// Copyright (c) .NET Foundation and contributors. All rights reserved.

// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;

using System.Collections.Generic;

using System.CommandLine;

using System.CommandLine.Builder;

using System.CommandLine.Invocation;

using System.CommandLine.Parsing;

using System.IO;

using System.Linq;

using System.Reflection;

using Newtonsoft.Json;

namespace MLS.WasmCodeRunner

{

public class CodeRunner

{

int sequence = -1;

public InteropMessage<WasmCodeRunnerResponse> ProcessRunRequest(string message)

{

var messageObject = JsonConvert.DeserializeObject<InteropMessage<WasmCodeRunnerRequest>>(message);

if (messageObject.Sequence > this.sequence)

{

this.sequence = messageObject.Sequence;

}

else

{

return null;

}

if (messageObject.Data.Base64Assembly == null && messageObject.Data.Diagnostics == null)

{

// Something was posted that wasn't meant for us

return null;

}

var sequence = messageObject.Sequence;

var runRequest = messageObject.Data;

if (runRequest.Succeeded)

{

return ExecuteRunRequest(runRequest, sequence);

}

var diagnostics = runRequest.Diagnostics.Select(d => d.Message);

return new InteropMessage<WasmCodeRunnerResponse>(sequence, new WasmCodeRunnerResponse(false, null, diagnostics.ToArray(), null, null));

}

public InteropMessage<WasmCodeRunnerResponse> ExecuteRunRequest(WasmCodeRunnerRequest runRequest, int sequence)

{

var output = new List<string>();

string runnerException = null;

var bytes = Convert.FromBase64String(runRequest.Base64Assembly);

var stdOut = new StringWriter();

var stdError = new StringWriter();

using (var consoleState = new PreserveConsoleState())

{

MethodInfo main;

try

{

var assembly = Assembly.Load(bytes);

Console.SetOut(stdOut);

Console.SetError(stdError);

main = EntryPointDiscoverer.FindStaticEntryMethod(assembly);

}

catch (InvalidProgramException)

{

var result = new WasmCodeRunnerResponse(succeeded: false, exception: null,

output: new[] { "error CS5001: Program does not contain a static 'Main' method suitable for an entry point" },

diagnostics: Array.Empty<SerializableDiagnostic>(),

runnerException: null);

return new InteropMessage<WasmCodeRunnerResponse>(sequence, result);

}

try

{

var args = runRequest.RunArgs;

var builder = new CommandLineBuilder()

.ConfigureRootCommandFromMethod(main);

var parser = builder.Build();

parser.InvokeAsync(args).GetAwaiter().GetResult();

}

catch (Exception e)

{

if ((e.InnerException ?? e) is TypeLoadException t)

{

runnerException = $"Missing type `{t.TypeName}`";

}

if ((e.InnerException ?? e) is MissingMethodException m)

{

runnerException = $"Missing method `{m.Message}`";

}

if ((e.InnerException ?? e) is FileNotFoundException f)

{

runnerException = $"Missing file: `{f.FileName}`";

}

output.AddRange(SplitOnNewlines(e.ToString()));

}

var errors = stdError.ToString();

if (!string.IsNullOrWhiteSpace(errors))

{

runnerException = errors;

output.AddRange(SplitOnNewlines(errors));

}

output.AddRange(SplitOnNewlines(stdOut.ToString()));

var rb = new WasmCodeRunnerResponse(

succeeded: true,

exception: null,

output: output.ToArray(),

diagnostics: null,

runnerException: runnerException);

return new InteropMessage<WasmCodeRunnerResponse>(sequence, rb);

}

}

private IEnumerable<string> SplitOnNewlines(string str)

{

str = str.Replace("\r\n", "\n");

return str.Split('\n');

}

}

}