feat(service): add hat geocoder

Closes #1414

lib/service/geospatial/hat.ex

@@ -0,0 +1,44 @@
+defmodule Mobilizon.Service.Geospatial.Hat do
+  @moduledoc """
+  Hat backend.
+  """
+
+  alias Mobilizon.Addresses.Address
+  alias Mobilizon.Service.Geospatial.Addok
+  alias Mobilizon.Service.Geospatial.Nominatim
+  alias Mobilizon.Service.Geospatial.Provider
+  import Mobilizon.Service.Geospatial.Provider, only: [endpoint: 1]
+  require Logger
+
+  @behaviour Provider
+
+  @impl Provider
+  @doc """
+  Hat implementation for `c:Mobilizon.Service.Geospatial.Provider.geocode/3`.
+  """
+  @spec geocode(String.t(), keyword()) :: list(Address.t())
+  def geocode(lon, lat, options \\ []) do
+    tasks = [
+      Task.async(fn -> Addok.geocode(lon, lat, options) end),
+      Task.async(fn -> Nominatim.geocode(lon, lat, options) end)
+    ]
+
+    [addrlist1, addrlist2] = Task.await_many(tasks, 12_000)
+    addrlist2 ++ addrlist1
+  end
+
+  @impl Provider
+  @doc """
+  Hat implementation for `c:Mobilizon.Service.Geospatial.Provider.search/2`.
+  """
+  @spec search(String.t(), keyword()) :: list(Address.t())
+  def search(q, options \\ []) do
+    tasks = [
+      Task.async(fn -> Addok.search(q, options) end),
+      Task.async(fn -> Nominatim.search(q, options) end)
+    ]
+
+    [addrlist1, addrlist2] = Task.await_many(tasks, 12_000)
+    addrlist2 ++ addrlist1
+  end
+end