// ****************************************************************

// This is free software licensed under the NUnit license. You

// may obtain a copy of the license as well as information regarding

// copyright ownership at http://nunit.org.

// ****************************************************************



namespace NUnit.Core

{

	using System;

	using System.IO;

	using System.Reflection;

	using System.Collections;



	/// <summary>

	/// Class adapted from NUnitAddin for use in handling assemblies that are not

    /// found in the test AppDomain.

	/// </summary>

    public class AssemblyResolver : MarshalByRefObject, IDisposable

	{

		static Logger log = InternalTrace.GetLogger(typeof(AssemblyResolver));



		private class AssemblyCache

		{

			private Hashtable _resolved = new Hashtable();



			public bool Contains( string name )

			{

				return _resolved.ContainsKey( name );

			}



			public Assembly Resolve( string name )

			{

				if ( _resolved.ContainsKey( name ) )

					return (Assembly)_resolved[name];

				

				return null;

			}



			public void Add( string name, Assembly assembly )

			{

				_resolved[name] = assembly;

			}

		}



		private AssemblyCache _cache = new AssemblyCache();



		private ArrayList _dirs = new ArrayList();



		public AssemblyResolver()

		{

			AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);

		}



		public void Dispose()

		{

			AppDomain.CurrentDomain.AssemblyResolve -= new ResolveEventHandler(CurrentDomain_AssemblyResolve);

		}



		public void AddFile( string file )

		{

			Assembly assembly = Assembly.LoadFrom( file );

			_cache.Add(assembly.GetName().FullName, assembly);

		}



		public void AddFiles( string directory, string pattern )

		{

			if ( Directory.Exists( directory ) )

				foreach( string file in Directory.GetFiles( directory, pattern ) )

					AddFile( file );

		}



		public void AddDirectory( string directory )

		{

			if ( Directory.Exists( directory ) )

				_dirs.Add( directory );

		}



		private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)

		{

			string fullName = args.Name;

			int index = fullName.IndexOf(',');

			if(index == -1)							// Only resolve using full name.

			{

				log.Debug( string.Format("Not a strong name: {0}", fullName ) );

				return null;

			}



			if ( _cache.Contains( fullName ) )

			{

				log.Info( string.Format( "Resolved from Cache: {0}", fullName ) );

				return _cache.Resolve(fullName);

			}



			foreach( string dir in _dirs )

			{

				foreach( string file in Directory.GetFiles( dir, "*.dll" ) )

				{

					string fullFile = Path.Combine( dir, file );

                    AssemblyReader rdr = new AssemblyReader(fullFile);

					try

					{

                        if (rdr.IsDotNetFile)

                        {

                            if (AssemblyName.GetAssemblyName(fullFile).FullName == fullName)

                            {

                                log.Info(string.Format("Added to Cache: {0}", fullFile));

                                AddFile(fullFile);

                                return _cache.Resolve(fullName);

                            }

                        }

					}

					catch(Exception ex)

					{

                        log.Error( "Unable to load addin assembly", ex );

                        throw;

					}

				}

			}



			log.Debug( string.Format( "Not in Cache: {0}", fullName) ); 

			return null;

		}

	}

}