using PrivaPub.Federation.Actors;
using PrivaPub.Models.User;

using System.Text.Json.Nodes;

namespace PrivaPub.Federation.Inbox.Handlers
{
	// An account pins one of its posts (Add to its `featured` collection) or unpins it (Remove), as Mastodon and Akkoma
	// send it; inside a community's announce, the community features a post made in it. A Hashtag added to or removed from
	// its `featured` collection (as Mastodon sends it) or its `featuredTags` is a featured tag (R8). On its wall
	// (Smithereen's, FEP-400e) it tells of a post someone wrote there, or takes it off. Any other target (a community's
	// moderators) is not ours to keep.
	public class FeaturedHandler : IActivityHandler
	{
		readonly IFeaturedPosts _featured;
		readonly IWalls _walls;
		readonly IRemoteActorService _remoteActors;
		readonly Infrastructure.Jobs.IJobQueue _queue;
		readonly Domain.Social.IFeaturedTags _tags;
		readonly bool _add;

		public FeaturedHandler(IFeaturedPosts featured, bool add, IWalls walls = default, IRemoteActorService remoteActors = default,
			Infrastructure.Jobs.IJobQueue queue = default, Domain.Social.IFeaturedTags tags = default)
		{
			_tags = tags;
			_featured = featured;
			_walls = walls;
			_remoteActors = remoteActors;
			_queue = queue;
			_add = add;
		}

		public string Type => _add ? "Add" : "Remove";

		public async Task Handle(JsonNode activity, ForeignAvatar actor, CancellationToken token)
		{
			if (_add && _queue != default && await ConversationContainers.Unwrap(activity, actor, _queue, token))
				return;
			var target = Objects.ActivityJson.Id(activity["target"]);
			// a collection of its own we do not know of: its document read again, at most hourly, in case it was kept before
			// we read that collection (a wall)
			if (_remoteActors != default && target != default && target != actor.FeaturedURL && target != actor.WallURL && target != actor.FeaturedTagsURL
				&& Objects.Origin.Same(target, actor.ActorURI) && actor.UpdatedAt < DateTime.UtcNow.AddHours(-1))
				actor = await _remoteActors.GetActor(actor.ActorURI, refresh: true, token) ?? actor;
			// a featured hashtag: an object of its own, with no id (its href is no post), so before anything reads it as one
			if (Objects.ActivityJson.Value(activity["object"], "type") == "Hashtag")
			{
				if (_tags != default && target != default && (target == actor.FeaturedURL || target == actor.FeaturedTagsURL))
					await _tags.Receive(activity, actor, _add, token);
				else
					Arrival.Drop("unknown-target");
				return;
			}
			if (_walls != default && !string.IsNullOrEmpty(actor.WallURL) && target == actor.WallURL)
				await _walls.Receive(activity, actor, _add, token);
			else
				await _featured.Receive(activity, actor, _add, token);
		}
	}
}