//------------------------------------------------------------------------------
// <copyright file="MainPage.xaml.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//------------------------------------------------------------------------------

using System.ComponentModel;
using System.IO;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.ApplicationModel.Resources;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using WindowsPreview.Kinect;

namespace Microsoft.Samples.Kinect.ColorBasics
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page, INotifyPropertyChanged
    {
        /// <summary>
        /// Resource loader for string resources
        /// </summary>
        private ResourceLoader resourceLoader = new ResourceLoader("Resources");

        /// <summary>
        /// Size of the RGB pixel in the bitmap
        /// </summary>
        private readonly uint bytesPerPixel;

        /// <summary>
        /// Active Kinect sensor
        /// </summary>
        private KinectSensor kinectSensor = null;

        /// <summary>
        /// Reader for color frames
        /// </summary>
        private ColorFrameReader colorFrameReader = null;

        /// <summary>
        /// Bitmap to display
        /// </summary>
        private WriteableBitmap bitmap = null;

        /// <summary>
        /// Intermediate storage for receiving frame data from the sensor
        /// </summary>
        private byte[] colorPixels = null;

        /// <summary>
        /// Current status text to display
        /// </summary>
        private string statusText = null;

        /// <summary>
        /// Initializes a new instance of the MainPage class.
        /// </summary>
        public MainPage()
        {
            // get the kinectSensor object
            this.kinectSensor = KinectSensor.GetDefault();

            // open the reader for the color frames
            this.colorFrameReader = this.kinectSensor.ColorFrameSource.OpenReader();

            // wire handler for frame arrival
            this.colorFrameReader.FrameArrived += this.Reader_ColorFrameArrived;

            // create the colorFrameDescription from the ColorFrameSource using rgba format
            FrameDescription colorFrameDescription = this.kinectSensor.ColorFrameSource.CreateFrameDescription(ColorImageFormat.Rgba);

            // rgba is 4 bytes per pixel
            this.bytesPerPixel = colorFrameDescription.BytesPerPixel;

            // allocate space to put the pixels to be rendered
            this.colorPixels = new byte[colorFrameDescription.Width * colorFrameDescription.Height * this.bytesPerPixel];

            // create the bitmap to display
            this.bitmap = new WriteableBitmap(colorFrameDescription.Width, colorFrameDescription.Height);

            // set IsAvailableChanged event notifier
            this.kinectSensor.IsAvailableChanged += this.Sensor_IsAvailableChanged;

            // open the sensor
            this.kinectSensor.Open();

            // set the status text
            this.StatusText = this.kinectSensor.IsAvailable ? resourceLoader.GetString("RunningStatusText")
                                                            : resourceLoader.GetString("NoSensorStatusText");

            // use the window object as the view model in this simple example
            this.DataContext = this;

            // initialize the components (controls) of the window
            this.InitializeComponent();
            theImage.Source = this.bitmap;
        }

        /// <summary>
        /// INotifyPropertyChangedPropertyChanged event to allow window controls to bind to changeable data.
        /// </summary>
        public event PropertyChangedEventHandler PropertyChanged;

        /// <summary>
        /// Gets or sets the current status text to display
        /// </summary>
        public string StatusText
        {
            get
            {
                return this.statusText;
            }

            set
            {
                if (this.statusText != value)
                {
                    this.statusText = value;

                    // notify any bound elements that the text has changed
                    if (this.PropertyChanged != null)
                    {
                        this.PropertyChanged(this, new PropertyChangedEventArgs("StatusText"));
                    }
                }
            }
        }

        /// <summary>
        /// Execute shutdown tasks.
        /// </summary>
        /// <param name="sender">object sending the event</param>
        /// <param name="e">event arguments</param>
        private void MainPage_Unloaded(object sender, RoutedEventArgs e)
        {
            if (this.colorFrameReader != null)
            {
                // ColorFrameReder is IDisposable
                this.colorFrameReader.Dispose();
                this.colorFrameReader = null;
            }

            if (this.kinectSensor != null)
            {
                this.kinectSensor.Close();
                this.kinectSensor = null;
            }
        }

        /// <summary>
        /// Handles the color frame data arriving from the sensor.
        /// </summary>
        /// <param name="sender">object sending the event</param>
        /// <param name="e">event arguments</param>
        private void Reader_ColorFrameArrived(object sender, ColorFrameArrivedEventArgs e)
        {
            bool colorFrameProcessed = false;

            // ColorFrame is IDisposable
            using (ColorFrame colorFrame = e.FrameReference.AcquireFrame())
            {
                if (colorFrame != null)
                {
                    FrameDescription colorFrameDescription = colorFrame.FrameDescription;

                    // verify data and write the new color frame data to the Writeable bitmap
                    if ((colorFrameDescription.Width == this.bitmap.PixelWidth) && (colorFrameDescription.Height == this.bitmap.PixelHeight))
                    {
                        if (colorFrame.RawColorImageFormat == ColorImageFormat.Bgra)
                        {
                            colorFrame.CopyRawFrameDataToBuffer(this.bitmap.PixelBuffer);
                        }
                        else
                        {
                            colorFrame.CopyConvertedFrameDataToBuffer(this.bitmap.PixelBuffer, ColorImageFormat.Bgra);
                        }

                        colorFrameProcessed = true;
                    }
                }
            }

            // we got a frame, render
            if (colorFrameProcessed)
            {
                this.bitmap.Invalidate();
            }
        }

        /// <summary>
        /// Handles the event which the sensor becomes unavailable (E.g. paused, closed, unplugged).
        /// </summary>
        /// <param name="sender">object sending the event</param>
        /// <param name="e">event arguments</param>
        private void Sensor_IsAvailableChanged(object sender, IsAvailableChangedEventArgs e)
        {
            // on failure, set the status text
            this.StatusText = this.kinectSensor.IsAvailable ? resourceLoader.GetString("RunningStatusText")
                                                            : resourceLoader.GetString("SensorNotAvailableStatusText");
        }
    }
}