using System;
using System.Runtime.InteropServices;
#if __IOS__
using MonoTouch.UIKit;
#endif

namespace Xamarin.Helpers {
	public static class Device {
#if __IOS__
		public enum iOSDevice {
			iPhone2G,
			iPhone3G,
			iPhone3Gs,
			iPhone4,
			iPod1G,
			iPod2G,
			iPod3G,
			Simulator,
			iPad1G,
			iPad2G,
			iPad3G,
			Unknown
		}

		[DllImport(MonoTouch.Constants.SystemLibrary)]
		internal static extern int sysctlbyname([MarshalAs(UnmanagedType.LPStr)] string property, IntPtr output, IntPtr oldLen, IntPtr newp,
		uint newlen);

		public static bool IsIPad { get; private set; }
		public static bool IsRetina { get; private set; }

		public static bool IsSeven {
			get {
				return UIDevice.CurrentDevice.CheckSystemVersion(7, 0);
			}
		}

		public static bool IsEight {
			get {
				return UIDevice.CurrentDevice.CheckSystemVersion(8, 0);
			}
		}

		public static bool IsTall {
			get {
				return UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Phone && Math.Abs(UIScreen.MainScreen.Bounds.Size.Height - 568) < 0.01;
			}
		}

		public static iOSDevice RealDevice { get; private set; }

		static Device() {
			RealDevice = GetHardwareVersion();
			IsRetina = UIScreen.MainScreen.Scale > 1.0;
		}

		public static iOSDevice GetHardwareVersion() {
			const string hardwareProperty = "hw.machine";

			var pLen = Marshal.AllocHGlobal(sizeof(int));
			sysctlbyname(hardwareProperty, IntPtr.Zero, pLen, IntPtr.Zero, 0);

			var length = Marshal.ReadInt32(pLen);

			if (length == 0) {
				Marshal.FreeHGlobal(pLen);
				return iOSDevice.Unknown;
			}

			var pStr = Marshal.AllocHGlobal(length);
			sysctlbyname(hardwareProperty, pStr, pLen, IntPtr.Zero, 0);

			var hardwareStr = Marshal.PtrToStringAnsi(pStr);
			var ret = iOSDevice.Unknown;

			switch (hardwareStr) {
				case "iPhone1,1":
					ret = iOSDevice.iPhone2G;
					break;

				case "iPhone1,2":
					ret = iOSDevice.iPhone3G;
					break;

				case "iPhone2,1":
					ret = iOSDevice.iPhone3Gs;
					break;

				case "iPhone3,1":
					ret = iOSDevice.iPhone4;
					break;

				case "iPod1,1":
					ret = iOSDevice.iPod1G;
					break;

				case "iPod2,1":
					ret = iOSDevice.iPod2G;
					break;

				case "iPod3,1":
					ret = iOSDevice.iPod3G;
					break;

				case "iPad1,1":
					ret = iOSDevice.iPad1G;
					break;

				case "iPad2,1":
					ret = iOSDevice.iPad2G;
					break;

				case "iPad3,1":
					ret = iOSDevice.iPad3G;
					break;

				case "x86_32":
				case "x86_64":
				case "i386":
					ret = iOSDevice.Simulator;
					break;
			}

			Marshal.FreeHGlobal(pLen);
			Marshal.FreeHGlobal(pStr);

			return ret;
		}
#elif __ANDROID__
		public static string GetHardwareVersion() {
			return string.Format("{0} {1} {2}", Android.OS.Build.Manufacturer, Android.OS.Build.Board, Android.OS.Build.Display);
		}
#endif

		public static string GetSoftwareVersion() {
#if __IOS__
			var dev = MonoTouch.UIKit.UIDevice.CurrentDevice;
			return string.Format("{0} {1}", dev.SystemName, dev.SystemVersion);
#elif __ANDROID__
			return string.Format("{0} ({1}) [{2}]", Android.OS.Build.VERSION.Sdk, Android.OS.Build.VERSION.SdkInt, Android.OS.Build.VERSION.Codename); 
#endif
		}
	}
}