messengerapi.Client/code/MessengerApi.Contracts/MessengerClient.cs

using portaloggy;
using System.Text;
using System.Text.Json.Nodes;

namespace MessengerApi.Contracts
{
    /// <summary>
    /// Exists for mocking reason. This is implemented by <see cref="MessengerClient"/>.
    /// </summary>
    public interface IMessengerClient
    {
        /// <summary>
        /// Receives pending messages from the messenger API.
        /// </summary>
        /// <param name="credentials">Credentials to the API.</param>
        IEnumerable<InboxMessage> GetMessages();

        /// <summary>
        /// Acknowledges message reception to the server.
        /// </summary>
        void AckMessage(InboxMessage message);

        /// <summary>
        /// Sends a message.
        /// </summary>
        /// <param name="credentials">Credentials to the API.</param>
        void SendMessage(OutboxMessage outboxMessage);

        /// <summary>
        /// Returns user ids for allowed message recipients.
        /// </summary>
        Contact[] GetYellowPages();
    }

    public class MessengerClient : IMessengerClient
    {
        private readonly HttpClient _httpClient;
        private readonly ILogger _logger;

        private DateTime _lastReceivedUtc;
        private Credentials _credentials;

        public MessengerClient(Credentials credentials, HttpClient httpClient = null, ILogger logger = null)
        {
            _credentials = credentials;
            _httpClient = httpClient ?? new HttpClient();
            _logger = logger ?? new ConsoleLogger();
            _lastReceivedUtc = DateTime.MinValue.ToUniversalTime();
        }

        public IEnumerable<InboxMessage> GetMessages()
        {
            var since = Uri.EscapeDataString(this._lastReceivedUtc.ToString("o"));
            var url = $"{_credentials.ApiUrl}/receive?sinceUtc={since}";
            var request = new HttpRequestMessage(HttpMethod.Get, url);
            request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", _credentials.ApiKey);
            
            _logger.Debug($"Sending query to {url} with content {request.ToString()} to obtain messages.");

            var response = _httpClient.Send(request);

            if (!response.IsSuccessStatusCode)
            {
                _logger.Error(response.ReasonPhrase);
                throw new HttpRequestException("Can't receive.", null, response.StatusCode);
            }

            var responseContent = response.Content
                .ReadAsStringAsync()
                .GetAwaiter()
                .GetResult();

            if (!string.IsNullOrWhiteSpace(responseContent))
            {
                _logger.Debug($"Received response of {responseContent}.");
            }

            if (string.IsNullOrWhiteSpace(responseContent))
            {
                return Enumerable.Empty<InboxMessage>().ToArray();
            }

            var json = JsonNode.Parse(responseContent);
            var messages = new List<InboxMessage>();

            foreach (var item in json["messages"].AsArray())
            {
                if (item["id"].GetValue<int>() == -1)
                {
                    continue;
                }

                messages.Add(new InboxMessage
                {
                    Id = item["id"].GetValue<Guid>(),
                    Payload = item["payload"].ToJsonString(),
                    PayloadType = item["payloadType"].ToJsonString(),
                    Sender = item["sender"].GetValue<Guid>(),
                });
            }

            _lastReceivedUtc = DateTime.UtcNow.Subtract(TimeSpan.FromSeconds(10));
            _logger.Debug($"Received {messages.Count} messages and last check timestamp is set to {_lastReceivedUtc.ToString("s")}.");

            return messages.ToArray();
        }

        public void SendMessage(OutboxMessage outboxMessage)
        {
            var body = new JsonObject();

            if(outboxMessage.ToUserId.HasValue)
            {
                body.Add("toUserId", JsonValue.Create<Guid>(outboxMessage.ToUserId.Value));
            }

            if(outboxMessage.Payload != null)
            {
                body.Add("payload", JsonValue.Create<string>(outboxMessage.Payload));
            }

            if(outboxMessage.PayloadType != null)
            {
                body.Add("payloadType", JsonValue.Create<string>(outboxMessage.PayloadType));
            }

            if(outboxMessage.LifespanInSeconds != null)
            {
                body.Add("lifespanInSeconds", JsonValue.Create<int>(outboxMessage.LifespanInSeconds.Value));
            }

            var content = new StringContent(body.ToString(), Encoding.UTF8, "application/json");

            var url = $"{_credentials.ApiUrl}/send";
            var request = new HttpRequestMessage(HttpMethod.Post, url);
            request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", _credentials.ApiKey);

            _logger.Debug($"Sending query to {url} with content {body.ToString()} to obtain messages.");

            var response = _httpClient.Send(request);

            if (!response.IsSuccessStatusCode)
            {
                _logger.Error(response.ReasonPhrase);
                throw new HttpRequestException("Can't send.", null, response.StatusCode);
            }
        }

        public Contact[] GetYellowPages()
        {
            var url = $"{_credentials.ApiUrl}/yellowpages";
            var request = new HttpRequestMessage(HttpMethod.Get, url);
            request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", _credentials.ApiKey);

            _logger.Debug($"Sending query to {url} with content {request.ToString()}.");

            var response = _httpClient.Send(request);

            if (!response.IsSuccessStatusCode)
            {
                _logger.Error(response.ReasonPhrase);
                throw new HttpRequestException("Can't receive.", null, response.StatusCode);
            }

            var responseContent = response.Content
                .ReadAsStringAsync()
                .GetAwaiter()
                .GetResult();

            var json = JsonNode.Parse(responseContent);

            var contacts = json["users"].AsArray().Select(x => new Contact
            {
                Id = x["id"].GetValue<Guid>(),
                Name = x["name"].GetValue<string>()
            }).ToArray();

            return contacts;
        }

        public void AckMessage(InboxMessage message)
        {
            
        }
    }
}