newsletter

elixir/newsletter/lib/newsletter.ex

@@ -0,0 +1,32 @@
+defmodule Newsletter do
+  def read_emails(path) do
+    path
+    |> File.stream!()
+    |> Stream.map(&String.trim/1)
+    |> Enum.to_list()
+  end
+
+  def open_log(path) do
+    File.open!(path, [:write])
+  end
+
+  def log_sent_email(pid, email) do
+    IO.puts(pid, email)
+  end
+
+  def close_log(pid) do
+    File.close(pid)
+  end
+
+  def send_newsletter(emails_path, log_path, send_fun) do
+    log_pid = open_log(log_path)
+
+    emails_path
+    |> read_emails()
+    |> Enum.map(fn email ->
+      if send_fun.(email) == :ok, do: log_sent_email(log_pid, email)
+    end)
+
+    close_log(log_pid)
+  end
+end