// This example shows how to subscribe to changes of multiple monitored items
// and display each change, identifying the different subscriptions by an
// object.
 
using System;
using System.Threading;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;
 
namespace UADocExamples._EasyUAClient
{
    partial class SubscribeMultipleMonitoredItems
    {
        class CustomObject
        {
            public CustomObject(string name)
            {
                Name = name;
            }
 
            public string Name { get; }
        }
 
 
        public static void StateAsObject()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (not in .NET Standard)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"
 
            // Instantiate the client object and hook events
            var client = new EasyUAClient();
            client.DataChangeNotification += ClientOnDataChangeNotification_StateAsObject;
 
            Console.WriteLine("Subscribing...");
            int[] handleArray = client.SubscribeMultipleMonitoredItems(new[]
                {
                    new EasyUAMonitoredItemArguments(null, endpointDescriptor, 
                        "nsu=http://test.org/UA/Data/;i=10845", 1000)
                        {State = new CustomObject("First")},    // A custom object that corresponds to the subscription
                    new EasyUAMonitoredItemArguments(null, endpointDescriptor, 
                        "nsu=http://test.org/UA/Data/;i=10853", 1000)
                        {State = new CustomObject("Second")},    // A custom object that corresponds to the subscription
                    new EasyUAMonitoredItemArguments(null, endpointDescriptor, 
                        "nsu=http://test.org/UA/Data/;i=10855", 1000)
                        {State = new CustomObject("Third")},    // A custom object that corresponds to the subscription
                });
 
            for (int i = 0; i < handleArray.Length; i++)
                Console.WriteLine($"handleArray[{i}]: {handleArray[i]}");
 
            Console.WriteLine("Processing monitored item changed events for 10 seconds...");
            Thread.Sleep(10 * 1000);
 
            Console.WriteLine("Unsubscribing...");
            client.UnsubscribeAllMonitoredItems();
 
            Console.WriteLine("Waiting for 5 seconds...");
            Thread.Sleep(5 * 1000);
 
            Console.WriteLine("Finished.");
        }
 
        static void ClientOnDataChangeNotification_StateAsObject(object sender, EasyUADataChangeNotificationEventArgs eventArgs)
        {
            // Obtain the custom object we have passed in.
            var stateAsObject = (CustomObject) eventArgs.Arguments.State;
 
            // Display the data
            if (eventArgs.Succeeded)
                Console.WriteLine($"{stateAsObject.Name}: {eventArgs.AttributeData}");
            else
                Console.WriteLine($"{stateAsObject.Name} *** Failure: {eventArgs.ErrorMessageBrief}");
        }

// This example shows that either a single client object, or multiple client objects can be used to read values from two
// servers.
 
using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;
 
namespace UADocExamples._EasyUAClient
{
    partial class ReadValue
    {
        public static void MultipleServers()
        {
            // Define which servers we will work with.
            UAEndpointDescriptor endpointDescriptor1 =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (not in .NET Standard)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"
            UAEndpointDescriptor endpointDescriptor2 =
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer";
 
 
 
            // Part 1: Use a single client object.
            // This demonstrates the fact the the client objects do *not* represent connections to individual servers.
            // Instead, they are able to maintain connections to multiple servers internally. API method calls on the client
            // object include the server's endpoint descriptor in their arguments, so you can specify a different endpoint
            // with each operation.
            Console.WriteLine();
 
            // Instantiate the client object
            var client = new EasyUAClient();
 
            Console.WriteLine("Obtaining values of nodes using a single client object...");
            object value1, value2;
            try
            {
                // The node Id we are reading returns the product name of the server.
                value1 = client.ReadValue(endpointDescriptor1, "nsu=http://opcfoundation.org/UA/ ;i=2261");
                value2 = client.ReadValue(endpointDescriptor2, "nsu=http://opcfoundation.org/UA/ ;i=2261");
                // Note: For efficiency (reading from the two servers in parallel), it would be better to use the
                // ReadMultipleValues method here, but this example is made for code clarity.
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }
 
            // Display results
            Console.WriteLine("value1: {0}", value1);
            Console.WriteLine("value2: {0}", value2);
 
 
 
            // Part 2: Use multiple client objects.
            // This demonstrates the fact that it is also possible to use multiple client objects, and on the OPC side, the
            // behavior will be the same as if you had used a single client object. Multiple client objects consume somewhat
            // more resources on the client side, but they come handy if, for example,
            // - you cannot easily pass around the single pre-created client object to various parts in your code, or
            // - you are using subscriptions and you want to hook separate event handlers for different purposes, or
            // - you need to set something in the instance parameters of the client object differently for different
            // connections.
            Console.WriteLine();
 
            // Instantiate the client object2
            var client1 = new EasyUAClient();
            var client2 = new EasyUAClient();
 
            Console.WriteLine("Obtaining values of nodes using a single client object...");
            try
            {
                // The node Id we are reading returns the product name of the server.
                value1 = client1.ReadValue(endpointDescriptor1, "nsu=http://opcfoundation.org/UA/ ;i=2261");
                value2 = client2.ReadValue(endpointDescriptor2, "nsu=http://opcfoundation.org/UA/ ;i=2261");
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }
 
            // Display results
            Console.WriteLine("value1: {0}", value1);
            Console.WriteLine("value2: {0}", value2);
 
 
 
            // Example output:
            //
            //Obtaining values of nodes using a single client object...
            //value1: OPC UA SDK Samples
            //value2: OPC UA Workshop Samples
            //
            //Obtaining values of nodes using a single client object...
            //value1: OPC UA SDK Samples
            //value2: OPC UA Workshop Samples
        }
    }
}