Implement search with PostgreSQL trigrams

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Rename function to reflect that we only get one result

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Add loggers and make Ecto call parallels during search

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Implement trigrams for events & replace pg similarity operator % with <%

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Fix tests

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon_web/api/search.ex

@@ -0,0 +1,99 @@
+defmodule MobilizonWeb.API.Search do
+  alias Mobilizon.Service.ActivityPub
+  alias Mobilizon.Actors
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Events
+  alias Mobilizon.Events.{Event, Comment}
+
+  require Logger
+
+  @doc """
+  Search
+  """
+  @spec search(String.t(), integer(), integer()) ::
+          {:ok, list(Actor.t())} | {:ok, []} | {:error, any()}
+  def search(search, page \\ 1, limit \\ 10) do
+    do_search(search, page, limit, %{events: true, actors: true})
+  end
+
+  @doc """
+  Not used at the moment
+  """
+  # TODO: Use me
+  @spec search_actors(String.t(), integer(), integer()) ::
+          {:ok, list(Actor.t())} | {:ok, []} | {:error, any()}
+  def search_actors(search, page \\ 1, limit \\ 10) do
+    do_search(search, page, limit, %{actors: true})
+  end
+
+  @doc """
+  Not used at the moment
+  """
+  # TODO: Use me
+  @spec search_events(String.t(), integer(), integer()) ::
+          {:ok, list(Event.t())} | {:ok, []} | {:error, any()}
+  def search_events(search, page \\ 1, limit \\ 10) do
+    do_search(search, page, limit, %{events: true})
+  end
+
+  # Do the actual search
+  @spec do_search(String.t(), integer(), integer(), map()) :: {:ok, list(any())}
+  defp do_search(search, page, limit, opts) do
+    search = String.trim(search)
+
+    cond do
+      search == "" ->
+        {:error, "Search can't be empty"}
+
+      String.match?(search, ~r/@/) ->
+        {:ok, process_from_username(search)}
+
+      String.starts_with?(search, "https://") ->
+        {:ok, process_from_url(search)}
+
+      String.starts_with?(search, "http://") ->
+        {:ok, process_from_url(search)}
+
+      true ->
+        events =
+          Task.async(fn ->
+            if Map.get(opts, :events, false),
+              do: Events.find_events_by_name(search, page, limit),
+              else: []
+          end)
+
+        actors =
+          Task.async(fn ->
+            if Map.get(opts, :actors, false),
+              do: Actors.find_actors_by_username_or_name(search, page, limit),
+              else: []
+          end)
+
+        {:ok, Task.await(events) ++ Task.await(actors)}
+    end
+  end
+
+  # If the search string is an username
+  @spec process_from_username(String.t()) :: Actor.t() | nil
+  defp process_from_username(search) do
+    with {:ok, actor} <- ActivityPub.find_or_make_actor_from_nickname(search) do
+      actor
+    else
+      {:error, _err} ->
+        Logger.debug("Unable to find or make actor '#{search}'")
+        nil
+    end
+  end
+
+  # If the search string is an URL
+  @spec process_from_url(String.t()) :: Actor.t() | Event.t() | Comment.t() | nil
+  defp process_from_url(search) do
+    with {:ok, object} <- ActivityPub.fetch_object_from_url(search) do
+      object
+    else
+      {:error, _err} ->
+        Logger.debug("Unable to find or make object from URL '#{search}'")
+        nil
+    end
+  end
+end