using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Xml;
using System.Xml.Linq;

/// <summary>
/// Extension methods for the dynamic object.
/// </summary>
public static class DynamicHelper
{
	/// <summary>
	/// Defines the simple types that is directly writeable to XML.
	/// </summary>
	private static readonly Type[] _writeTypes = new[] { typeof(string), typeof(DateTime), typeof(Enum), typeof(decimal), typeof(Guid) };

	/// <summary>
	/// Determines whether [is simple type] [the specified type].
	/// </summary>
	/// <param name="type">The type to check.</param>
	/// <returns>
	/// 	<c>true</c> if [is simple type] [the specified type]; otherwise, <c>false</c>.
	/// </returns>
	public static bool IsSimpleType(this Type type)
	{
		return type.IsPrimitive || _writeTypes.Contains(type);
	}

	/// <summary>
	/// Converts the specified dynamic object to XML.
	/// </summary>
	/// <param name="dynamicObject">The dynamic object.</param>
	/// <returns>Returns an Xml representation of the dynamic object.</returns>
	public static XElement ConvertToXml(dynamic dynamicObject)
	{
		return ConvertToXml(dynamicObject, null);
	}

	/// <summary>
	/// Converts the specified dynamic object to XML.
	/// </summary>
	/// <param name="dynamicObject">The dynamic object.</param>
	/// /// <param name="element">The element name.</param>
	/// <returns>Returns an Xml representation of the dynamic object.</returns>
	public static XElement ConvertToXml(dynamic dynamicObject, string element)
	{
		if (String.IsNullOrWhiteSpace(element))
		{
			element = "object";
		}

		element = XmlConvert.EncodeName(element);
		var ret = new XElement(element);

		Dictionary<string, object> members = new Dictionary<string, object>(dynamicObject);

		var elements = from prop in members
									 let name = XmlConvert.EncodeName(prop.Key)
									 let val = prop.Value.GetType().IsArray ? "array" : prop.Value
									 let value = prop.Value.GetType().IsArray ? GetArrayElement(prop.Key, (Array)prop.Value) : (prop.Value.GetType().IsSimpleType() ? new XElement(name, val) : val.ToXml(name))
									 where value != null
									 select value;

		ret.Add(elements);

		return ret;
	}

	/// <summary>
	/// Generates an XML string from the dynamic object.
	/// </summary>
	/// <param name="dynamicObject">The dynamic object.</param>
	/// <returns>Returns an XML string.</returns>
	public static string ToXmlString(dynamic dynamicObject)
	{
		XElement xml = DynamicHelper.ConvertToXml(dynamicObject);

		return xml.ToString();
	}

	/// <summary>
	/// Converts an anonymous type to an XElement.
	/// </summary>
	/// <param name="input">The input.</param>
	/// <returns>Returns the object as it's XML representation in an XElement.</returns>
	public static XElement ToXml(this object input)
	{
		return input.ToXml(null);
	}

	/// <summary>
	/// Converts an anonymous type to an XElement.
	/// </summary>
	/// <param name="input">The input.</param>
	/// <param name="element">The element name.</param>
	/// <returns>Returns the object as it's XML representation in an XElement.</returns>
	public static XElement ToXml(this object input, string element)
	{
		if (input == null)
		{
			return null;
		}

		if (String.IsNullOrWhiteSpace(element))
		{
			element = "object";
		}

		element = XmlConvert.EncodeName(element);
		var ret = new XElement(element);

		if (input != null)
		{
			var type = input.GetType();
			var props = type.GetProperties();

			var elements = from prop in props
										 let name = XmlConvert.EncodeName(prop.Name)
										 let val = prop.PropertyType.IsArray ? "array" : prop.GetValue(input, null)
										 let value = prop.PropertyType.IsArray ? GetArrayElement(prop, (Array)prop.GetValue(input, null)) : (prop.PropertyType.IsSimpleType() ? new XElement(name, val) : val.ToXml(name))
										 where value != null
										 select value;

			ret.Add(elements);
		}

		return ret;
	}

	/// <summary>
	/// Parses the specified XML string to a dynamic.
	/// </summary>
	/// <param name="xmlString">The XML string.</param>
	/// <returns>A dynamic object.</returns>
	public static dynamic ParseDynamic(this string xmlString)
	{
		throw new NotImplementedException();
	}

	/// <summary>
	/// Gets the array element.
	/// </summary>
	/// <param name="info">The property info.</param>
	/// <param name="input">The input object.</param>
	/// <returns>Returns an XElement with the array collection as child elements.</returns>
	private static XElement GetArrayElement(PropertyInfo info, Array input)
	{
		return GetArrayElement(info.Name, input);
	}

	/// <summary>
	/// Gets the array element.
	/// </summary>
	/// <param name="propertyName">The property name.</param>
	/// <param name="input">The input object.</param>
	/// <returns>Returns an XElement with the array collection as child elements.</returns>
	private static XElement GetArrayElement(string propertyName, Array input)
	{
		var name = XmlConvert.EncodeName(propertyName);

		XElement rootElement = new XElement(name);

		var arrayCount = input.GetLength(0);

		for (int i = 0; i < arrayCount; i++)
		{
			var val = input.GetValue(i);
			XElement childElement = val.GetType().IsSimpleType() ? new XElement(name + "Child", val) : val.ToXml();

			rootElement.Add(childElement);
		}

		return rootElement;
	}
}