using System;
using System.Collections.Generic;
using Jellyfin.Database.Implementations.Entities;
using Jellyfin.Plugin.WatchedTogether.Configuration;

namespace Jellyfin.Plugin.WatchedTogether.Services;

/// <summary>
/// Resolves shared-account groups from plugin configuration.
/// </summary>
public interface IGroupService
{
    /// <summary>
    /// Gets the active group owning the given shared account, if any.
    /// </summary>
    /// <param name="sharedUserId">The shared account identifier.</param>
    /// <returns>The group, or <c>null</c> if this user is not an enabled shared account.</returns>
    SharedGroup? GetGroupForSharedUser(Guid sharedUserId);

    /// <summary>
    /// Gets the members of a group that are currently eligible - existing and not disabled.
    /// </summary>
    /// <param name="group">The group whose members to resolve.</param>
    /// <returns>The eligible member users.</returns>
    IReadOnlyList<User> GetEligibleMembers(SharedGroup group);

    /// <summary>
    /// Determines whether the given user is a shared account managed by this plugin, regardless
    /// of whether its group is currently enabled.
    /// </summary>
    /// <param name="userId">The user identifier to test.</param>
    /// <returns><c>true</c> if the user is a managed shared account.</returns>
    bool IsSharedAccount(Guid userId);

    /// <summary>
    /// Removes a deleted user from every group, disabling any group left with fewer than two
    /// members, and persists the result.
    /// </summary>
    /// <param name="userId">The identifier of the user that was removed.</param>
    void PruneDeletedUser(Guid userId);
}