using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Hubs;
using ZB.MOM.WW.OtOpcUa.Commons.Messages.Drivers;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Hubs;

/// <summary>
///     Review R04 L1 + L5: the in-process stores evict driver instances that are no longer configured
///     (so <c>/hosts</c> stops rendering ghost rows), and a throwing subscriber no longer aborts the
///     multicast for the subscribers after it (nor escapes onto the bridge actor).
/// </summary>
public sealed class StoreEvictionAndIsolationTests
{
    private static readonly DateTime Now = new(2026, 10, 22, 12, 0, 0, DateTimeKind.Utc);
    private static readonly DateTime Stale = Now.AddMinutes(-5);   // stopped publishing
    private static readonly DateTime Fresh = Now.AddSeconds(-3);   // still publishing
    private static readonly DateTime Cutoff = Now.AddSeconds(-60); // what /hosts passes

    private static DriverHealthChanged Health(string instance, DateTime? publishedUtc = null) =>
        new("MAIN", instance, "Healthy", null, null, 0, publishedUtc ?? Now);

    private static DriverResilienceStatusChanged Res(string instance, string host, DateTime? publishedUtc = null) =>
        new(instance, host, false, 0, 0, null, publishedUtc ?? Now, publishedUtc ?? Now);

    private static HashSet<string> Configured(params string[] ids) => new(ids, StringComparer.OrdinalIgnoreCase);

    [Fact]
    public void HealthStore_evicts_only_unconfigured_and_stale()
    {
        var store = new InMemoryDriverStatusSnapshotStore();
        store.Upsert(Health("drv-deleted-stopped", Stale));   // unconfigured + stale ⇒ evicted
        store.Upsert(Health("drv-deleted-running", Fresh));   // unconfigured + fresh ⇒ kept (I1: deleted in /raw, not yet deployed)
        store.Upsert(Health("drv-configured-quiet", Stale));  // configured + stale ⇒ kept
        store.Upsert(Health("drv-configured-live", Fresh));   // configured + fresh ⇒ kept

        var removed = store.EvictUnconfiguredStale(Configured("drv-configured-quiet", "drv-configured-live"), Cutoff);

        removed.ShouldBe(1);
        store.TryGet("drv-deleted-stopped", out _).ShouldBeFalse();
        // Positive controls: a still-publishing driver survives even though the draft no longer has it,
        // and a configured driver survives whatever its age.
        store.TryGet("drv-deleted-running", out _).ShouldBeTrue();
        store.TryGet("drv-configured-quiet", out _).ShouldBeTrue();
        store.TryGet("drv-configured-live", out _).ShouldBeTrue();
    }

    [Fact]
    public void HealthStore_a_running_undeployed_delete_goes_once_it_stops_publishing()
    {
        var store = new InMemoryDriverStatusSnapshotStore();
        store.Upsert(Health("drv-x", Fresh));
        store.EvictUnconfiguredStale(Configured(), Cutoff).ShouldBe(0);

        // The deploy stops it: its last snapshot ages past the cutoff, and the next sweep evicts it.
        store.Upsert(Health("drv-x", Stale));
        store.EvictUnconfiguredStale(Configured(), Cutoff).ShouldBe(1);
        store.TryGet("drv-x", out _).ShouldBeFalse();
    }

    [Fact]
    public void HealthStore_matches_ids_case_insensitively()
    {
        var store = new InMemoryDriverStatusSnapshotStore();
        store.Upsert(Health("DRV-Live", Stale));

        store.EvictUnconfiguredStale(Configured("drv-live"), Cutoff).ShouldBe(0);
        store.TryGet("DRV-Live", out _).ShouldBeTrue();
    }

    [Fact]
    public void ResilienceStore_evicts_only_unconfigured_and_stale_hosts()
    {
        var store = new InMemoryDriverResilienceStatusStore();
        store.Upsert(Res("drv-live", "h1", Stale));
        store.Upsert(Res("drv-gone", "h1", Stale));
        store.Upsert(Res("drv-gone", "h2", Stale));
        store.Upsert(Res("drv-running", "h1", Fresh));

        var removed = store.EvictUnconfiguredStale(Configured("drv-live"), Cutoff);

        removed.ShouldBe(2);
        store.GetForInstance("drv-gone").ShouldBeEmpty();
        store.GetForInstance("drv-live").Count.ShouldBe(1);
        store.GetForInstance("drv-running").Count.ShouldBe(1);
    }

    [Fact]
    public void Failure_log_throttle_warns_at_most_once_per_interval()
    {
        long now = 1_000;
        var throttle = new FailureLogThrottle(() => now);

        throttle.NextLevel().ShouldBe(Microsoft.Extensions.Logging.LogLevel.Warning);
        throttle.NextLevel().ShouldBe(Microsoft.Extensions.Logging.LogLevel.Debug);
        now += (long)FailureLogThrottle.Interval.TotalMilliseconds - 1;
        throttle.NextLevel().ShouldBe(Microsoft.Extensions.Logging.LogLevel.Debug);
        // Positive control: once the interval has passed, the next failure is visible again.
        now += 1;
        throttle.NextLevel().ShouldBe(Microsoft.Extensions.Logging.LogLevel.Warning);
    }

    [Fact]
    public void HealthStore_throwing_subscriber_does_not_stop_later_subscribers()
    {
        var store = new InMemoryDriverStatusSnapshotStore();
        var received = new List<string>();
        store.SnapshotChanged += _ => throw new InvalidOperationException("renderer torn down");
        store.SnapshotChanged += s => received.Add(s.DriverInstanceId);

        Should.NotThrow(() => store.Upsert(Health("drv-1")));

        received.ShouldBe(["drv-1"]);
        store.TryGet("drv-1", out _).ShouldBeTrue();
    }

    [Fact]
    public void ResilienceStore_throwing_subscriber_does_not_stop_later_subscribers()
    {
        var store = new InMemoryDriverResilienceStatusStore();
        var received = 0;
        store.SnapshotChanged += _ => throw new InvalidOperationException("boom");
        store.SnapshotChanged += _ => received++;

        Should.NotThrow(() => store.Upsert(Res("drv-1", "h1")));

        received.ShouldBe(1);
    }

    [Fact]
    public void Broadcaster_throwing_subscriber_does_not_stop_later_subscribers()
    {
        var broadcaster = new InProcessBroadcaster<string>();
        var received = new List<string>();
        broadcaster.Received += _ => throw new InvalidOperationException("boom");
        broadcaster.Received += received.Add;

        Should.NotThrow(() => broadcaster.Publish("evt"));

        received.ShouldBe(["evt"]);
    }

    [Fact]
    public void Broadcaster_throwing_connection_subscriber_does_not_stop_later_subscribers()
    {
        var broadcaster = new InProcessBroadcaster<string>();
        var raised = new List<bool>();
        broadcaster.ConnectionStateChanged += _ => throw new InvalidOperationException("boom");
        broadcaster.ConnectionStateChanged += raised.Add;

        Should.NotThrow(() => broadcaster.SetConnected(true));

        raised.ShouldBe([true]);
        broadcaster.IsConnected.ShouldBeTrue();
    }
}

/// <summary>
///     Source pin (no bUnit): <c>/hosts</c> sweeps both stores after a successful config load, and the
///     sweep sits before the failure catch, so a failed load (which blanks the config) never evicts.
/// </summary>
[Trait("Category", "Unit")]
public sealed class HostsEvictionWiringTests
{
    [Fact]
    public void Hosts_page_evicts_both_stores_inside_the_successful_load_only()
    {
        var src = AdminUiSource.Read("Components", "Pages", "Hosts.razor");

        var load = src.IndexOf("private async Task<bool> LoadConfigAsync()", StringComparison.Ordinal);
        load.ShouldBeGreaterThan(0);
        var firstCatch = src.IndexOf("catch (Exception ex) when (ex is OperationCanceledException", load, StringComparison.Ordinal);
        firstCatch.ShouldBeGreaterThan(load);

        src.IndexOf("DriverStore.EvictUnconfiguredStale(", load, StringComparison.Ordinal).ShouldBeInRange(load, firstCatch);
        src.IndexOf("ResilienceStore.EvictUnconfiguredStale(", load, StringComparison.Ordinal).ShouldBeInRange(load, firstCatch);
    }
}