Windows 8 : Fun with sensors

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Cinch;
using MEFedMVVM.ViewModelLocator;
using System.ComponentModel.Composition;
using SimpleWin8App.Services;
using System.Diagnostics;

namespace SimpleWin8App.ViewModels
{
    [ExportViewModel("MainWindowViewModel")]
    [PartCreationPolicy(CreationPolicy.NonShared)]
    public class MainWindowViewModel : ViewModelBase
    {
        private IViewAwareStatusWindow viewAwareStatusService;
        private IMessageBoxService messageBoxService;
        private IDisposable lightSensorSubscripton;
        private IDisposable gyrometerSensorSubscription;
        private GyrometerReading previousGyrometerReading = null;

        [ImportingConstructor]
        public MainWindowViewModel(
            IViewAwareStatusWindow viewAwareStatusService, 
            IMessageBoxService messageBoxService, 
            ILightSensorService lightSensorService,
            IGyrometerSensorService gyrometerSensorService
            )
        {
            this.viewAwareStatusService = viewAwareStatusService;
            this.viewAwareStatusService.ViewWindowClosing += viewAwareStatusService_ViewWindowClosing;
            this.messageBoxService = messageBoxService;
            lightSensorSubscripton = lightSensorService.LightObservable.Subscribe(LightChanged, LightException);
            gyrometerSensorSubscription = gyrometerSensorService.GyrometerObservable.Subscribe(GyrometerChanged, GyrometerException);
        }

        void viewAwareStatusService_ViewWindowClosing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            lightSensorSubscripton.Dispose();
            gyrometerSensorSubscription.Dispose();
        }

        private void LightChanged(float reading)
        {
            SensorLightMode mode = reading > GlobalSettings.ValueToBeConsideredDark ? SensorLightMode.Light : SensorLightMode.Dark;
            ((ISupportBrowserChanges)this.viewAwareStatusService.View).ApplyChangeBasedOnLightReading(mode);
        }
        
        private void LightException(Exception lightReadingEx)
        {
            Console.WriteLine("Oh no the light is not reading any more");
        }

        private void GyrometerChanged(GyrometerReading reading)
        {
            if(previousGyrometerReading != null)
            {
                ISupportBrowserChanges supportBrowserChanges  = (ISupportBrowserChanges)this.viewAwareStatusService.View;

                double diffLongitude = reading.VelocityX - previousGyrometerReading.VelocityX;
                double diffLatitude = reading.VelocityY - previousGyrometerReading.VelocityY;

                if (Math.Abs(diffLongitude) > GlobalSettings.MinLongitudeChange)
                {
                    supportBrowserChanges.IncreaseLongitude();
                }
                else
                {
                    supportBrowserChanges.DecreaseLongitude();
                }

                if (Math.Abs(diffLatitude) > GlobalSettings.MinLatitudeChange)
                {
                    supportBrowserChanges.IncreaseLatitude();
                }
                else
                {
                    supportBrowserChanges.DecreaseLatitude();
                }
            }

            previousGyrometerReading = reading;
        }
        
        private void GyrometerException(Exception gyrometerReadingEx)
        {
            Console.WriteLine("Oh no the gyrometer is not reading any more");
        }
    }
}