messengerapi.SubscriptionClient/code/MessengerApi.SubscriptionClient/SubscriptionClient.cs

using MessengerApi.Model;
using portaloggy;

namespace MessengerApi
{
    /// <summary>
    /// This exists so you can mock it.
    /// </summary>
    public interface ISubscriptionClient : IDisposable
    {
        /// <summary>
        /// Subscribes to given message type mask. Thread-safe.
        /// </summary>
        /// <remarks>Expected format of mask: "MY-MESSAGE-TYPE". No wildcards or placeholders, we only compare MessageType.StartsWith using this value.</remarks>
        Subscription Subscribe(string payloadTypeMask);

        /// <summary>
        /// Unsubscribes from given subscriptions. Thread-safe.
        /// </summary>
        void Unsubscribe(Subscription subscription);
    }

    /// <summary>
    /// This is where you begin. Instantiate one of these and start subscribing with <see cref="Subscribe(string)"/>.
    /// </summary>
    public class SubscriptionClient : Client, ISubscriptionClient
    {
        private readonly SubscriptionPollingEngine _engine;

        private bool _isDisposed;

        public SubscriptionClient(Credentials credentials, HttpClient client = null, ILogger logger = null) : base(credentials, client, logger)
        {
            this._engine = new SubscriptionPollingEngine(this._logger, this);
        }

        public void Dispose()
        {
            if (this._isDisposed)
            {
                return;
            }

            this._engine.Dispose();
            this._isDisposed = true;
        }

        public Subscription Subscribe(string messageTypeMask)
        {
            var sub = new Subscription(messageTypeMask, this);
            this._engine.AddSubscription(sub);

            return sub;
        }

        public void Unsubscribe(Subscription subscription)
        {
            this._engine.RemoveSubscription(subscription);
        }
    }
}