# config/config.exs

config :my_app, mailgun_domain: "https://api.mailgun.net/v3/mydomain.com",
                mailgun_key: "key-##############"


# lib/mailer.ex
defmodule MyApp.Mailer do
  @config domain: Application.get_env(:my_app, :mailgun_domain),
          key: Application.get_env(:my_app, :mailgun_key)
  use Mailgun.Client, @config
                      

  @from "[email protected]"

  def send_welcome_text_email(user) do
    send_email to: user.email,
               from: @from,
               subject: "hello!",
               text: "Welcome!"
  end

  def send_welcome_html_email(user) do
    send_email to: user.email,
               from: @from,
               subject: "hello!",
               html: "<strong>Welcome!</strong>"
  end

 # attachments expect a list of maps. Each map should have a filename and path/content

  def send_greetings(user, file_path) do
    send_email to: user.email,
               from: @from,
               subject: "Happy b'day",
               html: "<strong>Cheers!</strong>",
               attachments: [%{path: file_path, filename: "greetings.png"}]
  end

  def send_invoice(user) do
    pdf = Invoice.create_for(user) # a string
    send_email to: user.email,
               from: @from,
               subject: "Invoice",
               html: "<strong>Your Invoice</strong>",
               attachments: [%{content: pdf, filename: "invoice.pdf"}]
  end
end


iex> MyApp.Mailer.send_welcome_text_email(user)
{:ok, ...}

def deps do
  [ {:mailgun, "~> 0.1.2"} ]
end

# lib/mailer.ex
defmodule MyApp.Mailer do
  @config domain: Application.get_env(:my_app, :mailgun_domain),
          key: Application.get_env(:my_app, :mailgun_key),
          mode: :test,
          test_file_path: "/tmp/mailgun.json"
  use Mailgun.Client, @config

...
end

# lib/mailer.ex
defmodule MyApp.Mailer do
  @config domain: Application.get_env(:my_app, :mailgun_domain),
          key: Application.get_env(:my_app, :mailgun_key),
          httpc_opts: [connect_timeout: 2000, timeout: 3000]
  use Mailgun.Client, @config
...