Export participants to different formats

* CSV
* PDF (requires Python dependency `weasyprint`)
* ODS (requires Python dependency `pyexcel_ods3`)

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

lib/service/export/participants/common.ex

@@ -0,0 +1,120 @@
+defmodule Mobilizon.Service.Export.Participants.Common do
+  @moduledoc """
+  Common functions for managing participants export
+  """
+
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Events.Participant
+  alias Mobilizon.Events.Participant.Metadata
+  alias Mobilizon.Export
+  alias Mobilizon.Storage.Repo
+  import Mobilizon.Web.Gettext, only: [gettext: 1]
+
+  @spec save_upload(String.t(), String.t(), String.t(), String.t(), String.t()) ::
+          {:ok, Export.t()} | {:error, atom() | Ecto.Changeset.t()}
+  def save_upload(full_path, file_path, reference, file_name, format) do
+    with {:ok, %File.Stat{size: file_size}} <- File.stat(full_path) do
+      %Export{}
+      |> Export.changeset(%{
+        file_size: file_size,
+        file_name: file_name,
+        file_path: file_path,
+        format: format,
+        reference: reference,
+        type: "event_participants"
+      })
+      |> Repo.insert()
+    end
+  end
+
+  @doc """
+  Match a participant role to it's translated version
+  """
+  @spec translate_role(Mobilizon.Events.ParticipantRole.t()) :: String.t()
+  def translate_role(role) do
+    case role do
+      :not_approved ->
+        gettext("Not approved")
+
+      :not_confirmed ->
+        gettext("Not confirmed")
+
+      :rejected ->
+        gettext("Rejected")
+
+      :participant ->
+        gettext("Participant")
+
+      :moderator ->
+        gettext("Moderator")
+
+      :administrator ->
+        gettext("Administrator")
+
+      :creator ->
+        gettext("Creator")
+    end
+  end
+
+  @spec columns :: list(String.t())
+  def columns do
+    [gettext("Participant name"), gettext("Participant status"), gettext("Participant message")]
+  end
+
+  # One hour
+  @expiration 60 * 60
+
+  @doc """
+  Clean outdated files in export folder
+  """
+  @spec clean_exports(String.t(), String.t(), integer()) :: :ok
+  def clean_exports(format, upload_path, expiration \\ @expiration) do
+    "event_participants"
+    |> Export.outdated(format, expiration)
+    |> Enum.each(&remove_export(&1, upload_path))
+  end
+
+  defp remove_export(%Export{file_path: filename} = export, upload_path) do
+    full_path = upload_path <> filename
+    File.rm(full_path)
+    Repo.delete!(export)
+  end
+
+  @spec to_list({Participant.t(), Actor.t()}) :: list(String.t())
+  def to_list(
+        {%Participant{role: role, metadata: metadata},
+         %Actor{domain: nil, preferred_username: "anonymous"}}
+      ) do
+    [gettext("Anonymous participant"), translate_role(role), convert_metadata(metadata)]
+  end
+
+  def to_list({%Participant{role: role, metadata: metadata}, %Actor{} = actor}) do
+    [Actor.display_name_and_username(actor), translate_role(role), convert_metadata(metadata)]
+  end
+
+  @spec convert_metadata(Metadata.t() | nil) :: String.t()
+  defp convert_metadata(%Metadata{message: message}) when is_binary(message) do
+    message
+  end
+
+  defp convert_metadata(_), do: ""
+
+  @spec export_modules :: list(module())
+  def export_modules do
+    export_config = Application.get_env(:mobilizon, :exports)
+    Keyword.get(export_config, :formats, [])
+  end
+
+  @spec enabled_formats :: list(String.t())
+  def enabled_formats do
+    export_modules()
+    |> Enum.map(& &1.extension())
+  end
+
+  @spec export_enabled?(module()) :: boolean
+  def export_enabled?(type) do
+    export_config = Application.get_env(:mobilizon, :exports)
+    formats = Keyword.get(export_config, :formats, [])
+    type in formats
+  end
+end