using System;
using System.Collections.Generic;
using Caplin.DataSource;
using Caplin.DataSource.Messaging.Record;
using Caplin.DataSource.Publisher;
using Caplin.DataSource.Namespace;

namespace DataSourceExamples.DataProvider
{
    public class ExampleDataProvider : IDataProvider
    {
        private readonly IPublisher publisher;
        private readonly DataSource dataSource;

        public ExampleDataProvider(DataSource dataSource)
        {
            this.publisher = dataSource.CreateActivePublisher(new PrefixNamespace("/"), this);
            this.dataSource = dataSource;
        }

        public void ReceiveRequest(IRequestEvent ev)
        {
            // Subscribe to back end system.
            // ...

            // Create a message for the DataSource subject.
            IRecordType1Message message = publisher.MessageFactory.CreateRecordType1Message(ev.Subject);

            // Mark the message as containing an image.
            message.Image = true;

            // Add data to the message.
            message["Bid"] = "1.23";

            // Send the image message to the newly subscribed DataSource peer.
            publisher.PublishInitialMessage(message);
        }

        public void ReceiveDiscard(IDiscardEvent ev)
        {
            // Unsubscribe from back end system 
            // ...
        }


        // Once this IDataProvider subscribed to the back end system, 
        // the back end pushes messages into this IDataProvider via this message
        // listener callback.
        public void OnDataUpdate(String subject, IDictionary<String, String> messageData)
        {
            // Create a message for the appropriate DataSource Subject.
            IRecordType1Message message = publisher.MessageFactory.CreateRecordType1Message(subject);

            // Transform the back end update's data into DataSource message fields.
            foreach (String name in messageData.Keys)
            {
                message[name] = messageData[name];
            }

            // Publish the message.
            publisher.PublishToSubscribedPeers(message);
        }
    }

}