using System;
using System.Threading;
using System.Threading.Tasks;

namespace GB5Shared.DALCache
{
    public interface IDALCache
    {
        /// <summary>
        /// Returns a cached result for <paramref name="cacheKey"/> if present; otherwise invokes
        /// <paramref name="factory"/>, stores the result, and returns it.
        /// Null factory results are not stored — they are returned as-is so the next request
        /// can retry without serving a stale null.
        /// </summary>
        Task<T?> GetOrSetAsync<T>(
            string cacheKey,
            Func<CancellationToken, Task<T?>> factory,
            int ttlSeconds,
            CancellationToken ct = default) where T : class;

        /// <summary>
        /// Removes the cached entry for <paramref name="cacheKey"/>.
        /// Call from BLL after any write that invalidates this key.
        /// </summary>
        Task InvalidateAsync(string cacheKey, CancellationToken ct = default);
    }
}