SocialPub/PrivaPub/Api/Mastodon/Controllers/InstanceController.cs

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

using MongoDB.Entities;

using PrivaPub.Api.Mastodon.Infrastructure;
using PrivaPub.Domain.Privacy;
using PrivaPub.Federation.Actors;
using PrivaPub.Models.User;

using PostEntity = PrivaPub.Models.Post.Post;

namespace PrivaPub.Api.Mastodon.Controllers
{
	public class InstanceController : MastodonController
	{
		public const string Version = "4.2.0 (compatible; PrivaPub)";
		const string Description = "A small ActivityPub server where one private login keeps several unlinkable public personas.";

		readonly ILocalActorService _localActors;

		public InstanceController(ILocalActorService localActors)
		{
			_localActors = localActors;
		}

		string Domain => new Uri(_localActors.BaseAddress).Authority;

		static object Statuses => new { max_characters = 5000, max_media_attachments = 4, characters_reserved_per_url = 23 };

		static object MediaAttachments => new
		{
			supported_mime_types = new[] { "image/jpeg", "image/png", "image/gif", "image/webp", "video/mp4", "video/webm", "audio/mpeg", "audio/ogg" },
			image_size_limit = 16 * 1024 * 1024,
			image_matrix_limit = 16_777_216,
			video_size_limit = 99 * 1024 * 1024,
			video_frame_rate_limit = 60,
			video_matrix_limit = 2_304_000
		};

		static object Polls => new { max_options = 4, max_characters_per_option = 50, min_expiration = 300, max_expiration = 2_629_746 };

		[HttpGet("/api/v1/instance"), AllowAnonymous]
		public async Task<IActionResult> V1(CancellationToken token)
		{
			var users = await DB.Default.CountAsync<Avatar>(a => !a.DeletionAt.HasValue, token);
			var statuses = await DB.Default.CountAsync<PostEntity>(f => f.Where(p => !p.IsFederatedCopy) & f.Where(VisibilityPolicy.IsPublic), token);
			var domains = (await DB.Default.Find<ForeignAvatar, string>().Project(a => a.Domain).ExecuteAsync(token)).Distinct().Count();
			return Json(new
			{
				uri = Domain,
				title = "PrivaPub",
				short_description = Description,
				description = Description,
				email = string.Empty,
				version = Version,
				urls = new { streaming_api = $"wss://{Domain}" },
				stats = new { user_count = users, status_count = statuses, domain_count = domains },
				thumbnail = $"{_localActors.BaseAddress}/media/missing-header.png",
				languages = new[] { "en" },
				registrations = false,
				approval_required = false,
				invites_enabled = false,
				configuration = new { accounts = new { max_featured_tags = 0 }, statuses = Statuses, media_attachments = MediaAttachments, polls = Polls },
				contact_account = default(object),
				rules = Array.Empty<object>()
			});
		}

		[HttpGet("/api/v2/instance"), AllowAnonymous]
		public IActionResult V2() => Json(new
		{
			domain = Domain,
			title = "PrivaPub",
			version = Version,
			api_versions = new { mastodon = 7 },
			source_url = "https://git.thepra.dev/thepra/SocialPub",
			description = Description,
			usage = new { users = new { active_month = 0 } },
			thumbnail = new { url = $"{_localActors.BaseAddress}/media/missing-header.png" },
			languages = new[] { "en" },
			configuration = new
			{
				urls = new { streaming = $"wss://{Domain}" },
				accounts = new { max_featured_tags = 0, max_pinned_statuses = 0 },
				statuses = Statuses,
				media_attachments = MediaAttachments,
				polls = Polls,
				translation = new { enabled = false }
			},
			registrations = new { enabled = false, approval_required = false, message = default(string) },
			contact = new { email = string.Empty, account = default(object) },
			rules = Array.Empty<object>()
		});

		[HttpGet("/api/v1/instance/peers"), AllowAnonymous]
		public IActionResult Peers() => Json(Array.Empty<string>());

		[HttpGet("/api/v1/instance/activity"), AllowAnonymous]
		public IActionResult Activity() => Json(Array.Empty<object>());

		[HttpGet("/api/v1/instance/rules"), AllowAnonymous]
		public IActionResult Rules() => Json(Array.Empty<object>());

		[HttpGet("/api/v1/instance/extended_description"), AllowAnonymous]
		public IActionResult ExtendedDescription() => Json(new { updated_at = MastodonJson.Day(DateTime.UtcNow), content = $"<p>{Description}</p>" });
	}
}