using System;
using System.Collections.Generic;
using Chernobyl.Update;

namespace Chernobyl.Input.Controls
{
    /// <summary>
    /// An <see cref="IControl"/> that uses it's <see cref="DecoratedController"/> 
    /// for all implementations.
    /// </summary>
    public abstract class ControlDecorator : UpdateableDecorator, IControl
    {
        /// <summary>
        /// The name of this control.
        /// </summary>
        public string Name { get { return DecoratedController.Name; } set { DecoratedController.Name = value; } }

        /// <summary>
        /// The parent of this control.
        /// </summary>
        public IControl ControlParent 
        { 
            get { return DecoratedController.ControlParent; }
            set { DecoratedController.ControlParent = value; }
        }

        /// <summary>
        /// The children of this control
        /// </summary>
        public ICollection<IControl> ControlChildren { get { return DecoratedController.ControlChildren; } }

        /// <summary>
        /// An event that is raised when this <see cref="IControl"/> is
        /// disconnected from the device it was previously connected to and is
        /// no longer available for use. Actions performed on the 
        /// <see cref="IControl"/> after it has been disconnected may result
        /// is an <see cref="DisconnectedException"/> being thrown.
        /// </summary>
        public virtual event EventHandler Disconnected
        {
            add
            {
                if (_disconnected == null && DecoratedController != null)
                    DecoratedController.Disconnected += OnDecoratedControllerDisconnected;
                _disconnected += value;
            }
            remove
            {
                _disconnected -= value;
                if (_disconnected == null && DecoratedController != null)
                    DecoratedController.Disconnected -= OnDecoratedControllerDisconnected;
            }
        }

        /// <summary>
        /// The <see cref="IControl"/> that implements the functionality of
        /// this <see cref="IControl"/>. Note that, when setting this property,
        /// the data from the previous value of this property will be copied to
        /// the new value using 
        /// <see cref="Control.ShallowCopy(IControl, IControl)"/>.
        /// </summary>
        protected abstract IControl DecoratedController { get; }

        /// <summary>
        /// The <see cref="IUpdateable"/> that implements the functionality of
        /// this <see cref="IUpdateable"/>. Note that, when setting this property,
        /// the data from the previous value of this property will be copied to
        /// the new value using 
        /// <see cref="Updateable.ShallowCopy(IUpdateable, IUpdateable)"/>.
        /// </summary>
        protected override IUpdateable DecoratedUpdateable { get { return DecoratedController; } }

        /// <summary>
        /// An event handler that is invoked whenever the 
        /// <see cref="DecoratedController"/> has been disconnected from the
        /// device it was previously connected to. This method raises the 
        /// <see cref="Disconnected"/> event of this class but using 'this' as
        /// the sender.
        /// </summary>
        /// <param name="sender">The instance that generated the event.</param>
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
        void OnDecoratedControllerDisconnected(object sender, EventArgs e)
        {
            if (_disconnected != null)
                _disconnected(this, e);
        }

        /// <summary>
        /// The backing field to <see cref="Disconnected"/>.
        /// </summary>
        EventHandler _disconnected;
    }
}