min_id)
+
+        query =
+          case Map.get(params, "max_id", Map.get(params, :max_id)) do
+            nil -> query
+            max_id -> where(query, [n], n.id < ^max_id)
+          end
+
+        {query, :asc}
+
+      since_id = Map.get(params, "since_id", Map.get(params, :since_id)) ->
+        {where(query, [n], n.id > ^since_id), :desc}
+
+      max_id = Map.get(params, "max_id", Map.get(params, :max_id)) ->
+        {where(query, [n], n.id < ^max_id), :desc}
+
+      true ->
+        {query, :desc}
+    end
+  end
+
+  defp grouped_limit(params) do
+    params
+    |> Map.get("limit", Map.get(params, :limit, 40))
+    |> parse_limit(40)
+    |> min(80)
+  end
+
+  defp take_grouped_page_notifications(notifications, grouped_types, group_limit) do
+    {notifications, _group_keys} =
+      Enum.reduce_while(notifications, {[], MapSet.new()}, fn notification,
+                                                              {notifications, group_keys} ->
+        group_key = Notification.group_key(notification, grouped_types)
+
+        cond do
+          MapSet.member?(group_keys, group_key) ->
+            {:cont, {[notification | notifications], group_keys}}
+
+          MapSet.size(group_keys) < group_limit ->
+            {:cont, {[notification | notifications], MapSet.put(group_keys, group_key)}}
+
+          true ->
+            {:halt, {notifications, group_keys}}
+        end
+      end)
+
+    Enum.reverse(notifications)
+  end
+
+  def unread_notification_group_count(user, params \\ %{}) do
+    grouped_types = Map.get(params, "grouped_types", Map.get(params, :grouped_types))
+    limit = unread_count_limit(params)
+
+    user
+    |> notifications_query(params)
+    |> where([n], n.seen == false)
+    |> order_by([n], desc: n.id)
+    |> limit(^limit)
+    |> Repo.all()
+    |> Notification.group_notifications(grouped_types)
+    |> length()
+  end
+
+  defp notifications_query(user, params) do
+    options = notification_options(user, params)
+
+    user
+    |> Notification.for_user_query(options)
+    |> restrict(:types, options)
+    |> restrict(:exclude_types, options)
+    |> restrict(:account_ap_id, options)
+  end
+
+  defp notification_options(user, params) do
     options =
+      params
+      |> cast_params()
+      |> Map.update(:include_types, [], fn include_types -> include_types end)
+
     if ("pleroma:report" not in options.include_types and
           User.privileged?(user, :reports_manage_reports)) or
          User.privileged?(user, :reports_manage_reports) do
@@ -75,15 +211,26 @@ defmodule Pleroma.Web.MastodonAPI.MastodonAPI do
         current_exclude_types ++ ["pleroma:report"]
       end)
     end
-
-    user
-    |> Notification.for_user_query(options)
-    |> restrict(:types, options)
-    |> restrict(:exclude_types, options)
-    |> restrict(:account_ap_id, options)
-    |> Pagination.fetch_paginated(params)
   end
 
+  defp unread_count_limit(params) do
+    params
+    |> Map.get("limit", Map.get(params, :limit, 100))
+    |> parse_limit(100)
+    |> min(1000)
+  end
+
+  defp parse_limit(limit, _default) when is_integer(limit) and limit > 0, do: limit
+
+  defp parse_limit(limit, default) when is_binary(limit) do
+    case Integer.parse(limit) do
+      {limit, _} when limit > 0 -> limit
+      _ -> default
+    end
+  end
+
+  defp parse_limit(_, default), do: default
+
   def get_scheduled_activities(user, params \\ %{}) do
     user
     |> ScheduledActivity.for_user_query()
@@ -95,6 +242,8 @@ defmodule Pleroma.Web.MastodonAPI.MastodonAPI do
       exclude_types: {:array, :string},
       types: {:array, :string},
       exclude_visibilities: {:array, :string},
+      grouped_types: {:array, :string},
+      limit: :integer,
       reblogs: :boolean,
       with_muted: :boolean,
       account_ap_id: :string,

lib/pleroma/web/mastodon_api/views/notification_view.ex

@@ -72,6 +72,49 @@ defmodule Pleroma.Web.MastodonAPI.NotificationView do
     safe_render_many(notifications, NotificationView, "show.json", opts)
   end
 
+  def render("grouped_index.json", %{notifications: notifications} = opts) do
+    grouped_types = Notification.normalize_grouped_types(opts[:grouped_types])
+
+    opts
+    |> Map.delete(:notifications)
+    |> Map.put(
+      :notification_groups,
+      Notification.group_notifications(notifications, grouped_types)
+    )
+    |> then(&render("grouped_index.json", &1))
+  end
+
+  def render(
+        "grouped_index.json",
+        %{notification_groups: notification_groups, for: reading_user} = opts
+      ) do
+    grouped_types = Notification.normalize_grouped_types(opts[:grouped_types])
+    notification_group_counts = Map.get(opts, :notification_group_counts, %{})
+
+    statuses =
+      notification_groups
+      |> Enum.map(&List.first/1)
+      |> Enum.map(&render("show.json", %{notification: &1, for: reading_user}))
+      |> Enum.map(& &1[:status])
+      |> Enum.filter(& &1)
+      |> Enum.uniq_by(& &1[:id])
+
+    actors =
+      notification_groups
+      |> List.flatten()
+      |> notification_actors()
+
+    %{
+      accounts: AccountView.render("index.json", %{users: actors, for: reading_user}),
+      statuses: statuses,
+      notification_groups:
+        Enum.map(
+          notification_groups,
+          &render_group(&1, reading_user, grouped_types, notification_group_counts)
+        )
+    }
+  end
+
   def render(
         "show.json",
         %{
@@ -95,7 +138,7 @@ defmodule Pleroma.Web.MastodonAPI.NotificationView do
 
     response = %{
       id: to_string(notification.id),
-      group_key: "ungrouped-" <> to_string(notification.id),
+      group_key: Notification.group_key(notification),
       type: notification.type,
       created_at: CommonAPI.Utils.to_masto_date(notification.inserted_at),
       account: account,
@@ -137,6 +180,81 @@ defmodule Pleroma.Web.MastodonAPI.NotificationView do
     Map.put(response, :report, report_render)
   end
 
+  defp render_group(
+         [%Notification{} = notification | _] = notifications,
+         _reading_user,
+         grouped_types,
+         notification_group_counts
+       ) do
+    latest_notification = List.first(notifications)
+    oldest_notification = List.last(notifications)
+    status_activity = status_activity_for_group(notifications, grouped_types)
+    group_key = Notification.group_key(notification, grouped_types)
+
+    response = %{
+      group_key: group_key,
+      notifications_count: Map.get(notification_group_counts, group_key, length(notifications)),
+      type: notification.type,
+      most_recent_notification_id: to_string(latest_notification.id),
+      page_min_id: to_string(oldest_notification.id),
+      page_max_id: to_string(latest_notification.id),
+      latest_page_notification_at: CommonAPI.Utils.to_masto_date(latest_notification.inserted_at),
+      sample_account_ids:
+        notifications
+        |> notification_actors()
+        |> Enum.map(&to_string(&1.id))
+    }
+
+    if status_activity do
+      Map.put(response, :status_id, to_string(status_activity.id))
+    else
+      response
+    end
+  end
+
+  defp status_activity_for_group([%Notification{} = notification | _], grouped_types) do
+    status_activity_for(notification, grouped_types)
+  end
+
+  defp status_activity_for(%Notification{type: type, activity: activity}, _grouped_types)
+       when type in ["mention", "status", "poll"] do
+    activity
+  end
+
+  defp status_activity_for(%Notification{type: type} = notification, grouped_types)
+       when type in ["favourite", "reblog"] do
+    group_key = Notification.group_key(notification, grouped_types)
+
+    case String.split(group_key, "-", parts: 3) do
+      [^type, activity_id, _bucket] ->
+        case Activity.create_by_id_with_object(activity_id) do
+          %Activity{} = activity -> activity
+          _ -> parent_status_activity(notification.activity)
+        end
+
+      _ ->
+        parent_status_activity(notification.activity)
+    end
+  end
+
+  defp status_activity_for(%Notification{type: type, activity: activity}, _grouped_types)
+       when type in ["update", "pleroma:emoji_reaction"] do
+    parent_status_activity(activity)
+  end
+
+  defp status_activity_for(_, _grouped_types), do: nil
+
+  defp parent_status_activity(activity) do
+    Activity.get_create_by_object_ap_id(object_id_for(activity))
+  end
+
+  defp notification_actors(notifications) do
+    notifications
+    |> Enum.map(&User.get_cached_by_ap_id(&1.activity.data["actor"]))
+    |> Enum.filter(& &1)
+    |> Enum.uniq_by(& &1.id)
+  end
+
   defp put_emoji(response, activity) do
     response
     |> Map.put(:emoji, activity.data["content"])

lib/pleroma/web/router.ex

@@ -844,6 +844,16 @@ defmodule Pleroma.Web.Router do
     get("/directory", DirectoryController, :index)
   end
 
+  scope "/api/v2", Pleroma.Web.MastodonAPI do
+    pipe_through(:authenticated_api)
+
+    get("/notifications", NotificationController, :grouped_index)
+    get("/notifications/unread_count", NotificationController, :unread_count)
+    get("/notifications/:group_key/accounts", NotificationController, :group_accounts)
+    get("/notifications/:group_key", NotificationController, :show_group)
+    post("/notifications/:group_key/dismiss", NotificationController, :dismiss_group)
+  end
+
   scope "/api/v2", Pleroma.Web.MastodonAPI do
     pipe_through(:api)
 

test/pleroma/web/mastodon_api/controllers/notification_controller_test.exs

@@ -577,6 +577,175 @@ defmodule Pleroma.Web.MastodonAPI.NotificationControllerTest do
     assert [%{"id" => ^notification4_id}, %{"id" => ^notification3_id}] = result
   end
 
+  describe "GET /api/v2/notifications" do
+    test "groups favourite notifications for the same status" do
+      %{user: user, conn: conn} = oauth_access(["read:notifications"])
+      other_user1 = insert(:user)
+      other_user2 = insert(:user)
+
+      {:ok, status} = CommonAPI.post(user, %{status: "hello"})
+      {:ok, _} = CommonAPI.favorite(status.id, other_user1)
+      {:ok, _} = CommonAPI.favorite(status.id, other_user2)
+
+      notification_ids =
+        Notification
+        |> Repo.all()
+        |> Enum.map(&to_string(&1.id))
+
+      result =
+        conn
+        |> get("/api/v2/notifications")
+        |> json_response_and_validate_schema(200)
+
+      assert [%{"id" => account_id1}, %{"id" => account_id2}] = result["accounts"]
+      assert account_id1 in [other_user1.id, other_user2.id]
+      assert account_id2 in [other_user1.id, other_user2.id]
+      assert [%{"id" => status_id}] = result["statuses"]
+      assert status_id == status.id
+
+      assert [group] = result["notification_groups"]
+      assert group["type"] == "favourite"
+      assert group["notifications_count"] == 2
+      assert group["status_id"] == status.id
+      assert group["most_recent_notification_id"] in notification_ids
+      assert group["page_min_id"] in notification_ids
+      assert group["page_max_id"] in notification_ids
+      assert group["latest_page_notification_at"]
+      assert Enum.sort(group["sample_account_ids"]) == Enum.sort([other_user1.id, other_user2.id])
+      group_key = group["group_key"]
+
+      assert [%{"group_key" => ^group_key}, %{"group_key" => ^group_key}] =
+               conn
+               |> get("/api/v1/notifications")
+               |> json_response_and_validate_schema(200)
+
+      assert %{"notification_groups" => [shown_group]} =
+               conn
+               |> get("/api/v2/notifications/#{group_key}")
+               |> json_response_and_validate_schema(200)
+
+      assert shown_group["group_key"] == group_key
+      assert shown_group["notifications_count"] == 2
+    end
+
+    test "round-trips ungrouped group keys when grouped_types excludes a type" do
+      %{user: user, conn: conn} = oauth_access(["read:notifications"])
+      other_user = insert(:user)
+
+      {:ok, status} = CommonAPI.post(user, %{status: "hello"})
+      {:ok, _} = CommonAPI.favorite(status.id, other_user)
+
+      %{"notification_groups" => [%{"group_key" => "ungrouped-" <> _ = group_key}]} =
+        conn
+        |> get("/api/v2/notifications?grouped_types[]=reblog")
+        |> json_response_and_validate_schema(200)
+
+      assert %{
+               "notification_groups" => [%{"group_key" => ^group_key, "notifications_count" => 1}]
+             } =
+               conn
+               |> get("/api/v2/notifications/#{group_key}")
+               |> json_response_and_validate_schema(200)
+    end
+
+    test "paginates notification groups instead of raw notifications" do
+      %{user: user, conn: conn} = oauth_access(["read:notifications"])
+      other_user1 = insert(:user)
+      other_user2 = insert(:user)
+      other_user3 = insert(:user)
+
+      {:ok, older_status} = CommonAPI.post(user, %{status: "older"})
+      {:ok, _} = CommonAPI.favorite(older_status.id, other_user3)
+
+      {:ok, newer_status} = CommonAPI.post(user, %{status: "newer"})
+      {:ok, _} = CommonAPI.favorite(newer_status.id, other_user1)
+      {:ok, _} = CommonAPI.favorite(newer_status.id, other_user2)
+      older_status_id = older_status.id
+      newer_status_id = newer_status.id
+
+      %{"notification_groups" => groups} =
+        conn
+        |> get("/api/v2/notifications?limit=2")
+        |> json_response_and_validate_schema(200)
+
+      assert [
+               %{"status_id" => ^newer_status_id, "notifications_count" => 2},
+               %{"status_id" => ^older_status_id, "notifications_count" => 1}
+             ] = groups
+    end
+
+    test "returns total notification count for a partially represented group" do
+      %{user: user, conn: conn} = oauth_access(["read:notifications"])
+      other_user1 = insert(:user)
+      other_user2 = insert(:user)
+      other_user3 = insert(:user)
+
+      {:ok, grouped_status} = CommonAPI.post(user, %{status: "grouped"})
+      {:ok, _} = CommonAPI.favorite(grouped_status.id, other_user1)
+
+      {:ok, other_status} = CommonAPI.post(user, %{status: "other"})
+      {:ok, _} = CommonAPI.favorite(other_status.id, other_user3)
+      {:ok, _} = CommonAPI.favorite(grouped_status.id, other_user2)
+      grouped_status_id = grouped_status.id
+
+      assert %{
+               "notification_groups" => [
+                 %{"status_id" => ^grouped_status_id, "notifications_count" => 2}
+               ]
+             } =
+               conn
+               |> get("/api/v2/notifications?limit=1")
+               |> json_response_and_validate_schema(200)
+    end
+
+    test "counts unread notification groups" do
+      %{user: user, conn: conn} = oauth_access(["read:notifications"])
+      other_user1 = insert(:user)
+      other_user2 = insert(:user)
+      mentioner = insert(:user)
+
+      {:ok, status} = CommonAPI.post(user, %{status: "hello"})
+      {:ok, _} = CommonAPI.favorite(status.id, other_user1)
+      {:ok, _} = CommonAPI.favorite(status.id, other_user2)
+      {:ok, _} = CommonAPI.post(mentioner, %{status: "hi @#{user.nickname}"})
+
+      assert %{"count" => 2} =
+               conn
+               |> get("/api/v2/notifications/unread_count")
+               |> json_response_and_validate_schema(200)
+    end
+
+    test "lists accounts from and dismisses a notification group" do
+      %{user: user, conn: conn} = oauth_access(["read:notifications", "write:notifications"])
+      other_user1 = insert(:user)
+      other_user2 = insert(:user)
+
+      {:ok, status} = CommonAPI.post(user, %{status: "hello"})
+      {:ok, _} = CommonAPI.favorite(status.id, other_user1)
+      {:ok, _} = CommonAPI.favorite(status.id, other_user2)
+
+      %{"notification_groups" => [%{"group_key" => group_key}]} =
+        conn
+        |> get("/api/v2/notifications")
+        |> json_response_and_validate_schema(200)
+
+      account_ids =
+        conn
+        |> get("/api/v2/notifications/#{group_key}/accounts")
+        |> json_response_and_validate_schema(200)
+        |> Enum.map(& &1["id"])
+
+      assert Enum.sort(account_ids) == Enum.sort([other_user1.id, other_user2.id])
+
+      assert %{} =
+               conn
+               |> post("/api/v2/notifications/#{group_key}/dismiss")
+               |> json_response_and_validate_schema(200)
+
+      assert [] = Notification.for_user(user)
+    end
+  end
+
   test "doesn't see notifications after muting user with notifications" do
     %{user: user, conn: conn} = oauth_access(["read:notifications"])
     user2 = insert(:user)

test/pleroma/web/mastodon_api/views/notification_view_test.exs

@@ -101,7 +101,7 @@ defmodule Pleroma.Web.MastodonAPI.NotificationViewTest do
 
     expected = %{
       id: to_string(notification.id),
-      group_key: "ungrouped-#{to_string(notification.id)}",
+      group_key: Notification.group_key(notification),
       pleroma: %{is_seen: false, is_muted: false},
       type: "favourite",
       account: AccountView.render("show.json", %{user: another_user, for: user}),
@@ -122,7 +122,7 @@ defmodule Pleroma.Web.MastodonAPI.NotificationViewTest do
 
     expected = %{
       id: to_string(notification.id),
-      group_key: "ungrouped-#{to_string(notification.id)}",
+      group_key: Notification.group_key(notification),
       pleroma: %{is_seen: false, is_muted: false},
       type: "reblog",
       account: AccountView.render("show.json", %{user: another_user, for: user}),
@@ -141,7 +141,7 @@ defmodule Pleroma.Web.MastodonAPI.NotificationViewTest do
 
     expected = %{
       id: to_string(notification.id),
-      group_key: "ungrouped-#{to_string(notification.id)}",
+      group_key: Notification.group_key(notification),
       pleroma: %{is_seen: false, is_muted: false},
       type: "follow",
       account: AccountView.render("show.json", %{user: follower, for: followed}),
@@ -333,7 +333,7 @@ defmodule Pleroma.Web.MastodonAPI.NotificationViewTest do
 
     expected = %{
       id: to_string(notification.id),
-      group_key: "ungrouped-#{to_string(notification.id)}",
+      group_key: Notification.group_key(notification),
       pleroma: %{is_seen: true, is_muted: true},
       type: "favourite",
       account: AccountView.render("show.json", %{user: another_user, for: user}),