using Microsoft.Extensions.Logging.Abstractions;

using PrivaPub.Infrastructure.Statistics;
using PrivaPub.Models.Statistics;
using PrivaPub.Tests.Support;

namespace PrivaPub.Tests.Statistics
{
	public class InteractionsTests
	{
		[Fact]
		public void The_local_kind_is_kept_only_on_public_and_unlisted_traffic()
		{
			Assert.Equal("person", Interactions.Sanitize(new InteractionEvent { Audience = "public", LocalKind = "person" }).LocalKind);
			Assert.Equal("group", Interactions.Sanitize(new InteractionEvent { Audience = "unlisted", LocalKind = "group" }).LocalKind);
			Assert.Null(Interactions.Sanitize(new InteractionEvent { Audience = "private", LocalKind = "group" }).LocalKind);
			Assert.Null(Interactions.Sanitize(new InteractionEvent { Audience = "none", LocalKind = "person" }).LocalKind);
			Assert.Null(Interactions.Sanitize(new InteractionEvent { LocalKind = "person" }).LocalKind);
			Assert.Null(Interactions.Sanitize(new InteractionEvent { Audience = "public", LocalKind = "circle" }).LocalKind);
		}

		[Fact]
		public void Junk_becomes_other_and_hosts_are_normalised()
		{
			var e = Interactions.Sanitize(new InteractionEvent
			{
				Host = "Mastodon.Social.",
				Channel = "sideways",
				Activity = "https://www.w3.org/ns/activitystreams#Create",
				Object = "Note",
				Outcome = "Dropped!",
				Reason = "not-addressed",
				Audience = "everyone",
				Inbox = "front-door",
				Signature = "cavage:rsa-sha256",
				Features = new() { "fep-044f", "Bad Feature", "fep-044f", "source:text/markdown" }
			});

			Assert.Equal("mastodon.social", e.Host);
			Assert.Equal("other", e.Channel);
			Assert.Equal("other", e.Activity);
			Assert.Equal("Note", e.Object);
			Assert.Equal("other", e.Outcome);
			Assert.Equal("not-addressed", e.Reason);
			Assert.Null(e.Audience);
			Assert.Null(e.Inbox);
			Assert.Equal("cavage:rsa-sha256", e.Signature);
			Assert.Equal(new[] { "fep-044f", "other", "source:text/markdown" }, e.Features);
			Assert.Equal("-", Interactions.Host("evil host/with path"));
			Assert.Equal("-", Interactions.Host(default));
			Assert.Equal("social.example", Interactions.HostOf("https://Social.Example:8443/users/x"));
		}

		[Fact]
		public void Latencies_and_waits_fall_into_buckets()
		{
			Assert.Equal("le50ms", Interactions.Latency(0));
			Assert.Equal("le250ms", Interactions.Latency(101));
			Assert.Equal("inf", Interactions.Latency(31_000));
			Assert.Equal("le1s", Interactions.Wait(900));
			Assert.Equal("le60s", Interactions.Wait(59_000));
			Assert.Equal("inf", Interactions.Wait(100_000_000));
		}

		[Fact]
		public void An_actor_hash_is_stable_for_a_salt_and_unlinkable_across_salts()
		{
			var monday = new byte[32];
			var tuesday = Enumerable.Repeat((byte)1, 32).ToArray();
			const string actor = "https://social.example/users/alice";

			var first = InteractionSalts.Hash(monday, actor);

			Assert.Equal(first, InteractionSalts.Hash(monday, actor));
			Assert.NotEqual(first, InteractionSalts.Hash(tuesday, actor));
			Assert.NotEqual(first, InteractionSalts.Hash(monday, actor + "2"));
			Assert.Equal(16, first.Length);
			Assert.DoesNotContain("alice", first);
			Assert.Null(InteractionSalts.Hash(default, actor));
		}

		[Fact]
		public void A_full_ledger_drops_and_counts_but_never_blocks_or_throws()
		{
			var ledger = new InteractionLedger(new InteractionSalts(), new StaticOptions<StatisticsOptions>(new StatisticsOptions()), NullLogger<InteractionLedger>.Instance);

			for (var i = 0; i < 10_005; i++)
				ledger.Record(new InteractionEvent { Channel = Interactions.In });
			ledger.Record(default);

			Assert.Equal(5, ledger.Dropped);
		}

		[Fact]
		public void A_disabled_ledger_records_nothing()
		{
			var ledger = new InteractionLedger(new InteractionSalts(), new StaticOptions<StatisticsOptions>(new StatisticsOptions { Enabled = false }), NullLogger<InteractionLedger>.Instance);

			for (var i = 0; i < 10_005; i++)
				ledger.Record(new InteractionEvent { Channel = Interactions.In });

			Assert.Equal(0, ledger.Dropped);
		}
	}
}