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

namespace TrackerBridge
{
    public class GazeDataProcessor
    {
        public event GazeDataHandler GazeDataProcessed {
            add {
                gazeFilters[gazeFilters.Length - 1].OutputAvailable += value;
            }
            remove {
                gazeFilters[gazeFilters.Length - 1].OutputAvailable -= value;
            }
        }

        private readonly IGazeFilter[] gazeFilters;
        private readonly Single screenHeight;
        private readonly Single screenWidth;
        private Single outputFrequency;

        public Single OutputFrequency {
            get { return outputFrequency; }
            set {
                outputFrequency = value;
                Initialize();
            }
        }

        public GazeDataProcessor()
        {
            outputFrequency = 60; //Default
            screenHeight = Convert.ToSingle(SystemParameters.PrimaryScreenHeight);
            screenWidth = Convert.ToSingle(SystemParameters.PrimaryScreenWidth);
            gazeFilters = new IGazeFilter[1];
            gazeFilters[0] = new GazeDecimator(this); //TODO: Refactor frequency passthrough

            //Chain filters
            for(Int32 index= 0; index < gazeFilters.Length-1; index++)
            {
                gazeFilters[index].OutputAvailable += gazeFilters[index + 1].Input;
            }
        }

        public void Initialize()
        {
            foreach (IGazeFilter filter in gazeFilters)
            {
                filter.Update(this);
                filter.Reset();
            }
        }
        
        public void Process(Object sender, GazeDataEventArgs e)
        {
            GazeData data = new GazeData(e.LeftEye.GazePoint.PositionOnDisplayArea.X * screenWidth,
                                         e.LeftEye.GazePoint.PositionOnDisplayArea.Y * screenHeight,
                                         e.RightEye.GazePoint.PositionOnDisplayArea.X * screenWidth,
                                         e.RightEye.GazePoint.PositionOnDisplayArea.Y * screenHeight,
                                         e.DeviceTimeStamp,
                                         e.SystemTimeStamp);

            gazeFilters[0].Input(data);
        }
        public void Process(Object sender, GazeData input)
        {
            gazeFilters[0].Input(input);
        }
    }
}