#region license
// Copyright (c) 2004, Rodrigo B. de Oliveira (rbo@acm.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//     * Neither the name of Rodrigo B. de Oliveira nor the names of its
//     contributors may be used to endorse or promote products derived from this
//     software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion

namespace Boo.Lang.Compiler.Steps
{
	using Boo.Lang.Compiler;
	using Boo.Lang.Compiler.Ast;
	using Boo.Lang.Compiler.TypeSystem;
	using System;
	using System.Reflection;
	using System.Collections;
	
	public class InitializeNameResolutionService : AbstractVisitorCompilerStep
	{
		public InitializeNameResolutionService()
		{
		}
		
		override public void Run()
		{
			NameResolutionService.GlobalNamespace = new GlobalNamespace();
			
			ResolveImportAssemblyReferences();
			
			OrganizeExternalNamespaces();
			ResolveInternalModules();
		}
		
		void ResolveInternalModules()
		{
			foreach (Boo.Lang.Compiler.Ast.Module module in CompileUnit.Modules)
			{
				TypeSystem.ModuleEntity moduleEntity = new TypeSystem.ModuleEntity(NameResolutionService, TypeSystemServices, module);
				module.Entity = moduleEntity;
				
				NamespaceDeclaration namespaceDeclaration = module.Namespace;
				if (null != namespaceDeclaration)
				{
					module.Imports.Add(new Import(namespaceDeclaration.LexicalInfo, namespaceDeclaration.Name));
				}
				AddInternalModule(moduleEntity);
			}
			AddInternalModule((ModuleEntity) TypeSystemServices.GetCompilerGeneratedExtensionsModule().Entity);
		}

		private void AddInternalModule(ModuleEntity moduleEntity)
		{
			NameResolutionService.GetNamespace(moduleEntity.Namespace).AddModule(moduleEntity);
		}
		
		void ResolveImportAssemblyReferences()
		{
			foreach (Boo.Lang.Compiler.Ast.Module module in CompileUnit.Modules)
			{
				ImportCollection imports = module.Imports;
				Import[] importArray = imports.ToArray();
				for (int i=0; i<importArray.Length; ++i)
				{
					Import u = importArray[i];
					ReferenceExpression reference = u.AssemblyReference;
					if (null != reference)
					{
						try
						{
							Assembly asm = Parameters.FindAssembly(reference.Name);
							if (null == asm)
							{
								asm = Parameters.LoadAssembly(reference.Name);
								if (null != asm)
								{
									Parameters.AddAssembly(asm);
								}
							}
							reference.Entity = new TypeSystem.AssemblyReference(asm);
						}
						catch (Exception x)
						{
							Errors.Add(CompilerErrorFactory.UnableToLoadAssembly(reference, reference.Name, x));
							imports.RemoveAt(i);
						}
					}
				}
			}
		}
		
		void OrganizeExternalNamespaces()
		{
			foreach (Assembly asm in Parameters.References)
			{
				try
				{
					NameResolutionService.OrganizeAssemblyTypes(asm);
				}
				catch (ReflectionTypeLoadException x)
				{
					System.IO.StringWriter loadErrors = new System.IO.StringWriter();
					loadErrors.Write("'" + asm.FullName + "' - (" + GetLocation(asm) + "):");
					loadErrors.WriteLine(x.Message);
					foreach(Exception e in x.LoaderExceptions)
					{
						loadErrors.WriteLine(e.Message);
					}
					Errors.Add(
						CompilerErrorFactory.FailedToLoadTypesFromAssembly(
							loadErrors.ToString(), x));
				}
				catch (Exception x)
				{
					Errors.Add(
						CompilerErrorFactory.FailedToLoadTypesFromAssembly(
							"'" + asm.FullName + "' - (" + GetLocation(asm) + "): " + x.Message, x));
				}
			}
		}
		
		string GetLocation(Assembly asm)
		{
			try { return asm.Location; } catch (Exception /*ignored*/) {}
			return "location unavailable";
		}
	}
}
