using MongoDB.Entities;

using PrivaPub.Api.Mastodon.Mappers;
using PrivaPub.Models.User;
using PrivaPub.Tests.Support;

using System.Text.Json.Nodes;

using static PrivaPub.Tests.Support.FederatedSeeds;

namespace PrivaPub.Tests.Federation
{
	// An account moving to another (Mastodon's Move), believed as Mastodon believes it: sent by the moving account about
	// itself, and the new account naming it among its alsoKnownAs
	[Trait("Category", "Integration")]
	public sealed class MoveTests : IAsyncLifetime
	{
		Harness _harness;

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

		public async ValueTask DisposeAsync()
		{
			if (_harness != default)
				await _harness.DisposeAsync();
		}

		// the new account, serving a document that names the old one (or not)
		RemoteActor Target(string name, RemoteActor aliasOf)
		{
			var target = new RemoteActor(_harness.Peer, name);
			var document = target.Document();
			if (aliasOf != default)
				document["alsoKnownAs"] = new JsonArray(aliasOf.Id);
			_harness.Peer.Serve(new Uri(target.Id).AbsolutePath, document.ToJsonString());
			return target;
		}

		Task Move(RemoteActor sender, RemoteActor moved, RemoteActor target) =>
			_harness.Deliver(sender, "/human-centipede", new JsonObject
			{
				["id"] = NewId(sender, "moves"), ["type"] = "Move", ["actor"] = sender.Id, ["object"] = moved.Id, ["target"] = target.Id
			});

		static Task<ForeignAvatar> Stored(RemoteActor actor) =>
			DB.Default.Find<ForeignAvatar>().Match(a => a.ActorURI == actor.Id).ExecuteFirstAsync(TestContext.Current.CancellationToken);

		[Fact]
		public async Task A_move_the_new_account_confirms_shows_the_old_account_moved_there()
		{
			var token = TestContext.Current.CancellationToken;
			var (_, alice) = await _harness.Persona("alice");
			var old = new RemoteActor(_harness.Peer, "old");
			await Follows(alice.Id, old);
			var target = Target("new", aliasOf: old);

			await Move(old, old, target);

			var stored = await Stored(old);
			Assert.Equal(target.Id, stored.MovedToURL);
			var account = await new MastodonMapper(_harness.Db, _harness.Local).Account(stored.ID, token);
			Assert.Equal(target.Name, account.Moved?.Username);
			Assert.Contains(_harness.Ledger.Of("in"), e => e.Activity == "Move" && e.Reason == "moved");
		}

		[Fact]
		public async Task A_move_the_new_account_does_not_confirm_or_someone_else_sends_changes_nothing()
		{
			var (_, alice) = await _harness.Persona("alice");
			var old = new RemoteActor(_harness.Peer, "old");
			var stranger = new RemoteActor(_harness.Peer, "stranger");
			await Follows(alice.Id, old);
			var unconfirmed = Target("new", aliasOf: default);
			var hijack = Target("hijack", aliasOf: stranger);

			await Move(old, old, unconfirmed);
			await Move(stranger, old, hijack);

			Assert.Null((await Stored(old)).MovedToURL);
			Assert.Equal(new[] { "not-aliased", "not-self" }, _harness.Ledger.Of("in").Where(e => e.Activity == "Move").Select(e => e.Reason));
		}
	}
}