using System;
using System.Threading.Tasks;
using Microsoft.Maui.Graphics;
using UIKit;
 
namespace Microsoft.Maui.Handlers
{
	public partial class ButtonHandler : ViewHandler<IButton, UIButton>
	{
		static readonly UIControlState[] ControlStates = { UIControlState.Normal, UIControlState.Highlighted, UIControlState.Disabled };
 
		// This appears to be the padding that Xcode has when "Default" content insets are used
		public readonly static Thickness DefaultPadding = new Thickness(12, 7);
 
		// Because we can't inherit from Button we use the container to handle
		// Life cycle events and things like monitoring focus changed
		public override bool NeedsContainer => true;
 
		protected override UIButton CreatePlatformView()
		{
			var button = new UIButton(UIButtonType.System);
			SetControlPropertiesFromProxy(button);
			return button;
		}
 
		readonly ButtonEventProxy _proxy = new ButtonEventProxy();
 
		protected override void SetupContainer()
		{
			base.SetupContainer();
			if (ContainerView is WrapperView wrapperView)
			{
				wrapperView.CrossPlatformLayout = VirtualView as ICrossPlatformLayout;
			}
		}
 
		protected override void ConnectHandler(UIButton platformView)
		{
			_proxy.Connect(VirtualView, platformView);
 
			base.ConnectHandler(platformView);
		}
 
		protected override void DisconnectHandler(UIButton platformView)
		{
			_proxy.Disconnect(platformView);
 
			base.DisconnectHandler(platformView);
		}
 
#if MACCATALYST
		//TODO: make this public on NET8
		internal static void MapBackground(IButtonHandler handler, IButton button)
		{
			//If this is a Mac optimized interface
			if (OperatingSystem.IsIOSVersionAtLeast(15) && UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Mac)
			{
				var config = handler.PlatformView?.Configuration ?? UIButtonConfiguration.BorderedButtonConfiguration;
				if (button?.Background is Paint paint)
				{
					if (paint is SolidPaint solidPaint)
					{
						Color backgroundColor = solidPaint.Color;
 
						if (backgroundColor == null)
							config.BaseBackgroundColor = ColorExtensions.BackgroundColor;
						else
							config.BaseBackgroundColor = backgroundColor.ToPlatform();
 
					}
				}
				if (handler.PlatformView != null)
					handler.PlatformView.Configuration = config;
			}
			else
			{
				handler.PlatformView?.UpdateBackground(button);
			}
		}
#endif
 
		public static void MapStrokeColor(IButtonHandler handler, IButtonStroke buttonStroke)
		{
			handler.PlatformView?.UpdateStrokeColor(buttonStroke);
		}
 
		public static void MapStrokeThickness(IButtonHandler handler, IButtonStroke buttonStroke)
		{
			handler.PlatformView?.UpdateStrokeThickness(buttonStroke);
		}
 
		public static void MapCornerRadius(IButtonHandler handler, IButtonStroke buttonStroke)
		{
			handler.PlatformView?.UpdateCornerRadius(buttonStroke);
		}
 
		public static void MapText(IButtonHandler handler, IText button)
		{
			handler.PlatformView?.UpdateText(button);
 
			// Any text update requires that we update any attributed string formatting
			MapFormatting(handler, button);
		}
 
		public static void MapTextColor(IButtonHandler handler, ITextStyle button)
		{
			//If this is a Mac optimized interface
			if (OperatingSystem.IsIOSVersionAtLeast(15) && UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Mac)
			{
				var config = handler.PlatformView?.Configuration ?? UIButtonConfiguration.BorderedButtonConfiguration;
				if (button?.TextColor != null && handler.PlatformView != null)
					config.BaseForegroundColor = button?.TextColor.ToPlatform();
				if (handler.PlatformView != null)
					handler.PlatformView.Configuration = config;
			}
			else
			{
				handler.PlatformView?.UpdateTextColor(button);
			}
		}
 
		public static void MapCharacterSpacing(IButtonHandler handler, ITextStyle button)
		{
			handler.PlatformView?.UpdateCharacterSpacing(button);
		}
 
		public static void MapPadding(IButtonHandler handler, IButton button)
		{
			handler.PlatformView?.UpdatePadding(button, DefaultPadding);
		}
 
		public static void MapFont(IButtonHandler handler, ITextStyle button)
		{
			var fontManager = handler.GetRequiredService<IFontManager>();
 
			handler.PlatformView?.UpdateFont(button, fontManager);
		}
 
		public static void MapFormatting(IButtonHandler handler, IText button)
		{
			// Update all of the attributed text formatting properties
			handler.PlatformView?.UpdateCharacterSpacing(button);
		}
 
		public static void MapImageSource(IButtonHandler handler, IImage image) =>
			MapImageSourceAsync(handler, image).FireAndForget(handler);
 
		public static Task MapImageSourceAsync(IButtonHandler handler, IImage image)
		{
			return handler.ImageSourceLoader.UpdateImageSourceAsync();
		}
 
		static void SetControlPropertiesFromProxy(UIButton platformView)
		{
			foreach (UIControlState uiControlState in ControlStates)
			{
				platformView.SetTitleColor(UIButton.Appearance.TitleColor(uiControlState), uiControlState); // If new values are null, old values are preserved.
				platformView.SetTitleShadowColor(UIButton.Appearance.TitleShadowColor(uiControlState), uiControlState);
				platformView.SetBackgroundImage(UIButton.Appearance.BackgroundImageForState(uiControlState), uiControlState);
			}
		}
 
		class ButtonEventProxy
		{
			WeakReference<IButton>? _virtualView;
 
			IButton? VirtualView => _virtualView is not null && _virtualView.TryGetTarget(out var v) ? v : null;
 
			public void Connect(IButton virtualView, UIButton platformView)
			{
				_virtualView = new(virtualView);
 
				platformView.TouchUpInside += OnButtonTouchUpInside;
				platformView.TouchUpOutside += OnButtonTouchUpOutside;
				platformView.TouchDown += OnButtonTouchDown;
				platformView.TouchCancel += OnButtonTouchCancel;
			}
 
			public void Disconnect(UIButton platformView)
			{
				_virtualView = null;
 
				platformView.TouchUpInside -= OnButtonTouchUpInside;
				platformView.TouchUpOutside -= OnButtonTouchUpOutside;
				platformView.TouchDown -= OnButtonTouchDown;
				platformView.TouchCancel -= OnButtonTouchCancel;
			}
 
			void OnButtonTouchCancel(object? sender, EventArgs e)
			{
				VirtualView?.Released();
			}
 
			void OnButtonTouchUpInside(object? sender, EventArgs e)
			{
				VirtualView?.Released();
				VirtualView?.Clicked();
			}
 
			void OnButtonTouchUpOutside(object? sender, EventArgs e)
			{
				VirtualView?.Released();
			}
 
			void OnButtonTouchDown(object? sender, EventArgs e)
			{
				VirtualView?.Pressed();
			}
		}
 
		partial class ButtonImageSourcePartSetter
		{
			public override void SetImageSource(UIImage? platformImage)
			{
				if (Handler?.PlatformView is not UIButton button)
					return;
 
				platformImage = platformImage?.ImageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal);
 
				button.SetImage(platformImage, UIControlState.Normal);
			}
		}
	}
}