// This example shows how to indicate that the write operation completes asynchronously. This is an example of the push
// data consumption model.
// You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server. 
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client, server and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-OPCStudio-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 System;
using System.Threading;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.NodeSpace;

namespace UAServerDocExamples._UADataVariable
{
    partial class WriteFunction
    {
        public static void GoodCompletesAsynchronously()
        {
            // Instantiate the server object.
            // By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
            var server = new EasyUAServer();

            // Create a writable data variable and add a function that will be called when the data variable is written to.
            // The function returns a status code that indicates the outcome of the Write operation. Since we do not know the
            // true outcome of the write operation at the time of the function call, we return status code
            // "GoodCompletesAsynchronously".
            server.Add(new UADataVariable("WriteToThisVariable").WriteFunction<int>(
                data =>
                {
                    // The actual write operation is performed asynchronously, on a separate thread.
                    var thread = new Thread(() => Console.WriteLine($"Attribute data written: {data}"));
                    thread.Start();

                    return UACodeBits.GoodCompletesAsynchronously;
                }));

            // Start the server.
            Console.WriteLine("The server is starting...");
            server.Start();

            Console.WriteLine("The server is started.");
            Console.WriteLine("Any value written to the example data variable will be displayed on the console.");
            Console.WriteLine();

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

            // Stop the server.
            Console.WriteLine("The server is stopping...");
            server.Stop();

            Console.WriteLine("The server is stopped.");
        }
    }
}