using System;
using System.IO;
using System.Linq;
using System.Text.Json;
using Xunit;

namespace GitConverter.TestsApp.ConsoleApp
{
    /// <summary>
    /// Tests that validate output file correctness, not just existence.
    /// Ensures converted files are valid and contain expected data.
    /// </summary>
    [Collection("Logging")]
    public class OutputValidationTests : IDisposable
    {
        private readonly TextWriter _originalOut;
        private readonly TextWriter _originalErr;
        private readonly StringWriter _outWriter;
        private readonly StringWriter _errWriter;
        private readonly string _tempRoot;

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

            _tempRoot = Path.Combine(Path.GetTempPath(), "GitConverter.ValidationTests", 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 = "CSV to GeoJSON produces valid JSON")]
        public void Run_CsvToGeoJson_ProducesValidJson()
        {
            var csvInput = Path.Combine(_tempRoot, "points.csv");
            File.WriteAllText(csvInput, "lon,lat,name\n-122.4,37.8,\"San Francisco\"\n-118.2,34.0,\"Los Angeles\"");

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

            var args = new[]
            {
                "gis_convert",
                csvInput,
                "GeoJson",
                outDir,
                tempDir,
                "unused"
            };

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

            if (exit != 0)
            {
                var output = _outWriter.ToString() + _errWriter.ToString();
                Assert.True(false, $"Conversion failed: {output}");
            }

            var outputFiles = Directory.GetFiles(outDir, "*.json", SearchOption.AllDirectories);
            Assert.NotEmpty(outputFiles);

            foreach (var file in outputFiles)
            {
                var json = File.ReadAllText(file);
                try
                {
                    var doc = JsonDocument.Parse(json);
                    Assert.True(doc.RootElement.TryGetProperty("type", out var typeElement));
                    var type = typeElement.GetString();
                    Assert.True(type == "FeatureCollection" || type == "Feature",
                        $"Expected GeoJSON type, got {type}");
                }
                catch (JsonException ex)
                {
                    Assert.True(false, $"Output file {file} is not valid JSON: {ex.Message}");
                }
            }
        }

        [Fact(DisplayName = "Output files are not empty")]
        public void Run_Conversion_OutputFilesNotEmpty()
        {
            var csvInput = Path.Combine(_tempRoot, "data.csv");
            File.WriteAllText(csvInput, "a,b,c\n1,2,3\n4,5,6");

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

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

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

            if (exit == 0)
            {
                var files = Directory.GetFiles(outDir, "*", SearchOption.AllDirectories);
                Assert.NotEmpty(files);

                foreach (var file in files)
                {
                    var info = new FileInfo(file);
                    Assert.True(info.Length > 0, $"Output file {file} is empty");
                }
            }
        }

        [Fact(DisplayName = "Unicode filenames are handled correctly")]
        public void Run_UnicodeFilename_HandledCorrectly()
        {
            var unicodeFilename = "שכבות_מידע.csv";
            var csvInput = Path.Combine(_tempRoot, unicodeFilename);
            File.WriteAllText(csvInput, "x,y\n1,2\n3,4");

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

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

            _outWriter.GetStringBuilder().Clear();
            _errWriter.GetStringBuilder().Clear();

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

            var output = _outWriter.ToString() + _errWriter.ToString();

            Assert.DoesNotContain("encoding", output.ToLowerInvariant());
            Assert.DoesNotContain("invalid", output.ToLowerInvariant());
        }

        [Fact(DisplayName = "Conversion preserves data integrity")]
        public void Run_CsvConversion_PreservesData()
        {
            var csvInput = Path.Combine(_tempRoot, "preserve.csv");
            var expectedData = "id,value\n1,test\n2,data";
            File.WriteAllText(csvInput, expectedData);

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

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

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

            if (exit == 0)
            {
                var outputFiles = Directory.GetFiles(outDir, "*.csv", SearchOption.AllDirectories);
                Assert.NotEmpty(outputFiles);

                foreach (var file in outputFiles)
                {
                    var content = File.ReadAllText(file);
                    Assert.Contains("id", content);
                    Assert.Contains("value", content);
                }
            }
        }
    }
}