/ThinkEmailFomatter/Models/BusinessObjects/ThinkStreamToObject.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Xml;
using System.Xml.Linq;
using ThinkEmailFormatter.Models;

namespace ThinkEmailFormatter.Models
{
    /// <summary>
    /// Convert the HTTP-POSTed XML stream coming from THINK into
    /// a Business object
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class ThinkStreamToObject<T> where T: new()
    {
        #region[ MEMBERS ]

        public readonly XElement _xmlElement;
        
        #endregion

        #region [ CONSTRUCTORS ]

        public ThinkStreamToObject(Stream xmlStream) 
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(xmlStream);
            _xmlElement = XElement.Load(new XmlNodeReader(doc));
        }

        public ThinkStreamToObject(XElement xmlElement)
        {
            _xmlElement = xmlElement;
        }

        #endregion

        #region [ METHODS ]

        /// <summary>
        /// Convert XML stream. So far that convertion can, at least,
        /// convert the XML related to the following THINK events:
        /// - Order Item Added
        /// - Customer Added
        /// - Order Renewed
        /// - Password Changed
        /// </summary>
        /// <returns></returns>
        public T Convert()
        {
            if (_xmlElement == null)
            {
                return default(T);
            }
            else
            {
                T convertedObj = new T();
                var properties = convertedObj.GetType().GetProperties();
                Type stringType = typeof(string);

                foreach (var property in properties)
                {
                    dynamic propertyValue = null;

                    // if this is a string, it means this is an attribute of node convertedObj.XmlElementName
                    // Gets its value from the xmlStream
                    if (property.PropertyType == stringType)
                    {
                        // TODO: FIx this horrible "td_email_recipient" hard-coded value
                        if (property.Name == "td_email_recipient")
                        {
                            var emailAddress = _xmlElement.Element("td_email_recipient").FirstNode;
                            propertyValue = emailAddress == null ? string.Empty : emailAddress.ToString();
                        }
                        else
                        {
                            var attrValue = _xmlElement.Attribute(property.Name);
                            if (attrValue != null)
                                propertyValue = (string)attrValue;
                        }
                    }
                    else if (property.PropertyType.IsGenericType) // This is a children of node convertedObj.XmlElementName, and there may be more than one
                    {
                        var childrenElements = _xmlElement.Elements(property.Name);

                        propertyValue = Activator.CreateInstance(property.PropertyType);

                        foreach (XElement xelement in childrenElements)
                        {
                            if (xelement != null)
                            {
                                dynamic o = CreateInstance(property.PropertyType.GetGenericArguments()[0], xelement);
                                propertyValue.Add(o.Convert());
                            }
                        }
                    }
                    else // This is a children of node convertedObj.XmlElementName
                    {
                        XElement childrenElement = _xmlElement.Elements(property.Name).FirstOrDefault();

                        if (childrenElement != null)
                        {
                            dynamic o = CreateInstance(property.PropertyType, childrenElement);
                            propertyValue = o.Convert();
                        }
                    }

                    if (propertyValue != null)
                        property.SetValue(convertedObj, propertyValue, null);
                }

                return convertedObj;
            }
        }

        private dynamic CreateInstance(Type genericType, XElement arg )
        {
            Type d1 = typeof(ThinkStreamToObject<>);
            Type[] typeArgs = { genericType };
            Type constructed = d1.MakeGenericType(typeArgs);
            object[] args = { arg };
            dynamic o = Activator.CreateInstance(constructed, args);

            return o;
        }

        #endregion
    }
}