Innovenergy_trunk/csharp/App/Backend/Websockets/RabbitMQManager.cs

using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.Json;
using InnovEnergy.App.Backend.Database;
using InnovEnergy.App.Backend.DataTypes;
using RabbitMQ.Client;
using RabbitMQ.Client.Events;

namespace InnovEnergy.App.Backend.Websockets;

public static class RabbitMqManager
{
    
    public static ConnectionFactory Factory = null!;
    public static IConnection Connection = null!;
    public static IModel Channel = null!;
    

    public static void InitializeEnvironment()
    {
        
        string vpnServerIp = "194.182.190.208";
        Factory = new ConnectionFactory { HostName = vpnServerIp};
        Connection = Factory.CreateConnection();
        Channel = Connection.CreateModel();
        Console.WriteLine("Middleware subscribed to RabbitMQ queue, ready for receiving messages");
        Channel.QueueDeclare(queue: "statusQueue", durable: true, exclusive: false, autoDelete: false, arguments: null);
    }
    
    public static async Task StartRabbitMqConsumer()
    {
        var consumer = new EventingBasicConsumer(Channel);
        consumer.Received += (_, ea) =>
        {
            var body = ea.Body.ToArray();
            var message = Encoding.UTF8.GetString(body);
            StatusMessage? receivedStatusMessage = JsonSerializer.Deserialize<StatusMessage>(message);
            var InstallationConnections = WebsocketManager.InstallationConnections;

            lock (InstallationConnections)
            {
                //Consumer received a message
                if (receivedStatusMessage != null)
                {
                    Console.WriteLine("----------------------------------------------");
                    Console.WriteLine("Received a message from installation: " + receivedStatusMessage.InstallationId + " and status is: " + receivedStatusMessage.Status);
                    var installationId = receivedStatusMessage.InstallationId;

                    //This is a heartbit message, just update the timestamp for this installation.
                    //There is no need to notify the corresponding front-ends.
                    if (receivedStatusMessage.Type == MessageType.Heartbit)
                    {
                        Console.WriteLine("This is a heartbit message from installation: " + installationId);
                    }
                    else
                    {
                        //Traverse the Warnings list, and store each of them to the database
                        if (receivedStatusMessage.Warnings != null)
                        {
                            foreach (var warning in receivedStatusMessage.Warnings)
                            {
                                Warning newWarning = new Warning
                                {
                                    InstallationId = receivedStatusMessage.InstallationId,
                                    Description = warning.Description,
                                    Date = warning.Date,
                                    Time = warning.Time,
                                    DeviceCreatedTheMessage = warning.CreatedBy,
                                    Seen = false
                                };
                                //Create a new warning and add it to the database
                                Db.HandleWarning(newWarning, receivedStatusMessage.InstallationId);
                            }
                        }


                        //Traverse the Alarm list, and store each of them to the database
                        if (receivedStatusMessage.Alarms != null)
                        {
                            foreach (var alarm in receivedStatusMessage.Alarms)
                            {
                                Error newError = new Error
                                {
                                    InstallationId = receivedStatusMessage.InstallationId,
                                    Description = alarm.Description,
                                    Date = alarm.Date,
                                    Time = alarm.Time,
                                    DeviceCreatedTheMessage = alarm.CreatedBy,
                                    Seen = false
                                };
                                //Create a new error and add it to the database
                                Db.HandleError(newError, receivedStatusMessage.InstallationId);
                            }
                        }
                    }

                    //This installation id does not exist in our data structure, add it.
                    if (!InstallationConnections.ContainsKey(installationId))
                    {
                        Console.WriteLine("Create new empty list for installation: " + installationId);
                        InstallationConnections[installationId] = new InstallationInfo
                        {
                            Status = receivedStatusMessage.Status,
                            Timestamp = DateTime.Now
                        };
                    }
                    else
                    {
                        InstallationConnections[installationId].Status = receivedStatusMessage.Status;
                        InstallationConnections[installationId].Timestamp = DateTime.Now;
                    }

                    //Console.WriteLine("----------------------------------------------");
                    //Update all the connected front-ends regarding this installation
                    if(InstallationConnections[installationId].Connections.Count > 0)
                    {
                        WebsocketManager.InformWebsocketsForInstallation(installationId);
                    }
                    
                }
            }
        };
        Channel.BasicConsume(queue: "statusQueue", autoAck: true, consumer: consumer);
    }
    
    public static void InformInstallationsToSubscribeToRabbitMq()
    {
        var installationIps = Db.Installations.Select(inst => inst.VpnIp).ToList();
        Console.WriteLine("Count is "+installationIps.Count);
        var maxRetransmissions = 2;
        
        UdpClient udpClient = new UdpClient();
        udpClient.Client.ReceiveTimeout = 2000;
        int port = 9000;
        //Send a message to each installation and tell it to subscribe to the queue
        using (udpClient)
        {
            for (int i = 0; i < installationIps.Count; i++)
            {
                if(installationIps[i]==""){continue;}
                Console.WriteLine("-----------------------------------------------------------");
                Console.WriteLine("Trying to reach installation with IP: " + installationIps[i]);
                //Try at most MAX_RETRANSMISSIONS times to reach an installation.
                for (int j = 0; j < maxRetransmissions; j++)
                {
                    string message = "This is a message from RabbitMQ server, you can subscribe to the RabbitMQ queue";
                    byte[] data = Encoding.UTF8.GetBytes(message);
                    udpClient.Send(data, data.Length, installationIps[i], port);

                    Console.WriteLine($"Sent UDP message to {installationIps[i]}:{port}: {message}");
                    IPEndPoint remoteEndPoint = new IPEndPoint(IPAddress.Parse(installationIps[i]), port);

                    try
                    {
                        byte[] replyData = udpClient.Receive(ref remoteEndPoint);
                        string replyMessage = Encoding.UTF8.GetString(replyData);
                        Console.WriteLine("Received " + replyMessage + " from installation " + installationIps[i]);
                        break;
                    }
                    catch (SocketException ex)
                    {
                        if (ex.SocketErrorCode == SocketError.TimedOut){Console.WriteLine("Timed out waiting for a response. Retry...");}
                        else{Console.WriteLine("Error: " + ex.Message);}
                    }
                }
            }
        }
        
        Console.WriteLine("Start RabbitMQ Consumer");
        
    }

}