using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace Jellyfin.Plugin.WatchedTogether.Services;

/// <summary>
/// Computes and applies the library access a shared account should have.
/// </summary>
public interface ILibraryAccessService
{
    /// <summary>
    /// Computes the set of libraries every one of the given members can reach.
    /// </summary>
    /// <param name="memberIds">The members to intersect.</param>
    /// <returns>
    /// The library identifiers common to all members. An empty set means the members have no
    /// library in common, and the shared account should see nothing.
    /// </returns>
    IReadOnlyList<Guid> ComputeIntersection(IReadOnlyList<Guid> memberIds);

    /// <summary>
    /// Recomputes the intersection for a group and writes it to its shared account.
    /// </summary>
    /// <param name="sharedUserId">The shared account to update.</param>
    /// <param name="memberIds">The group's members.</param>
    /// <returns>The libraries granted to the shared account.</returns>
    Task<IReadOnlyList<Guid>> ApplyIntersectionAsync(Guid sharedUserId, IReadOnlyList<Guid> memberIds);
}