//
// MetaModel.cs
//
// Authors:
//	Atsushi Enomoto <atsushi@ximian.com>
//      Marek Habersack <mhabersack@novell.com>
//
// Copyright (C) 2008 Novell Inc. http://novell.com
//

//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Globalization;
using System.Security.Permissions;
using System.Security.Principal;
using System.Web.Caching;
using System.Web.DynamicData.ModelProviders;

namespace System.Web.DynamicData
{
	[AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
	[AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
	public class MetaModel
	{
		const string DEFAULT_DYNAMIC_DATA_VIRTUAL_FOLDER_PATH = "~/DynamicData/";
		
		static object registered_models_lock = new object ();
		
		static MetaModel default_model;
		static Exception registration_exception;
		static Dictionary<Type, MetaModel> registered_models;

		string dynamicDataFolderVirtualPath;
		
		public static MetaModel Default {
			get { return default_model; }
			internal set { default_model = value; }
		}

		public static MetaModel GetModel (Type contextType)
		{
			if (contextType == null)
				throw new ArgumentNullException ("contextType");

			MetaModel m;
			if (!TryGetModel (contextType, out m))
				throw new InvalidOperationException (String.Format ("Type '{0}' is not registered as a MetaModel", contextType));

			return m;
		}

		public static void ResetRegistrationException ()
		{
			registration_exception = null;
		}

		public MetaModel ()
		{
			if (default_model == null)
				default_model = this;

			FieldTemplateFactory ftf = new FieldTemplateFactory ();
			ftf.Initialize (this);
			FieldTemplateFactory = ftf;
			
			Tables = new ReadOnlyCollection<MetaTable> (new MetaTable [0]);
			VisibleTables = new List<MetaTable> ();
		}

		public string DynamicDataFolderVirtualPath {
			get {
				if (dynamicDataFolderVirtualPath == null)
					return DEFAULT_DYNAMIC_DATA_VIRTUAL_FOLDER_PATH;

				return dynamicDataFolderVirtualPath;
			}
			
			set {
				if (!String.IsNullOrEmpty (value))
					dynamicDataFolderVirtualPath = VirtualPathUtility.AppendTrailingSlash (value);
				else
					dynamicDataFolderVirtualPath = value;
			}
		}

		public IFieldTemplateFactory FieldTemplateFactory { get; set; }

		public ReadOnlyCollection<MetaTable> Tables { get; private set; }

		public List<MetaTable> VisibleTables { get; private set; }

		void CheckRegistrationError ()
		{
			if (registration_exception != null)
				throw new InvalidOperationException ("An error occured during context model registration", registration_exception);
		}
		
		public string GetActionPath (string tableName, string action, object row)
		{
			return GetTable (tableName).GetActionPath (action, row);
		}

		internal static void GetDataFieldAttribute <T> (AttributeCollection attributes, ref T backingField) where T: Attribute
		{
			if (backingField != null)
				return;

			foreach (Attribute attr in attributes) {
				if (attr == null || !typeof (T).IsAssignableFrom (attr.GetType ()))
					continue;

				backingField = attr as T;
				break;
			}
		}
		
		public MetaTable GetTable (string uniqueTableName)
		{
			MetaTable mt;
			if (TryGetTable (uniqueTableName, out mt))
				return mt;
			throw new ArgumentException (String.Format ("Table '{0}' does not exist in registered context", uniqueTableName));
		}

		public MetaTable GetTable (Type entityType)
		{
			if (entityType == null)
				throw new ArgumentNullException ("entityType");

			foreach (var t in Tables) {
				if (t.EntityType == entityType)
					return t;
			}
			
			throw new ArgumentException (String.Format ("Entity type '{0}' does not exist in registered context", entityType));
		}

		public MetaTable GetTable (string tableName, Type contextType)
		{
			if (tableName == null)
				throw new ArgumentNullException ("tableName");

			MetaModel model;
			if (contextType != null && !TryGetModel (contextType, out model))
				throw new ArgumentException ("Unknown context type '" + contextType + "'. This context type has not been registered.");
			
			return GetModel (contextType).GetTable (tableName);
		}
		
		internal static ICustomTypeDescriptor GetTypeDescriptor (Type type)
		{
			return TypeDescriptor.GetProvider (type).GetTypeDescriptor (type);
		}

		public void RegisterContext (Func<object> contextFactory)
		{
			RegisterContext (contextFactory, null);
		}

		public void RegisterContext (Type contextType)
		{
			RegisterContext (contextType, null);
		}

		public void RegisterContext (DataModelProvider dataModelProvider)
		{
			RegisterContext (dataModelProvider, null);
		}

		public void RegisterContext (Type contextType, ContextConfiguration configuration)
		{
			if (contextType == null)
				throw new ArgumentNullException ("contextType");
			CheckRegistrationError ();
			RegisterContext (() => Activator.CreateInstance (contextType), configuration);
			RegisterModel (contextType, this, configuration);
		}

		public void RegisterContext (Func<object> contextFactory, ContextConfiguration configuration)
		{
			if (contextFactory == null)
				throw new ArgumentNullException ("contextFactory");
			CheckRegistrationError ();
			try {
				// FIXME: entity framework support is not done.
				RegisterContextCore (new DLinqDataModelProvider (contextFactory), configuration);
			} catch (Exception ex) {
				registration_exception = ex;
				throw;
			}
		}

		public void RegisterContext (DataModelProvider dataModelProvider, ContextConfiguration configuration)
		{
			if (dataModelProvider == null)
				throw new ArgumentNullException ("dataModelProvider");
			CheckRegistrationError ();
			try {
				RegisterContextCore (dataModelProvider, configuration);
			} catch (Exception ex) {
				registration_exception = ex;
				throw;
			}
		}

		void RegisterContextCore (DataModelProvider dataModelProvider, ContextConfiguration configuration)
		{
			RegisterModel (dataModelProvider.ContextType, this, configuration);
			
			var l = new List<MetaTable> (Tables);
			foreach (var t in dataModelProvider.Tables)
				l.Add (new MetaTable (this, t, configuration));
			
			Tables = new ReadOnlyCollection<MetaTable> (l);

			foreach (MetaTable t in l)
				t.Init ();
			
			VisibleTables = l;
		}

		static void RegisterModel (Type contextType, MetaModel model, ContextConfiguration configuration)
		{
			lock (registered_models_lock) {
				if (registered_models == null)
					registered_models = new Dictionary <Type, MetaModel> ();

				if (registered_models.ContainsKey (contextType))
					return;

				registered_models.Add (contextType, model);
			}
			RegisterTypeDescriptionProvider (contextType, configuration);
		}

		static void RegisterTypeDescriptionProvider (Type type, ContextConfiguration config)
		{
			Func <Type, TypeDescriptionProvider> factory = config == null ? null : config.MetadataProviderFactory;
			if (config == null || factory == null)
				return;

			TypeDescriptionProvider provider = factory (type);
			if (provider == null)
				return;

			TypeDescriptor.AddProvider (provider, type);
		}

		public bool TryGetTable (string uniqueTableName, out MetaTable table)
		{
			if (uniqueTableName == null)
				throw new ArgumentNullException ("uniqueTableName");
			foreach (var t in Tables)
				if (t.Name == uniqueTableName) {
					table = t;
					return true;
				}
			table = null;
			return false;
		}

		static bool TryGetModel (Type contextType, out MetaModel model)
		{
			model = null;
			if (registered_models != null && registered_models.TryGetValue (contextType, out model))
				return model != null;

			return false;
		}
		
	}
}