//
// System.Web.Compilation.BuildProvider
//
// Authors:
//	Chris Toshok (toshok@ximian.com)
//	Gonzalo Paniagua Javier (gonzalo@ximian.com)
//
// (C) 2006 Novell, Inc (http://www.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.
//

#if NET_2_0

using System;
using System.CodeDom.Compiler;
using System.Collections;
using System.Collections.Specialized;
using System.IO;
using System.Reflection;
using System.Web.Configuration;
using System.Web.Hosting;
using System.Web.Util;

namespace System.Web.Compilation {

	public abstract class BuildProvider {
		string virtual_path;
		ArrayList ref_assemblies;

		ICollection vpath_deps;

		protected BuildProvider()
		{
			ref_assemblies = new ArrayList ();
		}

		internal void SetVirtualPath (string path)
		{
			virtual_path = path;
		}

		public virtual void GenerateCode (AssemblyBuilder assemblyBuilder)
		{
		}

		public virtual string GetCustomString (CompilerResults results)
		{
			return null;
		}

		protected CompilerType GetDefaultCompilerType ()
		{
			CompilationSection config;
			config = (CompilationSection) WebConfigurationManager.GetSection ("system.web/compilation");
			return GetDefaultCompilerTypeForLanguage (config.DefaultLanguage, config);
		}

		void SetCommonParameters (CompilationSection config, CompilerParameters p)
		{
			p.IncludeDebugInformation = config.Debug;
			foreach (AssemblyInfo info in config.Assemblies) {
				if (info.Assembly != "*") {
					p.ReferencedAssemblies.Add (info.Assembly);
					ref_assemblies.Add (info.Assembly);
				} else {
					AddAssembliesInBin (p.ReferencedAssemblies);
				}
			}

			// explicit, strict?
			// embedded? linked?/resources
		}

		void AddAssembliesInBin (StringCollection coll)
		{
			foreach (string s in HttpApplication.BinDirectoryAssemblies) {
				coll.Add (s);
				ref_assemblies.Add (s);
			}
		}

		internal CompilerType GetDefaultCompilerTypeForLanguage (string language, CompilationSection configSection)
		{
			// MS throws when accesing a Hashtable, we do here.
			if (language == null || language == "")
				throw new ArgumentNullException ("language");

			CompilationSection config;
			if (configSection == null)
				config = WebConfigurationManager.GetSection ("system.web/compilation") as CompilationSection;
			else
				config = configSection;
			
			Compiler compiler = config.Compilers.Get (language);
			CompilerParameters p;
			if (compiler != null) {
				Type type = HttpApplication.LoadType (compiler.Type, true);
				p = new CompilerParameters ();
				p.CompilerOptions = compiler.CompilerOptions;
				p.WarningLevel = compiler.WarningLevel;
				SetCommonParameters (config, p);
				return new CompilerType (type, p);
			}

			if (!CodeDomProvider.IsDefinedLanguage (language))
				throw new HttpException (String.Format ("No compiler for language '{0}'.", language));

			CompilerInfo info = CodeDomProvider.GetCompilerInfo (language);
			CompilerParameters par = info.CreateDefaultCompilerParameters ();
			SetCommonParameters (config, par);
			return new CompilerType (info.CodeDomProviderType, par);
		}
		
		protected CompilerType GetDefaultCompilerTypeForLanguage (string language)
		{
			return GetDefaultCompilerTypeForLanguage (language, null);
		}

		public virtual Type GetGeneratedType (CompilerResults results)
		{
			return null;
		}

		public virtual BuildProviderResultFlags GetResultFlags (CompilerResults results)
		{
			return BuildProviderResultFlags.Default;
		}

		protected TextReader OpenReader ()
		{
			return OpenReader (VirtualPath);
		}

		protected TextReader OpenReader (string virtualPath)
		{
			Stream st = OpenStream (virtualPath);
			return new StreamReader (st, WebEncoding.FileEncoding);
		}

		protected Stream OpenStream ()
		{
			return OpenStream (VirtualPath);
		}

		protected Stream OpenStream (string virtualPath)
		{
			// MS also throws a NullReferenceException here when not hosted.
			return VirtualPathProvider.OpenFile (virtualPath);
		}

		public virtual CompilerType CodeCompilerType {
			get { return null; } // Documented to return null
		}

		protected ICollection ReferencedAssemblies {
			get { return ref_assemblies; }
		}

		protected internal string VirtualPath {
			get { return virtual_path; }
		}

		public virtual ICollection VirtualPathDependencies {
			get {
				if (vpath_deps == null)
					vpath_deps = new OneNullCollection ();

				return vpath_deps;
			}
		}
	}

	class OneNullCollection : ICollection {
		public int Count {
			get { return 1; }
		}

		public bool IsSynchronized {
			get { return false; }
		}

		public object SyncRoot {
			get { return this; }
		}

		public void CopyTo (Array array, int index)
		{
			if (array == null)
				throw new ArgumentNullException ();

			if (index < 0)
				throw new ArgumentOutOfRangeException ();

			if (array.Rank > 1)
				throw new ArgumentException ();

			int length = array.Length;
			if (index >= length || index > length - 1)
				throw new ArgumentException ();

			array.SetValue (null, index);
		}

		public IEnumerator GetEnumerator ()
		{
			yield return null;
		}
	}
}
#endif