// This example shows how to retrieve the metric data in the pull data consumption model. In this model, the data that
// Sparkplug applications send to the edge node or device is pulled and processed by your code when needed.
//
// You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
// program, to subscribe to the edge node data. SparkplugCmd, or other capable Sparkplug application, can be used to write
// data into the metric.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
// Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using OpcLabs.EasySparkplug;
using System;
using Timer = System.Timers.Timer;

namespace SparkplugDocExamples.EdgeNode._SparkplugMetric
{
    class WriteData
    {
        static public void Main1()
        {
            // Note that the default port for the "mqtt" scheme is 1883.
            var hostDescriptor = new SparkplugHostDescriptor("mqtt://localhost");

            // Instantiate the edge node object and hook events.
            var edgeNode = new EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo");
            edgeNode.SystemConnectionStateChanged += (sender, eventArgs) =>
            {
                // Display the new connection state (such as when the connection to the broker succeeds or fails).
                Console.WriteLine($"{nameof(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}");
            };

            // Create a read-write data variable with an initial value.
            var metric = SparkplugMetric.CreateIn(edgeNode, "WriteToThisMetric").ReadWriteValue(0);

            // Create a timer for pulling the data from OPC writes. In a real server the activity may also come from other
            // sources.
            var timer = new Timer
            {
                Interval = 1000,    // 1 second
                AutoReset = true,
            };

            // Periodically display the value of the metric on the console.
            timer.Elapsed += (sender, args) => Console.Write($"  {metric.WriteData.Value}");
            timer.Start();
            Console.WriteLine("Values of the example metric are displayed on the console periodically.");

            // Start the edge node.
            Console.WriteLine("The edge node is starting...");
            edgeNode.Start();

            Console.WriteLine("The edge node is started.");
            Console.WriteLine();

            // Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the edge node...");
            Console.ReadLine();

            // Stop the edge node.
            Console.WriteLine("The edge node is stopping...");
            edgeNode.Stop();

            Console.WriteLine("The edge node is stopped.");
            
            // Stop the timer.
            timer.Stop();
        }
    }
}