using System;
using System.Threading;
using System.Threading.Tasks;
using GB5Shared.GOP.Qualifier;
using GB5Shared.GOP.Qualifier.DTOs;
using GB5Shared.DTO.Framework.Login;

namespace GB5Shared.GOP.Qualifier
{
    public class QualifierEngineBLL : IQualifierEngineBLL
    {
        private readonly IQualifierDAL _QualifierDAL;

        public QualifierEngineBLL(IQualifierDAL qualifierDAL)
        {
            _QualifierDAL = qualifierDAL;
        }

        public async Task<string> RunQualifiersAsync(
            string payloadJson, string entityCode, byte stage, byte scope,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            if (string.IsNullOrWhiteSpace(payloadJson))
                throw new ArgumentException("Payload is required.");

            var bindings = await _QualifierDAL
                .GetEntityBindings(entityCode, stage, scope, loginDTO, ct)
                .ConfigureAwait(false);

            string currentPayload = payloadJson;

            foreach (var binding in bindings)
            {
                var version = await _QualifierDAL
                    .GetActiveQualifierPlan(binding.QualifierId, loginDTO, ct)
                    .ConfigureAwait(false);

                if (version == null) continue;

                currentPayload = EvaluateQualifier(currentPayload, version);
            }

            return currentPayload;
        }

        /// <summary>
        /// Integration point for qualifier script evaluation.
        /// In production, plug in Roslyn or a JS engine to execute version.SnapshotJson against the payload.
        /// </summary>
        private static string EvaluateQualifier(string payloadJson, QualifierVersionDTO version)
        {
            // Placeholder: real implementation executes version.SnapshotJson against payloadJson.
            // Validators return bool; Enrichers return modified JSON.
            return payloadJson;
        }
    }
}