using System;
using System.Windows.Data;
using System.Windows.Markup;
using Caliburn.Events.Brokering;
using Caliburn.Messaging;

namespace Caliburn.MarkupExtensions
{
    public class MessageExtension : MarkupExtension
    {
        #region Fields

        private string _action;
        private Parameter _parameter;
        private Publication _publication;
        private BindingBase _return;
        private object _trigger;

        #endregion

        #region Constructors

        public MessageExtension() {}

        public MessageExtension(string action)
        {
            _action = action;
        }

        #endregion

        #region Properties

        public object Trigger
        {
            get { return _trigger; }
            set { _trigger = value; }
        }

        public string Action
        {
            get { return _action; }
            set { _action = value; }
        }

        public Publication Publication
        {
            get { return _publication; }
            set { _publication = value; }
        }

        public BindingBase Return
        {
            get { return _return; }
            set { _return = value; }
        }

        public object ParamValue
        {
            set
            {
                if(_parameter == null)
                    _parameter = new Parameter();

                _parameter.Value = value;
            }
        }

        public Binding ParamBinding
        {
            set
            {
                if(_parameter == null)
                    _parameter = new Parameter();

                BindingOperations.SetBinding(_parameter, Parameter.ValueProperty, value);
            }
        }

        #endregion

        #region Overrides

        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            MessageBase message;

            if(Publication != null)
            {
                EventMessage eventMessage = new EventMessage();
                eventMessage.Publication = Publication;
                message = eventMessage;
            }
            else
            {
                ActionMessage actionMessage = new ActionMessage();
                actionMessage.Action = Action;
                actionMessage.Return = Return;
                message = actionMessage;
            }

            message.Trigger = Trigger;

            if(_parameter != null)
                message.Parameters.Add(_parameter);

            return message;
        }

        #endregion
    }
}