using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Ooui.Forms.Renderers;
using Xamarin.Forms;
using Xamarin.Forms.Internals;

namespace Ooui.Forms
{
	public class Platform : BindableObject, IPlatform, INavigation, IDisposable
	{
		bool _disposed;

		public Element Element { get; private set; }

		public Page Page { get; private set; }

		IReadOnlyList<Page> INavigation.ModalStack => throw new NotImplementedException ();

		IReadOnlyList<Page> INavigation.NavigationStack => throw new NotImplementedException ();

		public static readonly BindableProperty RendererProperty = BindableProperty.CreateAttached ("Renderer", typeof (IVisualElementRenderer), typeof (Platform), default (IVisualElementRenderer),
			propertyChanged: (bindable, oldvalue, newvalue) => {
				var view = bindable as VisualElement;
				if (view != null)
					view.IsPlatformEnabled = newvalue != null;
			});

		void IDisposable.Dispose()
		{
			if (_disposed)
				return;
			_disposed = true;

			MessagingCenter.Unsubscribe<Page, ActionSheetArguments>(this, Page.ActionSheetSignalName);
			MessagingCenter.Unsubscribe<Page, AlertArguments>(this, Page.AlertSignalName);
			MessagingCenter.Unsubscribe<Page, bool>(this, Page.BusySetSignalName);
		}

		public static IVisualElementRenderer CreateRenderer (VisualElement element)
		{
			var renderer = Registrar.Registered.GetHandler<IVisualElementRenderer> (element.GetType ()) ?? new DefaultRenderer ();
			//renderer.SetElement (element);
			return renderer;
		}

		public static IVisualElementRenderer GetRenderer (VisualElement bindable)
		{
			return (IVisualElementRenderer)bindable.GetValue (RendererProperty);
		}

		public static void SetRenderer (VisualElement bindable, IVisualElementRenderer value)
		{
			bindable.SetValue (RendererProperty, value);
		}

		protected override void OnBindingContextChanged ()
		{
			SetInheritedBindingContext (Page, BindingContext);

			base.OnBindingContextChanged ();
		}

		public SizeRequest GetNativeSize(VisualElement view, double widthConstraint, double heightConstraint)
		{
			return new SizeRequest(new Size(100, 100));
		}

		public void SetPage (Page newRoot)
		{
			if (newRoot == null)
				return;
			if (Page != null)
				throw new NotImplementedException ();
			Page = newRoot;

			Page.Platform = this;
			AddChild (Page);

			//Page.DescendantRemoved += HandleChildRemoved;

			Application.Current.NavigationProxy.Inner = this;
		}

		void AddChild (VisualElement view)
		{
			if (!Application.IsApplicationOrNull (view.RealParent))
				Console.Error.WriteLine ("Tried to add parented view to canvas directly");

			if (GetRenderer (view) == null) {
				var viewRenderer = CreateRenderer (view);
				SetRenderer (view, viewRenderer);

				//_renderer.View.AddSubview (viewRenderer.NativeView);
				//if (viewRenderer.ViewController != null)
				//	_renderer.AddChildViewController (viewRenderer.ViewController);
				//viewRenderer.NativeView.Frame = new RectangleF (0, 0, _renderer.View.Bounds.Width, _renderer.View.Bounds.Height);
				//viewRenderer.SetElementSize (new Size (_renderer.View.Bounds.Width, _renderer.View.Bounds.Height));
			}
			else
				Console.Error.WriteLine ("Potential view double add");
		}

		void INavigation.InsertPageBefore (Page page, Page before)
		{
			throw new NotImplementedException ();
		}

		Task<Page> INavigation.PopAsync ()
		{
			throw new NotImplementedException ();
		}

		Task<Page> INavigation.PopAsync (bool animated)
		{
			throw new NotImplementedException ();
		}

		Task<Page> INavigation.PopModalAsync ()
		{
			throw new NotImplementedException ();
		}

		Task<Page> INavigation.PopModalAsync (bool animated)
		{
			throw new NotImplementedException ();
		}

		Task INavigation.PopToRootAsync ()
		{
			throw new NotImplementedException ();
		}

		Task INavigation.PopToRootAsync (bool animated)
		{
			throw new NotImplementedException ();
		}

		Task INavigation.PushAsync (Page page)
		{
			throw new NotImplementedException ();
		}

		Task INavigation.PushAsync (Page page, bool animated)
		{
			throw new NotImplementedException ();
		}

		Task INavigation.PushModalAsync (Page page)
		{
			throw new NotImplementedException ();
		}

		Task INavigation.PushModalAsync (Page page, bool animated)
		{
			throw new NotImplementedException ();
		}

		void INavigation.RemovePage (Page page)
		{
			throw new NotImplementedException ();
		}
	}
}