// This example shows how to react to events in order to initiate and finalize data collection in the push data provision
// 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.Timers;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.NodeSpace;

namespace UAServerDocExamples._UAServerNode
{
    class Starting_Stopped
    {
        public static void Main1()
        {
            // Instantiate the server object.
            // By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
            var server = new EasyUAServer();

            // Create a read-only data variable.
            var dataVariable = UADataVariable.CreateIn(server.Objects, "ReadThisVariable")
                .ValueType<int>()
                .Writable(false);

            dataVariable.Starting += (sender, args) =>
            {
                // Create a timer for pushing the data for OPC reads.
                var timer = new Timer
                {
                    Interval = 1000,
                    AutoReset = true,
                };

                // Set the read attribute data of the data variable to a random value whenever the timer interval elapses.
                // Note that this example shows the basic concept, however there is also an UpdateReadAttributeData method that
                // can be used in most cases to achieve slightly more concise code.
                var random = new Random();
                timer.Elapsed += (s, a) =>
                    dataVariable.ReadAttributeData = new UAAttributeData(random.Next(), DateTime.UtcNow);
                timer.Start();

                // Associate the timer with the data variable.
                dataVariable.State = timer;
            };
            dataVariable.Stopped += (sender, args) =>
            {
                // Obtain the timer associated with the data variable.
                var timer = (Timer)((UADataVariable)sender).State;

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

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