phoenix_passkeys/lib/phoenix_passkeys_web/controllers/user_settings_controller.ex

defmodule PhoenixPasskeysWeb.UserSettingsController do
  use PhoenixPasskeysWeb, :controller

  alias PhoenixPasskeys.Accounts

  plug :assign_email_changesets

  def edit(conn, _params) do
    render(conn, :edit)
  end

  def update(conn, %{"action" => "update_email"} = params) do
    %{"user" => user_params} = params
    user = conn.assigns.current_user

    case Accounts.apply_user_email(user, user_params) do
      {:ok, applied_user} ->
        Accounts.deliver_user_update_email_instructions(
          applied_user,
          user.email,
          &url(~p"/users/settings/confirm_email/#{&1}")
        )

        conn
        |> put_flash(
          :info,
          "A link to confirm your email change has been sent to the new address."
        )
        |> redirect(to: ~p"/users/settings")

      {:error, changeset} ->
        render(conn, :edit, email_changeset: changeset)
    end
  end

  def confirm_email(conn, %{"token" => token}) do
    case Accounts.update_user_email(conn.assigns.current_user, token) do
      :ok ->
        conn
        |> put_flash(:info, "Email changed successfully.")
        |> redirect(to: ~p"/users/settings")

      :error ->
        conn
        |> put_flash(:error, "Email change link is invalid or it has expired.")
        |> redirect(to: ~p"/users/settings")
    end
  end

  defp assign_email_changesets(conn, _opts) do
    user = conn.assigns.current_user

    conn
    |> assign(:email_changeset, Accounts.change_user_email(user))
  end
end