using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using ZB.MOM.WW.Secrets.Abstractions;
using ZB.MOM.WW.Secrets.Replicator.SqlServer.Tests.Fakes;
using ZB.MOM.WW.Secrets.Sqlite;

namespace ZB.MOM.WW.Secrets.Replicator.SqlServer.Tests;

/// <summary>
/// Convergence behaviour of the bidirectional hub sweep, exercised against real stores on both
/// sides so the assertions are about actual persisted state rather than mock interactions.
/// </summary>
public sealed class SqlServerSecretSyncServiceTests : IDisposable
{
    private readonly List<string> _dbPaths = [];
    private readonly SqliteSecretStore _local;
    private readonly SqliteSecretStore _hubStore;
    private readonly SqliteBackedHub _hub;

    public SqlServerSecretSyncServiceTests()
    {
        _local = CreateStore();
        _hubStore = CreateStore();
        _hub = new SqliteBackedHub(_hubStore);
    }

    private SqliteSecretStore CreateStore()
    {
        string path = Path.Combine(Path.GetTempPath(), $"zb-sync-{Guid.NewGuid():N}.db");
        _dbPaths.Add(path);
        var factory = new SecretsSqliteConnectionFactory(path);
        new SqliteSecretsStoreMigrator(factory).MigrateAsync(CancellationToken.None).GetAwaiter().GetResult();
        return new SqliteSecretStore(factory);
    }

    private SqlServerSecretSyncService CreateService() => new(
        _local,
        _hub,
        cacheInvalidator: null,
        Options.Create(new SqlServerSecretsOptions { ConnectionString = "Server=unused;" }),
        NullLogger<SqlServerSecretSyncService>.Instance);

    private static StoredSecret Row(string name, byte marker) => new()
    {
        Name = new SecretName(name),
        ContentType = SecretContentType.Text,
        Ciphertext = [marker],
        Nonce = [1],
        Tag = [2],
        WrappedDek = [3],
        WrapNonce = [4],
        WrapTag = [5],
        KekId = "sha256:test",
        Revision = 0,
        CreatedUtc = DateTimeOffset.UtcNow,
        UpdatedUtc = DateTimeOffset.UtcNow,
    };

    [Fact]
    public async Task Sweep_pulls_a_secret_the_node_has_never_seen()
    {
        await _hubStore.UpsertAsync(Row("db/password", 0xAA), CancellationToken.None);

        (int pulled, int pushed) = await CreateService().SweepAsync(CancellationToken.None);

        Assert.Equal(1, pulled);
        Assert.Equal(0, pushed);

        StoredSecret? local = await _local.GetAsync(new SecretName("db/password"), CancellationToken.None);
        Assert.NotNull(local);
        Assert.Equal(0xAA, local!.Ciphertext[0]);
    }

    [Fact]
    public async Task Sweep_pushes_a_local_write_the_hub_never_received()
    {
        // The case that makes best-effort publishing safe: the publish failed (hub was down), so the
        // hub has never heard of this name and can never ask for it. Only a push sweep repairs this.
        await _local.UpsertAsync(Row("api/key", 0xBB), CancellationToken.None);

        (int pulled, int pushed) = await CreateService().SweepAsync(CancellationToken.None);

        Assert.Equal(0, pulled);
        Assert.Equal(1, pushed);

        StoredSecret? hub = await _hubStore.GetAsync(new SecretName("api/key"), CancellationToken.None);
        Assert.NotNull(hub);
        Assert.Equal(0xBB, hub!.Ciphertext[0]);
    }

    [Fact]
    public async Task Sweep_preserves_the_originating_revision_when_pushing()
    {
        // Pushed verbatim, not upserted: if the hub stamped its own revision the row would look newer
        // than the writer's copy and bounce straight back on the next sweep.
        await _local.UpsertAsync(Row("api/key", 0xBB), CancellationToken.None);
        await _local.UpsertAsync(Row("api/key", 0xCC), CancellationToken.None);

        StoredSecret localRow = (await _local.GetAsync(new SecretName("api/key"), CancellationToken.None))!;
        Assert.Equal(1, localRow.Revision);

        await CreateService().SweepAsync(CancellationToken.None);

        StoredSecret hubRow = (await _hubStore.GetAsync(new SecretName("api/key"), CancellationToken.None))!;
        Assert.Equal(localRow.Revision, hubRow.Revision);
        Assert.Equal(localRow.UpdatedUtc, hubRow.UpdatedUtc);
    }

    [Fact]
    public async Task Sweep_converges_both_directions_in_one_pass()
    {
        await _local.UpsertAsync(Row("only/local", 0x11), CancellationToken.None);
        await _hubStore.UpsertAsync(Row("only/hub", 0x22), CancellationToken.None);

        (int pulled, int pushed) = await CreateService().SweepAsync(CancellationToken.None);

        Assert.Equal(1, pulled);
        Assert.Equal(1, pushed);

        Assert.NotNull(await _local.GetAsync(new SecretName("only/hub"), CancellationToken.None));
        Assert.NotNull(await _hubStore.GetAsync(new SecretName("only/local"), CancellationToken.None));
    }

    [Fact]
    public async Task Sweep_is_idempotent_so_a_converged_pair_stays_quiet()
    {
        await _local.UpsertAsync(Row("api/key", 0xBB), CancellationToken.None);

        SqlServerSecretSyncService service = CreateService();
        await service.SweepAsync(CancellationToken.None);

        (int pulled, int pushed) = await service.SweepAsync(CancellationToken.None);

        // A steady-state cluster must not write on every tick — that would churn the hub forever.
        Assert.Equal(0, pulled);
        Assert.Equal(0, pushed);
    }

    [Fact]
    public async Task Sweep_propagates_a_delete_as_a_tombstone()
    {
        await _local.UpsertAsync(Row("api/key", 0xBB), CancellationToken.None);
        await CreateService().SweepAsync(CancellationToken.None);

        await _local.DeleteAsync(new SecretName("api/key"), "tester", CancellationToken.None);
        await CreateService().SweepAsync(CancellationToken.None);

        StoredSecret hubRow = (await _hubStore.GetAsync(new SecretName("api/key"), CancellationToken.None))!;
        Assert.True(hubRow.IsDeleted);
    }

    [Fact]
    public async Task Sweep_does_not_resurrect_a_secret_deleted_on_the_hub()
    {
        await _local.UpsertAsync(Row("api/key", 0xBB), CancellationToken.None);
        await CreateService().SweepAsync(CancellationToken.None);

        await _hubStore.DeleteAsync(new SecretName("api/key"), "admin", CancellationToken.None);
        await CreateService().SweepAsync(CancellationToken.None);

        StoredSecret localRow = (await _local.GetAsync(new SecretName("api/key"), CancellationToken.None))!;
        Assert.True(localRow.IsDeleted);
    }

    [Fact]
    public async Task Sweep_skips_the_hub_fetch_when_nothing_is_newer()
    {
        await CreateService().SweepAsync(CancellationToken.None);

        Assert.Equal(0, _hub.GetManyCallCount);
    }

    [Fact]
    public async Task Sweep_lets_the_newer_side_win_a_conflicting_write()
    {
        await _local.UpsertAsync(Row("api/key", 0x11), CancellationToken.None);
        await CreateService().SweepAsync(CancellationToken.None);

        // Both sides then write independently; the hub's write is later.
        await _local.UpsertAsync(Row("api/key", 0x22), CancellationToken.None);
        await Task.Delay(10);
        await _hubStore.UpsertAsync(Row("api/key", 0x33), CancellationToken.None);

        await CreateService().SweepAsync(CancellationToken.None);

        StoredSecret localRow = (await _local.GetAsync(new SecretName("api/key"), CancellationToken.None))!;
        Assert.Equal(0x33, localRow.Ciphertext[0]);
    }

    public void Dispose()
    {
        Microsoft.Data.Sqlite.SqliteConnection.ClearAllPools();

        foreach (string db in _dbPaths)
        {
            foreach (string path in new[] { db, db + "-wal", db + "-shm" })
            {
                if (File.Exists(path))
                {
                    File.Delete(path);
                }
            }
        }
    }
}