using GB5Shared.DTO.Framework.Login;
using GB5Shared.Telemetry;
using Microsoft.Extensions.Logging;
using PERMBLL.Interfaces;
using PERMDAL.DTOs;
using PERMDAL.Interfaces;
using System.Text.Json;

namespace PERMBLL.Implementations;

public class BellCurveBLL : IBellCurveBLL
{
    private readonly IBellCurveDAL          _dal;
    private readonly ILogger<BellCurveBLL>  _logger;

    public BellCurveBLL(IBellCurveDAL dal, ILogger<BellCurveBLL> logger)
    {
        _dal    = dal;
        _logger = logger;
    }

    public async Task<string> GetBellCurveReportAsync(int appraisalPlanId, int ouId, LoginDTO login, CancellationToken ct)
    {
        try
        {
            GB5Trace.Step("get-bellcurve", new { appraisalPlanId, ouId });

            var bands    = (await _dal.GetBellCurveBandsAsync(appraisalPlanId, ouId, login, ct).ConfigureAwait(false)).ToList();
            var planName = await _dal.GetAppraisalPlanNameAsync(appraisalPlanId, login, ct).ConfigureAwait(false) ?? string.Empty;

            int total = bands.Sum(b => b.EmployeeCount);
            foreach (var band in bands)
                band.Percentage = total > 0 ? Math.Round(band.EmployeeCount * 100m / total, 2) : 0m;

            var report = new BellCurveReportDTO
            {
                AppraisalPlanId   = appraisalPlanId,
                AppraisalPlanName = planName,
                TotalEmployees    = total,
                Bands             = bands
            };

            return JsonSerializer.Serialize(report);
        }
        catch (Exception ex)
        {
            GB5Trace.MarkFailed("get-bellcurve-failed", ex);
            _logger.LogError(ex, "GetBellCurveReport failed for PlanId {PlanId}", appraisalPlanId);
            throw;
        }
    }
}