using System.Collections.Concurrent;
using Models.Handler;
using Models.Model.Backend;

namespace Backend.Handler;

public class ThreadHandler
{
    private readonly DbHandler _dbHandler;
    private readonly Communication _communication;
    private readonly IpScanner _ipScanner;
    private readonly ContentFilter _contentFilter;
    
    private bool _communicationStopped;
    private bool _ipScannerStopped;
    private bool _contentFilterStopped;
    private bool _stopSignal;
    
    public ThreadHandler()
    {
        ConcurrentQueue<QueueItem> contentQueue = new();
        ConcurrentQueue<Discarded> discardedQueue = new();
        
        _dbHandler = new(contentQueue, discardedQueue);
        _communication = new(_dbHandler, this);
        _ipScanner = new(contentQueue, _dbHandler, discardedQueue);
        _contentFilter = new(contentQueue, _dbHandler);
    }
    
    public void Start()
    {
        Thread scanner = new(StartScanner);
        Thread indexer = new(StartIndexer);
        Thread database = new(StartDbHandler);
        Thread discarded = new(StartDiscardedDbHandler);
        Thread communication = new(StartCommunicationHandler);
        
        scanner.Start();
        indexer.Start();
        database.Start();
        discarded.Start();
        communication.Start();
        
        scanner.Join();
        indexer.Join();
        database.Join();
        discarded.Join();
        communication.Join();
    }
    
    public static void ManualGc()
    {
        GC.Collect();
        GC.WaitForPendingFinalizers();
        GC.Collect();
    }
    
    private void StartScanner()
    {
        Thread.Sleep(10000); // Let the database handler instantiate and warm up first.
        
        WaitHandle[] wait = _ipScanner.Start(4);
        
        WaitHandle.WaitAll(wait);
        
        Console.WriteLine("Scanner finished");
        
        _ipScannerStopped = true;
    }
    
    private void StartIndexer()
    {
        while (!_stopSignal)
        {
            WaitHandle[] wait = _contentFilter.Start();
            
            WaitHandle.WaitAll(wait);
            
            Thread.Sleep(300000); // 5 minutes
        }
        
        Console.WriteLine("Indexer finished");
        
        _contentFilterStopped = true;
    }
    
    private void StartDbHandler()
    {
        _dbHandler.StartContent();
    }
    
    private void StartDiscardedDbHandler()
    {
        WaitHandle[] wait = _dbHandler.Start(2);
        
        WaitHandle.WaitAll(wait);
        
        Console.WriteLine("Discarded DbHandler finished");
    }
    
    private void StartCommunicationHandler()
    {
        WaitHandle[] wait = _communication.Start();
        
        WaitHandle.WaitAll(wait);
        
        Console.WriteLine("Communicator finished");
        
        _communicationStopped = true;
        
        Stop();
    }

    private void Stop()
    {
        _stopSignal = true;
        _ipScanner.Stop();
        _contentFilter.Stop();
        
        bool stopping = true;
        
        while (stopping)
        {
            if (_communicationStopped && _ipScannerStopped && _contentFilterStopped)
            {
                _dbHandler.Stop();
                stopping = false;
            }
            
            Thread.Sleep(3000);
        }
    }
}