// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;

namespace System.CodeDom.Compiler
{
    public static class Executor
    {
        private const int ProcessTimeOut = 600000;

        private static FileStream CreateInheritedFile(string file) =>
            new FileStream(file, FileMode.CreateNew, FileAccess.Write, FileShare.Read | FileShare.Inheritable);

        public static void ExecWait(string cmd, TempFileCollection tempFiles)
        {
            string outputName = null, errorName = null;
            ExecWaitWithCapture(cmd, tempFiles, ref outputName, ref errorName);
        }

        public static int ExecWaitWithCapture(IntPtr userToken, string cmd, TempFileCollection tempFiles, ref string outputName, ref string errorName) =>
            ExecWaitWithCapture(userToken, cmd, Environment.CurrentDirectory, tempFiles, ref outputName, ref errorName);

        public static int ExecWaitWithCapture(string cmd, string currentDir, TempFileCollection tempFiles, ref string outputName, ref string errorName) =>
            ExecWaitWithCapture(IntPtr.Zero, cmd, currentDir, tempFiles, ref outputName, ref errorName);

        public static int ExecWaitWithCapture(string cmd, TempFileCollection tempFiles, ref string outputName, ref string errorName) =>
            ExecWaitWithCapture(IntPtr.Zero, cmd, Environment.CurrentDirectory, tempFiles, ref outputName, ref errorName);

        public static int ExecWaitWithCapture(IntPtr userToken, string cmd, string currentDir, TempFileCollection tempFiles, ref string outputName, ref string errorName)
        {
            if (userToken != IntPtr.Zero)
            {
                throw new PlatformNotSupportedException();
            }

            if (string.IsNullOrEmpty(outputName))
            {
                outputName = tempFiles.AddExtension("out");
            }

            if (string.IsNullOrEmpty(errorName))
            {
                errorName = tempFiles.AddExtension("err");
            }

            using (var outputWriter = new StreamWriter(CreateInheritedFile(outputName), Encoding.UTF8))
            using (var errorWriter = new StreamWriter(CreateInheritedFile(errorName), Encoding.UTF8))
            {
                // Output the command line...
                outputWriter.Write(currentDir);
                outputWriter.Write("> ");
                outputWriter.WriteLine(cmd);
                outputWriter.WriteLine();
                outputWriter.WriteLine();

                var psi = new ProcessStartInfo(cmd)
                {
                    WorkingDirectory = currentDir,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true
                };

                using (Process p = Process.Start(psi))
                {
                    p.OutputDataReceived += (s, e) =>
                    {
                        if (e.Data != null)
                        {
                            outputWriter.WriteLine(e.Data);
                        }
                    };
                    p.ErrorDataReceived += (s, e) =>
                    {
                        if (e.Data != null)
                        {
                            errorWriter.WriteLine(e.Data);
                        }
                    };

                    p.BeginOutputReadLine();
                    p.BeginErrorReadLine();

                    if (!p.WaitForExit(ProcessTimeOut))
                    {
                        const int WAIT_TIMEOUT = 0x102;
                        throw new ExternalException(SR.Format(SR.ExecTimeout, cmd), WAIT_TIMEOUT);
                    }

                    p.WaitForExit();

                    return p.ExitCode;
                }
            }
        }
    }
}