using DodoSSH.Infrastructure;
using Microsoft.EntityFrameworkCore;

namespace DodoSSH.Api.Features.Teams;

/// <summary>
/// Serialises the writes that decide what a team owns, for the life of the transaction.
/// </summary>
/// <remarks>
/// <para>
/// Archiving a team refuses while it owns a vault, and creating a vault refuses on an archived team — but each
/// used to check outside any transaction the other could see, so the two could pass each other: the archive
/// counted no vaults, a create landed a moment later, and the team was archived with a live vault in it that
/// nobody could reach. Both now take this lock inside their transaction and check again under it.
/// </para>
/// <para>
/// The same advisory lock the sync push takes per vault, keyed apart so a team and a vault never share one.
/// Requires <c>Multiplexing=false</c> on the connection, as that one does.
/// </para>
/// </remarks>
internal static class TeamLock
{
    internal static Task<int> AcquireAsync(DodoDbContext database, Guid teamId, CancellationToken cancellationToken) =>
        database.Database.ExecuteSqlAsync(
            $"SELECT pg_advisory_xact_lock(hashtextextended({"team:" + teamId.ToString()}, 0))",
            cancellationToken);
}