/Source/facebook.Linq/Linq/Metamodel.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Reflection;

using System.Data.Linq.Mapping;

using Microsoft.Xml.Schema.Linq;





namespace facebook.Linq

{

	/// <summary>

	/// Property metadata descriptor

	/// </summary>

	public class PropertyData

	{

		internal PropertyData()

		{

		}

		internal PropertyData(PropertyInfo pi)

		{

			this.PropertyInfo = pi;

			ColumnAttribute = ReflectionHelper.GetAttributes<ColumnAttribute>(pi, true).FirstOrDefault();

			FqlFieldName = GetLinqFieldName();

			IsLinqIdentity = GetIsLinqIdentity();

		}



		ColumnAttribute ColumnAttribute;



		internal PropertyInfo PropertyInfo;

		internal string FqlFieldName;

		internal bool IsLinqIdentity;





		internal bool GetIsLinqIdentity()

		{

			if (ColumnAttribute != null)

				return ColumnAttribute.IsPrimaryKey;

			return false; //TODO:

		}



		internal string GetLinqFieldName()

		{

			if (ColumnAttribute != null)

				return ColumnAttribute.Name;

			return PropertyInfo.Name.ToFqlIdentifier();

		}

	}



	/// <summary>

	/// Type metadata descriptor cache

	/// </summary>

	internal class KnownTypeData

	{

		static object GetTypeDataEntrance = new object();

		internal static TypeData GetTypeData(Type t)

		{

			if (Types.ContainsKey(t))

				return Types[t];

			lock (GetTypeDataEntrance)

			{

				if (Types.ContainsKey(t))

					return Types[t];

				var td = new TypeData(t);

				Types.Add(t, td);

				if(td.FqlTableName!=null)

					TypesByTableName.Add(td.FqlTableName, td);

				return td;

			}

		}





		internal static TypeData GetTypeDataByTableName(string tableName)

		{

			return TypesByTableName.TryGetValue(tableName);

		}



		static Dictionary<string, TypeData> TypesByTableName = new Dictionary<string, TypeData>();

		static Dictionary<Type, TypeData> Types = new Dictionary<Type, TypeData>();

	}



	/// <summary>

	/// Type metadata descriptor

	/// </summary>

	internal class TypeData

	{

		internal TypeData()

		{

		}



		internal TypeData(Type t)

		{

			this.Type = t;

			FqlTableName = t.GetLinqTableName();

			if (FqlTableName != null)

			{

				foreach (var p in t.GetProperties())

				{

					if (p.IsFqlColumn())

					{

						var pd = new PropertyData(p);

						Properties.Add(p.Name, pd);

						PropertiesByFieldName.Add(pd.FqlFieldName, pd);

						if (pd.IsLinqIdentity)

						{

							if (IdentityProperty == null)

								IdentityProperty = pd;

							else

								throw new Exception("Type " + t.FullName + " has more than one identity property specified");

						}

					}



				}

			}

		}



		internal Type Type;

		internal string FqlTableName;

		internal Dictionary<string, PropertyData> Properties = new Dictionary<string, PropertyData>();

		internal Dictionary<string, PropertyData> PropertiesByFieldName = new Dictionary<string, PropertyData>();



		internal PropertyData GetPropertyByFieldName(string propertyName)

		{

			if (PropertiesByFieldName.ContainsKey(propertyName))

				return PropertiesByFieldName[propertyName];

			return null;

		}

		internal PropertyData IdentityProperty;

	}



	internal static class Helper

	{

		internal static bool IsFqlColumn(this PropertyInfo pi)

		{

			if (pi.DeclaringType.IsSubclassOf(typeof(XTypedElement)) && pi.GetSetMethod()!=null && IsSupported(pi.PropertyType))

				return true;

			return pi.GetCustomAttributes(typeof(ColumnAttribute), true).Length > 0;

		}



		static HashSet<Type> SupportedTypes = new HashSet<Type> { typeof(Int64), typeof(Decimal), typeof(string), typeof(bool), typeof(DateTime) };

		private static bool IsSupported(Type type)

		{

			if (type.IsEnum)

				return true;

			if (SupportedTypes.Contains(type))

				return true;

			var uType = Nullable.GetUnderlyingType(type);

			if (uType!=null && uType != type)

				return IsSupported(uType);

			return false;

		}







		internal static string ToFqlIdentifier(this string s)

		{

			return StringHelper.SplitByCaps(s).StringConcat("").ToLower();

		}



		internal static string GetLinqTableName(this Type type)

		{

			if (type.IsSubclassOf(typeof(XTypedElement)))

			{

				if (type.Name == "facebookevent")

					return "event";

				else if (type.Name == "friend_info")

					return "friend";

				return type.Name;

			}

			var t = type.GetCustomAttributes(typeof(TableAttribute), true);

			if (t.Length > 0)

				return (t[0] as TableAttribute).Name;

			return null;

		}

	}

}