using GitConverter.Lib.Factories;
using GitConverter.Lib.Models;
using GitConverter.TestsApp.TestSupport;

namespace GitConverter.TestsApp.Converters
{
    /// <summary>
    /// Integration-style tests for CSV conversion flows.
    /// </summary>
    /// <remarks>
    /// Purpose
    /// - Exercise end-to-end CSV conversion using the real ConversionService and CsvConverter
    ///   against small sample files/archives placed under TestData\Csv.
    ///
    /// Behavior & expectations
    /// - Tests are defensive: they skip when no TestData is present so CI remains non-fatal.
    /// - For each sample the tests create isolated output and temp folders under a unique temp root.
    /// - When ConversionService or CsvConverter returns Success the test asserts that at least one file
    ///   was created inside the output folder. When the result is Failure the test asserts a non-empty
    ///   diagnostic message is present.
    ///
    /// Test data
    /// - Place representative, small CSV samples (or archives containing CSV) under TestData\Csv in the test project
    ///   and mark them with CopyToOutputDirectory=PreserveNewest so they are available at runtime via AppContext.BaseDirectory.
    ///
    /// Notes
    /// - Integration tests avoid asserting exact filenames; they verify that outputs exist. When asserting suffixes
    ///   prefer FileExtensionHelpers.FromOption(...) + ToDotExtension() to compute expectations.
    /// </remarks>
    [Collection("Integration")]
    public class CsvConverterIntegrationTests : IDisposable
    {
        private readonly string _root;

        public CsvConverterIntegrationTests()
        {
            _root = Path.Combine(Path.GetTempPath(), "GitConverter.CsvTests", Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(_root);
        }

        public void Dispose()
        {
            try { if (Directory.Exists(_root)) Directory.Delete(_root, true); } catch { }
        }

        private static string TestDataCsvFolder => IntegrationTestConstants.TestDataCsvFolder;


        /// <summary>
        /// Execute CSV conversion against the first available CSV sample found under the configured test data folder.
        /// </summary>
        /// <remarks>
        /// Preconditions:
        /// - Small CSV samples or archives must be present under <see cref="TestDataCsvFolder"/> and copied to test output.
        ///
        /// Test steps:
        /// 1. Locate the first *.csv file under the test data folder. If none exists the test is skipped (no failure).
        /// 2. Use <see cref="ConverterFactory"/> to resolve a converter for the input file. A failed detection is treated
        ///    as a test failure (indicates misconfiguration or regression in detection logic).
        /// 3. For each supported <c>target</c> option from <see cref="IntegrationTestConstants.TargetOptions"/>:
        ///    a. Create isolated output and temp directories under the per-test temp root.
        ///    b. Invoke the converter's <c>Convert</c> method with the input, target, output and temp paths.
        ///    c. On success (ConversionResult.IsSuccess == true) assert that one or more files were written to the output directory.
        ///    d. On failure assert that the returned <c>ConversionResult.Message</c> is non-empty and fail the test with that message.
        ///
        /// Cleanup:
        /// - Output and temp folders created for a target are deleted in a finally block to avoid leaving artifacts.
        ///
        /// Logging & diagnostics:
        /// - Converters emit diagnostics via the configured logging adapter; this test surface captures filesystem outputs
        ///   and conversion results to determine pass/fail.
        ///
        /// Determinism:
        /// - Tests deliberately do not assert on exact output filenames to remain resilient to implementation changes.
        /// - Sample artifacts should be small to keep tests fast and reliable in CI.
        /// </remarks>
        [Fact(DisplayName = "CsvConverter.Convert direct call against first CSV (if present)")]
        public void Convert_SingleCsv_ToAllTargetOptions()
        {
            if (!Directory.Exists(TestDataCsvFolder))
                return;

            var csvFile = Directory.EnumerateFiles(TestDataCsvFolder, "*.csv", SearchOption.TopDirectoryOnly).FirstOrDefault();
            if (csvFile == null)
                return;

            var factory = new ConverterFactory();

            foreach (var targetFormatOption in IntegrationTestConstants.TargetOptions)
            {
                var outDir = Path.Combine(_root, $"{Path.GetFileNameWithoutExtension(csvFile)}_{targetFormatOption}_out");
                var tempDir = Path.Combine(_root, $"{Path.GetFileNameWithoutExtension(csvFile)}_{targetFormatOption}_tmp");
                Directory.CreateDirectory(outDir);
                Directory.CreateDirectory(tempDir);

                try
                {
                    // Resolve a converter for the input; treat detection failure as a test failure.
                    if (!factory.TryCreateForInput(csvFile, out var converter, out var detectedSourceFormat, out var detectReason) || converter == null)
                    {
                        throw new Xunit.Sdk.XunitException($"Failed to detect converter for '{csvFile}': {detectReason ?? "<no reason>"}");
                    }

                    // Execute conversion
                    ConversionResult result = converter.Convert(csvFile, detectedSourceFormat, targetFormatOption, outDir, tempDir);

                    Assert.NotNull(result);
                    if (result.IsSuccess)
                    {
                        var files = Directory.EnumerateFiles(outDir, "*", SearchOption.AllDirectories).ToList();
                        Assert.True(files.Count > 0, $"No output files for target format option '{targetFormatOption}' when converting '{csvFile}'.");
                    }
                    else
                    {
                        // On failure ensure a diagnostic message is present and fail clearly.
                        Assert.False(string.IsNullOrWhiteSpace(result.Message), $"Conversion to '{targetFormatOption}' failed with empty message ({csvFile}).");
                        throw new Xunit.Sdk.XunitException($"Conversion to '{targetFormatOption}' failed: {result.Message ?? "<empty>"} ({csvFile}).");
                    }
                }
                finally
                {
                    try { if (Directory.Exists(outDir)) Directory.Delete(outDir, true); } catch { }
                    try { if (Directory.Exists(tempDir)) Directory.Delete(tempDir, true); } catch { }
                }
            }
        }
    }
}