'use strict';
const express   = require('express');
const router    = express.Router();
const axios     = require('axios');
const FormData  = require('form-data');
const ExcelJS   = require('exceljs');
const { verifyToken } = require('../middleware/auth');

const https = require('https');
const httpsAgent = new https.Agent({ rejectUnauthorized: false });

// ── helpers ────────────────────────────────────────────────────────────────
function safeDate(d) {
  if (!/^\d{4}-\d{2}-\d{2}$/.test(d)) throw new Error(`Invalid date: ${d}`);
  return d;
}

// HSN/DOC SQL uses CONVERT(VARCHAR(6),date,112) = YYYYMM; TCS wants MMYYYY
function toMMYYYY(fp) {
  const s = String(fp || '').replace(/\D/g, '');
  if (s.length === 6) {
    const yr = parseInt(s.slice(0, 4), 10);
    if (yr >= 2000 && yr <= 2099) return s.slice(4, 6) + s.slice(0, 4);
  }
  return fp;
}

function r2(n) {
  const num = parseFloat(String(n ?? '0'));
  if (isNaN(num)) return 0;
  // Use Number() on toFixed result to strip trailing zeros and prevent scientific notation
  return parseFloat(num.toFixed(2));
}

// Map SAP unit codes → valid GST UQC codes (TCS validates against GSTN list)
const VALID_UQC = new Set([
  'BAG','BAL','BDL','BKL','BOU','BOX','BTL','BUN','CAN','CBM','CCM','CMS','CTN',
  'DOZ','DRM','GGK','GMS','GRS','GYD','KGS','KLR','KME','KNO','KWT','LTR','MBE',
  'MLT','MTR','MTS','NOS','OTH','PAC','PCS','PRS','QTL','ROL','SET','SQC','SQF',
  'SQM','TBS','TGM','TON','TUB','UGS','UNT','YDS',
]);
const UQC_MAP = {
  KG:'KGS', GM:'GMS', GRM:'GMS', LT:'LTR', L:'LTR', LITRE:'LTR',
  MT:'MTR', M:'MTR', METRE:'MTR', QTL:'QTL', TON:'TON', TNE:'TON',
  PC:'PCS', PCS:'PCS', PEC:'PCS', EA:'NOS', EACH:'NOS', NO:'NOS', NOS:'NOS',
  ROLL:'ROL', ROL:'ROL', ROLE:'ROL', ROOL:'ROL',
  PKT:'PAC', PACK:'PAC', PAC:'PAC',
  BTL:'BTL', BOT:'BTL', TUB:'TUB', CAN:'CAN', CTN:'CTN',
  BAG:'BAG', BDL:'BDL', BOX:'BOX', SET:'SET',
  SQM:'SQM', SQF:'SQF', SQC:'SQC', CBM:'CBM', MTR:'MTR', MTS:'MTS',
  KGS:'KGS', LTR:'LTR', GMS:'GMS',
};
function validUQC(code) {
  const up = String(code || '').toUpperCase().trim();
  const mapped = UQC_MAP[up] || up;
  return VALID_UQC.has(mapped) ? mapped : 'OTH';
}

// ── SQL builders ──────────────────────────────────────────────────────────

function sqlB2B(from, to) {
  return `
WITH TaxData AS (
    SELECT T_DOC1.DocEntry, T_DOC1.LineNum,
        CAST(MAX(T_TAX1.BaseSum) AS DECIMAL(11,2)) AS ItemTaxableValue,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END AS TaxRate,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS CGST_Amt,
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS SGST_Amt,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS IGST_Amt,
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END) AS rchrg
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV1 T_DOC1 ON T_TAX1.SrcArrType=12 AND T_TAX1.SrcLineNum=T_DOC1.LineNum AND T_DOC1.DocEntry=T_ODOC.DocEntry
    WHERE T_ODOC.GSTTranTyp='GA' AND T_ODOC.DocStatus<>'C' AND T_ODOC.InvntSttus<>'C'
    GROUP BY T_DOC1.DocEntry, T_DOC1.LineNum
    UNION ALL
    SELECT T_DOC1.DocEntry, T_TAX1.SrcLineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV2 T_DOC2 ON T_DOC2.DocEntry=T_ODOC.DocEntry AND T_DOC2.LineNum=T_TAX1.SrcLineNum AND T_TAX1.SrcGrpNum=T_DOC2.GroupNum
    INNER JOIN INV1 T_DOC1 ON T_DOC1.DocEntry=T_DOC2.DocEntry AND T_DOC1.LineNum=T_DOC2.LineNum
    WHERE T_ODOC.GSTTranTyp='GA'
    GROUP BY T_DOC1.DocEntry, T_TAX1.SrcLineNum, T_TAX1.SrcGrpNum
    UNION ALL
    SELECT T_DOC3.DocEntry, T_DOC3.LineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV3 T_DOC3 ON T_DOC3.DocEntry=T_ODOC.DocEntry AND T_DOC3.LineNum=T_TAX1.SrcLineNum
    WHERE T_ODOC.GSTTranTyp='GA' AND (T_TAX1.BaseSum>0 OR T_OSTT.NfTaxId=-60)
    GROUP BY T_DOC3.DocEntry, T_DOC3.LineNum
), ITS AS (
    SELECT DocEntry, TaxRate,
        SUM(ItemTaxableValue) AS TotalTaxableValue,
        SUM(CGST_Amt) AS CGST_Amt, SUM(SGST_Amt) AS SGST_Amt, SUM(IGST_Amt) AS IGST_Amt,
        CASE WHEN MAX(rchrg)='Y' THEN 'Y' ELSE 'N' END AS ReverseCharge
    FROM TaxData GROUP BY DocEntry, TaxRate
)
SELECT
    CASE WHEN EXISTS (SELECT 1 FROM INV1 T_DE WHERE T_DE.DocEntry=T_ODOC.DocEntry AND T_DE.AcctCode IN ('4110202001','4110202003')) THEN 'DE'
         WHEN T_DOC12.CountryB<>'IN' THEN 'EXP'
         WHEN T_ODOC.U_CustomerCategory='Indirect Export' THEN 'B2B'
         WHEN T_DOC12.BpGSTN IS NULL AND T_DOC12.CountryS='IN' THEN 'B2CS'
         ELSE 'B2B' END AS trans_type_code,
    RIGHT('0'+CAST(MONTH(T_ODOC.DocDate) AS VARCHAR(2)),2)+CAST(YEAR(T_ODOC.DocDate) AS VARCHAR(4)) AS fp,
    ROW_NUMBER() OVER(ORDER BY T_DOC12.DocEntry) AS ack_sr_no,
    T_DOC12.LocGSTN AS self_gstin,
    CASE WHEN T_ODOC.CANCELED='Y' THEN 'C' ELSE 'A' END AS resultflag,
    'R' AS invoice_type,
    T_DOC12.BpGSTN AS cp_gstin, T_ODOC.CardName AS cp_gstin_name,
    CONCAT(T_NNM1.BeginStr, T_ODOC.DocNum) AS invoice_no,
    FORMAT(T_ODOC.DocDate,'dd-MM-yyyy') AS invoice_dt,
    T_ODOC.DocTotal AS invoice_val,
    ITS.TaxRate AS rate_of_tax,
    ITS.CGST_Amt AS cgst_amnt, ITS.SGST_Amt AS sgst_amnt, ITS.IGST_Amt AS igst_amnt,
    ITS.TotalTaxableValue AS taxable_val,
    CASE WHEN T_DOC12.BpGSTN IS NOT NULL THEN LEFT(T_DOC12.BpGSTN,2) ELSE T_OCST_S.GSTCode END AS pos,
    ITS.ReverseCharge AS rchrg
FROM ITS
INNER JOIN OINV T_ODOC ON ITS.DocEntry=T_ODOC.DocEntry
INNER JOIN INV12 T_DOC12 ON T_DOC12.DocEntry=T_ODOC.DocEntry
INNER JOIN NNM1 T_NNM1 ON T_NNM1.Series=T_ODOC.Series
LEFT JOIN OCST T_OCST_S ON T_OCST_S.Code=T_DOC12.StateS
WHERE T_ODOC.CANCELED='N'
  AND T_ODOC.DocDate>='${from}' AND T_ODOC.DocDate<='${to}'
  AND (
    EXISTS (SELECT 1 FROM INV1 T_DE WHERE T_DE.DocEntry=T_ODOC.DocEntry AND T_DE.AcctCode IN ('4110202001','4110202003'))
    OR (
      T_DOC12.CountryB='IN'
      AND (T_DOC12.BpGSTN IS NOT NULL OR T_ODOC.U_CustomerCategory='Indirect Export')
      AND T_OCST_S.GSTCode IS NOT NULL
    )
  )
ORDER BY ITS.DocEntry, ITS.TaxRate`;
}

function sqlB2CL(from, to) {
  return `
WITH TaxData AS (
    SELECT T_DOC1.DocEntry, T_DOC1.LineNum,
        CAST(MAX(T_TAX1.BaseSum) AS DECIMAL(11,2)) AS ItemTaxableValue,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END AS TaxRate,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS CGST_Amt,
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS SGST_Amt,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS IGST_Amt,
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END) AS rchrg
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV1 T_DOC1 ON T_TAX1.SrcArrType=12 AND T_TAX1.SrcLineNum=T_DOC1.LineNum AND T_DOC1.DocEntry=T_ODOC.DocEntry
    WHERE T_ODOC.GSTTranTyp='GA' AND T_ODOC.DocStatus<>'C' AND T_ODOC.InvntSttus<>'C'
    GROUP BY T_DOC1.DocEntry, T_DOC1.LineNum
    UNION ALL
    SELECT T_DOC1.DocEntry, T_TAX1.SrcLineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV2 T_DOC2 ON T_DOC2.DocEntry=T_ODOC.DocEntry AND T_DOC2.LineNum=T_TAX1.SrcLineNum AND T_TAX1.SrcGrpNum=T_DOC2.GroupNum
    INNER JOIN INV1 T_DOC1 ON T_DOC1.DocEntry=T_DOC2.DocEntry AND T_DOC1.LineNum=T_DOC2.LineNum
    WHERE T_ODOC.GSTTranTyp='GA'
    GROUP BY T_DOC1.DocEntry, T_TAX1.SrcLineNum, T_TAX1.SrcGrpNum
    UNION ALL
    SELECT T_DOC3.DocEntry, T_DOC3.LineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV3 T_DOC3 ON T_DOC3.DocEntry=T_ODOC.DocEntry AND T_DOC3.LineNum=T_TAX1.SrcLineNum
    WHERE T_ODOC.GSTTranTyp='GA' AND (T_TAX1.BaseSum>0 OR T_OSTT.NfTaxId=-60)
    GROUP BY T_DOC3.DocEntry, T_DOC3.LineNum
), ITS AS (
    SELECT DocEntry, TaxRate,
        SUM(ItemTaxableValue) AS TotalTaxableValue,
        SUM(CGST_Amt) AS CGST_Amt, SUM(SGST_Amt) AS SGST_Amt, SUM(IGST_Amt) AS IGST_Amt,
        CASE WHEN MAX(rchrg)='Y' THEN 'Y' ELSE 'N' END AS ReverseCharge
    FROM TaxData GROUP BY DocEntry, TaxRate
)
SELECT
    'B2CL' AS trans_type_code,
    RIGHT('0'+CAST(MONTH(T_ODOC.DocDate) AS VARCHAR(2)),2)+CAST(YEAR(T_ODOC.DocDate) AS VARCHAR(4)) AS fp,
    ROW_NUMBER() OVER(ORDER BY T_DOC12.DocEntry) AS ack_sr_no,
    T_DOC12.LocGSTN AS self_gstin,
    CASE WHEN T_ODOC.CANCELED='Y' THEN 'C' ELSE 'A' END AS resultflag,
    'R' AS invoice_type,
    CONCAT(T_NNM1.BeginStr, T_ODOC.DocNum) AS invoice_no,
    FORMAT(T_ODOC.DocDate,'dd-MM-yyyy') AS invoice_dt,
    T_ODOC.DocTotal AS invoice_val,
    ITS.TaxRate AS rate_of_tax,
    ITS.CGST_Amt AS cgst_amnt, ITS.SGST_Amt AS sgst_amnt, ITS.IGST_Amt AS igst_amnt,
    ITS.TotalTaxableValue AS taxable_val,
    T_OCST_S.GSTCode AS pos
FROM ITS
INNER JOIN OINV T_ODOC ON ITS.DocEntry=T_ODOC.DocEntry
INNER JOIN INV12 T_DOC12 ON T_DOC12.DocEntry=T_ODOC.DocEntry
INNER JOIN NNM1 T_NNM1 ON T_NNM1.Series=T_ODOC.Series
LEFT JOIN OCST T_OCST_S ON T_OCST_S.Code=T_DOC12.StateS
WHERE T_ODOC.CANCELED='N'
  AND T_ODOC.DocDate>='${from}' AND T_ODOC.DocDate<='${to}'
  AND T_DOC12.CountryB='IN' AND T_DOC12.BpGSTN IS NULL
  AND T_OCST_S.GSTCode IS NOT NULL
  AND T_ODOC.DocTotal > 100000 AND ITS.IGST_Amt > 0
ORDER BY ITS.DocEntry, ITS.TaxRate`;
}

function sqlB2CS(from, to) {
  return `
WITH TaxData AS (
    SELECT T_DOC1.DocEntry, T_DOC1.LineNum,
        CAST(MAX(T_TAX1.BaseSum) AS DECIMAL(11,2)) AS ItemTaxableValue,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END AS TaxRate,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS CGST_Amt,
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS SGST_Amt,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)) AS IGST_Amt,
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END) AS rchrg
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV1 T_DOC1 ON T_TAX1.SrcArrType=12 AND T_TAX1.SrcLineNum=T_DOC1.LineNum AND T_DOC1.DocEntry=T_ODOC.DocEntry
    WHERE T_ODOC.GSTTranTyp='GA' AND T_ODOC.DocStatus<>'C' AND T_ODOC.InvntSttus<>'C'
    GROUP BY T_DOC1.DocEntry, T_DOC1.LineNum
    UNION ALL
    SELECT T_DOC1.DocEntry, T_TAX1.SrcLineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV2 T_DOC2 ON T_DOC2.DocEntry=T_ODOC.DocEntry AND T_DOC2.LineNum=T_TAX1.SrcLineNum AND T_TAX1.SrcGrpNum=T_DOC2.GroupNum
    INNER JOIN INV1 T_DOC1 ON T_DOC1.DocEntry=T_DOC2.DocEntry AND T_DOC1.LineNum=T_DOC2.LineNum
    WHERE T_ODOC.GSTTranTyp='GA'
    GROUP BY T_DOC1.DocEntry, T_TAX1.SrcLineNum, T_TAX1.SrcGrpNum
    UNION ALL
    SELECT T_DOC3.DocEntry, T_DOC3.LineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-100 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId IN(-110,-150) THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        CAST(SUM(CASE WHEN T_OSTT.AbsId=-120 THEN T_TAX1.VatSum ELSE 0 END) AS DECIMAL(13,2)),
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV3 T_DOC3 ON T_DOC3.DocEntry=T_ODOC.DocEntry AND T_DOC3.LineNum=T_TAX1.SrcLineNum
    WHERE T_ODOC.GSTTranTyp='GA' AND (T_TAX1.BaseSum>0 OR T_OSTT.NfTaxId=-60)
    GROUP BY T_DOC3.DocEntry, T_DOC3.LineNum
), ITS AS (
    SELECT DocEntry, TaxRate,
        SUM(ItemTaxableValue) AS TotalTaxableValue,
        SUM(CGST_Amt) AS CGST_Amt, SUM(SGST_Amt) AS SGST_Amt, SUM(IGST_Amt) AS IGST_Amt,
        CASE WHEN MAX(rchrg)='Y' THEN 'Y' ELSE 'N' END AS ReverseCharge
    FROM TaxData GROUP BY DocEntry, TaxRate
)
SELECT
    'B2CS' AS trans_type_code,
    RIGHT('0'+CAST(MONTH(T_ODOC.DocDate) AS VARCHAR(2)),2)+CAST(YEAR(T_ODOC.DocDate) AS VARCHAR(4)) AS fp,
    ROW_NUMBER() OVER(ORDER BY T_DOC12.DocEntry) AS ack_sr_no,
    T_DOC12.LocGSTN AS self_gstin,
    CASE WHEN T_ODOC.CANCELED='Y' THEN 'C' ELSE 'A' END AS resultflag,
    'R' AS invoice_type,
    CONCAT(T_NNM1.BeginStr, T_ODOC.DocNum) AS invoice_no,
    FORMAT(T_ODOC.DocDate,'dd-MM-yyyy') AS invoice_dt,
    T_ODOC.DocTotal AS invoice_val,
    ITS.TaxRate AS rate_of_tax,
    ITS.CGST_Amt AS cgst_amnt, ITS.SGST_Amt AS sgst_amnt, ITS.IGST_Amt AS igst_amnt,
    ITS.TotalTaxableValue AS taxable_val,
    T_OCST_S.GSTCode AS pos
FROM ITS
INNER JOIN OINV T_ODOC ON ITS.DocEntry=T_ODOC.DocEntry
INNER JOIN INV12 T_DOC12 ON T_DOC12.DocEntry=T_ODOC.DocEntry
INNER JOIN NNM1 T_NNM1 ON T_NNM1.Series=T_ODOC.Series
LEFT JOIN OCST T_OCST_S ON T_OCST_S.Code=T_DOC12.StateS
WHERE T_ODOC.CANCELED='N'
  AND T_ODOC.DocDate>='${from}' AND T_ODOC.DocDate<='${to}'
  AND T_DOC12.CountryB='IN' AND T_DOC12.BpGSTN IS NULL
  AND T_OCST_S.GSTCode IS NOT NULL
  AND (T_ODOC.DocTotal<=100000 OR (T_ODOC.DocTotal>100000 AND ITS.CGST_Amt>0))
ORDER BY ITS.DocEntry, ITS.TaxRate`;
}

// EXP — no invoice_type in SELECT (TCS throws NREQ error if present)
function sqlExport(from, to) {
  return `
WITH TaxData AS (
    SELECT T_DOC1.DocEntry, T_DOC1.LineNum,
        CAST(MAX(T_TAX1.BaseSum) AS DECIMAL(11,2)) AS ItemTaxableValue,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END AS TaxRate,
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END) AS rchrg
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV1 T_DOC1 ON T_TAX1.SrcArrType=12 AND T_TAX1.SrcLineNum=T_DOC1.LineNum AND T_DOC1.DocEntry=T_ODOC.DocEntry
    WHERE T_ODOC.GSTTranTyp='GA' AND T_ODOC.DocStatus<>'C' AND T_ODOC.InvntSttus<>'C'
    GROUP BY T_DOC1.DocEntry, T_DOC1.LineNum
    UNION ALL
    SELECT T_DOC1.DocEntry, T_TAX1.SrcLineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV2 T_DOC2 ON T_DOC2.DocEntry=T_ODOC.DocEntry AND T_DOC2.LineNum=T_TAX1.SrcLineNum AND T_TAX1.SrcGrpNum=T_DOC2.GroupNum
    INNER JOIN INV1 T_DOC1 ON T_DOC1.DocEntry=T_DOC2.DocEntry AND T_DOC1.LineNum=T_DOC2.LineNum
    WHERE T_ODOC.GSTTranTyp='GA'
    GROUP BY T_DOC1.DocEntry, T_TAX1.SrcLineNum, T_TAX1.SrcGrpNum
    UNION ALL
    SELECT T_DOC3.DocEntry, T_DOC3.LineNum, 0,
        CASE WHEN MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)=0
             THEN MAX(CASE WHEN T_OSTT.AbsId=-100 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
                + MAX(CASE WHEN T_OSTT.AbsId IN(-110,-150) AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
             ELSE MAX(CASE WHEN T_OSTT.AbsId=-120 AND T_ODOC.DutyStatus='Y' THEN T_TAX1.VatPercent ELSE 0 END)
        END,
        MAX(CASE WHEN T_TAX1.RvsChrgPrc>0 THEN 'Y' ELSE 'N' END)
    FROM TAX1 T_TAX1
    INNER JOIN OSTA T1 ON T_TAX1.StaCode=T1.Code
    INNER JOIN OSTT T_OSTT ON T1.Type=T_OSTT.AbsId
    INNER JOIN OTAX T_OTAX ON T_OTAX.AbsEntry=T_TAX1.AbsEntry
    INNER JOIN OINV T_ODOC ON T_OTAX.SrcObjType=13 AND T_OTAX.SrcObjAbs=T_ODOC.DocEntry
    INNER JOIN INV3 T_DOC3 ON T_DOC3.DocEntry=T_ODOC.DocEntry AND T_DOC3.LineNum=T_TAX1.SrcLineNum
    WHERE T_ODOC.GSTTranTyp='GA' AND (T_TAX1.BaseSum>0 OR T_OSTT.NfTaxId=-60)
    GROUP BY T_DOC3.DocEntry, T_DOC3.LineNum
), ITS AS (
    SELECT DocEntry, TaxRate,
        SUM(ItemTaxableValue) AS TotalTaxableValue,
        CASE WHEN MAX(rchrg)='Y' THEN 'Y' ELSE 'N' END AS ReverseCharge
    FROM TaxData GROUP BY DocEntry, TaxRate
)
SELECT
    'EXP' AS trans_type_code,
    RIGHT('0'+CAST(MONTH(T_ODOC.DocDate) AS VARCHAR(2)),2)+CAST(YEAR(T_ODOC.DocDate) AS VARCHAR(4)) AS fp,
    ROW_NUMBER() OVER(ORDER BY T_DOC12.DocEntry) AS ack_sr_no,
    T_DOC12.LocGSTN AS self_gstin,
    CASE WHEN T_ODOC.CANCELED='Y' THEN 'C' ELSE 'A' END AS resultflag,
    'WOPAY' AS export_type_desc,
    CONCAT(T_NNM1.BeginStr, T_ODOC.DocNum) AS invoice_no,
    FORMAT(T_ODOC.DocDate,'dd-MM-yyyy') AS invoice_dt,
    T_ODOC.DocTotal AS invoice_val,
    ITS.TaxRate AS rate_of_tax,
    ITS.TotalTaxableValue AS taxable_val
FROM ITS
INNER JOIN OINV T_ODOC ON ITS.DocEntry=T_ODOC.DocEntry
INNER JOIN INV12 T_DOC12 ON T_DOC12.DocEntry=T_ODOC.DocEntry
INNER JOIN NNM1 T_NNM1 ON T_NNM1.Series=T_ODOC.Series
LEFT JOIN OCST T_OCST_S ON T_OCST_S.Code=T_DOC12.StateS
WHERE T_ODOC.CANCELED='N'
  AND T_ODOC.DocDate>='${from}' AND T_ODOC.DocDate<='${to}'
  AND T_DOC12.ImpORExp='Y' AND T_DOC12.CountryB<>'IN'
  AND T_DOC12.BpGSTN IS NULL AND T_OCST_S.GSTCode IS NULL
  AND NOT EXISTS (SELECT 1 FROM INV1 T_DE WHERE T_DE.DocEntry=T_ODOC.DocEntry AND T_DE.AcctCode IN ('4110202001','4110202003'))
ORDER BY ITS.DocEntry, ITS.TaxRate`;
}

function sqlHsn(from, to) {
  return `
;WITH INV_TAX AS (
    SELECT 
        DocEntry,
        LineNum,
        SUM(CASE WHEN staType = '-120' THEN TaxSum ELSE 0 END) AS iamt,
        SUM(CASE WHEN staType = '-110' THEN TaxSum ELSE 0 END) AS camt,
        SUM(CASE WHEN staType = '-100' THEN TaxSum ELSE 0 END) AS samt,
        SUM(CASE WHEN staType = '10'   THEN TaxSum ELSE 0 END) AS tcs
    FROM INV4
    GROUP BY DocEntry, LineNum
),

RIN_TAX AS (
    SELECT 
        DocEntry,
        LineNum,
        SUM(CASE WHEN staType = '-120' THEN TaxSum ELSE 0 END) AS iamt,
        SUM(CASE WHEN staType = '-110' THEN TaxSum ELSE 0 END) AS camt,
        SUM(CASE WHEN staType = '-100' THEN TaxSum ELSE 0 END) AS samt,
        SUM(CASE WHEN staType = '10'   THEN TaxSum ELSE 0 END) AS tcs
    FROM RIN4
    GROUP BY DocEntry, LineNum
),

HSN_Lines AS (
    -- AR Invoice
    SELECT
        CONCAT('INV-', OINV.DocEntry) AS doc_key,
        CONVERT(VARCHAR(6), OINV.DocDate, 112) AS fp,
        INV12.LocGSTN AS self_gstin,
        REPLACE(OCHP.ChapterID, '.', '') AS hsn_sc,
        CASE 
            WHEN OCHP.ChapterID NOT LIKE '99%' THEN 'Goods'
            ELSE 'Service'
        END AS gstr1Desc,
        CASE
            WHEN ISNULL(INV12.BpGSTN, '') = '' THEN 'B2C'
            ELSE 'B2B'
        END AS section,
        ISNULL(INV1.unitMsr, 'OTH') AS uqc,
        INV1.Quantity AS qty,
        INV1.LineTotal + INV1.VatSum AS val,
        INV1.LineTotal AS txval,
        ISNULL(T.iamt, 0) AS iamt,
        ISNULL(T.camt, 0) AS camt,
        ISNULL(T.samt, 0) AS samt,
        ISNULL(T.tcs, 0) AS tcs
    FROM OINV
    INNER JOIN INV1
        ON OINV.DocEntry = INV1.DocEntry
    LEFT JOIN INV_TAX T
        ON OINV.DocEntry = T.DocEntry
       AND INV1.LineNum = T.LineNum
    INNER JOIN INV12
        ON OINV.DocEntry = INV12.DocEntry
    INNER JOIN OITM
        ON INV1.ItemCode = OITM.ItemCode
    INNER JOIN OCHP
        ON OITM.ChapterID = OCHP.AbsEntry
    WHERE OINV.DocDate BETWEEN '${from}' AND '${to}'
      AND OINV.CANCELED = 'N'

    UNION ALL

    -- AR Credit Memo
    SELECT
        CONCAT('CM-', ORIN.DocEntry) AS doc_key,
        CONVERT(VARCHAR(6), ORIN.DocDate, 112) AS fp,
        RIN12.LocGSTN AS self_gstin,
        REPLACE(OCHP.ChapterID, '.', '') AS hsn_sc,
        CASE 
            WHEN OCHP.ChapterID NOT LIKE '99%' THEN 'Goods'
            ELSE 'Service'
        END AS gstr1Desc,
        CASE
            WHEN ISNULL(RIN12.BpGSTN, '') = '' THEN 'B2C'
            ELSE 'B2B'
        END AS section,
        ISNULL(RIN1.unitMsr, 'OTH') AS uqc,
        -RIN1.Quantity AS qty,
        -(RIN1.LineTotal + RIN1.VatSum) AS val,
        -RIN1.LineTotal AS txval,
        -ISNULL(T.iamt, 0) AS iamt,
        -ISNULL(T.camt, 0) AS camt,
        -ISNULL(T.samt, 0) AS samt,
        -ISNULL(T.tcs, 0) AS tcs
    FROM ORIN
    INNER JOIN RIN1
        ON ORIN.DocEntry = RIN1.DocEntry
    LEFT JOIN RIN_TAX T
        ON ORIN.DocEntry = T.DocEntry
       AND RIN1.LineNum = T.LineNum
    INNER JOIN RIN12
        ON ORIN.DocEntry = RIN12.DocEntry
    INNER JOIN OITM
        ON RIN1.ItemCode = OITM.ItemCode
    INNER JOIN OCHP
        ON OITM.ChapterID = OCHP.AbsEntry
    WHERE ORIN.DocDate BETWEEN '${from}' AND '${to}'
      AND ORIN.CANCELED = 'N'
),

HSN_Agg AS (
    SELECT
        fp,
        self_gstin,
        hsn_sc,
        gstr1Desc,
        section,
        uqc,
        SUM(qty)   AS qty_n,
        SUM(val)   AS val_n,
        SUM(txval) AS txval_n,
        SUM(iamt)  AS iamt_n,
        SUM(camt)  AS camt_n,
        SUM(samt)  AS samt_n,
        SUM(tcs)   AS tcs_n,
        CASE
            WHEN SUM(txval) = 0 THEN 0
            WHEN ROUND(
                    (SUM(iamt) + SUM(camt) + SUM(samt)) * 100.0 / SUM(txval),
                    0
                 ) IN (0, 5, 12, 18, 28)
            THEN ROUND(
                    (SUM(iamt) + SUM(camt) + SUM(samt)) * 100.0 / SUM(txval),
                    0
                 )
            ELSE 0
        END AS rate_of_tax_n
    FROM HSN_Lines
    GROUP BY
        fp,
        self_gstin,
        hsn_sc,
        gstr1Desc,
        section,
        uqc
)

SELECT
    ROW_NUMBER() OVER (ORDER BY hsn_sc, uqc, section, rate_of_tax_n) AS ack_sr_no,
    fp,
    self_gstin,
    hsn_sc,
    gstr1Desc,
    section,
    uqc,
    -- num: occurrence index of this HSN/SAC code — 1 if the code appears only
    -- once, 1,2,... if the same code repeats across different UQC/rate/section rows
    ROW_NUMBER() OVER (PARTITION BY hsn_sc ORDER BY uqc, section, rate_of_tax_n) AS num,

    -- Return values as formatted strings to avoid scientific notation
    LTRIM(STR(qty_n,   20, 3)) AS qty,
    LTRIM(STR(val_n,   20, 2)) AS val,
    LTRIM(STR(txval_n, 20, 2)) AS txval,
    LTRIM(STR(iamt_n,  20, 2)) AS iamt,
    LTRIM(STR(camt_n,  20, 2)) AS camt,
    LTRIM(STR(samt_n,  20, 2)) AS samt,
    LTRIM(STR(tcs_n,   20, 2)) AS tcs,
    LTRIM(STR(rate_of_tax_n, 20, 2)) AS rate_of_tax

FROM HSN_Agg
ORDER BY
    hsn_sc, uqc, section, rate_of_tax_n;`;
}

function sqlDocs(from, to) {
  return `
WITH DocStatus AS (
    SELECT T0.DocEntry, T0.DocNum, T0.Series, T0.DocDate, 'Invoice' AS DocumentType,
        CASE WHEN T0.CANCELED='Y' OR CM.BaseEntry IS NOT NULL THEN 1 ELSE 0 END AS IsCanceled
    FROM OINV T0
    LEFT JOIN (SELECT DISTINCT R1.BaseEntry FROM RIN1 R1 INNER JOIN ORIN R0 ON R0.DocEntry=R1.DocEntry WHERE R1.BaseType=13 AND R0.CANCELED='N') CM ON CM.BaseEntry=T0.DocEntry
    WHERE T0.DocDate>='${from}' AND T0.DocDate<'${to}'
    UNION ALL
    SELECT D0.DocEntry, D0.DocNum, D0.Series, D0.DocDate, 'Delivery',
        CASE WHEN D0.CANCELED='Y' THEN 1 ELSE 0 END
    FROM ODLN D0 INNER JOIN NNM1 N1 ON N1.Series=D0.Series
    WHERE N1.SeriesName LIKE '%FOC%' AND D0.DocDate>='${from}' AND D0.DocDate<'${to}'
    UNION ALL
    SELECT W0.DocEntry, W0.DocNum, W0.Series, W0.DocDate,
        CASE WHEN N1.SeriesName LIKE '%JW%' THEN 'JW' WHEN N1.SeriesName LIKE '%IT%' AND N1.SeriesName NOT LIKE '%ITR%' THEN 'IT' END,
        CASE WHEN W0.CANCELED='Y' THEN 1 ELSE 0 END
    FROM OWTR W0 INNER JOIN NNM1 N1 ON N1.Series=W0.Series
    WHERE (N1.SeriesName LIKE '%JW%' OR (N1.SeriesName LIKE '%IT%' AND N1.SeriesName NOT LIKE '%ITR%'))
      AND W0.DocDate>='${from}' AND W0.DocDate<'${to}'
    UNION ALL
    SELECT P0.DocEntry, P0.DocNum, P0.Series, P0.DocDate, 'AP Invoice (RCM)',
        CASE WHEN P0.CANCELED='Y' THEN 1 ELSE 0 END
    FROM OPCH P0 INNER JOIN NNM1 N1 ON N1.Series=P0.Series
    WHERE N1.SeriesName LIKE '%rev%' AND P0.DocDate>='${from}' AND P0.DocDate<'${to}'
    UNION ALL
    SELECT R0.DocEntry, R0.DocNum, R0.Series, R0.DocDate, 'AR Credit Memo',
        CASE WHEN R0.CANCELED='Y' THEN 1 ELSE 0 END
    FROM ORIN R0 INNER JOIN NNM1 N1 ON N1.Series=R0.Series
    WHERE N1.SeriesName LIKE '%ARCN%' AND R0.DocDate>='${from}' AND R0.DocDate<'${to}'
)
SELECT CONVERT(char(6),DocDate,112) AS fp, Series, DocumentType,
    CASE WHEN DocumentType='AR Credit Memo' THEN CONCAT('CN-',MIN(DocNum))
         WHEN DocumentType IN ('Invoice','Delivery') THEN CONCAT('1511',MIN(DocNum))
         ELSE CAST(MIN(DocNum) AS varchar(20)) END AS sr_from,
    CASE WHEN DocumentType='AR Credit Memo' THEN CONCAT('CN-',MAX(DocNum))
         WHEN DocumentType IN ('Invoice','Delivery') THEN CONCAT('1511',MAX(DocNum))
         ELSE CAST(MAX(DocNum) AS varchar(20)) END AS sr_to,
    COUNT(*) AS totnum, SUM(IsCanceled) AS canceled, COUNT(*)-SUM(IsCanceled) AS net_issue
FROM DocStatus
GROUP BY CONVERT(char(6),DocDate,112), Series, DocumentType
ORDER BY fp, Series, DocumentType`;
}

// ── route handlers ────────────────────────────────────────────────────────
async function handleQuery(req, res, sqlFn) {
  try {
    const from = safeDate(req.query.from || '');
    const to   = safeDate(req.query.to   || '');
    const { getPool } = require('../services/sqlPool');
    const pool = await getPool();
    const result = await pool.request().query(sqlFn(from, to));
    const data = result.recordset || [];
    // Normalize all numeric-looking values to actual JS numbers
    // prevents DECIMAL(18,2) from being stringified as "1.568E7" downstream
    const normalized = data.map(row => {
      const out = {};
      for (const [k, v] of Object.entries(row)) {
        if (v !== null && v !== undefined && typeof v === 'string' && /^-?[\d.]+([eE][+-]?\d+)?$/.test(v)) {
          out[k] = parseFloat(v);
        } else {
          out[k] = v;
        }
      }
      return out;
    });
    res.json({ success: true, data: normalized });
  } catch (err) {
    res.status(500).json({ success: false, message: err.message });
  }
}

router.get('/b2b',    verifyToken, (req, res) => handleQuery(req, res, sqlB2B));
router.get('/b2cl',   verifyToken, (req, res) => handleQuery(req, res, sqlB2CL));
router.get('/b2cs',   verifyToken, (req, res) => handleQuery(req, res, sqlB2CS));
router.get('/export', verifyToken, (req, res) => handleQuery(req, res, sqlExport));
router.get('/hsn',    verifyToken, (req, res) => handleQuery(req, res, sqlHsn));
router.get('/docs',   verifyToken, (req, res) => handleQuery(req, res, sqlDocs));

// ── TCS token ─────────────────────────────────────────────────────────────
async function getTcsToken() {
  const baseUrl  = process.env.TCS_GSP_BASE_URL || 'https://g31.tcsgsp.in';
  const username = process.env.TCS_GSP_USERNAME  || '';
  const password = process.env.TCS_GSP_PASSWORD  || '';
  const resp = await axios.get(
    `${baseUrl}/Tax-Tool-Core/services/accessMgmt/generateToken`,
    { headers: { 'Content-Type': 'application/json', username, password }, httpsAgent }
  );
  const token = resp.data?.access_token || resp.data?.token || resp.data?.accessToken;
  if (!token) throw new Error(`TCS token missing. Response: ${JSON.stringify(resp.data)}`);
  console.log('[TCS] Token obtained successfully');
  return token;
}

// ── Build TCS-format Excel workbook ───────────────────────────────────────
async function buildTcsExcel({ b2b = [], b2cl = [], b2cs = [], exp = [], hsn = [], docs = [] }, gstin) {
  const wb = new ExcelJS.Workbook();

  // Columns that must never render as scientific notation in Excel/TCS
  const NUMERIC_COLS = new Set([
    'fp','ack_sr_no','num','doc_num',
    'invoice_val','taxable_val','rate_of_tax',
    'igst_amnt','cgst_amnt','sgst_amnt','cess_amnt',
    'diff_igst_amnt','diff_cgst_amnt','diff_sgst_amnt','diff_cess_amnt',
    'diff_value','diff_percent','items_serial_no',
    'txval','rt','iamt','camt','samt','csamt',
    'qty','val','totnum','cancel','net_issue','pos',
  ]);

  function addSheet(name, headers, rows) {
    const ws = wb.addWorksheet(name);
    ws.addRow(headers);
    rows.forEach(r => {
      const rowData = headers.map(h => {
        const v = r[h];
        return (v === null || v === undefined) ? null : v;
      });
      const excelRow = ws.addRow(rowData);
      // Force plain decimal format — prevents 1.568502177E7 → "SANITY FAILED"
      headers.forEach((h, colIdx) => {
        if (NUMERIC_COLS.has(h)) {
          const cell = excelRow.getCell(colIdx + 1);
          if (typeof cell.value === 'number') {
            cell.numFmt = '0.##';   // no trailing zeros, never scientific
          }
        }
      });
    });
  }
  addSheet('B2B',
    ['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','invoice_type','cp_gstin','cp_gstin_name','invoice_no','invoice_dt','invoice_val','taxable_val','items_serial_no','rate_of_tax','igst_amnt','cgst_amnt','sgst_amnt','cess_amnt','pos','rchrg','is_gstn_for_ecom_app','gstn_for_ecom_app','or_cp_gstin','orignal_invoice_no','orignal_invoice_dt'],
    b2b.map((r,i)=>({trans_type_code:'B2B',fp:Number(r.fp),ack_sr_no:i+1,self_gstin:gstin,system_cd:null,branch_cd:null,vertical_cd:null,resultflag:r.resultflag||'A',invoice_type:r.trans_type_code==='DE'?'DE':'R',cp_gstin:r.cp_gstin||null,cp_gstin_name:r.cp_gstin_name||null,invoice_no:r.invoice_no,invoice_dt:r.invoice_dt,invoice_val:r.invoice_val,taxable_val:r.taxable_val,items_serial_no:r.items_serial_no||1,rate_of_tax:r.rate_of_tax,igst_amnt:r.igst_amnt||null,cgst_amnt:r.cgst_amnt||null,sgst_amnt:r.sgst_amnt||null,cess_amnt:r.cess_amnt||null,pos:r.pos,rchrg:r.rchrg||'N',is_gstn_for_ecom_app:r.is_gstn_for_ecom_app||'N',gstn_for_ecom_app:r.gstn_for_ecom_app||null,or_cp_gstin:null,orignal_invoice_no:null,orignal_invoice_dt:null}))
  );
  addSheet('B2BA',['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','invoice_type','cp_gstin','cp_gstin_name','invoice_no','invoice_dt','invoice_val','taxable_val','items_serial_no','rate_of_tax','igst_amnt','cgst_amnt','sgst_amnt','cess_amnt','pos','rchrg','is_gstn_for_ecom_app','gstn_for_ecom_app','or_cp_gstin','orignal_invoice_no','orignal_invoice_dt','diff_percent'],[]);
  addSheet('B2CL',
    ['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','invoice_type','invoice_no','invoice_dt','invoice_val','taxable_val','items_serial_no','rate_of_tax','igst_amnt','cess_amnt','pos','is_gstn_for_ecom_app','gstn_for_ecom_app','orignal_invoice_no','orignal_invoice_dt','diff_percent'],
    b2cl.map((r,i)=>({trans_type_code:'B2CL',fp:Number(r.fp),ack_sr_no:i+1,self_gstin:gstin,system_cd:null,branch_cd:null,vertical_cd:null,resultflag:r.resultflag||'A',invoice_type:null,invoice_no:r.invoice_no,invoice_dt:r.invoice_dt,invoice_val:r.invoice_val,taxable_val:r.taxable_val,items_serial_no:r.items_serial_no||1,rate_of_tax:r.rate_of_tax,igst_amnt:r.igst_amnt||null,cess_amnt:r.cess_amnt||null,pos:r.pos,is_gstn_for_ecom_app:r.is_gstn_for_ecom_app||'N',gstn_for_ecom_app:r.gstn_for_ecom_app||null,orignal_invoice_no:null,orignal_invoice_dt:null,diff_percent:0.65}))
  );
  addSheet('B2CLA',['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','invoice_type','invoice_no','invoice_dt','invoice_val','taxable_val','items_serial_no','rate_of_tax','igst_amnt','cess_amnt','pos','is_gstn_for_ecom_app','gstn_for_ecom_app','orignal_invoice_no','orignal_invoice_dt','diff_percent'],[]);
  addSheet('CDNR',['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','cp_gstin','cp_gstin_name','type_of_note','reason_code','is_pre_gst_regime','dbt_crdt_note_no','dbt_crdt_note_dt','dbt_crdt_note_val','invoice_no','invoice_dt','diff_value','items_serial_no','rate_of_tax','diff_igst_amnt','diff_cgst_amnt','diff_sgst_amnt','diff_cess_amnt','or_cp_gstin','or_dbt_crdt_note_no','or_dbt_crdt_note_dt'],[]);
  addSheet('CDNRA',['ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','cp_gstin','cp_gstin_name','type_of_note','reason_code','is_pre_gst_regime','dbt_crdt_note_no','dbt_crdt_note_dt','dbt_crdt_note_val','invoice_no','invoice_dt','diff_value','items_serial_no','rate_of_tax','diff_igst_amnt','diff_cgst_amnt','diff_sgst_amnt','diff_cess_amnt','or_cp_gstin','or_dbt_crdt_note_no','or_dbt_crdt_note_dt','diff_percent'],[]);
  addSheet('CDNUR',['fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','trans_cat_type','type_of_note','reason_code','is_pre_gst_regime','dbt_crdt_note_no','dbt_crdt_note_dt','dbt_crdt_note_val','invoice_no','invoice_dt','diff_value','items_serial_no','rate_of_tax','diff_igst_amnt','diff_cess_amnt','or_dbt_crdt_note_no','or_dbt_crdt_note_dt','diff_percent'],[]);
  addSheet('CDNURA',['fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','trans_cat_type','type_of_note','reason_code','is_pre_gst_regime','dbt_crdt_note_no','dbt_crdt_note_dt','dbt_crdt_note_val','invoice_no','invoice_dt','diff_value','items_serial_no','rate_of_tax','diff_igst_amnt','diff_cess_amnt','or_dbt_crdt_note_no','or_dbt_crdt_note_dt','diff_percent'],[]);
  addSheet('EXP',
    ['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','export_type_desc','invoice_no','invoice_dt','invoice_val','taxable_val','port_code','export_shipping_bill_no','export_shipping_bill_dt','rate_of_tax','igst_amnt','cess_amnt','orignal_invoice_no','orignal_invoice_dt','diff_percent'],
    exp.map((r,i)=>({trans_type_code:'EXP',fp:Number(r.fp),ack_sr_no:i+1,self_gstin:gstin,system_cd:null,branch_cd:null,vertical_cd:null,resultflag:r.resultflag||'A',export_type_desc:r.export_type_desc||'WOPAY',invoice_no:r.invoice_no,invoice_dt:r.invoice_dt,invoice_val:r.invoice_val,taxable_val:r.taxable_val,port_code:null,export_shipping_bill_no:r.export_shipping_bill_no||null,export_shipping_bill_dt:r.export_shipping_bill_dt||null,rate_of_tax:r.rate_of_tax,igst_amnt:r.igst_amnt||null,cess_amnt:r.cess_amnt||null,orignal_invoice_no:null,orignal_invoice_dt:null,diff_percent:0.65}))
  );
  addSheet('EXPA',['trans_type_code','fp','ack_sr_no','self_gstin','system_cd','branch_cd','vertical_cd','resultflag','export_type_desc','invoice_no','invoice_dt','invoice_val','taxable_val','port_code','export_shipping_bill_no','export_shipping_bill_dt','rate_of_tax','igst_amnt','cess_amnt','orignal_invoice_no','orignal_invoice_dt','diff_percent'],[]);

  const b2csGrouped = {};
  b2cs.forEach(r => {
    const key = `${r.pos}_${r.rate_of_tax}`;
    if (!b2csGrouped[key]) {
      b2csGrouped[key] = {
        pos: r.pos, rt: r.rate_of_tax,
        txval: 0, iamt: 0, camt: 0, samt: 0,
        sply_ty: Number(r.igst_amnt) > 0 ? 'INTER' : 'INTRA',
      };
    }
    b2csGrouped[key].txval += Number(r.taxable_val) || 0;
    b2csGrouped[key].iamt  += Number(r.igst_amnt)   || 0;
    b2csGrouped[key].camt  += Number(r.cgst_amnt)   || 0;
    b2csGrouped[key].samt  += Number(r.sgst_amnt)   || 0;
  });

  addSheet('B2CS',
    ['trans_type_code','fp','ack_sr_no','self_gstin','sply_ty','pos','txval','rt','iamt','camt','samt','csamt','typ','etin'],
    Object.values(b2csGrouped).map((r,i)=>({trans_type_code:'B2CS',fp:b2cs[0]?Number(b2cs[0].fp):null,ack_sr_no:i+1,self_gstin:gstin,sply_ty:r.sply_ty,pos:Number(r.pos),txval:Math.round(r.txval*100)/100,rt:Number(r.rt),iamt:r.iamt>0?Math.round(r.iamt*100)/100:null,camt:r.camt>0?Math.round(r.camt*100)/100:null,samt:r.samt>0?Math.round(r.samt*100)/100:null,csamt:null,typ:'OE',etin:null}))
  );
  addSheet('B2CSA',['trans_type_code','fp','ack_sr_no','self_gstin','sply_ty','pos','txval','rt','iamt','camt','samt','csamt','typ','etin','omon','opos'],[]);
  addSheet('Nil',['trans_type_code','fp','ack_sr_no','self_gstin','sply_ty','nil_amt','expt_amt','ngsup_amt'],[]);

  // Aggregate HSN by (hsn_sc, uqc, rate_of_tax) — TCS requires this combination to be unique
  const hsnAgg = {};
  hsn.forEach(r => {
    const uqc = validUQC(r.uqc);
    const rt  = r.rate_of_tax || 0;
    const section = r.section || 'B2B';
    const key = `${r.hsn_sc}_${uqc}_${rt}_${section}`;
    if (!hsnAgg[key]) {
      hsnAgg[key] = {
        fp: r.fp,
        hsn_sc: r.hsn_sc,
        gstr1Desc: r.gstr1Desc || 'Goods',
        uqc,
        rate_of_tax: rt,
        section,
        qty: 0, val: 0, txval: 0, iamt: 0, camt: 0, samt: 0,
      };
    }
    hsnAgg[key].qty   += parseFloat(r.qty)   || 0;
    hsnAgg[key].val   += parseFloat(r.val)   || 0;
    hsnAgg[key].txval += parseFloat(r.txval) || 0;
    hsnAgg[key].iamt  += parseFloat(r.iamt)  || 0;
    hsnAgg[key].camt  += parseFloat(r.camt)  || 0;
    hsnAgg[key].samt  += parseFloat(r.samt)  || 0;
  });

  // num: occurrence index of this HSN/SAC code among the rows being uploaded —
  // 1 if the code appears once, 1,2,... if the same code repeats across
  // different UQC/rate/section rows (verified against hsn_sc + uqc + rate_of_tax)
  const hsnRowsArr = Object.values(hsnAgg)
    .sort((a, b) => (a.hsn_sc < b.hsn_sc ? -1 : a.hsn_sc > b.hsn_sc ? 1 :
                     a.uqc    < b.uqc    ? -1 : a.uqc    > b.uqc    ? 1 :
                     a.section< b.section? -1 : a.section> b.section? 1 :
                     a.rate_of_tax - b.rate_of_tax));
  const hsnSeen = {};
  addSheet('HSN',
    ['trans_type_code','fp','ack_sr_no','self_gstin','num','hsn_sc','gstr1Desc','uqc','qty','val','txval','iamt','camt','samt','csamt','rate_of_tax','section'],
    hsnRowsArr.map((r, i) => {
      hsnSeen[r.hsn_sc] = (hsnSeen[r.hsn_sc] || 0) + 1;
      return {
      trans_type_code: 'HSNSAC',
      fp:          r.fp ? Number(toMMYYYY(r.fp)) : null,
      ack_sr_no:   i + 1,
      self_gstin:  gstin,
      num:         hsnSeen[r.hsn_sc],
      hsn_sc:      r.hsn_sc,
      gstr1Desc:   r.gstr1Desc,
      uqc:         r.uqc,
      qty:         r2(r.qty),
      val:         r2(r.val),
      txval:       r2(r.txval),
      iamt:        r.iamt ? r2(r.iamt) : null,
      camt:        r.camt ? r2(r.camt) : null,
      samt:        r.samt ? r2(r.samt) : null,
      csamt:       null,
      rate_of_tax: r.rate_of_tax,
      section:     r.section || 'B2B',
      };
    })
  );

  const DOC_TYPE_MAP={'Invoice':'Invoices for outward supply','AR Credit Memo':'Credit Notes','Delivery':'Delivery Challan in cases other than by way of supply (excluding job work, supply on approval, liquid gas )','AP Invoice (RCM)':'Invoices for inward supply from unregistered person','JW':'Delivery Challan for job work','IT':'Delivery Challan for supply on approval'};
  const DOC_NUM_MAP={'Invoice':1,'AR Credit Memo':4,'Delivery':12,'AP Invoice (RCM)':2,'JW':9,'IT':10};
  addSheet('DOC',
    ['trans_type_code','fp','ack_sr_no','self_gstin','doc_num','num','docType','sr_from','sr_to','totnum','cancel','net_issue'],
    docs.map((r,i)=>({trans_type_code:'DOCISSUE',fp:r.fp?Number(toMMYYYY(r.fp)):null,ack_sr_no:i+1,self_gstin:gstin,doc_num:DOC_NUM_MAP[r.DocumentType]||1,num:1,docType:DOC_TYPE_MAP[r.DocumentType]||r.DocumentType,sr_from:r.sr_from,sr_to:r.sr_to,totnum:r.totnum,cancel:r.canceled,net_issue:r.net_issue}))
  );
  addSheet('AT_ATA',['trans_type_code','fp','ack_sr_no','self_gstin','sply_ty','pos','ad_amt','rt','iamt','camt','samt','csamt','omon','or_pos','or_sply_ty'],[]);
  addSheet('TXPD_TXPDA',['trans_type_code','fp','ack_sr_no','self_gstin','sply_ty','pos','ad_amt','rt','iamt','camt','samt','csamt','omon','or_sply_ty','or_pos'],[]);
  return wb.xlsx.writeBuffer();
}

// ── postSummaryRaw: for HSN rows whose numeric fields are already plain
// decimal STRINGS from .toFixed(). Uses plain JSON.stringify — no replacer
// that could reconvert those strings back to numbers (and trigger scientific
// notation again).
async function postSummaryRaw(baseUrl, clientCode, endpoint, mappingCd, templateCd, gstin, period, token, rows) {
  const url = `${baseUrl}/Tax-Tool-Core/services/auth/invoiceUpload/${endpoint}`
    + `/${clientCode}/${mappingCd}/${templateCd}/${gstin}/JSON/${period}?oprFlag=SALESSUMMARY`;
  console.log(`[TCS] ${endpoint} URL:`, url, '| rows:', rows.length);
  // Plain stringify — values are already formatted strings, must NOT be reconverted to numbers
  const resp = await axios.post(url, JSON.stringify(rows), {
    headers: { 'Content-Type': 'application/json', gstin, clientCode, Authorization: `Bearer ${token}` },
    httpsAgent,
  });
  console.log(`[TCS] ${endpoint} status:`, resp.status, JSON.stringify(resp.data));
  return resp.data;
}

// Replacer: keep numbers as numbers (no quotes) but round to 2dp.
// JSON.stringify never uses scientific notation for finite numbers below 1e21.
function tcsJson(rows) {
  return JSON.stringify(rows, (_k, v) => {
    if (typeof v === 'number' && isFinite(v)) return parseFloat(v.toFixed(2));
    return v;
  });
}

async function postSummary(baseUrl, clientCode, endpoint, mappingCd, templateCd, gstin, period, token, rows) {
  const url = `${baseUrl}/Tax-Tool-Core/services/auth/invoiceUpload/${endpoint}`
    + `/${clientCode}/${mappingCd}/${templateCd}/${gstin}/JSON/${period}?oprFlag=SALESSUMMARY`;
  console.log(`[TCS] ${endpoint} URL:`, url, '| rows:', rows.length);
  const resp = await axios.post(url, tcsJson(rows), {
    headers: { 'Content-Type': 'application/json', gstin, clientCode, Authorization: `Bearer ${token}` },
    httpsAgent,
  });
  console.log(`[TCS] ${endpoint} status:`, resp.status, JSON.stringify(resp.data));
  return resp.data;
}

const DOC_TYPE_MAP = {
  'Invoice':          'Invoices for outward supply',
  'AR Credit Memo':   'Credit Notes',
  'Delivery':         'Delivery Challan in cases other than by way of supply (excluding job work, supply on approval, liquid gas )',
  'AP Invoice (RCM)': 'Invoices for inward supply from unregistered person',
  'JW':               'Delivery Challan for job work',
  'IT':               'Delivery Challan for supply on approval',
};
const DOC_NUM_MAP = { 'Invoice': 1, 'AR Credit Memo': 4, 'Delivery': 12, 'AP Invoice (RCM)': 2, 'JW': 9, 'IT': 10 };

// ═══════════════════════════════════════════════════════════════════════════
// POST /upload-tcs
// Uploads all GSTR-1 sections via their respective TCS JSON APIs:
//   B2B/B2CL/EXP → salesInvUpld (transactional)
//   B2CS         → salesSummaryUpldB2csb2csa   (summary)
//   HSN          → salesSummaryUpldAtatatxpd   (summary) — uses postSummaryRaw
//   DOC          → salesSummaryUpldDocumentsIssued (summary)
// ═══════════════════════════════════════════════════════════════════════════
router.post('/upload-tcs', verifyToken, async (req, res) => {
  try {
    const { period, b2b = [], b2cl = [], export: exp = [], b2cs = [], hsn = [], docs = [] } = req.body;
    if (!period) return res.status(400).json({ success: false, message: 'period required (MMYYYY)' });

    const baseUrl    = process.env.TCS_GSP_BASE_URL   || 'https://g31.tcsgsp.in';
    const gstin      = process.env.TCS_GSP_GSTIN       || '';
    const clientCode = process.env.TCS_GSP_CLIENT_CODE || '';
    const mappingCd  = process.env.TCS_GSP_MAPPING_CD  || 'MFHSIDTN0000005';
    const templateCd = process.env.TCS_GSP_TEMPLATE_CD || 'SalesInvoiceData802';

    const missing = [];
    if (!gstin)      missing.push('TCS_GSP_GSTIN');
    if (!clientCode) missing.push('TCS_GSP_CLIENT_CODE');
    if (missing.length) return res.status(400).json({ success: false, message: `Missing .env: ${missing.join(', ')}` });

    const token = await getTcsToken();
    let srNo = 0;

    const mappedB2B = b2b.map(row => ({
      trans_type_code:         'B2B',
      fp:                      row.fp,
      ack_sr_no:               ++srNo,
      self_gstin:              gstin,
      system_cd: '', branch_cd: '', vertical_cd: '',
      resultflag:              row.resultflag || 'A',
      export_type_desc:        '',
      invoice_type:            row.trans_type_code === 'DE' ? 'DE' : 'R',
      cp_gstin:                row.cp_gstin || '',
      cp_gstin_name:           row.cp_gstin_name || '',
      invoice_no:              row.invoice_no,
      invoice_dt:              row.invoice_dt,
      invoice_val:             row.invoice_val,
      taxable_val:             row.taxable_val,
      export_shipping_bill_no: '',
      export_shipping_bill_dt: '',
      items_serial_no:         row.items_serial_no || 1,
      rate_of_tax:             row.rate_of_tax,
      igst_amnt:               row.igst_amnt || '',
      cgst_amnt:               row.cgst_amnt || '',
      sgst_amnt:               row.sgst_amnt || '',
      cess_amnt:               row.cess_amnt || '',
      pos:                     String(row.pos || '').padStart(2, '0'),
      rchrg:                   row.rchrg || 'N',
      is_gstn_for_ecom_app:    row.is_gstn_for_ecom_app || 'N',
      gstn_for_ecom_app:       row.gstn_for_ecom_app || '',
      or_cp_gstin: '', orignal_invoice_no: '', orignal_invoice_dt: '',
      diff_percent:            0.65,
    }));

    const mappedB2CL = b2cl.map(row => ({
      trans_type_code:         'B2CL',
      fp:                      row.fp,
      ack_sr_no:               ++srNo,
      self_gstin:              gstin,
      system_cd: '', branch_cd: '', vertical_cd: '',
      resultflag:              row.resultflag || 'A',
      export_type_desc:        '',
      invoice_type:            '',
      cp_gstin: '', cp_gstin_name: '',
      invoice_no:              row.invoice_no,
      invoice_dt:              row.invoice_dt,
      invoice_val:             row.invoice_val,
      taxable_val:             row.taxable_val,
      export_shipping_bill_no: '',
      export_shipping_bill_dt: '',
      items_serial_no:         row.items_serial_no || 1,
      rate_of_tax:             row.rate_of_tax,
      igst_amnt:               row.igst_amnt || '',
      cgst_amnt: '', sgst_amnt: '',
      cess_amnt:               row.cess_amnt || '',
      pos:                     String(row.pos || '').padStart(2, '0'),
      rchrg:                   '',
      is_gstn_for_ecom_app:    row.is_gstn_for_ecom_app || 'N',
      gstn_for_ecom_app:       row.gstn_for_ecom_app || '',
      or_cp_gstin: '', orignal_invoice_no: '', orignal_invoice_dt: '',
      diff_percent:            0.65,
    }));

    // EXP — invoice_type field MUST NOT be included
    const mappedExp = exp.map(row => ({
      trans_type_code:         'EXP',
      fp:                      row.fp,
      ack_sr_no:               ++srNo,
      self_gstin:              gstin,
      system_cd: '', branch_cd: '', vertical_cd: '',
      resultflag:              row.resultflag || 'A',
      export_type_desc:        row.export_type_desc || 'WOPAY',
      cp_gstin: '', cp_gstin_name: '',
      invoice_no:              row.invoice_no,
      invoice_dt:              row.invoice_dt,
      invoice_val:             row.invoice_val,
      taxable_val:             row.taxable_val,
      export_shipping_bill_no: row.export_shipping_bill_no || '',
      export_shipping_bill_dt: row.export_shipping_bill_dt || '',
      items_serial_no:         '',
      rate_of_tax:             row.rate_of_tax,
      igst_amnt:               row.igst_amnt || '',
      cgst_amnt: '', sgst_amnt: '', cess_amnt: '',
      pos: '', rchrg: '', is_gstn_for_ecom_app: '', gstn_for_ecom_app: '',
      or_cp_gstin: '', orignal_invoice_no: '', orignal_invoice_dt: '',
      diff_percent:            0.65,
    }));

    const allRows = [...mappedB2B, ...mappedB2CL, ...mappedExp];
    const results = {};
    const errors  = [];

    // ── 1. Transactional: B2B + B2CL + EXP ──────────────────────────────
    if (allRows.length) {
      const jsonUrl = `${baseUrl}/Tax-Tool-Core/services/auth/invoiceUpload/salesInvUpld`
        + `/${clientCode}/${mappingCd}/${templateCd}/${gstin}/JSON/${period}?oprFlag=SALES`;
      console.log('[TCS] Invoice URL:', jsonUrl);
      console.log('[TCS] B2B:', mappedB2B.length, '| B2CL:', mappedB2CL.length, '| EXP:', mappedExp.length);
      const r = await axios.post(jsonUrl, allRows, {
        headers: { 'Content-Type': 'application/json', gstin, clientCode, Authorization: `Bearer ${token}` },
        httpsAgent,
      });
      console.log('[TCS] Invoice status:', r.status, JSON.stringify(r.data));
      results.invoices = r.data;
      if (r.data?.statusCd === 400 || r.data?.statusCd === '400') {
        const fe = Object.entries(r.data).filter(([k])=>k!=='statusCd').map(([k,v])=>`${k}: ${v}`).join(' | ');
        errors.push(`Invoices (B2B/B2CL/EXP): ${fe}`);
      }
    }

    // ── 2. B2CS summary ──────────────────────────────────────────────────
    if (b2cs.length) {
      const grouped = {};
      b2cs.forEach(r => {
        const key = `${r.pos}_${r.rate_of_tax}`;
        if (!grouped[key]) grouped[key] = { pos: r.pos, rt: r.rate_of_tax, txval: 0, iamt: 0, camt: 0, samt: 0,
          sply_ty: Number(r.igst_amnt) > 0 ? 'INTER' : 'INTRA' };
        grouped[key].txval += Number(r.taxable_val) || 0;
        grouped[key].iamt  += Number(r.igst_amnt)   || 0;
        grouped[key].camt  += Number(r.cgst_amnt)   || 0;
        grouped[key].samt  += Number(r.sgst_amnt)   || 0;
      });
      const b2csSummary = Object.values(grouped).map((r, i) => ({
        trans_type_code: 'B2CS',
        fp:        Number(b2cs[0]?.fp) || null,   // integer e.g. 42026
        ack_sr_no: i + 1,
        self_gstin: gstin,
        sply_ty:   r.sply_ty,
        pos:       String(r.pos),                  // 2-char string e.g. "23"
        txval:     Math.round(r.txval * 100) / 100,
        rt:        Number(r.rt),
        iamt:      r.iamt > 0 ? Math.round(r.iamt * 100) / 100 : 0,
        camt:      r.camt > 0 ? Math.round(r.camt * 100) / 100 : 0,
        samt:      r.samt > 0 ? Math.round(r.samt * 100) / 100 : 0,
        csamt:     0,
        typ:       'OE',
      }));
      const d = await postSummary(baseUrl, clientCode, 'salesSummaryUpldB2csb2csa',
        'MFHGSFTN0000714', 'GSTR1SummaryFormB2CSB2CSA835', gstin, period, token, b2csSummary);
      results.b2cs = d;
      if (d?.statusCd === 400 || d?.statusCd === '400') {
        const fe = Object.entries(d).filter(([k])=>k!=='statusCd').map(([k,v])=>`${k}: ${v}`).join(' | ');
        errors.push(`B2CS: ${fe}`);
      }
    }

    // ── 3. HSN summary ───────────────────────────────────────────────────
    if (hsn.length) {
      const hsnAggJson = {};
      hsn.forEach(r => {
        const uqc = validUQC(r.uqc);
        const rt  = r.rate_of_tax || 0;
        const section = r.section || 'B2B';
        const key = `${r.hsn_sc}_${uqc}_${rt}_${section}`;
        if (!hsnAggJson[key]) hsnAggJson[key] = {
          fp: r.fp, hsn_sc: r.hsn_sc, gstr1Desc: r.gstr1Desc || 'Goods',
          uqc, rate_of_tax: rt, section, qty: 0, val: 0, txval: 0, iamt: 0, camt: 0, samt: 0,
        };
        hsnAggJson[key].qty   += Number(r.qty)   || 0;
        hsnAggJson[key].val   += Number(r.val)   || 0;
        hsnAggJson[key].txval += Number(r.txval) || 0;
        hsnAggJson[key].iamt  += Number(r.iamt)  || 0;
        hsnAggJson[key].camt  += Number(r.camt)  || 0;
        hsnAggJson[key].samt  += Number(r.samt)  || 0;
      });

      // num: occurrence index of this HSN/SAC code among the rows being uploaded —
      // 1 if the code appears once, 1,2,... if the same code repeats across
      // different UQC/rate/section rows (verified against hsn_sc + uqc + rate_of_tax)
      const hsnRowsSorted = Object.values(hsnAggJson)
        .sort((a, b) => (a.hsn_sc < b.hsn_sc ? -1 : a.hsn_sc > b.hsn_sc ? 1 :
                         a.uqc    < b.uqc    ? -1 : a.uqc    > b.uqc    ? 1 :
                         a.section< b.section? -1 : a.section> b.section? 1 :
                         a.rate_of_tax - b.rate_of_tax));
      const hsnSeenJson = {};

      // All numeric fields serialized as plain decimal STRINGS via .toFixed()
      // so JSON.stringify never sees a raw float and cannot produce scientific notation
      const hsnRows = hsnRowsSorted.map((r, i) => {
        hsnSeenJson[r.hsn_sc] = (hsnSeenJson[r.hsn_sc] || 0) + 1;
        return {
        fp:          toMMYYYY(r.fp),
        ack_sr_no:   i + 1,
        self_gstin:  gstin,
        num:         hsnSeenJson[r.hsn_sc],
        hsn_sc:      r.hsn_sc,
        gstr1Desc:   r.gstr1Desc,
        uqc:         r.uqc,
        qty:         Number(parseFloat(r.qty   || 0).toFixed(2)),
        val:         parseFloat(r.val   || 0).toFixed(2),  // string "15685021.77"
        txval:       parseFloat(r.txval || 0).toFixed(2),  // string "15685021.77"
        iamt:        parseFloat(r.iamt  || 0).toFixed(2),
        camt:        parseFloat(r.camt  || 0).toFixed(2),
        samt:        parseFloat(r.samt  || 0).toFixed(2),
        csamt:       '',
        rate_of_tax: parseFloat(r.rate_of_tax || 0).toFixed(2),
        section:     r.section || 'B2B',
        };
      });

      // Log first 2 rows so you can verify no scientific notation before it hits TCS
      console.log('[TCS] HSN payload sample:', JSON.stringify(hsnRows.slice(0, 2), null, 2));

      // Use postSummaryRaw — plain JSON.stringify, no replacer that could reconvert strings
      const d = await postSummaryRaw(baseUrl, clientCode, 'salesSummaryUpldAtatatxpd',
        'MFHGSFTN0000716', 'GSTR1SummaryFormHSNSACSummary837', gstin, period, token, hsnRows);
      results.hsn = d;
      if (d?.statusCd === 400 || d?.statusCd === '400') {
        const fe = Object.entries(d).filter(([k])=>k!=='statusCd').map(([k,v])=>`${k}: ${v}`).join(' | ');
        errors.push(`HSN: ${fe}`);
      }
    }

    // ── 4. Documents Issued summary ──────────────────────────────────────
    if (docs.length) {
      const docRows = docs.map((r, i) => ({
        fp:        Number(toMMYYYY(r.fp)) || null,     // integer e.g. 42026
        ack_sr_no: i + 1,                               // integer
        self_gstin: gstin,
        doc_num:   DOC_NUM_MAP[r.DocumentType] || 1,   // integer
        num:       1,                                   // integer
        docType:   DOC_TYPE_MAP[r.DocumentType] || r.DocumentType,
        sr_from:   String(r.sr_from),
        sr_to:     String(r.sr_to),
        totnum:    parseInt(r.totnum, 10) || 0,         // integer
        cancel:    parseInt(r.canceled, 10) || 0,       // integer
        net_issue: parseInt(r.net_issue, 10) || 0,      // integer
      }));
      const d = await postSummary(baseUrl, clientCode, 'salesSummaryUpldDocumentsIssued',
        'MFHGSFTN0000717', 'GSTR1SummaryFormDocumentsIssuedSummary838', gstin, period, token, docRows);
      results.docs = d;
      if (d?.statusCd === 400 || d?.statusCd === '400') {
        const fe = Object.entries(d).filter(([k])=>k!=='statusCd').map(([k,v])=>`${k}: ${v}`).join(' | ');
        errors.push(`DOC: ${fe}`);
      }
    }

    if (!Object.keys(results).length) {
      return res.status(400).json({ success: false, message: 'No data to upload' });
    }

    if (errors.length) {
      return res.status(400).json({ success: false, message: errors.join(' | '), data: results });
    }

    const primaryAck = results.invoices?.ackNo || results.b2cs?.ackNo || results.hsn?.ackNo || results.docs?.ackNo;
    return res.json({ success: true, data: { ackNo: primaryAck, ...results }, method: 'JSON' });

  } catch (err) {
    const msg = err.response?.data ? `[${err.response.status}] ${JSON.stringify(err.response.data)}` : err.message;
    console.error('[TCS] Error:', msg);
    res.status(500).json({ success: false, message: msg });
  }
});

// ── POST /upload-tcs-excel — Excel format upload ──────────────────────────
router.post('/upload-tcs-excel', verifyToken, async (req, res) => {
  try {
    const { period, b2b = [], b2cl = [], b2cs = [], export: exp = [], hsn = [], docs = [] } = req.body;
    if (!period) return res.status(400).json({ success: false, message: 'period required' });

    const baseUrl    = process.env.TCS_GSP_BASE_URL   || 'https://g31.tcsgsp.in';
    const gstin      = process.env.TCS_GSP_GSTIN       || '';
    const clientCode = process.env.TCS_GSP_CLIENT_CODE || '';
    const mappingCd  = process.env.TCS_GSP_MAPPING_CD  || 'MFHSIDTN0000005';
    const templateCd = process.env.TCS_GSP_TEMPLATE_CD || 'SalesInvoiceData802';

    const token = await getTcsToken();
    const excelBuf = await buildTcsExcel({ b2b, b2cl, b2cs, exp, hsn, docs }, gstin);

    const form = new FormData();
    form.append('file', excelBuf, { filename: `GSTR1_${period}.xlsx`, contentType: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', knownLength: excelBuf.length });
    form.append('UpldGstinLst', gstin);

    const uploadUrl = `${baseUrl}/Tax-Tool-Core/services/auth/invoiceUpload/salesInvUpldForEXCEL/${clientCode}/${mappingCd}/${templateCd}/${gstin}/EXCEL/${period}?oprFlag=SALES`;
    console.log('[TCS] Excel Upload URL:', uploadUrl);

    const uploadResp = await axios.post(uploadUrl, form, {
      headers: { ...form.getHeaders(), gstin, clientCode, Authorization: `Bearer ${token}` },
      maxContentLength: Infinity, maxBodyLength: Infinity, httpsAgent,
    });

    console.log('[TCS] Excel Status  :', uploadResp.status);
    console.log('[TCS] Excel Response:', JSON.stringify(uploadResp.data, null, 2));

    const tcsData = uploadResp.data;
    if (tcsData?.statusCd === 400 || tcsData?.statusCd === '400') {
      const fieldErrors = Object.entries(tcsData).filter(([k])=>k!=='statusCd').map(([k,v])=>`${k}: ${v}`).join(' | ');
      return res.status(400).json({ success: false, message: `TCS Excel error — ${fieldErrors}`, raw: tcsData });
    }

    res.json({ success: true, data: tcsData, method: 'EXCEL' });

  } catch (err) {
    const msg = err.response?.data ? JSON.stringify(err.response.data) : err.message;
    res.status(500).json({ success: false, message: msg });
  }
});

module.exports = router;