using System.Collections.Generic;
using System.Runtime.CompilerServices;
using AnalyticsBLL.AnalysisAggregation;
using AnalyticsDAL.DTO.AnalysisAggregation.V1;
using FastEndpoints;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.DTO.Framework.ResponseStandard;
using GB5Shared.DTO.Report;
using GB5Shared.FastEndPoint;
using static GB5Shared.GB5Constant.Constant;

namespace AnalyticsSL.EndPoints.BI
{
    /// <summary>The unified BI engine endpoint — resolves any of the three MBICATALOG dataset
    /// kinds (Warehouse/AnalysisQuery/ApiService) via IAnalysisAggregationService and returns
    /// the shaped AnalysisResult contract.
    ///
    /// Deliberately separate from the legacy AnalysisDynamicOutput.cs (AnalysisQueryId +
    /// ReportViewId params, flat JSON list response) — that endpoint's shipped contract stays
    /// untouched for existing consumers. This endpoint inherits BaseReportEndpoint so
    /// Excel/CSV/PDF/NDJSON export come for free via IReportExport, without duplicating any
    /// export plumbing.</summary>
    public class RunBIQuery : BaseReportEndpoint<RunBIQuery.RunBIQueryParameters, Dictionary<string, object?>>
    {
        private readonly IAnalysisAggregationService _aggregationService;

        public RunBIQuery(IAnalysisAggregationService aggregationService)
        {
            _aggregationService = aggregationService;
        }

        public override void Configure()
        {
            Post("/BI/RunBIQuery");
            AllowAnonymous();
        }

        public record RunBIQueryParameters(
            [property: FromHeader] string Login,
            [property: FromBody] AnalysisQueryDefinition Definition
        );

        // Export path — streams ALL rows (per BaseReportEndpoint contract, paging is ignored here).
        protected override async IAsyncEnumerable<Dictionary<string, object?>> ExecuteReportAsync(
            RunBIQueryParameters req, LoginDTO login, [EnumeratorCancellation] CancellationToken ct)
        {
            var result = await _aggregationService.ExecuteAsync(req.Definition, login, ct).ConfigureAwait(false);
            foreach (var row in result.Data)
                yield return row;
        }

        // Plain-JSON/UI-grid path — overridden (per BaseReportEndpoint's documented extension
        // point) to return the full AnalysisResult (meta + data), not just a capped flat list.
        protected override async Task<ResponseStandardDTO<object>> ExecutePagedAsync(
            RunBIQueryParameters req, LoginDTO login, CancellationToken ct)
        {
            var result = await _aggregationService.ExecuteAsync(req.Definition, login, ct).ConfigureAwait(false);

            // NOT_REQUIRED here — BLL-level IDALCache already caches the computed AnalysisResult
            // (AnalysisAggregationService §7); caching again at the SL response layer under a
            // different key scheme would double-cache the same result for no benefit.
            return await GB5Shared.ResponseStandard.Response.CreateSuccessResponse(
                result, CacheKeyLevel.NOT_REQUIRED, login);
        }

        // BaseReportEndpoint.HandleAsync requires a ReportCallingDTO on the request to trigger
        // export formats; RunBIQueryParameters intentionally has none (AnalysisQueryDefinition
        // is the sole FromBody payload, matching this module's one-FromBody-property convention —
        // see SaveAnalysis.cs/AnalysisDynamicOutput.cs). Synthesize a minimal one instead of adding
        // an export-specific field to the versioned analytics contract.
        protected override ReportCallingDTO? GetReportCallingDTOFromRequest(RunBIQueryParameters req)
            => new ReportCallingDTO { ReportTitle = "Analysis Result" };
    }
}