using LehrerApp.Sync.Crypto;
using Xunit;

namespace LehrerApp.Sync.Tests;

public sealed class SyncKeyRecoveryServiceTests
{
    [Fact]
    public void CreateRecoveryFileUndRestoreFromFile_Roundtrip()
    {
        using var temp = new TempKeyFile();
        var originalKey = SyncCrypto.GenerateKey();
        var service = new SyncKeyRecoveryService(originalKey, temp.KeyPath);
        const string code = "TEST-CODE-4711";

        var fileContent = service.CreateRecoveryFile(code);
        // Ein zweites Gerät (anderer aktuell geladener Schlüssel) löst dieselbe Datei ein.
        var redeemer = new SyncKeyRecoveryService(SyncCrypto.GenerateKey(), temp.KeyPath);
        redeemer.RestoreFromFile(fileContent, code);

        Assert.Equal(originalKey, SyncCrypto.LoadKey(temp.KeyPath));
    }

    [Fact]
    public void RestoreFromFile_FalscherCode_WirftUndSchreibtKeyPathNicht()
    {
        using var temp = new TempKeyFile();
        var service = new SyncKeyRecoveryService(SyncCrypto.GenerateKey(), temp.KeyPath);
        var fileContent = service.CreateRecoveryFile("RICHTIGER-CODE");

        Assert.ThrowsAny<Exception>(() => service.RestoreFromFile(fileContent, "FALSCHER-CODE"));
        Assert.Null(SyncCrypto.LoadKey(temp.KeyPath));
    }

    [Fact]
    public void RestoreFromFile_UngueltigesDateiformat_WirftInvalidOperationException()
    {
        using var temp = new TempKeyFile();
        var service = new SyncKeyRecoveryService(SyncCrypto.GenerateKey(), temp.KeyPath);

        Assert.Throws<InvalidOperationException>(() => service.RestoreFromFile("{}", "IRGENDEIN-CODE"));
    }

    private sealed class TempKeyFile : IDisposable
    {
        private readonly string _directory = Path.Combine(
            Path.GetTempPath(), $"lehrerapp-synckeyrecovery-tests-{Guid.NewGuid():N}");
        public string KeyPath { get; }

        public TempKeyFile()
        {
            Directory.CreateDirectory(_directory);
            KeyPath = Path.Combine(_directory, "sync.key");
        }

        public void Dispose()
        {
            if (Directory.Exists(_directory)) Directory.Delete(_directory, recursive: true);
        }
    }
}