using System.Diagnostics;
using OpenCvSharp;
using Serilog;
using VisionBuilder.UI.Common.Commands;
using VisionBuilder.UI.Common.ViewModel.Classes;

namespace VisionBuilder.UI.Common.Processing;

public abstract class BaseRecognitionControl: IRecognitionControl
{
    private readonly BaseRecognitionControlSettings _settings;
    private readonly ILoadingService _loadingService;

    private CancellationTokenSource _cts;
    private Task _loopTask;

    public BaseRecognitionControl(BaseRecognitionControlSettings settings, ILoadingService loadingService)
    {
        _settings = settings;
        _loadingService = loadingService;
    }

    public abstract List<RecipeData> GetRecipesData();
    

    RecipeData _currentRecipe;

    public void SetRecipe(RecipeData recipe)
    {
        // error if running
        if (IsRunning)
        {
            throw new InvalidOperationException("Cannot change recipe while recognition is running.");
        }
        _currentRecipe = recipe;
    }

    public bool IsRunning { get; set; }
    public bool IsPaused { get; set; }

    public RecipeData CurrentRecipe => _currentRecipe;

    public ILoadingService LoadingService => _loadingService;

    private DateTime _startTime;

    public void Start()
    {

        if (_currentRecipe == null)
        {
            throw new InvalidOperationException("No recipe set.");
        }
        if (IsRunning)
        {
            throw new InvalidOperationException("Recognition is already running.");
        }
        _loadingService.StartLoading($"Starting recipe {_currentRecipe.RecipeName} on {_settings.CameraName}...");
        Initialize(_currentRecipe);
        _startTime = DateTime.Now;
        IsRunning = true;
        _cts = new CancellationTokenSource();


        Log.Information($"Warming up");
        try
        {
            var swWarmup = Stopwatch.StartNew();
            WarmUp();
            swWarmup.Stop();
            Log.Information($"Warmup run took {swWarmup.ElapsedMilliseconds} ms");
        }
        catch (Exception ex)
        {
            Log.Error(ex, "Error during warmup run");
        }

        _loopTask = Task.Run(() => Loop(_cts.Token), _cts.Token);

        SessionStarted?.Invoke(new SessionStartedEvent
        {
            RecipeName = _currentRecipe.RecipeName,
            SessionStarted = _startTime,

        });
        _loadingService.StopLoading($"Starting recipe {_currentRecipe.RecipeName} on {_settings.CameraName}...");

    }

    protected abstract void Initialize(RecipeData currentRecipe);

    protected abstract void WarmUp();

    protected abstract (Mat originalImage, Mat analysisImage, TimeSpan processingTime, TimeSpan acquisitionTime, string[] errorNames)? ProcessImage(CancellationToken token);

    public void Stop()
    {
        if (!IsRunning)
            return;
        _loadingService.StartLoading($"Stopping {_settings.CameraName}");
        _cts?.Cancel();
        try
        {
            _loopTask?.Wait();
        }
        catch (TaskCanceledException)
        {
            // Ignore cancellation exceptions
        }
        catch (AggregateException ex) when (ex.Flatten().InnerExceptions.Any(x=>x is TaskCanceledException))
        {
            // Ignore cancellation exceptions
        }
        catch(Exception ex)
        {
            Log.Error(ex, "Error while stopping recognition loop");
        }
        finally
        {
            IsRunning = false;
            _cts?.Dispose();
            _cts = null;
            _loopTask = null;
        }

        SessionEnded?.Invoke(new SessionEndedEvent
        {
            SessionEnded = DateTime.Now
        });
        _loadingService.StopLoading($"Stopping {_settings.CameraName}");

    }

    public void Pause()
    {
        IsPaused = true;
    }

    public void Resume()
    {
        IsPaused = false;
    }

    private async Task Loop(CancellationToken token)
    {
     

        while (!token.IsCancellationRequested)
        {
            if (IsPaused)
            {
                await Task.Delay(100, token);
                continue;
            }

            var processed = ProcessImage(token);

            if (processed == null)
            {
                return;
            }

            if (processed.Value.processingTime.Milliseconds < _settings.MinimumProcessingTime)
            {
                Thread.Sleep(_settings.MinimumProcessingTime - (int)processed.Value.processingTime.Milliseconds);
            }


            var processingResult = new ImageProcessedEvent()
            {
                SessionStart = _startTime,
                RecipeName = _currentRecipe.RecipeName,
                AnalysisTime = processed.Value.processingTime - processed.Value.acquisitionTime,
                ErrorNames = processed.Value.errorNames.ToList(),
                HasError = processed.Value.errorNames.Length > 0,
                ImageSource = _settings.CameraName,
                ImageOriginal = processed.Value.originalImage,
                ImageAnalysis = processed.Value.analysisImage
            };

            var swProcessed = Stopwatch.StartNew();
            ImageProcessed(processingResult);
            swProcessed.Stop();
            Log.Information($"ImageProcessed event handled in {swProcessed.ElapsedMilliseconds} ms");


        }
    }

    public event Action<ImageProcessedEvent> ImageProcessed = delegate { };
    public event Action<SessionStartedEvent>? SessionStarted = delegate { };
    public event Action<SessionEndedEvent>? SessionEnded = delegate { };
}