///////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2017, Carnegie Mellon University and University of Cambridge,
// all rights reserved.
//
// ACADEMIC OR NON-PROFIT ORGANIZATION NONCOMMERCIAL RESEARCH USE ONLY
//
// BY USING OR DOWNLOADING THE SOFTWARE, YOU ARE AGREEING TO THE TERMS OF THIS LICENSE AGREEMENT.  
// IF YOU DO NOT AGREE WITH THESE TERMS, YOU MAY NOT USE OR DOWNLOAD THE SOFTWARE.
//
// License can be found in OpenFace-license.txt

//     * Any publications arising from the use of this software, including but
//       not limited to academic journal and conference publications, technical
//       reports and manuals, must cite at least one of the following works:
//
//       OpenFace: an open source facial behavior analysis toolkit
//       Tadas Baltrušaitis, Peter Robinson, and Louis-Philippe Morency
//       in IEEE Winter Conference on Applications of Computer Vision, 2016  
//
//       Rendering of Eyes for Eye-Shape Registration and Gaze Estimation
//       Erroll Wood, Tadas Baltrušaitis, Xucong Zhang, Yusuke Sugano, Peter Robinson, and Andreas Bulling 
//       in IEEE International. Conference on Computer Vision (ICCV),  2015 
//
//       Cross-dataset learning and person-speci?c normalisation for automatic Action Unit detection
//       Tadas Baltrušaitis, Marwa Mahmoud, and Peter Robinson 
//       in Facial Expression Recognition and Analysis Challenge, 
//       IEEE International Conference on Automatic Face and Gesture Recognition, 2015 
//
//       Constrained Local Neural Fields for robust facial landmark detection in the wild.
//       Tadas Baltrušaitis, Peter Robinson, and Louis-Philippe Morency. 
//       in IEEE Int. Conference on Computer Vision Workshops, 300 Faces in-the-Wild Challenge, 2013.    
//
///////////////////////////////////////////////////////////////////////////////

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using System.Windows;
using System.Windows.Threading;
using System.Windows.Media.Imaging;
using System.IO;
using Microsoft.Win32;

// Internal libraries
using OpenCVWrappers;
using CppInterop.LandmarkDetector;
using CameraInterop;
using FaceAnalyser_Interop;
using GazeAnalyser_Interop;
using FaceDetectorInterop;
using MediaReader;
using Microsoft.WindowsAPICodePack.Dialogs;

namespace OpenFaceOffline
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {

        // Timing for measuring FPS
        #region High-Resolution Timing
        static DateTime startTime;
        static Stopwatch sw = new Stopwatch();

        static MainWindow()
        {
            startTime = DateTime.Now;
            sw.Start();
        }

        public static DateTime CurrentTime
        {
            get { return startTime + sw.Elapsed; }
        }
        #endregion

        // -----------------------------------------------------------------
        // Members
        // -----------------------------------------------------------------

        Thread processing_thread;

        // Some members for displaying the results
        private Capture capture;
        private WriteableBitmap latest_img;
        private WriteableBitmap latest_aligned_face;
        private WriteableBitmap latest_HOG_descriptor;

        // Managing the running of the analysis system
        private volatile bool thread_running;
        private volatile bool thread_paused = false;
        // Allows for going forward in time step by step
        // Useful for visualising things
        private volatile int skip_frames = 0;

        FpsTracker processing_fps = new FpsTracker();

        volatile bool detectionSucceeding = false;

        // For tracking
        private FaceDetector face_detector;
        FaceModelParameters face_model_params;
        CLNF clnf_model;

        // For face analysis
        FaceAnalyserManaged face_analyser;
        GazeAnalyserManaged gaze_analyser;

        // Recording parameters (default values)
        Recorder recorder;

        public bool RecordAligned { get; set; } = false; // Aligned face images
        public bool RecordHOG { get; set; } = false; // HOG features extracted from face images
        public bool Record2DLandmarks { get; set; } = true; // 2D locations of facial landmarks (in pixels)
        public bool Record3DLandmarks { get; set; } = true; // 3D locations of facial landmarks (in pixels)
        public bool RecordModelParameters { get; set; } = true; // Facial shape parameters (rigid and non-rigid geometry)
        public bool RecordPose { get; set; } = true; // Head pose (position and orientation)
        public bool RecordAUs { get; set; } = true; // Facial action units
        public bool RecordGaze { get; set; } = true; // Eye gaze

        // Visualisation options
        public bool ShowTrackedVideo { get; set; } = true; // Showing the actual tracking
        public bool ShowAppearance { get; set; } = true; // Showing appeaance features like HOG
        public bool ShowGeometry { get; set; } = true; // Showing geometry features, pose, gaze, and non-rigid
        public bool ShowAUs { get; set; } = true; // Showing Facial Action Units

        int image_output_size = 112;
        
        // Where the recording is done (by default in a record directory, from where the application executed)
        String record_root = "./record";

        // For AU prediction, if videos are long dynamic models should be used
        public bool DynamicAUModels { get; set; } = true;

        // Camera calibration parameters
        public double fx = -1, fy = -1, cx = -1, cy = -1;
        bool estimate_camera_parameters = true;

        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this; // For WPF data binding

            // Set the icon
            Uri iconUri = new Uri("logo1.ico", UriKind.RelativeOrAbsolute);
            this.Icon = BitmapFrame.Create(iconUri);
            
            String root = AppDomain.CurrentDomain.BaseDirectory;

            face_model_params = new FaceModelParameters(root, false);
            clnf_model = new CLNF(face_model_params);

            gaze_analyser = new GazeAnalyserManaged();

        }

        // ----------------------------------------------------------
        // Actual work gets done here

        // The main function call for processing images or video files, TODO rename this as it is not a loop
        private void ProcessingLoop(String[] filenames, int cam_id = -1, int width = -1, int height = -1, bool multi_face = false)
        {
            SetupFeatureExtractionMode();

            thread_running = true;

            // Create the video capture and call the VideoLoop
            if (filenames != null)
            {
                face_model_params.optimiseForVideo();
                if (cam_id == -2)
                {
                    List<String> image_files_all = new List<string>();
                    foreach (string image_name in filenames)
                        image_files_all.Add(image_name);

                    // Loading an image sequence that represents a video                   
                    capture = new Capture(image_files_all);

                    if (capture.isOpened())
                    {
                        // Prepare recording if any based on the directory
                        String file_no_ext = System.IO.Path.GetDirectoryName(filenames[0]);
                        file_no_ext = System.IO.Path.GetFileName(file_no_ext);

                        // Start the actual processing and recording
                        FeatureExtractionLoop(file_no_ext);                        

                    }
                    else
                    {
                        string messageBoxText = "Failed to open an image";
                        string caption = "Not valid file";
                        MessageBoxButton button = MessageBoxButton.OK;
                        MessageBoxImage icon = MessageBoxImage.Warning;

                        // Display message box
                        MessageBox.Show(messageBoxText, caption, button, icon);
                    }
                }
                else
                {
                    face_model_params.optimiseForVideo();
                    // Loading a video file (or a number of them)
                    foreach (string filename in filenames)
                    {
                        if (!thread_running)
                        {
                            continue;
                        }

                        capture = new Capture(filename);

                        if (capture.isOpened())
                        {
                            String file_no_ext = System.IO.Path.GetFileNameWithoutExtension(filename);
                            
                            // Start the actual processing                        
                            FeatureExtractionLoop(file_no_ext);

                        }
                        else
                        {
                            string messageBoxText = "File is not a video or the codec is not supported.";
                            string caption = "Not valid file";
                            MessageBoxButton button = MessageBoxButton.OK;
                            MessageBoxImage icon = MessageBoxImage.Warning;

                            // Display message box
                            MessageBox.Show(messageBoxText, caption, button, icon);
                        }
                    }
                }
            }

            EndMode();

        }

        // TODO here
        private void ProcessIndividualImages(ImageReader reader) // TODO need interface for recording settings
        {
            // Make sure the GUI is setup appropriately
            SetupFeatureExtractionMode();

            // Indicate we will start running the thread
            thread_running = true;

            // Setup the parameters optimized for working on individual images rather than sequences
            face_model_params.optimiseForImages();

            // Initialize the face detector if it has not been initialized yet
            if(face_detector == null)
            {
                face_detector = new FaceDetector();
            }

            // Initialize the face analyser
            face_analyser = new FaceAnalyserManaged(AppDomain.CurrentDomain.BaseDirectory, DynamicAUModels, image_output_size);

            // Loading an image file (or a number of them)
            while (reader.isOpened())
            {
                if (!thread_running)
                {
                    continue;
                }

                // Start the actual processing, TODO this should change?
                Thread.CurrentThread.IsBackground = true;

                clnf_model.Reset();

                var frame = new RawImage(reader.GetNextImage());
                var grayFrame = new RawImage(reader.GetCurrentFrameGray());

                double progress = reader.GetProgress();

                // Detect faces here and return bounding boxes
                List<Rect> face_detections = new List<Rect>();
                List<double> confidences = new List<double>();
                face_detector.DetectFacesHOG(face_detections, grayFrame, confidences);

                // For visualizing landmarks
                List<Point> landmark_points = new List<Point>();

                for (int i = 0; i < face_detections.Count; ++i)
                {
                    bool success = clnf_model.DetectFaceLandmarksInImage(grayFrame, face_detections[i], face_model_params);

                    var landmarks = clnf_model.CalculateAllLandmarks();
                    
                    // Predict action units
                    var au_preds = face_analyser.PredictStaticAUsAndComputeFeatures(grayFrame, landmarks);

                    // Predic eye gaze
                    gaze_analyser.AddNextFrame(clnf_model, success, fx, fy, cx, cy); // TODO fx should be from reader

                    // Only the final face will contain the details
                    VisualizeFeatures(frame, landmarks, fx, fy, cx, cy, progress);

                    foreach (var p in landmarks)
                    {
                        landmark_points.Add(new Point(p.Item1, p.Item2));
                    }

                }

                // Visualisation TODO this should be lifted out? and actually be grabbed from the visualizer? rather than drawing points ourselves?
                //if (ShowTrackedVideo)
                //{

                //    Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 0, 200), (Action)(() =>
                //    {
                //        if (latest_img == null)
                //        {
                //            latest_img = frame.CreateWriteableBitmap();
                //        }

                //        frame.UpdateWriteableBitmap(latest_img);

                //        video.Source = latest_img;
                //        video.Confidence = 1;
                //        video.FPS = processing_fps.GetFPS();
                //        video.Progress = progress;

                //        video.OverlayLines = new List<Tuple<Point, Point>>();

                //        video.OverlayPoints = landmark_points;

                //        // TODO unify with other visualization

                //    }));
                //}
                latest_img = null;

                // TODO how to report errors from the reader here? exceptions? logging? Problem for future versions?
            }

            // TODO is this still needed?
            EndMode();

        }

        // Capturing and processing the video frame by frame
        private void FeatureExtractionLoop(string output_file_name)
        {

            DateTime? startTime = CurrentTime;

            var lastFrameTime = CurrentTime;

            clnf_model.Reset();
            face_analyser = new FaceAnalyserManaged(AppDomain.CurrentDomain.BaseDirectory, DynamicAUModels, image_output_size);

            // If the camera calibration parameters are not set (indicated by -1), guesstimate them
            if(estimate_camera_parameters || fx == -1 || fy == -1 || cx == -1 || cy == -1)
            { 
                fx = 500.0 * (capture.width / 640.0);
                fy = 500.0 * (capture.height / 480.0);

                fx = (fx + fy) / 2.0;
                fy = fx;

                cx = capture.width / 2f;
                cy = capture.height / 2f;
            }

            // Setup the recorder first
            recorder = new Recorder(record_root, output_file_name, capture.width, capture.height, Record2DLandmarks, Record3DLandmarks, RecordModelParameters, RecordPose,
                RecordAUs, RecordGaze, RecordAligned, RecordHOG, clnf_model, face_analyser, fx, fy, cx, cy, DynamicAUModels);

            int frame_id = 0;

            double fps = capture.GetFPS();
            if (fps <= 0) fps = 30;

            while (thread_running)
            {
                //////////////////////////////////////////////
                // CAPTURE FRAME AND DETECT LANDMARKS FOLLOWED BY THE REQUIRED IMAGE PROCESSING
                //////////////////////////////////////////////
                RawImage frame = null;
                double progress = -1;

                frame = new RawImage(capture.GetNextFrame(false));
                progress = capture.GetProgress();

                if (frame.Width == 0)
                {
                    // This indicates that we reached the end of the video file
                    break;
                }

                lastFrameTime = CurrentTime;
                processing_fps.AddFrame();

                var grayFrame = new RawImage(capture.GetCurrentFrameGray());

                if (grayFrame == null)
                {
                    Console.WriteLine("Gray is empty");
                    continue;
                }

                detectionSucceeding = ProcessFrame(clnf_model, face_model_params, frame, grayFrame, fx, fy, cx, cy);

                // The face analysis step (for AUs and eye gaze)
                face_analyser.AddNextFrame(frame, clnf_model.CalculateAllLandmarks(), detectionSucceeding, false, ShowAppearance); // TODO change
                gaze_analyser.AddNextFrame(clnf_model, detectionSucceeding, fx, fy, cx, cy);

                recorder.RecordFrame(clnf_model, face_analyser, gaze_analyser, detectionSucceeding, frame_id + 1, ((double)frame_id) / fps);

                List<Tuple<double, double>> landmarks = clnf_model.CalculateVisibleLandmarks();

                VisualizeFeatures(frame, landmarks, fx, fy, cx, cy, progress);

                while (thread_running & thread_paused && skip_frames == 0)
                {
                    Thread.Sleep(10);
                }

                frame_id++;

                if (skip_frames > 0)
                    skip_frames--;

            }

            latest_img = null;
            skip_frames = 0;

            // Unpause if it's paused
            if (thread_paused)
            {
                Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 0, 200), (Action)(() =>
                {
                    PauseButton_Click(null, null);
                }));
            }

            recorder.FinishRecording(clnf_model, face_analyser);

        }

        private void VisualizeFeatures(RawImage frame, List<Tuple<double, double>> landmarks, double fx, double fy, double cx, double cy, double progress)
        {
            List<Tuple<Point, Point>> lines = null;
            List<Tuple<double, double>> eye_landmarks = null;
            List<Tuple<Point, Point>> gaze_lines = null;
            Tuple<double, double> gaze_angle = new Tuple<double, double>(0, 0);

            List<double> pose = new List<double>();
            clnf_model.GetPose(pose, fx, fy, cx, cy);
            List<double> non_rigid_params = clnf_model.GetNonRigidParams();

            double confidence = (-clnf_model.GetConfidence()) / 2.0 + 0.5;

            if (confidence < 0)
                confidence = 0;
            else if (confidence > 1)
                confidence = 1;

            double scale = 0;

            if (detectionSucceeding)
            {
                
                eye_landmarks = clnf_model.CalculateVisibleEyeLandmarks();
                lines = clnf_model.CalculateBox((float)fx, (float)fy, (float)cx, (float)cy);

                scale = clnf_model.GetRigidParams()[0];

                gaze_lines = gaze_analyser.CalculateGazeLines(scale, (float)fx, (float)fy, (float)cx, (float)cy);
                gaze_angle = gaze_analyser.GetGazeAngle();
            }

            // Visualisation (as a separate function)
            Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 0, 200), (Action)(() =>
            {
                if (ShowAUs)
                {
                    // TODO this should be done through the visualizer?
                    var au_classes = face_analyser.GetCurrentAUsClass();
                    var au_regs = face_analyser.GetCurrentAUsReg();

                    auClassGraph.Update(au_classes);

                    var au_regs_scaled = new Dictionary<String, double>();
                    foreach (var au_reg in au_regs)
                    {
                        au_regs_scaled[au_reg.Key] = au_reg.Value / 5.0;
                        if (au_regs_scaled[au_reg.Key] < 0)
                            au_regs_scaled[au_reg.Key] = 0;

                        if (au_regs_scaled[au_reg.Key] > 1)
                            au_regs_scaled[au_reg.Key] = 1;
                    }
                    auRegGraph.Update(au_regs_scaled);
                }

                if (ShowGeometry)
                {
                    int yaw = (int)(pose[4] * 180 / Math.PI + 0.5);
                    int roll = (int)(pose[5] * 180 / Math.PI + 0.5);
                    int pitch = (int)(pose[3] * 180 / Math.PI + 0.5);

                    YawLabel.Content = yaw + "°";
                    RollLabel.Content = roll + "°";
                    PitchLabel.Content = pitch + "°";

                    XPoseLabel.Content = (int)pose[0] + " mm";
                    YPoseLabel.Content = (int)pose[1] + " mm";
                    ZPoseLabel.Content = (int)pose[2] + " mm";

                    nonRigidGraph.Update(non_rigid_params);

                    // Update eye gaze
                    String x_angle = String.Format("{0:F0}°", gaze_angle.Item1 * (180.0 / Math.PI));
                    String y_angle = String.Format("{0:F0}°", gaze_angle.Item2 * (180.0 / Math.PI));
                    GazeXLabel.Content = x_angle;
                    GazeYLabel.Content = y_angle;
                }

                if (ShowTrackedVideo)
                {
                    if (latest_img == null)
                    {
                        latest_img = frame.CreateWriteableBitmap();
                    }

                    frame.UpdateWriteableBitmap(latest_img);

                    video.Source = latest_img;
                    video.Confidence = confidence;
                    video.FPS = processing_fps.GetFPS();
                    video.Progress = progress;
                    video.FaceScale = scale;

                    if (!detectionSucceeding)
                    {
                        video.OverlayLines.Clear();
                        video.OverlayPoints.Clear();
                        video.OverlayEyePoints.Clear();
                        video.GazeLines.Clear();
                    }
                    else
                    {
                        video.OverlayLines = lines;

                        List<Point> landmark_points = new List<Point>();
                        foreach (var p in landmarks)
                        {
                            landmark_points.Add(new Point(p.Item1, p.Item2));
                        }

                        List<Point> eye_landmark_points = new List<Point>();
                        foreach (var p in eye_landmarks)
                        {
                            eye_landmark_points.Add(new Point(p.Item1, p.Item2));
                        }


                        video.OverlayPoints = landmark_points;
                        video.OverlayEyePoints = eye_landmark_points;
                        video.GazeLines = gaze_lines;
                    }
                }

                if (ShowAppearance)
                {
                    // TODO how to do this for images, now this is only for videos, one possibility is only doing this on replay for images, and showing the selected face only
                    RawImage aligned_face = face_analyser.GetLatestAlignedFace();
                    RawImage hog_face = face_analyser.GetLatestHOGDescriptorVisualisation();

                    if (latest_aligned_face == null)
                    {
                        latest_aligned_face = aligned_face.CreateWriteableBitmap();
                        latest_HOG_descriptor = hog_face.CreateWriteableBitmap();
                    }

                    aligned_face.UpdateWriteableBitmap(latest_aligned_face);
                    hog_face.UpdateWriteableBitmap(latest_HOG_descriptor);

                    AlignedFace.Source = latest_aligned_face;
                    AlignedHOG.Source = latest_HOG_descriptor;
                }
            }));


        }

        private void StopTracking()
        {
            // First complete the running of the thread
            if (processing_thread != null)
            {
                // Tell the other thread to finish
                thread_running = false;
                processing_thread.Join();
            }
        }



        // ----------------------------------------------------------
        // Interacting with landmark detection and face analysis

        private bool ProcessFrame(CLNF clnf_model, FaceModelParameters clnf_params, RawImage frame, RawImage grayscale_frame, double fx, double fy, double cx, double cy)
        {
            detectionSucceeding = clnf_model.DetectLandmarksInVideo(grayscale_frame, clnf_params);
            return detectionSucceeding;

        }

        // ----------------------------------------------------------
        // Mode handling (image, video)
        // ----------------------------------------------------------

        // Disable GUI components that should not be active during processing
        private void SetupFeatureExtractionMode()
        {
            Dispatcher.Invoke((Action)(() =>
            {
                SettingsMenu.IsEnabled = false;
                RecordingMenu.IsEnabled = false;
                AUSetting.IsEnabled = false;

                PauseButton.IsEnabled = true;
                StopButton.IsEnabled = true;
                NextFiveFramesButton.IsEnabled = false;
                NextFrameButton.IsEnabled = false;
            }));
        }

        // When the processing is done re-enable the components
        private void EndMode()
        {
            Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 1, 0), (Action)(() =>
            {

                SettingsMenu.IsEnabled = true;
                RecordingMenu.IsEnabled = true;
                AUSetting.IsEnabled = true;

                PauseButton.IsEnabled = false;
                StopButton.IsEnabled = false;
                NextFiveFramesButton.IsEnabled = false;
                NextFrameButton.IsEnabled = false;

                // Clean up the interface itself
                video.Source = null;
                
                auClassGraph.Update(new Dictionary<string, double>());
                auRegGraph.Update(new Dictionary<string, double>());
                YawLabel.Content = "0°";
                RollLabel.Content = "0°";
                PitchLabel.Content = "0°";

                XPoseLabel.Content = "0 mm";
                YPoseLabel.Content = "0 mm";
                ZPoseLabel.Content = "0 mm";

                nonRigidGraph.Update(new List<double>());

                GazeXLabel.Content = "0°";
                GazeYLabel.Content = "0°";
                
                AlignedFace.Source = null;
                AlignedHOG.Source = null;

            }));
        }

        // ----------------------------------------------------------
        // Opening Videos/Images
        // ----------------------------------------------------------

        private void videoFileOpenClick(object sender, RoutedEventArgs e)
        {
            new Thread(() => openVideoFile()).Start();
        }

        private void openVideoFile()
        {
            StopTracking();

            Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 2, 0), (Action)(() =>
            {
                var d = new OpenFileDialog();
                d.Multiselect = true;
                d.Filter = "Video files|*.avi;*.wmv;*.mov;*.mpg;*.mpeg;*.mp4";

                if (d.ShowDialog(this) == true)
                {

                    string[] video_files = d.FileNames;

                    processing_thread = new Thread(() => ProcessingLoop(video_files));
                    processing_thread.Start();

                }
            }));
        }

        // Some utilities for opening images/videos and directories
        private ImageReader openMediaDialog(bool images)
        {
            string[] image_files = new string[0];
            Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 2, 0), (Action)(() =>
            {
                var d = new OpenFileDialog();
                d.Multiselect = true;
                if(images)
                { 
                    d.Filter = "Image files|*.jpg;*.jpeg;*.bmp;*.png;*.gif";
                }
                else
                {
                    d.Filter = "Video files|*.avi;*.wmv;*.mov;*.mpg;*.mpeg;*.mp4";
                }
                if (d.ShowDialog(this) == true)
                {

                    image_files = d.FileNames;

                }
            }));
            List<string> img_files_list = new List<string>(image_files);
            return new ImageReader(img_files_list);
        }

        private void individualImageFilesOpenClick(object sender, RoutedEventArgs e)
        {
            // First clean up existing tracking
            StopTracking();

            ImageReader reader = openMediaDialog(true);

            processing_thread = new Thread(() => ProcessIndividualImages(reader));
            processing_thread.Start();

        }

        private void individualImageDirectoryOpenClick(object sender, RoutedEventArgs e)
        {

            StopTracking();

            // TODO open directory here
            new Thread(() => imageOpen()).Start();
        }

        // TODO old
        private void imageFileOpenClick(object sender, RoutedEventArgs e)
        {
            
            new Thread(() => imageOpen()).Start();
        }

        // TODO old
        private void imageOpen()
        {
            StopTracking();

            Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 2, 0), (Action)(() =>
            {
                var d = new OpenFileDialog();
                d.Multiselect = true;
                d.Filter = "Image files|*.jpg;*.jpeg;*.bmp;*.png;*.gif";

                if (d.ShowDialog(this) == true)
                {

                    string[] image_files = d.FileNames;

                    processing_thread = new Thread(() => ProcessingLoop(image_files, -3));
                    processing_thread.Start();

                }
            }));
        }

        private void imageSequenceFileOpenClick(object sender, RoutedEventArgs e)
        {
            new Thread(() => imageSequenceOpen()).Start();
        }

        private void imageSequenceOpen()
        {
            StopTracking();

            Dispatcher.Invoke(DispatcherPriority.Render, new TimeSpan(0, 0, 0, 2, 0), (Action)(() =>
            {
                var d = new OpenFileDialog();
                d.Multiselect = true;
                d.Filter = "Image files|*.jpg;*.jpeg;*.bmp;*.png;*.gif";

                if (d.ShowDialog(this) == true)
                {

                    string[] image_files = d.FileNames;

                    processing_thread = new Thread(() => ProcessingLoop(image_files, -2));
                    processing_thread.Start();

                }
            }));
        }

        // --------------------------------------------------------
        // Button handling
        // --------------------------------------------------------

        // Cleanup stuff when closing the window
        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            if (processing_thread != null)
            {
                // Stop capture and tracking
                thread_running = false;
                processing_thread.Join();

                capture.Dispose();
            }
            face_analyser.Dispose();
        }

        // Stopping the tracking
        private void StopButton_Click(object sender, RoutedEventArgs e)
        {
            if (processing_thread != null)
            {
                // Stop capture and tracking
                thread_paused = false;
                thread_running = false;
                // Let the processing thread finish
                processing_thread.Join();

                // Clean up the interface
                EndMode();
            }
        }

        private void PauseButton_Click(object sender, RoutedEventArgs e)
        {
            if (processing_thread != null)
            {
                // Stop capture and tracking                
                thread_paused = !thread_paused;

                NextFrameButton.IsEnabled = thread_paused;
                NextFiveFramesButton.IsEnabled = thread_paused;

                if (thread_paused)
                {
                    PauseButton.Content = "Resume";
                }
                else
                {
                    PauseButton.Content = "Pause";
                }
            }
        }

        private void SkipButton_Click(object sender, RoutedEventArgs e)
        {
            if (sender.Equals(NextFrameButton))
            {
                skip_frames += 1;
            }
            else if (sender.Equals(NextFiveFramesButton))
            {
                skip_frames += 5;
            }
        }


        private void VisualisationChange(object sender, RoutedEventArgs e)
        {
            // Collapsing or restoring the windows here
            if (!ShowTrackedVideo)
            {
                VideoBorder.Visibility = System.Windows.Visibility.Collapsed;
                MainGrid.ColumnDefinitions[0].Width = new GridLength(0, GridUnitType.Star);
            }
            else
            {
                VideoBorder.Visibility = System.Windows.Visibility.Visible;
                MainGrid.ColumnDefinitions[0].Width = new GridLength(2.1, GridUnitType.Star);
            }

            if (!ShowAppearance)
            {
                AppearanceBorder.Visibility = System.Windows.Visibility.Collapsed;
                MainGrid.ColumnDefinitions[1].Width = new GridLength(0, GridUnitType.Star);
            }
            else
            {
                AppearanceBorder.Visibility = System.Windows.Visibility.Visible;
                MainGrid.ColumnDefinitions[1].Width = new GridLength(0.8, GridUnitType.Star);
            }

            // Collapsing or restoring the windows here
            if (!ShowGeometry)
            {
                GeometryBorder.Visibility = System.Windows.Visibility.Collapsed;
                MainGrid.ColumnDefinitions[2].Width = new GridLength(0, GridUnitType.Star);
            }
            else
            {
                GeometryBorder.Visibility = System.Windows.Visibility.Visible;
                MainGrid.ColumnDefinitions[2].Width = new GridLength(1.0, GridUnitType.Star);
            }

            // Collapsing or restoring the windows here
            if (!ShowAUs)
            {
                ActionUnitBorder.Visibility = System.Windows.Visibility.Collapsed;
                MainGrid.ColumnDefinitions[3].Width = new GridLength(0, GridUnitType.Star);
            }
            else
            {
                ActionUnitBorder.Visibility = System.Windows.Visibility.Visible;
                MainGrid.ColumnDefinitions[3].Width = new GridLength(1.6, GridUnitType.Star);
            }

        }
       
        private void setOutputImageSize_Click(object sender, RoutedEventArgs e)
        {

            NumberEntryWindow number_entry_window = new NumberEntryWindow(image_output_size);
            number_entry_window.Icon = this.Icon;

            number_entry_window.WindowStartupLocation = WindowStartupLocation.CenterScreen;

            if (number_entry_window.ShowDialog() == true)
            {
                image_output_size = number_entry_window.OutputInt;
            }
        }

        private void setCameraParameters_Click(object sender, RoutedEventArgs e)
        {
            CameraParametersEntry camera_params_entry_window = new CameraParametersEntry(fx, fy, cx, cy);
            camera_params_entry_window.Icon = this.Icon;

            camera_params_entry_window.WindowStartupLocation = WindowStartupLocation.CenterScreen;

            if (camera_params_entry_window.ShowDialog() == true)
            {
                fx = camera_params_entry_window.Fx;
                fy = camera_params_entry_window.Fy;
                cx = camera_params_entry_window.Cx;
                cy = camera_params_entry_window.Cy;
                if(fx == -1 || fy == -1 || cx == -1 || cy == -1)
                {
                    estimate_camera_parameters = true;
                }
                else
                {
                    estimate_camera_parameters = false;
                }
            }
        }

        private void OutputLocationItem_Click(object sender, RoutedEventArgs e)
        {
            var dlg = new CommonOpenFileDialog();
            dlg.Title = "Select output directory";
            dlg.IsFolderPicker = true;
            dlg.AllowNonFileSystemItems = false;
            dlg.EnsureFileExists = true;
            dlg.EnsurePathExists = true;
            dlg.EnsureReadOnly = false;
            dlg.EnsureValidNames = true;
            dlg.Multiselect = false;
            dlg.ShowPlacesList = true;

            if (dlg.ShowDialog() == CommonFileDialogResult.Ok)
            {
                var folder = dlg.FileName;
                record_root = folder;
            }
        }

    }
}