RSE/Backend/Handler/Communication.cs

using System.Diagnostics.CodeAnalysis;
using System.Text.Json;
using Backend.Helper;
using Models.Handler;
using Models.Model.Backend;
using Models.Model.External;
using NetMQ;
using NetMQ.Sockets;

namespace Backend.Handler;

public class Communication
{
    private readonly DbHandler _dbHandler;
    private readonly ThreadHandler _threadHandler;
    private readonly IpScanner _ipScanner;
    private readonly ContentFilter _contentFilter;
    private bool _isRunning = true;
    private string _basePath;
    
    public Communication(DbHandler dbHandler, ThreadHandler threadHandler, IpScanner ipScanner, ContentFilter contentFilter, string basePath)
    {
        _dbHandler = dbHandler;
        _threadHandler = threadHandler;
        _ipScanner = ipScanner;
        _contentFilter = contentFilter;
        _basePath = basePath;
    }
    
    public WaitHandle[] Start()
    {
        WaitHandle[] waitHandles = new WaitHandle[1];
        EventWaitHandle handle = new(false, EventResetMode.ManualReset);
        waitHandles[0] = handle;
        
        Thread thread = new(Server!);
        thread.Start(handle);
        
        return waitHandles;
    }
    
    private void Server(object obj)
    {
        using ResponseSocket rep = new();
        
        //rep.Options.IPv4Only = true;
        
        rep.Bind("tcp://127.0.0.1:5556");
        
        while (_isRunning)
        {
            byte[] message = rep.ReceiveFrameBytes();
            
            CommunicationObject? communicationObject = JsonSerializer.Deserialize<CommunicationObject>(message);

            //rep.SendFrame(JsonSerializer.SerializeToUtf8Bytes("Success"));
            
            if (communicationObject is null)
            {
                continue;
            }
            
            OnServerOnReceiveReady(communicationObject, rep);
        }
        
        ((EventWaitHandle) obj).Set();
    }
    
    [RequiresDynamicCode("Calls System.Text.Json.JsonSerializer.Serialize<TValue>(TValue, JsonSerializerOptions)")]
    [RequiresUnreferencedCode("Calls System.Text.Json.JsonSerializer.Serialize<TValue>(TValue, JsonSerializerOptions)")]
    private void OnServerOnReceiveReady(CommunicationObject communicationObject, ResponseSocket rep)
    {
        switch (communicationObject.Command)
        {
            case CommunicationCommand.GetScanningProgress:
            {
                DatabaseSizes databaseSizes = FilesystemHelper.GetDatabaseSizes(_basePath);
                
                long discardedIndexes = _dbHandler.GetDiscardedIndexes();
                
                ScanningStatus status = new();
                // 4294967296 is all Ipv4 addresses.
                
                if (discardedIndexes != 0)
                {
                    status.PercentageOfIpv4Scanned = (float)discardedIndexes / 4294967296 * 100;
                }
                else
                {
                    // This is a workaround for the frontend not understanding a 0f as an actual float, so we use a very small float.
                    status.PercentageOfIpv4Scanned = 0.0000000001f;
                }
                
                status.AmountOfIpv4Left = 4294967296 - discardedIndexes;
                status.TotalFiltered = _dbHandler.GetFilteredIndexes();
                status.TotalDiscarded = discardedIndexes;
                status.MyDbSize = databaseSizes.MyDbSize;
                status.FilteredDbSize = databaseSizes.FilteredDbSize;
                status.DiscardedDbSize = databaseSizes.DiscardedDbSize;
                
                byte[] serializedResult = JsonSerializer.SerializeToUtf8Bytes(status);
                
                rep.SendFrame(serializedResult);
                
                break;
            }
            
            case CommunicationCommand.DbReindex:
            {
                _dbHandler.ReIndex();
                
                SendStringResponse(rep, "All Dbs have been reindexed.");
                break;
            }
            
            case CommunicationCommand.DbVacuum:
            {
                _dbHandler.Vacuum();
                
                SendStringResponse(rep, "All Dbs have been vacuumed.");
                break;
            }
            
            case CommunicationCommand.GetSearches:
            {
                if (!string.IsNullOrWhiteSpace(communicationObject.SearchTerm))
                {
                    SendSearchResponse(rep, communicationObject.SearchTerm);
                }
                
                break;
            }
            
            case CommunicationCommand.StopScanning:
            {
                _isRunning = false;
                break;
            }
            
            case CommunicationCommand.ChangeRuntimeVariable:
            {
                if (string.IsNullOrWhiteSpace(communicationObject.VariableValue)) break;
                
                if (communicationObject.Variable == RuntimeVariable.DbContent.ToString())
                {
                    int value = int.Parse(communicationObject.VariableValue);
                    _dbHandler.SetContentWaitTime(value);
                }
                
                if (communicationObject.Variable == RuntimeVariable.DbDiscarded.ToString())
                {
                    int value = int.Parse(communicationObject.VariableValue);
                    _dbHandler.SetDiscardedWaitTime(value);
                }
                
                if (communicationObject.Variable == RuntimeVariable.ScannerTimeout.ToString())
                {
                    int value = int.Parse(communicationObject.VariableValue);
                    _ipScanner.SetTimeout(value);
                }
                
                if (communicationObject.Variable == RuntimeVariable.ContentFilter.ToString())
                {
                    int value = int.Parse(communicationObject.VariableValue);
                    _contentFilter.SetTimeout(value);
                }
                
                rep.SendFrame(JsonSerializer.SerializeToUtf8Bytes("Success"));
                
                break;
            }
        }
    }
    
    private static void SendStringResponse(ResponseSocket rep, string response)
    {
        byte[] serializedResult = JsonSerializer.SerializeToUtf8Bytes(response);
        
        rep.SendFrame(serializedResult);
    }

    private static void SendSearchResponse(ResponseSocket rep, string searchTerm)
    {
        //SearchResults result = SearchHelper.Search(communicationObject.SearchTerm!, _dbHandler);
        SearchResults result = new()
        {
            Results = []
        };
        SearchResult lol = new()
        {
            Url = "Remember to use an actual search tearm. Like 'dotnet 9.0'",
            Title = "Remember to use an actual search tearm. Like 'dotnet 9.0'",
        };
        
        result.Results.Add(lol);
        
        string serializedResult = JsonSerializer.Serialize(result);
        
        rep.SendFrame(serializedResult);
    }
}