using MongoDB.Entities;

using PrivaPub.Federation.Actors;
using PrivaPub.Federation.Objects;
using PrivaPub.Federation.Outbox;
using PrivaPub.Federation.Rendering;
using PrivaPub.Models.Federation;
using PrivaPub.Models.Group;
using PrivaPub.Models.Post;
using PrivaPub.Models.User;
using PrivaPub.StaticServices;

using System.Text.Json.Nodes;

using static PrivaPub.Federation.Inbox.ForeignMembers;
using static PrivaPub.Federation.Objects.ActivityJson;

using PostEntity = PrivaPub.Models.Post.Post;

namespace PrivaPub.Federation.Inbox.Handlers
{
	public class UndoHandler : IActivityHandler
	{
		readonly DbEntities _dbEntities;
		readonly ILocalActorService _localActors;
		readonly IRemoteActorService _remoteActors;
		readonly IDeliveryService _delivery;

		public UndoHandler(DbEntities dbEntities, ILocalActorService localActors, IRemoteActorService remoteActors, IDeliveryService delivery)
		{
			_dbEntities = dbEntities;
			_localActors = localActors;
			_remoteActors = remoteActors;
			_delivery = delivery;
		}

		public string Type => "Undo";

		public async Task Handle(JsonNode activity, ForeignAvatar actor, CancellationToken token)
		{
			var undo = activity;

			var inner = undo["object"];
			var innerType = inner is JsonObject ? Value(inner, "type") : default;
			var innerId = Id(inner);

			if (inner is JsonObject && Id(inner["actor"]) != actor.ActorURI)
				return;
			if (innerType is not (null or "Follow"))
				return;

			var followers = await _dbEntities.Followers.Match(f => f.ActorURI == actor.ActorURI).ExecuteAsync(token);
			var targetUri = inner is JsonObject ? Id(inner["object"]) : default;
			foreach (var follower in followers)
			{
				var matchesActivity = innerId != default && follower.FollowActivityURI == innerId;
				var target = targetUri == default ? default : await _localActors.FindByUri(targetUri, token);
				var matchesTarget = target != default && target.Id == follower.LocalActorId && target.Kind == follower.LocalActorKind;
				if (!matchesActivity && !matchesTarget)
					continue;

				await DB.Default.DeleteAsync<Follower>(follower.ID);
				if (follower.LocalActorKind == LocalActorKind.Group)
					await RemoveForeignMember(follower.LocalActorId, actor.ActorURI, token);
			}
			return;
				}
	}
}