/*
Licence verification gate for the .NET 10 port (devdocs/modernization/NET10-PORT.md, section 0).

Runs every v8 row of Sockeye's alicense fixture through AyaNova's own License.Parse, by
reflection, so the production verification code is tested unchanged: signature, payload
extraction, JSON parse, build-date check (MExBB) and build-type check.

The fixture is customer data and stays outside the repo. Export it as described in
sockeye\sockeye.tests\ResignTests.cs. Format 1 rows are v7 keys and are not used here.

Set AYANOVA_LICENCE_GATE_OUT to a file path to also write "id outcome" lines (no key text),
so two builds can be diffed.

Tests reference AyaNova.csproj without SUBSCRIPTION_BUILD, so this is the perpetual build.
*/

using System.Reflection;
using Microsoft.Extensions.Logging.Abstractions;
using Newtonsoft.Json.Linq;

[assembly: CollectionBehavior(DisableTestParallelization = true)]

namespace ayanova.tests;

public record LicenceRow(long Id, int Format, string Key);

public static class LicenceFixture
{
    static readonly Lazy<Dictionary<long, LicenceRow>> _rows = new(Load);
    public static IReadOnlyDictionary<long, LicenceRow> V8Rows => _rows.Value;

    static Dictionary<long, LicenceRow> Load()
    {
        var path = "C:\\data\\sockeye-fixtures\\resign.json";
        if (!File.Exists(path))
            throw new InvalidOperationException($"Licence fixture not found at {path}. Export it as described in sockeye\\sockeye.tests\\ResignTests.cs.");

        var rows = System.Text.Json.JsonSerializer.Deserialize<List<LicenceRow>>(
            File.ReadAllText(path),
            new System.Text.Json.JsonSerializerOptions { PropertyNameCaseInsensitive = true });

        return rows.Where(r => r.Format != 1).ToDictionary(r => r.Id);
    }
}

// Reflection access to AyaNova's internal licence code
public static class AyaNovaLicence
{
    static readonly Assembly Asm = typeof(AyaNova.Program).Assembly;
    static readonly Type LicenseType = Asm.GetType("AyaNova.Core.License", true);
    static readonly Type FileUtilType = Asm.GetType("AyaNova.Util.FileUtil", true);
    static readonly MethodInfo ParseMethod = LicenseType.GetMethod("Parse", BindingFlags.NonPublic | BindingFlags.Static);
    static readonly MethodInfo MExBBMethod = LicenseType.GetMethod("MExBB", BindingFlags.NonPublic | BindingFlags.Static);
    static readonly PropertyInfo ServerDbIdProperty = LicenseType.GetProperty("ServerDbId", BindingFlags.NonPublic | BindingFlags.Static);
    static readonly MethodInfo LinkerTimestampMethod = FileUtilType.GetMethod("GetLinkerTimestampUtc", BindingFlags.Public | BindingFlags.Static, new[] { typeof(Assembly) });

    public static string MismatchToBuildError =>
        (string)LicenseType.GetField("LICENSE_MISMATCH_TO_BUILD_ERROR", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null);

    public static DateTime BuildTimestampUtc => (DateTime)LinkerTimestampMethod.Invoke(null, new object[] { Asm });

    public static void SetServerDbId(string dbId) => ServerDbIdProperty.SetValue(null, dbId);

    // Returns the parsed key object, or throws the exception Parse threw (unwrapped from reflection)
    public static object Parse(string keyText)
    {
        try
        {
            return ParseMethod.Invoke(null, new object[] { keyText, NullLogger.Instance });
        }
        catch (TargetInvocationException e)
        {
            System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(e.InnerException).Throw();
            throw;
        }
    }

    public static bool MExBB(DateTime buildDate, object key) => (bool)MExBBMethod.Invoke(null, new object[] { buildDate, key });

    public static object NewKey() => Activator.CreateInstance(LicenseType.GetNestedType("AyaNovaLicenseKey", BindingFlags.NonPublic), true);

    public static object Get(object o, string name) => o.GetType().GetProperty(name).GetValue(o);

    public static void Set(object o, string name, object value) => o.GetType().GetProperty(name).SetValue(o, value);
}

public class LicenceGateTests
{
    const string OK = "ok";
    const string MISMATCH = "mismatch-to-build";

    public static IEnumerable<object[]> RowIds() =>
        LicenceFixture.V8Rows.Keys.Select(id => new object[] { id });

    [Fact]
    public void Fixture_has_v8_rows()
    {
        Assert.NotEmpty(LicenceFixture.V8Rows);
        Assert.All(LicenceFixture.V8Rows.Values, r => Assert.Equal("8", (string)KeyJson(r)["Key"]["LicenseFormat"]));
    }

    [Theory]
    [MemberData(nameof(RowIds))]
    public void Stored_v8_licence_verifies(long id)
    {
        var row = LicenceFixture.V8Rows[id];
        var json = KeyJson(row)["Key"];
        AyaNovaLicence.SetServerDbId((string)json["DBID"]);

        var expected = ExpectedOutcome(json);
        string actual;
        object parsed = null;
        try
        {
            parsed = AyaNovaLicence.Parse(row.Key);
            actual = OK;
        }
        catch (ApplicationException e) when (e.InnerException?.Message == AyaNovaLicence.MismatchToBuildError)
        {
            actual = MISMATCH;
        }
        catch (Exception e)
        {
            // Signature, format, parse or server-match failure: never acceptable for a stored key
            actual = $"error: {e.InnerException?.Message ?? e.Message}";
        }

        RecordOutcome(id, actual);
        Assert.Equal(expected, actual);

        if (parsed != null)
        {
            Assert.Equal((string)json["RegisteredTo"], (string)AyaNovaLicence.Get(parsed, "RegisteredTo"));
            Assert.Equal((string)json["DBID"], (string)AyaNovaLicence.Get(parsed, "DbId"));
            Assert.Equal((bool?)json["Perpetual"] ?? true, (bool)AyaNovaLicence.Get(parsed, "Perpetual"));
            Assert.Equal((DateTime)json["LicenseExpiration"], (DateTime)AyaNovaLicence.Get(parsed, "LicenseExpiration"));
            Assert.Equal((DateTime)json["MaintenanceExpiration"], (DateTime)AyaNovaLicence.Get(parsed, "MaintenanceExpiration"));
            var features = (System.Collections.IList)AyaNovaLicence.Get(parsed, "Features");
            Assert.Equal(((JArray)json["Features"]).Count, features.Count);
        }
    }

    [Fact]
    public void Tampered_v8_licence_fails_signature()
    {
        var row = LicenceFixture.V8Rows.Values.First();
        AyaNovaLicence.SetServerDbId((string)KeyJson(row)["Key"]["DBID"]);
        // Any change to the signed payload must fail the signature check
        var tampered = row.Key.Replace("KEY]", "xKEY]");
        var e = Assert.Throws<ApplicationException>(() => AyaNovaLicence.Parse(tampered));
        Assert.Contains("integrity check", e.InnerException.Message);
    }

    // Guards the build date that MExBB compares against: it comes from the PE linker timestamp,
    // which is only a real date while AyaNova.csproj has <Deterministic>False</Deterministic>
    [Fact]
    public void Build_timestamp_is_a_real_recent_date()
    {
        var built = AyaNovaLicence.BuildTimestampUtc;
        Assert.InRange(built, new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc), DateTime.UtcNow.AddMinutes(5));
    }

    [Fact]
    public void MExBB_compares_maintenance_with_build_date()
    {
        var built = AyaNovaLicence.BuildTimestampUtc;
        var key = AyaNovaLicence.NewKey();
        AyaNovaLicence.Set(key, "Perpetual", true);

        AyaNovaLicence.Set(key, "MaintenanceExpiration", built.AddDays(-1));
        Assert.True(AyaNovaLicence.MExBB(built, key));

        AyaNovaLicence.Set(key, "MaintenanceExpiration", built.AddDays(1));
        Assert.False(AyaNovaLicence.MExBB(built, key));
    }

    // What production must do with this key on a perpetual build, worked out from the key itself
    static string ExpectedOutcome(JToken json)
    {
        if ((string)json["RegisteredTo"] == "REVOKED")
            return OK;
        var perpetual = (bool?)json["Perpetual"] ?? true;
        var trial = ((JArray)json["Features"]).Any(f => string.Equals((string)f["Name"], "TrialMode", StringComparison.OrdinalIgnoreCase));
        var maintenanceBeforeBuild = perpetual && !trial && (DateTime)json["MaintenanceExpiration"] < AyaNovaLicence.BuildTimestampUtc;
        if (maintenanceBeforeBuild || !perpetual)
            return MISMATCH;
        return OK;
    }

    static JObject KeyJson(LicenceRow row)
    {
        var a = row.Key.IndexOf("[KEY", StringComparison.Ordinal) + 4;
        var b = row.Key.IndexOf("KEY]", StringComparison.Ordinal);
        return JObject.Parse(row.Key.Substring(a, b - a));
    }

    static readonly object OutLock = new();
    static void RecordOutcome(long id, string outcome)
    {
        var path = Environment.GetEnvironmentVariable("AYANOVA_LICENCE_GATE_OUT");
        if (string.IsNullOrWhiteSpace(path))
            return;
        lock (OutLock)
            File.AppendAllText(path, $"{id} {outcome}{Environment.NewLine}");
    }
}