using MongoDB.Entities;

using PrivaPub.Models.Federation;
using PrivaPub.Models.Post;
using PrivaPub.Tests.Support;

using System.Text.Json.Nodes;

namespace PrivaPub.Tests.Federation
{
	// relays the configuration names: the instance actor follows Public there, and the public posts the relay passes on,
	// forwarded or announced, come to the federated timeline as their authors' posts; nothing else is taken from it
	[Trait("Category", "Integration")]
	[Xunit.Collection(nameof(Exclusive))]
	public sealed class RelayTests : IAsyncLifetime
	{
		Harness _harness;

		public async ValueTask InitializeAsync()
		{
			Assert.SkipUnless(MongoFixture.Enabled, MongoFixture.Skip);
			_harness = await Harness.Start();
		}

		public async ValueTask DisposeAsync()
		{
			if (_harness != default)
			{
				_harness.RelayOptions.Relays.Clear();
				await _harness.Relays.Reconcile(TestContext.Current.CancellationToken);
				await _harness.DisposeAsync();
			}
		}

		static CancellationToken Token => TestContext.Current.CancellationToken;
		static string Origin(RemoteActor actor) => new Uri(actor.Id).GetLeftPart(UriPartial.Authority);

		string Note(RemoteActor author, string text, string to = "https://www.w3.org/ns/activitystreams#Public")
		{
			var path = $"/notes/{Guid.NewGuid():N}";
			_harness.Peer.Serve(path, new JsonObject
			{
				["id"] = Origin(author) + path, ["type"] = "Note", ["attributedTo"] = author.Id, ["content"] = $"<p>{text}</p>",
				["to"] = new JsonArray(to), ["published"] = DateTime.UtcNow.ToString("O")
			}.ToJsonString());
			return Origin(author) + path;
		}

		JsonObject Create(RemoteActor author, string noteId) => new()
		{
			["id"] = noteId + "/activity", ["type"] = "Create", ["actor"] = author.Id,
			["to"] = new JsonArray("https://www.w3.org/ns/activitystreams#Public"),
			["object"] = new JsonObject { ["id"] = noteId, ["type"] = "Note", ["attributedTo"] = author.Id }
		};

		// a relay the instance actor subscribes to, which accepts
		async Task<RemoteActor> Subscribed()
		{
			var relay = new RemoteActor(_harness.Peer, "relay", type: "Service");
			_harness.RelayOptions.Relays.Add(relay.Id);
			await _harness.Relays.Reconcile(Token);
			var follow = Assert.Single(await _harness.Outgoing(relay.Id + "/inbox"), a => a["type"]!.GetValue<string>() == "Follow");
			await _harness.Deliver(relay, "/human-centipede", new JsonObject
			{
				["id"] = $"{relay.Id}#accept-{Guid.NewGuid():N}", ["type"] = "Accept", ["actor"] = relay.Id, ["object"] = follow.DeepClone()
			});
			return relay;
		}

		[Fact]
		public async Task The_instance_actor_follows_public_at_a_configured_relay_and_takes_its_answer()
		{
			var relay = await Subscribed();

			var follow = Assert.Single(await _harness.Outgoing(relay.Id + "/inbox"));
			Assert.Equal(("Follow", "https://www.w3.org/ns/activitystreams#Public"), (follow["type"]!.GetValue<string>(), follow["object"]!.GetValue<string>()));
			Assert.Equal((await _harness.Local.GetInstanceActor(Token)).Uri, follow["actor"]!.GetValue<string>());
			Assert.Equal(RelayState.Accepted, (await DB.Default.Find<RelaySubscription>().Match(s => s.ActorURI == relay.Id).ExecuteSingleAsync(Token)).State);
			Assert.True(await _harness.Relays.Passes(relay.Id, Token));

			_harness.RelayOptions.Relays.Clear();
			await _harness.Relays.Reconcile(Token);

			Assert.Contains(await _harness.Outgoing(relay.Id + "/inbox"), a => a["type"]!.GetValue<string>() == "Undo");
			Assert.False(await DB.Default.Find<RelaySubscription>().Match(s => s.ActorURI == relay.Id).ExecuteAnyAsync(Token));
		}

		[Fact]
		public async Task A_public_post_a_subscribed_relay_forwards_is_kept_and_one_from_anyone_else_is_not()
		{
			var relay = await Subscribed();
			var stranger = new RemoteActor(_harness.Peer, "stranger", type: "Service");
			var author = new RemoteActor(_harness.Peer, "author", _harness.Peer.B);
			var relayed = Note(author, "through the relay");
			var forwarded = Note(author, "through a stranger");
			var followersOnly = Note(author, "for followers", author.Id + "/followers");

			await _harness.Deliver(relay, "/human-centipede", Create(author, relayed));
			await _harness.Deliver(stranger, "/human-centipede", Create(author, forwarded));
			await _harness.Deliver(relay, "/human-centipede", Create(author, followersOnly));

			var kept = await DB.Default.Find<Post>().Match(p => p.ActorURI == author.Id).ExecuteAsync(Token);
			Assert.Equal(new[] { relayed }, kept.Select(p => p.ObjectURI));
			Assert.Equal(PostVisibility.Public, kept[0].Visibility);
		}

		[Fact]
		public async Task A_post_a_relay_announces_is_its_authors_never_the_relays_boost()
		{
			var relay = await Subscribed();
			var author = new RemoteActor(_harness.Peer, "author", _harness.Peer.B);
			var noteId = Note(author, "announced by the relay");

			await _harness.Deliver(relay, "/human-centipede", new JsonObject
			{
				["id"] = $"{relay.Id}/activities/{Guid.NewGuid():N}", ["type"] = "Announce", ["actor"] = relay.Id,
				["to"] = new JsonArray(relay.Id + "/followers"), ["object"] = noteId
			});

			var post = await DB.Default.Find<Post>().Match(p => p.ObjectURI == noteId).ExecuteSingleAsync(Token);
			Assert.Equal(author.Id, post.ActorURI);
			Assert.False(await DB.Default.Find<Post>().Match(p => p.ReblogOfPostId == post.ID).ExecuteAnyAsync(Token));
		}
	}
}