﻿namespace Caliburn.PresentationFramework
{
    using System;
    using System.ComponentModel;
    using System.Linq.Expressions;
    using Core;
    using Invocation;

#if !SILVERLIGHT
    [Serializable]
#endif
    /// <summary>
    /// A base class that implements the infrastructure for property change notification and automatically performs UI thread marshalling.
    /// </summary>
    public class PropertyChangedBase : INotifyPropertyChangedEx
    {
        /// <summary>
        /// Creates an instance of <see cref="PropertyChangedBase"/>.
        /// </summary>
        public PropertyChangedBase()
        {
            IsNotifying = true;
        }

#if !SILVERLIGHT
        [field: NonSerialized]
#endif
        /// <summary>
        /// Occurs when a property value changes.
        /// </summary>
        public event PropertyChangedEventHandler PropertyChanged = delegate { };

        /// <summary>
        /// Enables/Disables property change notification.
        /// </summary>
        public bool IsNotifying { get; set; }

        /// <summary>
        /// Raises a change notification indicating that all bindings should be refreshed.
        /// </summary>
        public void Refresh()
        {
            NotifyOfPropertyChange(string.Empty);
        }

        /// <summary>
        /// Notifies subscribers of the property change.
        /// </summary>
        /// <param name="propertyName">Name of the property.</param>
        public virtual void NotifyOfPropertyChange(string propertyName)
        {
            if (IsNotifying)
                Execute.OnUIThread(() => RaisePropertyChangedEventCore(propertyName));
        }

        /// <summary>
        /// Notifies subscribers of the property change.
        /// </summary>
        /// <typeparam name="TProperty">The type of the property.</typeparam>
        /// <param name="property">The property expression.</param>
        public virtual void NotifyOfPropertyChange<TProperty>(Expression<Func<TProperty>> property)
        {
            NotifyOfPropertyChange(property.GetMemberInfo().Name);
        }

        /// <summary>
        /// Raises the property changed event immediately.
        /// </summary>
        /// <param name="propertyName">Name of the property.</param>
        public virtual void RaisePropertyChangedEventImmediately(string propertyName)
        {
            if (IsNotifying)
                RaisePropertyChangedEventCore(propertyName);
        }

        void RaisePropertyChangedEventCore(string propertyName)
        {
            var handler = PropertyChanged;
            if(handler != null)
                handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}