using MongoDB.Entities;

using PrivaPub.Models.User;
using PrivaPub.StaticServices;

namespace PrivaPub.Services
{
	public interface IRootRemoval
	{
		Task<bool> Remove(string rootId, CancellationToken token);
	}

	// Deleting a root deletes everything public it had (owner decision 2026-10-04): each of its personas goes as a persona
	// is deleted (PersonaRemoval: each group it owns, a Delete of the actor to everyone who follows it and everyone it
	// follows, its posts emptied, its name kept reserved and its documents answering 410). The root's sessions end first, so
	// nothing acts as it while it goes, and it keeps only a deleted-{id} name.
	public class RootRemoval : IRootRemoval
	{
		readonly DbEntities _dbEntities;
		readonly IRootSessions _sessions;
		readonly IPersonaRemoval _personas;

		public RootRemoval(DbEntities dbEntities, IRootSessions sessions, IPersonaRemoval personas)
		{
			_dbEntities = dbEntities;
			_sessions = sessions;
			_personas = personas;
		}

		public async Task<bool> Remove(string rootId, CancellationToken token)
		{
			var root = await _dbEntities.RootUsers.MatchID(rootId).Match(u => u.DeletedAt == null).ExecuteFirstAsync(token);
			if (root == default)
				return false;
			await _sessions.Revoke(root.ID, token);
			var now = DateTime.UtcNow;

			var avatarIds = (await _dbEntities.RootToAvatars.Match(ra => ra.RootId == root.ID).ExecuteAsync(token)).Select(ra => ra.AvatarId).ToList();
			foreach (var avatarId in avatarIds)
				await _personas.Remove(avatarId, token);

			await DB.Default.Update<RootUser>().MatchID(root.ID)
				.Modify(u => u.UserName, $"deleted-{root.ID}")//unique, so a second deletion never collides with the first
				.Modify(u => u.Email, null)
				.Modify(u => u.HashedPassword, null)
				.Modify(u => u.Policies, new List<string>())
				.Modify(u => u.IsBanned, false)
				.Modify(u => u.IsEmailValidated, false)
				.Modify(u => u.DeletedAt, now)
				.ExecuteAsync(token);
			await DB.Default.DeleteAsync<EmailRecovery>(r => r.RootUserId == root.ID);
			await Domain.Moderation.Restrictions.Reload(CancellationToken.None);
			return true;
		}
	}
}