﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#nullable disable

using System;
using System.IO;
using System.Runtime.InteropServices;
using Microsoft.CodeAnalysis;
using Microsoft.VisualStudio.LanguageServices.Implementation.CodeModel.ExternalElements;
using Microsoft.VisualStudio.LanguageServices.Implementation.Interop;
using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
using Microsoft.VisualStudio.LanguageServices.Implementation.Utilities;
using Roslyn.Utilities;

namespace Microsoft.VisualStudio.LanguageServices.Implementation.CodeModel
{
    [ComVisible(true)]
    [ComDefaultInterface(typeof(EnvDTE.CodeModel))]
    public sealed class RootCodeModel : AbstractCodeModelObject, ICodeElementContainer<AbstractExternalCodeElement>, EnvDTE.CodeModel, EnvDTE80.CodeModel2
    {
        internal static EnvDTE.CodeModel Create(CodeModelState state, EnvDTE.Project parent, ProjectId projectId)
        {
            var rootCodeModel = new RootCodeModel(state, parent, projectId);
            return (EnvDTE.CodeModel)ComAggregate.CreateAggregatedObject(rootCodeModel);
        }

        private readonly ParentHandle<EnvDTE.Project> _parentHandle;
        private readonly ProjectId _projectId;

        private RootCodeModel(CodeModelState state, EnvDTE.Project parent, ProjectId projectId)
            : base(state)
        {
            _parentHandle = new ParentHandle<EnvDTE.Project>(parent);
            _projectId = projectId;
        }

        private Project GetProject()
            => Workspace.CurrentSolution.GetProject(_projectId);

        private Compilation GetCompilation()
            => GetProject().GetCompilationAsync().Result;

        private ComHandle<EnvDTE80.FileCodeModel2, FileCodeModel> GetFileCodeModel(object location)
        {
            if (location is string locationString)
            {
                var vsProject = _parentHandle.Value;
                var vsProjectItems = vsProject.ProjectItems;

                if (vsProjectItems == null)
                {
                    throw Exceptions.ThrowEFail();
                }

                var project = GetProject();
                var projectDirectory = Path.GetDirectoryName(project.FilePath);
                var absoluteFilePath = Path.GetFullPath(Path.Combine(projectDirectory, locationString));

                var foundFile = false;
                foreach (var documentId in project.DocumentIds)
                {
                    var document = project.GetDocument(documentId);
                    if (document.FilePath != null && string.Equals(absoluteFilePath, document.FilePath, StringComparison.OrdinalIgnoreCase))
                    {
                        foundFile = true;
                        break;
                    }
                }

                if (!foundFile)
                {
                    // File doesn't belong to the project, prepare & add it to project
                    using (FileUtilities.CreateFileStreamChecked(File.Create, absoluteFilePath))
                    {
                        // Note: We just want to create an empty file here, so we immediately close it.
                    }

                    vsProjectItems.AddFromFile(absoluteFilePath);
                }

                return this.State.ProjectCodeModelFactory.GetProjectCodeModel(_projectId).GetOrCreateFileCodeModel(absoluteFilePath);
            }

            throw Exceptions.ThrowEInvalidArg();
        }

        public EnvDTE.Project Parent
        {
            get { return _parentHandle.Value; }
        }

        public bool IsCaseSensitive
        {
            get { return SyntaxFactsService.IsCaseSensitive; }
        }

        public EnvDTE.CodeAttribute AddAttribute(string name, object location, string value, object position)
            => GetFileCodeModel(location).Object.AddAttribute(name, value, position);

        public EnvDTE.CodeClass AddClass(string name, object location, object position, object bases, object implementedInterfaces, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddClass(name, position, bases, implementedInterfaces, access);

        public EnvDTE.CodeDelegate AddDelegate(string name, object location, object type, object position, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddDelegate(name, type, position, access);

        public EnvDTE.CodeEnum AddEnum(string name, object location, object position, object bases, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddEnum(name, position, bases, access);

        public EnvDTE.CodeFunction AddFunction(string name, object location, EnvDTE.vsCMFunction kind, object type, object position, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddFunction(name, kind, type, position, access);

        public EnvDTE.CodeInterface AddInterface(string name, object location, object position, object bases, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddInterface(name, position, bases, access);

        public EnvDTE.CodeNamespace AddNamespace(string name, object location, object position)
            => GetFileCodeModel(location).Object.AddNamespace(name, position);

        public EnvDTE.CodeStruct AddStruct(string name, object location, object position, object bases, object implementedInterfaces, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddStruct(name, position, bases, implementedInterfaces, access);

        public EnvDTE.CodeVariable AddVariable(string name, object location, object type, object position, EnvDTE.vsCMAccess access)
            => GetFileCodeModel(location).Object.AddVariable(name, type, position, access);

        EnvDTE.CodeElements ICodeElementContainer<AbstractExternalCodeElement>.GetCollection()
            => CodeElements;

        public EnvDTE.CodeElements CodeElements
        {
            get
            {
                var compilation = GetCompilation();
                var rootNamespace = ExternalCodeNamespace.Create(this.State, _projectId, compilation.GlobalNamespace);
                return rootNamespace.Members;
            }
        }

        public EnvDTE.CodeType CodeTypeFromFullName(string name)
        {
            var compilation = GetCompilation();
            var typeSymbol = CodeModelService.GetTypeSymbolFromFullName(name, compilation);
            if (typeSymbol == null ||
                typeSymbol.TypeKind == TypeKind.Error ||
                typeSymbol.TypeKind == TypeKind.Unknown)
            {
                return null;
            }

            return (EnvDTE.CodeType)CodeModelService.CreateCodeType(this.State, _projectId, typeSymbol);
        }

        public EnvDTE.CodeTypeRef CreateCodeTypeRef(object type)
            => CodeModelService.CreateCodeTypeRef(this.State, _projectId, type);

        public bool IsValidID(string name)
            => SyntaxFactsService.IsValidIdentifier(name);

        public void Remove(object element)
            => throw Exceptions.ThrowENotImpl();

        public string DotNetNameFromLanguageSpecific(string languageName)
        {
            var compilation = GetCompilation();
            var typeSymbol = CodeModelService.GetTypeSymbolFromFullName(languageName, compilation);
            if (typeSymbol == null)
            {
                throw Exceptions.ThrowEInvalidArg();
            }

            return MetadataNameHelpers.GetMetadataName(typeSymbol);
        }

        public EnvDTE.CodeElement ElementFromID(string id)
            => throw Exceptions.ThrowENotImpl();

        public string LanguageSpecificNameFromDotNet(string dotNetName)
        {
            // VB implemented this but C# never did. Does it matter?
            throw Exceptions.ThrowENotImpl();
        }

        public void Synchronize()
            => throw Exceptions.ThrowENotImpl();
    }
}
