SocialPub/PrivaPub/Domain/Relationships/ReportService.cs

using MongoDB.Entities;

using PrivaPub.Federation.Actors;
using PrivaPub.Federation.Outbox;
using PrivaPub.Federation.Rendering;
using PrivaPub.Models.Social;
using PrivaPub.Models.User;
using PrivaPub.StaticServices;

using System.Text.Json.Nodes;

namespace PrivaPub.Domain.Relationships
{
	public interface IReportService
	{
		Task<Report> File(LocalActor reporter, string targetAccountId, IReadOnlyList<string> postIds, string comment, string category, bool forward,
			CancellationToken token);
	}

	public class ReportService : IReportService
	{
		readonly DbEntities _dbEntities;
		readonly ILocalActorService _localActors;
		readonly IDeliveryService _delivery;

		public ReportService(DbEntities dbEntities, ILocalActorService localActors, IDeliveryService delivery)
		{
			_dbEntities = dbEntities;
			_localActors = localActors;
			_delivery = delivery;
		}

		public async Task<Report> File(LocalActor reporter, string targetAccountId, IReadOnlyList<string> postIds, string comment, string category,
			bool forward, CancellationToken token)
		{
			var localTarget = await _dbEntities.Avatars.MatchID(targetAccountId).ExecuteFirstAsync(token);
			var remoteTarget = localTarget == default ? await _dbEntities.ForeignAvatars.MatchID(targetAccountId).ExecuteFirstAsync(token) : default;
			if (localTarget == default && remoteTarget == default)
				return default;
			var targetUri = localTarget != default ? _localActors.FromAvatar(localTarget).Uri : remoteTarget.ActorURI;
			var posts = postIds.Count == 0
				? new List<Models.Post.Post>()
				: await _dbEntities.Posts.Match(p => postIds.Contains(p.ID) && p.ActorURI == targetUri).ExecuteAsync(token);

			var report = new Report
			{
				ReporterAvatarId = reporter.Id,
				TargetAccountId = targetAccountId,
				TargetActorURI = targetUri,
				PostIds = posts.Select(p => p.ID).ToList(),
				ObjectURIs = posts.Select(p => p.ObjectURI).ToList(),
				Comment = comment?.Trim(),
				Category = category is "spam" or "legal" or "violation" ? category : "other",
				Forwarded = forward && remoteTarget != default
			};
			await DB.Default.SaveAsync(report, token);

			if (report.Forwarded)
			{
				var instance = await _localActors.GetInstanceActor(token);
				var flag = new JsonObject
				{
					["@context"] = ActivityPubRenderer.ActivityStreams,
					["id"] = instance.ActivityUri($"flag-{report.ID}"),
					["type"] = "Flag",
					["actor"] = instance.Uri,
					["content"] = report.Comment ?? string.Empty,
					["object"] = new JsonArray(report.ObjectURIs.Prepend(targetUri).Select(u => (JsonNode)u).ToArray())
				};
				await _delivery.Enqueue(instance, new[] { remoteTarget.SharedInboxURL ?? remoteTarget.InboxURL }, flag, token);
			}
			return report;
		}
	}
}