// 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.
 
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Test.Utilities;
using Roslyn.Test.Utilities;
using Roslyn.Utilities;
using Xunit;
using Xunit.Abstractions;
using Xunit.Sdk;
using Microsoft.CodeAnalysis.VisualBasic;
#if NET
using Roslyn.Test.Utilities.CoreClr;
using System.Runtime.Loader;
#else
using Roslyn.Test.Utilities.Desktop;
#endif
 
namespace Microsoft.CodeAnalysis.UnitTests
{
 
#if NET
 
    public sealed class InvokeUtil
    {
        internal void Exec(
            ITestOutputHelper testOutputHelper,
            ImmutableArray<IAnalyzerPathResolver> pathResolvers,
            ImmutableArray<IAnalyzerAssemblyResolver> assemblyResolvers,
            AssemblyLoadTestFixture fixture,
            AnalyzerTestKind kind,
            string typeName,
            string methodName,
            object? state = null)
        {
            using var tempRoot = new TempRoot();
            switch (kind)
            {
                case AnalyzerTestKind.LoadDirect:
                    assemblyResolvers = [.. assemblyResolvers, AnalyzerAssemblyLoader.DiskAnalyzerAssemblyResolver];
                    break;
                case AnalyzerTestKind.LoadStream:
                    assemblyResolvers = [.. assemblyResolvers, AnalyzerAssemblyLoader.StreamAnalyzerAssemblyResolver];
                    break;
                case AnalyzerTestKind.ShadowLoad:
                    pathResolvers = [.. pathResolvers, new ShadowCopyAnalyzerPathResolver(tempRoot.CreateDirectory().Path)];
                    assemblyResolvers = [.. assemblyResolvers, AnalyzerAssemblyLoader.DiskAnalyzerAssemblyResolver];
                    break;
                default:
                    throw ExceptionUtilities.Unreachable();
            }
 
            var loader = new AnalyzerAssemblyLoader(pathResolvers, assemblyResolvers, compilerLoadContext: null);
            var compilerContextAssemblyCount = loader.CompilerLoadContext.Assemblies.Count();
            try
            {
                Exec(testOutputHelper, fixture, loader, typeName, methodName, state);
            }
            finally
            {
                // When using the actual compiler load context (the one shared by all of our unit tests) the test
                // did not load any additional assemblies that could interfere with later tests.
                Assert.Equal(compilerContextAssemblyCount, loader.CompilerLoadContext.Assemblies.Count());
            }
        }
 
        internal void Exec(
            ITestOutputHelper testOutputHelper,
            AssemblyLoadTestFixture fixture,
            AnalyzerAssemblyLoader loader,
            string typeName,
            string methodName,
            object? state = null)
        {
            // Ensure that the test did not load any of the test fixture assemblies into 
            // the default load context. That should never happen. Assemblies should either 
            // load into the compiler or directory load context.
            //
            // Not only is this bad behavior it also pollutes future test results.
            var defaultContextCount = AssemblyLoadContext.Default.Assemblies.Count();
            using var tempRoot = new TempRoot();
 
            try
            {
                AnalyzerAssemblyLoaderTests.InvokeTestCode(loader, fixture, typeName, methodName, state);
            }
            finally
            {
                testOutputHelper.WriteLine($"Test fixture root: {fixture.TempDirectory}");
 
                foreach (var context in loader.GetDirectoryLoadContextsSnapshot())
                {
                    testOutputHelper.WriteLine($"Directory context: {context.Directory}");
                    foreach (var assembly in context.Assemblies)
                    {
                        testOutputHelper.WriteLine($"\t{assembly.FullName}");
                    }
                }
 
                if (loader.AnalyzerPathResolvers.OfType<ShadowCopyAnalyzerPathResolver>().FirstOrDefault() is { } shadowResolver)
                {
                    testOutputHelper.WriteLine($"{nameof(ShadowCopyAnalyzerPathResolver)}: {shadowResolver.BaseDirectory}");
                }
 
                testOutputHelper.WriteLine($"Loader path maps");
                foreach (var pair in loader.GetPathMapSnapshot())
                {
                    testOutputHelper.WriteLine($"\t{pair.OriginalAssemblyPath} -> {pair.ResolvedAssemblyPath}");
                }
 
                Assert.Equal(defaultContextCount, AssemblyLoadContext.Default.Assemblies.Count());
            }
        }
    }
 
#else

    public sealed class InvokeUtil : MarshalByRefObject
    {
        internal void Exec(
            ITestOutputHelper testOutputHelper,
            AssemblyLoadTestFixture fixture,
            AnalyzerTestKind kind,
            string typeName,
            string methodName,
            IAnalyzerPathResolver[] pathResolvers,
            object? state)
        {
            using var tempRoot = new TempRoot();
            pathResolvers = kind switch
            {
                AnalyzerTestKind.LoadDirect => pathResolvers,
                AnalyzerTestKind.ShadowLoad => [.. pathResolvers, new ShadowCopyAnalyzerPathResolver(tempRoot.CreateDirectory().Path)],
                _ => throw ExceptionUtilities.Unreachable(),
            };
 
            var loader = new AnalyzerAssemblyLoader(pathResolvers.ToImmutableArray());
 
            try
            {
                AnalyzerAssemblyLoaderTests.InvokeTestCode(loader, fixture, typeName, methodName, state);
            }
            catch (TargetInvocationException ex) when (ex.InnerException is XunitException)
            {
                var inner = ex.InnerException;
                throw new Exception(inner.Message + inner.StackTrace);
            }
            finally
            {
                testOutputHelper.WriteLine($"Test fixture root: {fixture.TempDirectory}");
 
                testOutputHelper.WriteLine($"Loaded Assemblies");
                foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies().OrderByDescending(x => x.FullName))
                {
                    testOutputHelper.WriteLine($"\t{assembly.FullName} -> {assembly.Location}");
                }
 
                if (loader.AnalyzerPathResolvers.OfType<ShadowCopyAnalyzerPathResolver>().FirstOrDefault() is { } shadowResolver)
                {
                    testOutputHelper.WriteLine($"{nameof(ShadowCopyAnalyzerPathResolver)}: {shadowResolver.BaseDirectory}");
                }
 
                testOutputHelper.WriteLine($"Loader path maps");
                foreach (var pair in loader.GetPathMapSnapshot())
                {
                    testOutputHelper.WriteLine($"\t{pair.OriginalAssemblyPath} -> {pair.ResolvedAssemblyPath}");
                }
            }
        }
    }
 
#endif
 
}