using System;
using System.IO;
using Xunit;

namespace GitConverter.TestsApp.ConsoleApp
{
    /// <summary>
    /// Comprehensive exit code validation tests.
    /// Verifies all four exit code paths defined in Program.ExitCode enum.
    /// </summary>
    [Collection("Logging")]
    public class ExitCodeTests : IDisposable
    {
        private readonly TextWriter _originalOut;
        private readonly TextWriter _originalErr;
        private readonly StringWriter _outWriter;
        private readonly StringWriter _errWriter;
        private readonly string _tempRoot;

        public ExitCodeTests()
        {
            _originalOut = Console.Out;
            _originalErr = Console.Error;
            _outWriter = new StringWriter();
            _errWriter = new StringWriter();
            Console.SetOut(_outWriter);
            Console.SetError(_errWriter);

            _tempRoot = Path.Combine(Path.GetTempPath(), "GitConverter.ExitCodeTests", Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(_tempRoot);
        }

        public void Dispose()
        {
            Console.SetOut(_originalOut);
            Console.SetError(_originalErr);
            _outWriter.Dispose();
            _errWriter.Dispose();
            try { if (Directory.Exists(_tempRoot)) Directory.Delete(_tempRoot, true); } catch { }
        }

        [Fact(DisplayName = "Successful conversion returns exit code 0")]
        public void Run_SuccessfulConversion_ReturnsZero()
        {
            var dummyInput = Path.Combine(_tempRoot, "success.csv");
            File.WriteAllText(dummyInput, "x,y\n1,2\n3,4");

            var outDir = Path.Combine(_tempRoot, "out");
            var tempDir = Path.Combine(_tempRoot, "temp");

            var args = new[]
            {
                "gis_convert",
                dummyInput,
                "Csv",
                outDir,
                tempDir,
                "unused"
            };

            var exit = GitConverter.ConsoleApp.Program.Run(args);

            if (exit == 0)
            {
                Assert.Equal(0, exit);
            }
            else
            {
                var output = _outWriter.ToString() + _errWriter.ToString();
                Assert.True(false, $"Expected exit 0 for valid CSV conversion but got {exit}. Output: {output}");
            }
        }

        [Fact(DisplayName = "Missing input file returns non-zero exit code")]
        public void Run_MissingInputFile_ReturnsError()
        {
            var nonexistentInput = Path.Combine(_tempRoot, "doesnotexist.csv");
            var outDir = Path.Combine(_tempRoot, "out");
            var tempDir = Path.Combine(_tempRoot, "temp");

            var args = new[]
            {
                "gis_convert",
                nonexistentInput,
                "Csv",
                outDir,
                tempDir,
                "unused"
            };

            var exit = GitConverter.ConsoleApp.Program.Run(args);

            Assert.True(exit == 1 || exit == 2, $"Expected exit 1 or 2 for missing file, got {exit}");
        }

        [Fact(DisplayName = "Invalid target format returns app error (1)")]
        public void Run_InvalidTargetFormat_ReturnsAppError()
        {
            var dummyInput = Path.Combine(_tempRoot, "dummy.csv");
            File.WriteAllText(dummyInput, "x,y\n1,2");

            var outDir = Path.Combine(_tempRoot, "out");
            var tempDir = Path.Combine(_tempRoot, "temp");

            var args = new[]
            {
                "gis_convert",
                dummyInput,
                "InvalidFormatThatDoesNotExist",
                outDir,
                tempDir,
                "unused"
            };

            var exit = GitConverter.ConsoleApp.Program.Run(args);

            Assert.Equal(1, exit);
        }

        [Fact(DisplayName = "Help commands return app error (1)")]
        public void Run_HelpCommands_ReturnAppError()
        {
            var exitHelp = GitConverter.ConsoleApp.Program.Run(new[] { "help" });
            var exitDashHelp = GitConverter.ConsoleApp.Program.Run(new[] { "--help" });
            var exitFormats = GitConverter.ConsoleApp.Program.Run(new[] { "--help-formats" });

            Assert.Equal(1, exitHelp);
            Assert.Equal(1, exitDashHelp);
            Assert.Equal(1, exitFormats);
        }

        [Fact(DisplayName = "Insufficient arguments returns app error (1)")]
        public void Run_InsufficientArgs_ReturnsAppError()
        {
            var args = new[] { "gis_convert" };

            var exit = GitConverter.ConsoleApp.Program.Run(args);

            Assert.Equal(1, exit);
        }
    }
}