using System.Text.Json;
using Omika.Core.Observability;
using Omika.Core.Observability.Diagnostic;

namespace Omika.Tests.Observability.Diagnostic;

public class LocalFileTelemetryExporterTests : IDisposable
{
    private readonly string _dir = DiagnosticTestHarness.CreateTempDirectory();

    [Fact]
    public async Task Export_WritesValidJsonLine()
    {
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = _dir });

        await exporter.ExportAsync([Event()]);
        await exporter.DisposeAsync();

        string file = Assert.Single(Directory.EnumerateFiles(_dir, "*.jsonl"));
        string[] lines = File.ReadAllLines(file);
        Assert.Single(lines);

        using JsonDocument doc = JsonDocument.Parse(lines[0]);
        Assert.Equal("OMK-MOB-APP-001", doc.RootElement.GetProperty("eventCode").GetString());
        Assert.Equal("INFO", doc.RootElement.GetProperty("level").GetString());
        Assert.Equal("P3", doc.RootElement.GetProperty("priority").GetString());
    }

    [Fact]
    public async Task Export_PreservesFrenchAccents()
    {
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = _dir });
        var e = new TelemetryEvent
        {
            EventCode = TelemetryEventCodes.MobileAppStarted,
            Component = "échec-créé-démarré-télémétrie"
        };

        await exporter.ExportAsync([e]);
        await exporter.DisposeAsync();

        string content = File.ReadAllText(Assert.Single(Directory.EnumerateFiles(_dir, "*.jsonl")));
        Assert.Contains("échec", content);
        Assert.Contains("créé", content);
        Assert.Contains("démarré", content);
        Assert.Contains("télémétrie", content);
    }

    [Fact]
    public async Task Export_SerializesUsageAndDeviceDimensions()
    {
        // T17-B/T18 : le fichier local doit porter appBuild, dimensions d'écran et
        // usage fonctionnel (screenCode/featureCode), alignés sur le DTO transport.
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = _dir });
        var e = new TelemetryEvent
        {
            EventCode = TelemetryEventCodes.MobileScreenView,
            Component = "Navigation",
            AppBuild = "1",
            ScreenWidth = 1220,
            ScreenHeight = 2712,
            LogicalWidth = 375,
            LogicalHeight = 834,
            DisplayScale = 3.25,
            ScreenCode = DiagnosticScreenCodes.SiteDetail,
            FeatureCode = DiagnosticFeatureCodes.ReportGenerate
        };

        await exporter.ExportAsync([e]);
        await exporter.DisposeAsync();

        using JsonDocument doc = JsonDocument.Parse(
            File.ReadAllLines(Assert.Single(Directory.EnumerateFiles(_dir, "*.jsonl")))[0]);
        Assert.Equal("1", doc.RootElement.GetProperty("appBuild").GetString());
        Assert.Equal(1220, doc.RootElement.GetProperty("screenWidth").GetInt32());
        Assert.Equal(2712, doc.RootElement.GetProperty("screenHeight").GetInt32());
        Assert.Equal(DiagnosticScreenCodes.SiteDetail, doc.RootElement.GetProperty("screenCode").GetString());
        Assert.Equal(DiagnosticFeatureCodes.ReportGenerate, doc.RootElement.GetProperty("featureCode").GetString());
    }

    [Fact]
    public async Task Export_SerializesExceptionDetail()
    {
        // Phase 6 : le fichier local (joint à l'email support) porte le détail
        // d'exception (message/type/stack trace), aligné sur le DTO transport.
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = _dir });
        var e = new DiagnosticEvent
        {
            EventCode = TelemetryEventCodes.MobileHandledException,
            Message = "Échec d'écriture",
            ExceptionType = "System.IO.IOException",
            StackTrace = "at Omika.App.Services.SyncEngine.Run()"
        };

        await exporter.ExportAsync([e]);
        await exporter.DisposeAsync();

        using JsonDocument doc = JsonDocument.Parse(
            File.ReadAllLines(Assert.Single(Directory.EnumerateFiles(_dir, "*.jsonl")))[0]);
        Assert.Equal("Échec d'écriture", doc.RootElement.GetProperty("message").GetString());
        Assert.Equal("System.IO.IOException", doc.RootElement.GetProperty("exceptionType").GetString());
        Assert.Equal("at Omika.App.Services.SyncEngine.Run()", doc.RootElement.GetProperty("stackTrace").GetString());
    }

    [Fact]
    public async Task ActiveExporter_AllowsConcurrentRead_CompleteJsonLines()
    {
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = _dir });

        // L'exporteur reste ACTIF (fichier ouvert en écriture, FileShare.Read).
        await exporter.ExportAsync([Event(), Event()]);
        string file = Assert.Single(Directory.EnumerateFiles(_dir, "*.jsonl"));

        // Lecture concurrente : FileShare.ReadWrite (le writer autorise la lecture).
        // File.ReadAllText (FileShare.Read) échouerait ici avec « used by another process ».
        using var stream = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
        using var reader = new StreamReader(stream);
        string content = reader.ReadToEnd();

        // Le JSONL lu est exploitable : deux lignes JSON complètes, aucune demi-ligne.
        string[] lines = content.Split('\n', StringSplitOptions.RemoveEmptyEntries);
        Assert.Equal(2, lines.Length);
        foreach (string line in lines)
        {
            using JsonDocument doc = JsonDocument.Parse(line);
            Assert.Equal("OMK-MOB-APP-001", doc.RootElement.GetProperty("eventCode").GetString());
        }

        await exporter.DisposeAsync();
    }

    [Fact]
    public async Task Rotation_WhenSizeExceeded()
    {
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions
        {
            Directory = _dir,
            MaxFileSizeBytes = 300,
            MaxFiles = 20
        });

        for (int i = 0; i < 20; i++)
        {
            await exporter.ExportAsync([Event()]);
        }

        await exporter.DisposeAsync();

        Assert.True(Directory.EnumerateFiles(_dir, "*.jsonl").Count() >= 2);
    }

    [Fact]
    public async Task MaxFiles_IsEnforced()
    {
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions
        {
            Directory = _dir,
            MaxFileSizeBytes = 100,
            MaxFiles = 3
        });

        for (int i = 0; i < 50; i++)
        {
            await exporter.ExportAsync([Event()]);
        }

        await exporter.DisposeAsync();

        Assert.True(Directory.EnumerateFiles(_dir, "*.jsonl").Count() <= 3);
    }

    [Fact]
    public async Task InaccessibleDirectory_DoesNotThrow()
    {
        // Un FICHIER existant utilisé comme dossier → Directory.CreateDirectory échoue.
        string fileAsDirectory = Path.Combine(_dir, "not-a-dir");
        File.WriteAllText(fileAsDirectory, "x");

        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = fileAsDirectory });

        await exporter.ExportAsync([Event()]);
        await exporter.DisposeAsync();
    }

    [Fact]
    public async Task EmptyDirectory_NoFileCreated()
    {
        var exporter = new LocalFileTelemetryExporter(new LocalDiagnosticOptions { Directory = string.Empty });

        await exporter.ExportAsync([Event()]);
        await exporter.DisposeAsync();

        Assert.Empty(Directory.EnumerateFiles(_dir, "*.jsonl"));
    }

    private static OmikaEvent Event() => new TelemetryEvent { EventCode = TelemetryEventCodes.MobileAppStarted };

    public void Dispose() => DiagnosticTestHarness.DeleteDirectory(_dir);
}