using System;
using System.Diagnostics;
using Xamarin.Forms;
using Xamarin.Forms.Internals;
using Ooui.Forms;
using System.IO;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Ooui;

namespace Xamarin.Forms
{
    public static class Forms
    {
        public static bool IsInitialized { get; private set; }

        public static void Init ()
        {
            if (IsInitialized)
                return;
            IsInitialized = true;

            Log.Listeners.Add (new DelegateLogListener ((c, m) => Trace.WriteLine (m, c)));

            Device.SetIdiom (TargetIdiom.Desktop);
            Device.PlatformServices = new OouiPlatformServices ();
            Device.Info = new OouiDeviceInfo ();

            Registrar.RegisterAll (new[] {
                typeof(ExportRendererAttribute),
				//typeof(ExportCellAttribute),
				//typeof(ExportImageSourceHandlerAttribute),
			});
        }

        public static event EventHandler<ViewInitializedEventArgs> ViewInitialized;

        public static void SendViewInitialized (this VisualElement self, Ooui.Element nativeView)
        {
            ViewInitialized?.Invoke (self, new ViewInitializedEventArgs { View = self, NativeView = nativeView });
        }

        class OouiDeviceInfo : DeviceInfo
        {
            public override Size PixelScreenSize => new Size (640, 480);

            public override Size ScaledScreenSize => PixelScreenSize;

            public override double ScalingFactor => 1;
        }

        class OouiPlatformServices : IPlatformServices
        {
            public bool IsInvokeRequired => false;

            public string RuntimePlatform => "Ooui";

            public void BeginInvokeOnMainThread (Action action)
            {
                Task.Run (action);
            }

            public Ticker CreateTicker ()
            {
                throw new NotImplementedException ();
            }

            public Assembly[] GetAssemblies ()
            {
                return AppDomain.CurrentDomain.GetAssemblies ();
            }

            public string GetMD5Hash (string input)
            {
                throw new NotImplementedException ();
            }

            public double GetNamedSize (NamedSize size, Type targetElementType, bool useOldSizes)
            {
                switch (size) {
                    default:
                    case NamedSize.Default:
                        return 16;
                    case NamedSize.Micro:
                        return 9;
                    case NamedSize.Small:
                        return 12;
                    case NamedSize.Medium:
                        return 22;
                    case NamedSize.Large:
                        return 32;
                }
            }

            public Task<Stream> GetStreamAsync (Uri uri, CancellationToken cancellationToken)
            {
                throw new NotImplementedException ();
            }

            public IIsolatedStorageFile GetUserStoreForApplication ()
            {
                throw new NotImplementedException ();
            }

            public void OpenUriAction (Uri uri)
            {
                throw new NotImplementedException ();
            }

            public void StartTimer (TimeSpan interval, Func<bool> callback)
            {
                throw new NotImplementedException ();
            }
        }

        public class ViewInitializedEventArgs
        {
            public VisualElement View { get; set; }
            public Ooui.Element NativeView { get; set; }
        }
    }
}