using WxAgent.Service;
using Xunit;

namespace WxAgent.Service.Tests;

public sealed class EventHubTests
{
    [Fact]
    public async Task ReplayAndGapAreExplicitAndSubscriptionsAreOwnerScoped()
    {
        var hub = new EventHub();
        var first = new AgentEvent("one", "account", "chat", "message", "summary", DateTimeOffset.UtcNow);
        hub.Publish("alice", first);
        var replay = hub.Subscribe("alice", "one");
        Assert.Empty(replay.Replay); Assert.False(replay.Gap);
        var gap = hub.Subscribe("alice", "gone");
        Assert.True(gap.Gap);
        Assert.False(hub.TryGet(replay.SubscriptionId, "bob", out _));
        hub.Publish("alice", new AgentEvent("two", "account", "chat", "message", "summary", DateTimeOffset.UtcNow));
        Assert.True(hub.TryGet(replay.SubscriptionId, "alice", out var subscription));
        Assert.True(await subscription.Channel.Reader.WaitToReadAsync());
    }

    [Fact]
    public void ReplayNeverCrossesPrincipalBoundary()
    {
        var hub = new EventHub();
        hub.Publish("alice", new AgentEvent("alice-1", "account-a", "chat-a", "message", "summary", DateTimeOffset.UtcNow));
        hub.Publish("bob", new AgentEvent("bob-1", "account-b", "chat-b", "message", "summary", DateTimeOffset.UtcNow));

        var alice = hub.Subscribe("alice", "alice-1");
        var bob = hub.Subscribe("bob", "bob-1");
        Assert.Empty(alice.Replay);
        Assert.Empty(bob.Replay);
        Assert.False(alice.Gap);
        Assert.False(bob.Gap);

        var aliceAfterBob = hub.Subscribe("alice", "bob-1");
        Assert.Empty(aliceAfterBob.Replay);
        Assert.True(aliceAfterBob.Gap);
    }

    [Fact]
    public void SlowConsumerGetsAnExplicitGapInsteadOfSilentDrop()
    {
        var hub = new EventHub();
        var subscription = hub.Subscribe("alice", null);
        for (var i = 0; i < 102; i++) hub.Publish("alice", new AgentEvent(i.ToString(), "account", "chat", "message", "summary", DateTimeOffset.UtcNow));
        Assert.True(hub.TryGet(subscription.SubscriptionId, "alice", out var current));
        var foundGap = false;
        while (current.Channel.Reader.TryRead(out var item)) foundGap |= item.Kind == "gap";
        Assert.True(foundGap);
    }
}