//
// System.Web.Compilation.BuildManager
//
// Authors:
//	Chris Toshok (toshok@ximian.com)
//	Gonzalo Paniagua Javier (gonzalo@novell.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;
using System.CodeDom.Compiler;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Web;
using System.Web.Configuration;
using System.Web.Hosting;

namespace System.Web.Compilation {
	public sealed class BuildManager {
		private static List<Assembly> AppCode_Assemblies = new List<Assembly>();
		private static List<Assembly> TopLevel_Assemblies = new List<Assembly>();
		private static bool haveResources;
		
		internal BuildManager ()
		{
		}

		internal static void ThrowNoProviderException (string extension)
		{
			string msg = "No registered provider for extension '{0}'.";
			throw new HttpException (String.Format (msg, extension));
		}

		public static object CreateInstanceFromVirtualPath (string virtualPath, Type requiredBaseType)
		{
			// virtualPath + Exists done in GetCompiledType()
			if (requiredBaseType == null)
				throw new NullReferenceException (); // This is what MS does, but from somewhere else.

			// Get the Type.
			Type type = GetCompiledType (virtualPath);
			if (!requiredBaseType.IsAssignableFrom (type)) {
				string msg = String.Format ("Type '{0}' does not inherit from '{1}'.",
								type.FullName, requiredBaseType.FullName);
				throw new HttpException (500, msg);
			}

			return Activator.CreateInstance (type, null);
		}

		[MonoTODO ("Not implemented, always returns null")]
		public static BuildDependencySet GetCachedBuildDependencySet (HttpContext context, string virtualPath)
		{
			return null; // null is ok here until we store the dependency set in the Cache.
		}

		internal static BuildProvider GetBuildProviderForPath (string virtualPath, bool throwOnMissing)
		{
			string extension = VirtualPathUtility.GetExtension (virtualPath);
			CompilationSection c = WebConfigurationManager.GetSection ("system.web/compilation", virtualPath) as CompilationSection;
			if (c == null)
				ThrowNoProviderException (extension);
			
			BuildProviderCollection coll = c.BuildProviders;
			if (coll == null || coll.Count == 0)
				ThrowNoProviderException (extension);
			
			BuildProvider provider = coll.GetProviderForExtension (extension);
			if (provider == null && throwOnMissing)
				ThrowNoProviderException (extension);

			return provider;
		}
		
		public static Assembly GetCompiledAssembly (string virtualPath)
		{
			BuildProvider provider;
			CompilerParameters parameters;

			AssemblyBuilder abuilder = GetAssemblyBuilder (virtualPath, out provider);
			CompilerType ctype = provider.CodeCompilerType;
			parameters = PrepareParameters (abuilder.TempFiles, virtualPath, ctype.CompilerParameters);
			CompilerResults results = abuilder.BuildAssembly (virtualPath, parameters);
			return results.CompiledAssembly;
		}

		static AssemblyBuilder GetAssemblyBuilder (string virtualPath, out BuildProvider provider)
		{
			if (virtualPath == null || virtualPath == "")
				throw new ArgumentNullException ("virtualPath");

			if (virtualPath [0] != '/')
				throw new ArgumentException ("The virtual path is not rooted", "virtualPath");

			if (!HostingEnvironment.VirtualPathProvider.FileExists (virtualPath))
				throw new HttpException (String.Format ("The file '{0}' does not exist.", virtualPath));
			provider = GetBuildProviderForPath (virtualPath, true);
			CompilerType compiler_type = provider.CodeCompilerType;
			Type ctype = compiler_type.CodeDomProviderType;
			CodeDomProvider dom_provider = (CodeDomProvider) Activator.CreateInstance (ctype, null);

			AssemblyBuilder abuilder = new AssemblyBuilder (virtualPath, dom_provider);
			provider.SetVirtualPath (virtualPath);
			provider.GenerateCode (abuilder);
			return abuilder;
		}

		public static string GetCompiledCustomString (string virtualPath)
		{
			BuildProvider provider = GetBuildProviderForPath (virtualPath, false);
			if (provider == null)
				return null;
			// FIXME: where to get the CompilerResults from?
			return provider.GetCustomString (null);
		}

		static CompilerParameters PrepareParameters (TempFileCollection temp_files,
								string virtualPath,
								CompilerParameters base_params)
		{
			CompilerParameters res = new CompilerParameters ();
			res.TempFiles = temp_files;
			res.CompilerOptions = base_params.CompilerOptions;
			res.IncludeDebugInformation = base_params.IncludeDebugInformation;
			res.TreatWarningsAsErrors = base_params.TreatWarningsAsErrors;
			res.WarningLevel = base_params.WarningLevel;
			string dllfilename = Path.GetFileName (temp_files.AddExtension ("dll", true));
			res.OutputAssembly = Path.Combine (temp_files.TempDir, dllfilename);
			return res;
		}

		public static Type GetCompiledType (string virtualPath)
		{
			BuildProvider provider;
			CompilerParameters parameters;

			AssemblyBuilder abuilder = GetAssemblyBuilder (virtualPath, out provider);
			CompilerType ctype = provider.CodeCompilerType;
			parameters = PrepareParameters (abuilder.TempFiles, virtualPath, ctype.CompilerParameters);
			CompilerResults results = abuilder.BuildAssembly (virtualPath, parameters);
			return provider.GetGeneratedType (results);
		}

		// The 2 GetType() overloads work on the global.asax, App_GlobalResources, App_WebReferences or App_Browsers
		public static Type GetType (string typeName, bool throwOnError)
		{
			return GetType (typeName, throwOnError, false);
		}

		public static Type GetType (string typeName, bool throwOnError, bool ignoreCase)
		{
			Type ret = null;
			try {
				foreach (Assembly asm in TopLevel_Assemblies) {
					ret = asm.GetType (typeName, throwOnError, ignoreCase);
					if (ret != null)
						break;
				}
			} catch (Exception ex) {
				throw new HttpException ("Failed to find the specified type.", ex);
			}
			return ret;
		}

		internal static ICollection GetVirtualPathDependencies (string virtualPath, BuildProvider bprovider)
		{
			BuildProvider provider = bprovider;
			if (provider == null)
				provider = GetBuildProviderForPath (virtualPath, false);
			if (provider == null)
				return null;
			return provider.VirtualPathDependencies;
		}
		
		public static ICollection GetVirtualPathDependencies (string virtualPath)
		{
			return GetVirtualPathDependencies (virtualPath, null);
		}

		// Assemblies built from the App_Code directory
		public static IList CodeAssemblies {
			get { return AppCode_Assemblies; }
		}

		internal static IList TopLevelAssemblies {
			get { return TopLevel_Assemblies; }
		}

		internal static bool HaveResources {
			get { return haveResources; }
			set { haveResources = value; }
		}
	}
}

#endif