// 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.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Text;
using Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim.Interop;
 
namespace Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim;
 
/// <summary>
/// An implementation a TempPE compiler that is called by the project system.
///
/// This class is free-threaded.
/// </summary>
internal sealed class TempPECompilerService : ICSharpTempPECompilerService
{
    private readonly IMetadataService _metadataService;
 
    public TempPECompilerService(IMetadataService metadataService)
        => _metadataService = metadataService;
 
    public int CompileTempPE(string pszOutputFileName, int sourceCount, string[] fileNames, string[] fileContents, int optionCount, string[] optionNames, object[] optionValues)
    {
        var baseDirectory = Path.GetDirectoryName(pszOutputFileName);
        var parsedArguments = ParseCommandLineArguments(baseDirectory, optionNames, optionValues);
 
        Contract.ThrowIfFalse(fileNames.Length == fileContents.Length);
 
        var trees = new List<SyntaxTree>(capacity: sourceCount);
 
        for (var i = 0; i < fileNames.Length; i++)
        {
            var sourceText = SourceText.From(fileContents[i], parsedArguments.Encoding, parsedArguments.ChecksumAlgorithm);
            trees.Add(SyntaxFactory.ParseSyntaxTree(sourceText, parsedArguments.ParseOptions, fileNames[i]));
        }
 
        // TODO (tomat): Revisit compilation options: app.config, strong name, search paths, etc? (bug #869604)
        // TODO (tomat): move resolver initialization (With* methods below) to CommandLineParser.Parse
 
        var metadataResolver = new WorkspaceMetadataFileReferenceResolver(
            _metadataService,
            new RelativePathResolver([], baseDirectory: null));
 
        var compilation = CSharpCompilation.Create(
            Path.GetFileName(pszOutputFileName),
            trees,
            parsedArguments.ResolveMetadataReferences(metadataResolver).Where(m => m is not UnresolvedMetadataReference),
            parsedArguments.CompilationOptions
                .WithAssemblyIdentityComparer(DesktopAssemblyIdentityComparer.Default)
                .WithSourceReferenceResolver(SourceFileResolver.Default)
                .WithXmlReferenceResolver(XmlFileResolver.Default)
                .WithMetadataReferenceResolver(metadataResolver));
 
        var result = compilation.Emit(pszOutputFileName);
 
        return result.Success ? VSConstants.S_OK : VSConstants.S_FALSE;
    }
 
    private static CSharpCommandLineArguments ParseCommandLineArguments(string baseDirectory, string[] optionNames, object[] optionValues)
    {
        Contract.ThrowIfFalse(optionNames.Length == optionValues.Length);
 
        var arguments = new List<string>();
 
        for (var i = 0; i < optionNames.Length; i++)
        {
            var optionName = optionNames[i];
            var optionValue = optionValues[i];
 
            if (optionName == "r")
            {
                // We get a pipe-delimited list of references, so split them back apart
                foreach (var reference in ((string)optionValue).Split(['|'], StringSplitOptions.RemoveEmptyEntries))
                {
                    arguments.Add(string.Format("/r:\"{0}\"", reference));
                }
            }
            else if (optionValue is bool)
            {
                if ((bool)optionValue)
                {
                    arguments.Add($"/{optionName}+");
                }
                else
                {
                    arguments.Add($"/{optionName}-");
                }
            }
            else
            {
                arguments.Add(string.Format("/{0}:{1}", optionName, optionValue));
            }
        }
 
        return CSharpCommandLineParser.Default.Parse(arguments, baseDirectory, RuntimeEnvironment.GetRuntimeDirectory());
    }
}