using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tobii.Research;

namespace TrackerBridge
{
    public class TobiiEyeTracker : IBridgeTracker
    {
        public event ConnectionEventHandler ConnectionEvent;
        public event ConnectionEventHandler ConnectionTimeout;
        public event GazeDataHandler GazeDataAvailable {
            add {
                gazeDataProcessor.GazeDataProcessed += value;
            }
            remove {
                gazeDataProcessor.GazeDataProcessed -= value;
            }
        }

        private readonly GazeDataProcessor gazeDataProcessor;
        private IEyeTracker eyeTracker = null;

        public Boolean IsConnected { get; private set; } = false;
        public Single OutputFrequency {
            get => gazeDataProcessor.OutputFrequency;
            set => gazeDataProcessor.OutputFrequency = value;
        }
        public String SerialNumber { get; private set; } = null;
        public Single TrackingFrequency {
            get {
                if (eyeTracker != null)
                {
                    return eyeTracker.GetGazeOutputFrequency();
                }
                else
                {
                    return 0f;
                }
            }
            set {
                if (eyeTracker != null && eyeTracker.GetAllGazeOutputFrequencies().Contains(value))
                {
                    eyeTracker.SetGazeOutputFrequency(value);
                }
            }
        }

        public TobiiEyeTracker()
        {
            gazeDataProcessor = new GazeDataProcessor();
        }
        public TobiiEyeTracker(String serialNumber) : this()
        {
            SerialNumber = serialNumber;
        }

        public void Connect()
        {
            Task.Run(() => InitiateConnection());
        }
        private void InitiateConnection()
        {
            DateTime time = DateTime.Now;
            while (eyeTracker == null)
            {
                EyeTrackerCollection eyeTrackers = EyeTrackingOperations.FindAllEyeTrackers();
                Console.WriteLine("Searching for Tobii eye trackers");

                if (eyeTrackers.Count > 0)
                {
                    if (SerialNumber == null)
                    {
                        eyeTracker = eyeTrackers[0];
                        break;
                    }
                    else
                    {
                        foreach (IEyeTracker t in eyeTrackers)
                        {
                            if (SerialNumber == t.SerialNumber)
                            {
                                eyeTracker = t;
                                break;
                            }
                        }
                    }
                }

                if (eyeTracker != null)
                {
                    break;
                }

                if ((DateTime.Now - time) > (new TimeSpan(0, 0, 30)))
                {
                    ConnectionTimeout?.Invoke(this);
                }
            }
            eyeTracker.GazeDataReceived += gazeDataProcessor.Process;
            SerialNumber = eyeTracker.SerialNumber;
            TrackingFrequency = 600f;
            ConnectionEvent?.Invoke(this);
        }
    }
}