using MongoDB.Entities;

using PrivaPub.StaticServices;

using PostEntity = PrivaPub.Models.Post.Post;

namespace PrivaPub.Federation.Inbox
{
	public static class Communities
	{
		// the remote community a post was made in: its own audience, or the first one its thread names on the way up (a
		// comment fetched for its thread, or delivered to a persona, may name none)
		public static async Task<string> Of(PostEntity post, DbEntities dbEntities, CancellationToken token)
		{
			for (var depth = 0; post != default && depth < RemotePosts.MaxDepth; depth++)
			{
				if (!string.IsNullOrEmpty(post.AudienceURI))
					return post.AudienceURI;
				post = string.IsNullOrEmpty(post.AnsweringToPostId) ? default : await dbEntities.Posts.MatchID(post.AnsweringToPostId).ExecuteFirstAsync(token);
			}
			return default;
		}
	}
}