using PayRollDAL.DTO.SAP;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;

namespace PayRollBLL.SAP.Builders
{
    /// <summary>
    /// SAP Infotype 580 — Previous Employer Income.
    /// Service: ZPY_ITDEC_PREVIOUS_SRV / ITDecPreviousHeaderSet
    /// Source: TDECLARATION header fields only (one SAP record per declaration).
    /// </summary>
    public class SAP580Builder : ISapInfotypeBuilder
    {
        public int    Infotype       => 580;
        public string DisplayName    => "Previous Employer Income";
        public string EndpointPath   => "/sap/opu/odata/sap/ZPY_ITDEC_PREVIOUS_SRV/ITDecPreviousHeaderSet";
        public string MsgNavProperty => "NAV2ITDECPREVMSG";

        public string Build(IEnumerable<ITDeclarationSapDTO> rows, string date, string remarks)
        {
            var items = rows
                .GroupBy(r => r.DeclarationId)
                .Select(g =>
                {
                    var r = g.First();
                    return new Sap580Item
                    {
                        EmployeeId           = r.EmployeeCode,
                        FiscalYear           = r.FiscalYear,
                        FromDate             = r.PeriodFromDate.ToString("dd.MM.yyyy"),
                        ToDate               = r.PeriodToDate.ToString("dd.MM.yyyy"),
                        PreviousSalary       = SapFmt.Integer(r.PreviousSalary),
                        PreviousPerquisites  = "0",
                        PreviousProfitInLieu = "0",
                        PreviousExemptions   = "0",
                        PreviousPTAX         = SapFmt.Integer(r.PreviousPT),
                        PreviousPF           = SapFmt.Integer(r.PreviousPF),
                        PreviousIncomeTax    = SapFmt.Integer(r.PreviousTDS),
                    };
                })
                .ToList();

            if (items.Count == 0) return string.Empty;

            var payload = new Sap580Payload
            {
                Date              = date,
                NAV2ITDECPREVITEM = items,
            };

            return JsonSerializer.Serialize(payload, SapJsonOptions.Plain);
        }
    }
}