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 DmPostEntity = PrivaPub.Models.Post.DmPost;
using PostEntity = PrivaPub.Models.Post.Post;

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

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

		public string Type => "Follow";

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

			var target = await _localActors.FindByUri(Id(follow["object"]), token);
			if (target is not { IsFederated: true } || target.Kind == LocalActorKind.Application)
				return;

			var existing = await _dbEntities.Followers
				.Match(f => f.LocalActorId == target.Id && f.LocalActorKind == target.Kind && f.ActorURI == follower.ActorURI)
				.ExecuteFirstAsync(token);
			var record = existing ?? new Follower
			{
				LocalActorId = target.Id,
				LocalActorKind = target.Kind,
				ActorURI = follower.ActorURI
			};
			record.InboxURL = follower.InboxURL;
			record.SharedInboxURL = follower.SharedInboxURL;
			record.FollowActivityURI = Id(follow);
			record.IsAccepted = existing?.IsAccepted == true || !target.ManuallyApprovesFollowers;
			await DB.Default.SaveAsync(record, token);

			if (!record.IsAccepted)
				return;

			if (target.Kind == LocalActorKind.Group)
				await AddForeignMember(target.Id, follower.ActorURI, token);

			var accept = ActivityPubRenderer.Accept(target, follow, $"accept-{record.ID}-{DateTime.UtcNow.Ticks}");
			await _delivery.Enqueue(target, new[] { follower.InboxURL }, accept, token);
			return;
				}
	}
}