using System.Collections.Generic;
using AnalyticsDAL.DTO.Warehouse;

namespace AnalyticsDAL.DTO.AnalysisAggregation.V1
{
    /// <summary>Describes one computed field actually evaluated for a RunBIQuery response —
    /// carried on AnalysisResultMetaDTO.ComputedFieldsUsed. Deliberately has NO Expression
    /// property: Meta ships to every browser on every query; the raw formula is admin
    /// configuration and belongs on the admin-facing MBIFIELDMAPPING picker response, not here.</summary>
    public class AnalysisComputedFieldDTO
    {
        public string Field { get; set; } = "";
        public string Label { get; set; } = "";
        public byte DataType { get; set; }
        public List<string> SourceFields { get; set; } = new();

        /// <summary>Always NonAdditive — a computed field is never safe to re-aggregate at a
        /// coarser grain, even when every source it references is Additive (the operators
        /// involved, e.g. Abs()/IIf(), are non-linear: Abs(a)+Abs(b) != Abs(a+b)).</summary>
        public AdditivityType Additivity { get; set; } = AdditivityType.NonAdditive;

        /// <summary>The most restrictive additivity among SourceFields — diagnostic only (e.g.
        /// lets a reviewer see at a glance that a computed field derives from a SemiAdditive
        /// balance), not itself used to gate anything.</summary>
        public AdditivityType InheritedAdditivity { get; set; } = AdditivityType.Additive;

        /// <summary>Rows where evaluation yielded null (divide-by-zero, bad cast) — surfaces a
        /// formula that silently nulls every row instead of leaving it mysterious.</summary>
        public int NullRowCount { get; set; }
    }
}