using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Omika.Core.Configuration;
using Omika.Core.Contracts.Mobile.Languages;
using Omika.Core.Services.Mobile;

namespace Omika.Tests.Mobile;

/// <summary>
/// Tests du service de téléchargement des modèles de langue (ONNX).
/// Vérifie le chargement du manifeste, le remplissage des URLs relatives et la
/// résolution de fichiers avec protection anti path traversal.
/// </summary>
public class LanguageModelServiceTests
{
    [Fact]
    public async Task GetManifest_Absent_RetourneNull()
    {
        string root = CreateRoot();
        try
        {
            var service = CreateService(root);

            var result = await service.GetManifestAsync();

            Assert.Null(result);
        }
        finally
        {
            Directory.Delete(root, true);
        }
    }

    [Fact]
    public async Task GetManifest_Present_RemplitUrlsRelatives()
    {
        string root = CreateRoot();
        try
        {
            string manifest = """
                {
                  "packs": [
                    {
                      "code": "es",
                      "libelle": "Espagnol",
                      "version": "1.0.0",
                      "fichiers": [
                        { "sens": "versFrancais", "nomFichier": "encoder.onnx", "tailleOctets": 123, "sha256": "abc" }
                      ]
                    }
                  ]
                }
                """;
            await File.WriteAllTextAsync(Path.Combine(root, "manifest.json"), manifest);
            var service = CreateService(root);

            var result = await service.GetManifestAsync();

            Assert.NotNull(result);
            var pack = Assert.Single(result.Packs);
            Assert.Equal("es", pack.Code);
            Assert.Equal("Espagnol", pack.Libelle);
            Assert.Equal("1.0.0", pack.Version);
            var fichier = Assert.Single(pack.Fichiers);
            Assert.Equal("/api/langues/es/versFrancais/encoder.onnx", fichier.Url);
        }
        finally
        {
            Directory.Delete(root, true);
        }
    }

    [Fact]
    public async Task ResolveFile_Existant_RetourneCheminEtContenu()
    {
        string root = CreateRoot();
        try
        {
            string dir = Path.Combine(root, "es", "versFrancais");
            Directory.CreateDirectory(dir);
            await File.WriteAllTextAsync(Path.Combine(dir, "encoder.onnx"), "fake-model");
            var service = CreateService(root);

            var result = await service.ResolveFileAsync("es", "versFrancais", "encoder.onnx");

            Assert.NotNull(result);
            Assert.Equal("encoder.onnx", result.FileName);
            Assert.Equal("application/octet-stream", result.ContentType);
            Assert.Equal("fake-model", await File.ReadAllTextAsync(result.FullPath));
        }
        finally
        {
            Directory.Delete(root, true);
        }
    }

    [Fact]
    public async Task ResolveFile_RootPathVide_RetombeSurDossierApplication()
    {
        // Une RootPath vide (section « Langues:RootPath » laissée vide) ne doit pas
        // résoudre relativement au répertoire de travail courant (System32 en service
        // Windows), mais relativement au dossier de l'application.
        var service = new LanguageModelService(
            Options.Create(new LanguageModelOptions { RootPath = "", ManifestFileName = "manifest.json" }),
            NullLogger<LanguageModelService>.Instance);

        // Sans manifeste ni fichier, le service doit retourner null (pas de throw),
        // ce qui prouve qu'il a bien utilisé un dossier de repli déterministe.
        var manifest = await service.GetManifestAsync();
        var fichier = await service.ResolveFileAsync("es", "versFrancais", "encoder.onnx");

        Assert.Null(manifest);
        Assert.Null(fichier);
    }

    [Fact]
    public async Task ResolveFile_Introuvable_RetourneNull()
    {
        string root = CreateRoot();
        try
        {
            var service = CreateService(root);

            var result = await service.ResolveFileAsync("es", "versFrancais", "absent.onnx");

            Assert.Null(result);
        }
        finally
        {
            Directory.Delete(root, true);
        }
    }

    [Fact]
    public async Task ResolveFile_CodeLangueTraversal_RetourneNull()
    {
        string root = CreateRoot();
        try
        {
            var service = CreateService(root);

            // Segment « .. » ou contenant un séparateur → rejeté avant toute résolution.
            var result = await service.ResolveFileAsync("..", "versFrancais", "encoder.onnx");

            Assert.Null(result);
        }
        finally
        {
            Directory.Delete(root, true);
        }
    }

    [Fact]
    public async Task ResolveFile_SensInvalide_RetourneNull()
    {
        string root = CreateRoot();
        try
        {
            var service = CreateService(root);

            var result = await service.ResolveFileAsync("es", "../depuisFrancais", "encoder.onnx");

            Assert.Null(result);
        }
        finally
        {
            Directory.Delete(root, true);
        }
    }

    [Fact]
    public async Task ResolveFile_FichierHorsRacine_RetourneNull()
    {
        string root = CreateRoot();
        string sibling = CreateRoot();
        try
        {
            await File.WriteAllTextAsync(Path.Combine(sibling, "secret.txt"), "secret");
            var service = CreateService(root);

            // Un nom de fichier portant des segments « .. » est réduit au nom seul :
            // il ne peut jamais remonter hors de la racine configurée.
            var result = await service.ResolveFileAsync("es", "versFrancais", "..\\..\\secret.txt");

            Assert.Null(result);
        }
        finally
        {
            Directory.Delete(root, true);
            Directory.Delete(sibling, true);
        }
    }

    private static string CreateRoot()
    {
        string root = Path.Combine(Path.GetTempPath(), "omika-langues-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(root);
        return root;
    }

    private static LanguageModelService CreateService(string root)
        => new(
            Options.Create(new LanguageModelOptions { RootPath = root, ManifestFileName = "manifest.json" }),
            NullLogger<LanguageModelService>.Instance);
}