// 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.IO;
using System.Reflection.Metadata.Ecma335;
using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
using Microsoft.CodeAnalysis.Test.Utilities;
using Roslyn.Test.Utilities;
using Xunit;
 
namespace Microsoft.CodeAnalysis.Emit.UnitTests;
 
public class CompilationOutputsTests
{
    private class TestCompilationOutputs : CompilationOutputs
    {
        private readonly Func<Stream?>? _openAssemblyStream;
        private readonly Func<Stream?>? _openPdbStream;
 
        public TestCompilationOutputs(Func<Stream?>? openAssemblyStream = null, Func<Stream?>? openPdbStream = null)
        {
            _openAssemblyStream = openAssemblyStream;
            _openPdbStream = openPdbStream;
        }
 
        public override string AssemblyDisplayPath => "assembly";
        public override string PdbDisplayPath => "pdb";
        protected override Stream? OpenAssemblyStream() => (_openAssemblyStream ?? throw new NotImplementedException()).Invoke();
        protected override Stream? OpenPdbStream() => (_openPdbStream ?? throw new NotImplementedException()).Invoke();
    }
 
    [Theory]
    [InlineData(true, false)]
    [InlineData(false, true)]
    public void OpenStream_Errors(bool canRead, bool canSeek)
    {
        var outputs = new TestCompilationOutputs(
            openAssemblyStream: () => new TestStream(canRead, canSeek, canWrite: true),
            openPdbStream: () => new TestStream(canRead, canSeek, canWrite: true));
 
        Assert.Throws<InvalidOperationException>(() => outputs.OpenAssemblyMetadata(prefetch: false));
        Assert.Throws<InvalidOperationException>(() => outputs.OpenPdb());
    }
 
    [Theory]
    [InlineData(DebugInformationFormat.PortablePdb)]
    [InlineData(DebugInformationFormat.Embedded)]
    [InlineData(DebugInformationFormat.Pdb)]
    public void AssemblyAndPdb(DebugInformationFormat format)
    {
        var source = @"class C { public static void Main() { int x = 1; } }";
        var compilation = CSharpTestBase.CreateCompilationWithMscorlib40AndSystemCore(source, parseOptions: TestOptions.Regular.WithNoRefSafetyRulesAttribute(), options: TestOptions.DebugDll, assemblyName: "lib");
 
        var pdbStream = (format != DebugInformationFormat.Embedded) ? new MemoryStream() : null;
        var peImage = compilation.EmitToArray(new EmitOptions(debugInformationFormat: format), pdbStream: pdbStream);
 
        Stream? currentPEStream = null;
        Stream? currentPdbStream = null;
 
        var outputs = new TestCompilationOutputs(
            openAssemblyStream: () => currentPEStream = new MemoryStream([.. peImage]),
            openPdbStream: () =>
            {
                if (pdbStream == null)
                {
                    return null;
                }
 
                currentPdbStream = new MemoryStream();
                pdbStream.Position = 0;
                pdbStream.CopyTo(currentPdbStream);
                currentPdbStream.Position = 0;
                return currentPdbStream;
            });
 
        using (var pdb = outputs.OpenPdb())
        {
            var encReader = pdb!.CreateEditAndContinueMethodDebugInfoReader();
            Assert.Equal(format != DebugInformationFormat.Pdb, encReader.IsPortable);
            var localSig = encReader.GetLocalSignature(MetadataTokens.MethodDefinitionHandle(1));
            Assert.Equal(MetadataTokens.StandaloneSignatureHandle(1), localSig);
        }
 
        if (format == DebugInformationFormat.Embedded)
        {
            Assert.Throws<ObjectDisposedException>(() => currentPEStream!.Length);
        }
        else
        {
            Assert.Throws<ObjectDisposedException>(() => currentPdbStream!.Length);
        }
 
        using (var metadata = outputs.OpenAssemblyMetadata(prefetch: false))
        {
            Assert.NotEqual(0, currentPEStream!.Length);
 
            var mdReader = metadata!.GetMetadataReader();
            Assert.Equal("lib", mdReader.GetString(mdReader.GetAssemblyDefinition().Name));
        }
 
        Assert.Throws<ObjectDisposedException>(() => currentPEStream.Length);
 
        using (var metadata = outputs.OpenAssemblyMetadata(prefetch: true))
        {
            // the stream has been closed since we prefetched the metadata:
            Assert.Throws<ObjectDisposedException>(() => currentPEStream.Length);
 
            var mdReader = metadata!.GetMetadataReader();
            Assert.Equal("lib", mdReader.GetString(mdReader.GetAssemblyDefinition().Name));
        }
 
        Assert.NotEqual(Guid.Empty, outputs.ReadAssemblyModuleVersionId());
    }
 
    [Fact]
    public void ReadAssemblyModuleVersionId_NoAssembly()
    {
        var outputs = new TestCompilationOutputs(
            openAssemblyStream: () => null,
            openPdbStream: () => null);
 
        Assert.Equal(Guid.Empty, outputs.ReadAssemblyModuleVersionId());
    }
}