/// <summary>
/// Converts a single Facebook messenger message to a Bot Framework activity.
/// </summary>
/// <param name="message">The message to be processed.</param>
/// <returns>An Activity with the result.</returns>
/// <exception cref="ArgumentNullException"><paramref name="message"/> is null.</exception>
/// <remarks>A webhook call may deliver more than one message at a time.</remarks>
public static Activity ProcessSingleMessage(FacebookMessage message)
{
if (message == null)
{
throw new ArgumentNullException(nameof(message));
}
if (message.Sender == null && message.OptIn?.UserRef != null)
{
message.Sender = new FacebookBotUser {
Id = message.OptIn?.UserRef
};
}
var activity = new Activity()
{
ChannelId = "facebook",
Timestamp = default,
