using System;
using Emgu.CV;
using Emgu.CV.Structure;
using System.Timers;
using System.Threading;
using System.Diagnostics;
using System.Runtime.ExceptionServices;
using System.Threading.Tasks;

namespace BBIWARG.Input.InputProviding
{
    class InputProviderIntel : MarshalByRefObject, IInputProvider
    {
        IntelCameraWrapper wrapper;

        public int CurrentFrameID
        {
            get;
            set;
        }

        public float FieldOfViewHorizontal
        {
            get;
            set;
        }

        public float FieldOfViewVertical
        {
            get;
            set;
        }

        public int ImageWidth
        {
            get { return 640; }
        }

        public int ImageHeight
        {
            get { return 480; }
        }
        
        public bool IsActive
        {
            get;
            set;
        }

        public event DeviceStartedEventHandler DeviceStartedEvent;

        public event NewFrameEventHandler NewFrameEvent;

        public UInt16 lowConfidenceValue;
        private AppDomain domain;
        private System.Threading.Timer watchdogTimer;

        public void initialize()
        {
            CurrentFrameID = 0;
            watchdogTimer = new System.Threading.Timer(Timer_Elapsed, null, 2000, 1000);
        }

        private bool errorstate = false;

        private void Timer_Elapsed(object state)
        {
            checkExitErrorstate();

            errorstate = true;
        }

        int startId = 0;
        Stopwatch startTimeWatch;

        [HandleProcessCorruptedStateExceptions]
        public void start()
        {
            startTimeWatch = Stopwatch.StartNew();
            Console.WriteLine("starting new AppDomain (" + startId +")...");
            domain = System.AppDomain.CreateDomain("AppDomain-" + startId);

            startId++;

            Task startTask = null;
            bool errorDuringInit = false;

            try
            {
                wrapper = (IntelCameraWrapper)domain.CreateInstanceAndUnwrap(typeof(IntelCameraWrapper).Assembly.GetName().ToString(), typeof(IntelCameraWrapper).FullName);
                startTask = Task.Run(() => wrapper.init(this));
                errorDuringInit = startTask.Wait(TimeSpan.FromSeconds(4));
            }
            catch (Exception)
            {
                Console.WriteLine("Camera crashed while init");
                errorstate = true;
                scheduledForRestart = false;
                errorDuringInit = true;
            }

            if (errorDuringInit)
            {
                Console.WriteLine("Timeout during init");
                errorstate = true;
                scheduledForRestart = false;
            }
            else {
                IsActive = true;

                if (DeviceStartedEvent != null)
                {
                    DeviceStartedEvent(this, new EventArgs());
                    DeviceStartedEvent = null; //only notify once...
                }

                scheduledForRestart = false;

                try
                {
                    if(!errorDuringInit)
                        wrapper.run();
                }
                catch (System.AccessViolationException)
                {
                    Console.WriteLine("Camera caused corrupted process state.");
                    errorstate = true;
                }
                catch (Exception)
                {
                    Console.WriteLine("Camera Thread crashed.");
                    errorstate = true;
                }
            }

            checkExitErrorstate();
        }

        private bool scheduledForRestart = false;

        private void checkExitErrorstate()
        {
            if (errorstate && !scheduledForRestart)
            {
                if (startTimeWatch != null && startTimeWatch.ElapsedMilliseconds < 5000) {
                    Console.WriteLine("...");
                    return;
                }
                    
                //startTimeWatch.Stop();

                //we have crashed. Kill the app domain and try again.
                Console.WriteLine("Killing AppDomain (" + domain.FriendlyName + ")...");
                scheduledForRestart = true;
                //wrapper.terminated = true;

                try
                {
                    System.AppDomain.Unload(domain);
                }
                catch (Exception)
                {
                    Console.WriteLine("Could not unload app domain. We will just wait a moment and try to start a new one.");
                }

                domain = null;
                wrapper = null;

                Thread.Sleep(5000);
                start();
            }
        }

        public void stop()
        {
            IsActive = false;
        }

        internal bool hasNewFrameEvent()
        {
            return NewFrameEvent != null;
        }


        internal void newFrame(int currentFrameID, Image<Gray, ushort> dImg)
        {
            errorstate = false;
            if (startTimeWatch != null)
            {
                Console.WriteLine("done");
                startTimeWatch.Stop();
                startTimeWatch = null;
            }

            NewFrameEvent(this, new NewFrameEventArgs(currentFrameID, dImg));
        }
    }
}