using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Data;
using System.Windows.Media;

namespace Tango.SharedUI
{
    /// <summary>
    /// Represents a binding event container.
    /// </summary>
    /// <seealso cref="System.Windows.DependencyObject" />
    public class BindingEventContainer : DependencyObject
    {
        private Action _renewAction;

        /// <summary>
        /// Occurs when the dependency property value has changed.
        /// </summary>
        public event EventHandler<BindingEventArgs> ValueChanged;

        /// <summary>
        /// Gets or sets the value.
        /// </summary>
        public Object Value
        {
            get { return (Object)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }
        public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register("Value", typeof(Object), typeof(BindingEventContainer), new PropertyMetadata(null, (d, e) => (d as BindingEventContainer).OnValueChanged()));

        /// <summary>
        /// Gets or sets the binding property.
        /// </summary>
        public BindingProperty BindingProperty { get; set; }

        /// <summary>
        /// Gets or sets the dependency object.
        /// </summary>
        public DependencyObject DependencyObject { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="BindingEventContainer"/> class.
        /// </summary>
        /// <param name="takeElement">The dependency object.</param>
        /// <param name="bindingProperty">The binding property.</param>
        public BindingEventContainer(DependencyObject dependencyObject, BindingProperty bindingProperty)
        {
            DependencyObject = dependencyObject;
            BindingProperty = bindingProperty;
        }

        /// <summary>
        /// Called when the value has been changed
        /// </summary>
        protected virtual void OnValueChanged()
        {
            ValueChanged?.Invoke(this, new BindingEventArgs()
            {
                BindingProperty = BindingProperty,
                DependencyObject = DependencyObject,
                Value = Value,
                _renewAction = _renewAction
            });
        }

        /// <summary>
        /// Generates a new <see cref="BindingEventContainer"/> for the specified Take element and binding property.
        /// </summary>
        /// <param name="dependencyObject">The take element.</param>
        /// <param name="dependencyProperty">The binding property.</param>
        /// <returns></returns>
        public static BindingEventContainer Generate(DependencyObject dependencyObject, DependencyProperty dependencyProperty)
        {
            BindingEventContainer container = new BindingEventContainer(dependencyObject, new BindingProperty(dependencyProperty));

            container._renewAction = () =>
            {
                Binding binding = new Binding();
                binding.Mode = BindingMode.OneWay;
                binding.Source = dependencyObject;
                binding.Path = new PropertyPath(dependencyProperty);
                BindingOperations.SetBinding(container, BindingEventContainer.ValueProperty, binding);
            };

            container._renewAction.Invoke();

            return container;
        }
    }
}