using GB5Shared.DTO.Framework.Login;
using GB5Shared.DTO.Report;
using GB5Shared.Query.Report;
using GB5Shared.QueryExecutor;
using Microsoft.Extensions.Caching.Memory;

namespace GB5Shared.Export
{
    // Loads the computed-field definitions (MREPORTVSFIELDS.COMPUTEEXPRESSION) configured on a
    // given ReportViewId. Static with the two services passed in (not DI-registered) so this can be
    // called from BOTH the grid path (GB5Shared/FastEndPoint/BaseReportEndpoint.cs, which has no
    // IReportExport dependency) and the export path (ReportExport.cs) without adding a new
    // registration to every host's Program.cs -- IQueryExecutor/IMemoryCache are already registered
    // nearly everywhere; IReportExport is registered in only a handful of hosts.
    public static class ComputedFieldCatalog
    {
        public static async Task<List<ComputedFieldDTO>> GetForViewAsync(
            IQueryExecutor? queryExecutor,
            IMemoryCache? cache,
            int reportViewId,
            LoginDTO login,
            CancellationToken ct)
        {
            // Outermost no-op guard -- most grid calls have no ReportViewId at all (it's an
            // export/pivot concept the plain JSON path never needed before this feature).
            if (reportViewId <= 0 || queryExecutor == null)
                return new List<ComputedFieldDTO>();

            var cacheKey = $"cfd:{reportViewId}:{login.DatabaseName}";
            if (cache != null && cache.TryGetValue(cacheKey, out List<ComputedFieldDTO>? cached) && cached != null)
                return cached;

            var parameters = new Dictionary<string, object> { { "@ReportViewId", reportViewId } };
            var result = (await queryExecutor
                .QueryAsync<ComputedFieldDTO>(login, ReportQB.GET_COMPUTED_FIELDS_BY_REPORTVIEW, parameters, cancellationToken: ct)
                .ConfigureAwait(false)).ToList();

            cache?.Set(cacheKey, result, TimeSpan.FromMinutes(5));
            return result;
        }
    }
}