#nullable disable
using System;
using Microsoft.Maui.Controls.Xaml;
 
namespace Microsoft.Maui.Controls
{
	/// <include file="../../../docs/Microsoft.Maui.Controls/BindingCondition.xml" path="Type[@FullName='Microsoft.Maui.Controls.BindingCondition']/Docs/*" />
	public sealed class BindingCondition : Condition
	{
		readonly BindableProperty _boundProperty;
 
		BindingBase _binding;
		object _triggerValue;
 
		/// <include file="../../../docs/Microsoft.Maui.Controls/BindingCondition.xml" path="//Member[@MemberName='.ctor']/Docs/*" />
		public BindingCondition()
		{
			_boundProperty = BindableProperty.CreateAttached("Bound", typeof(object), typeof(BindingCondition), null, propertyChanged: OnBoundPropertyChanged);
		}
 
		/// <include file="../../../docs/Microsoft.Maui.Controls/BindingCondition.xml" path="//Member[@MemberName='Binding']/Docs/*" />
		public BindingBase Binding
		{
			get { return _binding; }
			set
			{
				if (_binding == value)
					return;
				if (IsSealed)
					throw new InvalidOperationException("Cannot change Binding once the Condition has been applied.");
				_binding = value;
			}
		}
 
		/// <include file="../../../docs/Microsoft.Maui.Controls/BindingCondition.xml" path="//Member[@MemberName='Value']/Docs/*" />
		public object Value
		{
			get { return _triggerValue; }
			set
			{
				if (_triggerValue == value)
					return;
				if (IsSealed)
					throw new InvalidOperationException("Cannot change Value once the Condition has been applied.");
				_triggerValue = value;
			}
		}
 
		internal override bool GetState(BindableObject bindable)
		{
			object newValue = bindable.GetValue(_boundProperty);
			return EqualsToValue(newValue);
		}
 
		internal override void SetUp(BindableObject bindable)
		{
			if (Binding != null)
				bindable.SetBinding(_boundProperty, Binding.Clone());
		}
 
		internal override void TearDown(BindableObject bindable)
		{
			bindable.RemoveBinding(_boundProperty);
			bindable.ClearValue(_boundProperty, SetterSpecificity.FromBinding);
		}
 
		static IValueConverterProvider s_valueConverter = DependencyService.Get<IValueConverterProvider>();
 
		bool EqualsToValue(object other)
		{
			if ((other == Value) || (other != null && other.Equals(Value)))
				return true;
 
			object converted = null;
			if (s_valueConverter != null)
				converted = s_valueConverter.Convert(Value, other != null ? other.GetType() : typeof(object), null, null);
			else
				return false;
 
			return (other == converted) || (other != null && other.Equals(converted));
		}
 
		void OnBoundPropertyChanged(BindableObject bindable, object oldValue, object newValue)
		{
			bool oldState = EqualsToValue(oldValue);
			bool newState = EqualsToValue(newValue);
 
			if (newState == oldState)
				return;
 
			ConditionChanged?.Invoke(bindable, oldState, newState);
		}
	}
}