Add task to add attendees without sending emails

lib/mix/tasks/gen.users_from_csv_without_email.ex

@@ -0,0 +1,123 @@
+defmodule Mix.Tasks.Gen.UsersFromCsv do
+  use Mix.Task
+  alias Ecto.Multi
+  alias Safira.Repo
+  alias Safira.Auth
+  alias Safira.Accounts.User
+  alias Safira.Accounts.Attendee
+
+  alias NimbleCSV.RFC4180, as: CSV
+
+  @shortdoc "Generates the attendees from a CSV"
+
+  @moduledoc """
+  This task is waiting for a CSV where the 3rd collumn is name,
+   4th collumn is last name and 5th collumn is email
+  and a flag ("Local"/"Remote") indicating if the file is local or remote
+
+  ex:
+  mix gen.users_from_csv "assets/participantes_sei_exemplo.csv" "Local"
+  mix gen.users_from_csv "https://sample.url.participantes_sei_exemplo.csv" "Remote"
+  """
+
+  def run(args) do
+    cond do
+      length(args) != 2 ->
+        Mix.shell().info("Needs to receive a file URL and a flag.")
+
+      true ->
+        args |> create
+    end
+  end
+
+  defp create(args) do
+    Mix.Task.run("app.start")
+
+    file_url = Enum.at(args, 0)
+    location_flag = Enum.at(args, 1)
+
+    case location_flag do
+      "Local" ->
+        try do
+          file_url
+          |> parse_csv
+          |> create_users
+        rescue
+          e in File.Error -> IO.inspect e
+        end
+
+       "Remote" ->
+
+        :inets.start()
+        :ssl.start()
+
+        case :httpc.request(:get, {to_charlist(file_url), []}, [], stream: '/tmp/user.csv') do
+          {:ok, _resp} ->
+            "/tmp/user.csv"
+            |> parse_csv
+            |> create_users
+
+          {:error, resp} -> IO.inspect resp
+        end
+    end
+
+
+  end
+
+  defp parse_csv(path) do
+    path
+    |> File.stream!(read_ahead: 1_000)
+    |> CSV.parse_stream()
+    |> Stream.map(fn row ->
+      %{
+        name: "#{Enum.at(row, 2)} #{Enum.at(row, 3)}",
+        email: Enum.at(row, 4)
+      }
+    end)
+  end
+
+  defp create_users(user_csv_stream) do
+    Enum.map(user_csv_stream, fn user_csv_entry ->
+      Multi.new()
+      |> Multi.insert(
+        :user,
+        create_user_aux(user_csv_entry)
+      )
+      |> Multi.insert(
+        :attendee,
+        fn %{user: user} ->
+          create_attendee_aux(user, user_csv_entry)
+        end
+      )
+      |> Repo.transaction()
+    end)
+  end
+
+  defp create_user_aux(user) do
+    password = random_string(8)
+
+    user = %{
+      "email" => user.email,
+      "password" => password,
+      "password_confirmation" => password
+    }
+
+    User.changeset(%User{}, user)
+  end
+
+  defp create_attendee_aux(user, user_csv_entry) do
+    Attendee.only_user_changeset(
+      %Attendee{},
+      %{
+        user_id: user.id,
+        name: user_csv_entry.name
+      }
+    )
+  end
+
+  defp random_string(length) do
+    :crypto.strong_rand_bytes(length)
+    |> Base.url_encode64()
+    |> binary_part(0, length)
+  end
+end