defmodule Mv.MailerSmtpConfigTest do
  @moduledoc """
  Unit tests for Mv.Mailer.smtp_config/0.

  Ensures both port 587 (STARTTLS) and 465 (implicit SSL) work:
  - 587: sockopts must NOT contain :verify (gen_tcp:connect would raise ArgumentError).
  - 465: sockopts MUST contain :verify so initial ssl:connect uses verify_none/verify_peer.
  Uses ENV to drive config; async: false.
  """
  use Mv.DataCase, async: false

  alias Mv.Mailer

  defp set_smtp_env(key, value), do: System.put_env(key, value)

  defp clear_smtp_env do
    System.delete_env("SMTP_HOST")
    System.delete_env("SMTP_PORT")
    System.delete_env("SMTP_USERNAME")
    System.delete_env("SMTP_PASSWORD")
    System.delete_env("SMTP_PASSWORD_FILE")
    System.delete_env("SMTP_SSL")
  end

  describe "smtp_config/0" do
    test "port 587 (TLS): does not include :verify in sockopts so gen_tcp:connect does not crash" do
      set_smtp_env("SMTP_HOST", "smtp.example.com")
      set_smtp_env("SMTP_PORT", "587")
      set_smtp_env("SMTP_SSL", "tls")

      config = Mailer.smtp_config()

      assert config != [], "expected non-empty config when SMTP_HOST is set"

      sockopts = Keyword.get(config, :sockopts, [])

      refute Keyword.has_key?(sockopts, :verify),
             "for 587 gen_tcp is used first; sockopts must not contain :verify"
    after
      clear_smtp_env()
    end

    test "port 465 (SSL): includes :verify in sockopts so initial ssl:connect accepts verify mode" do
      set_smtp_env("SMTP_HOST", "smtp.example.com")
      set_smtp_env("SMTP_PORT", "465")
      set_smtp_env("SMTP_SSL", "ssl")

      config = Mailer.smtp_config()

      assert config != []
      sockopts = Keyword.get(config, :sockopts, [])

      assert Keyword.has_key?(sockopts, :verify),
             "for 465 initial connection is ssl:connect; sockopts must contain :verify"

      assert Keyword.get(sockopts, :verify) in [:verify_none, :verify_peer]
    after
      clear_smtp_env()
    end

    test "builds TLS mode for port 587 (STARTTLS)" do
      set_smtp_env("SMTP_HOST", "smtp.example.com")
      set_smtp_env("SMTP_PORT", "587")
      set_smtp_env("SMTP_SSL", "tls")

      config = Mailer.smtp_config()

      assert config != []
      assert Keyword.get(config, :tls) == :always
      assert Keyword.get(config, :ssl) == false
    after
      clear_smtp_env()
    end

    test "builds SSL mode for port 465 (implicit SSL)" do
      set_smtp_env("SMTP_HOST", "smtp.example.com")
      set_smtp_env("SMTP_PORT", "465")
      set_smtp_env("SMTP_SSL", "ssl")

      config = Mailer.smtp_config()

      assert config != []
      assert Keyword.get(config, :ssl) == true
      assert Keyword.get(config, :tls) == :never
    after
      clear_smtp_env()
    end
  end
end