Update the backend to fetch Milk Bill data from Oracle DB using the exact query flow below.

⚠️ STRICT RULES
Do NOT change database structure
Do NOT simplify logic
Follow steps exactly as provided
Keep frontend response clean and structured
Use existing Oracle connection
🧠 IMPLEMENT THIS FLOW AS A SERVICE

Create a backend function:

getMilkBill({ fromDate, toDate, dcsCode })
🔹 STEP 1: FETCH BILL HEADER

Use this query:

SELECT
B.BILLID,
D.DCSDISPLAYCODE,
D.DCSNAME,
B.BILLDATE,
B.BILLNO,
B.RATEDISPLAYONBILL,
B.BILLAMOUNT,
F.BANKNAME,
T.ACCOUNTNO
FROM FA_DCSBILL_T B
INNER JOIN PI_DCS_M D ON D.DCSCODE = B.DCSCODE
INNER JOIN PI_DCSBANK_T T ON T.DCSCODE = D.DCSCODE
INNER JOIN FA_BANK_M F ON T.BANKID = F.BANKID
WHERE B.BILLFROMDATE = :fromDate
AND B.BILLTILLDATE = :toDate
AND T.BANKUSAGEID = 'Z011'
AND D.DCSDISPLAYCODE = :dcsCode

👉 This returns BILLID → required for all next steps

🔹 STEP 2: FETCH BILL DETAILS
SELECT
MILKDATE,
SHIFT,
QUALITY,
QUANTITY,
FATPERCENTAGE AS FAT,
SNFPERCENTAGE AS SNF,
CALCULATEDRATE AS RATE,
CALCULATEDAMOUNT AS AMOUNT
FROM FA_DCSBILLDETAILS_T
WHERE BILLID = :billId
ORDER BY MILKDATE

👉 Convert:

SHIFT: 1 → E, 0 → M
🔹 STEP 3: TOTALS
Total Quantity = SUM(QUANTITY)
Total Amount = SUM(AMOUNT)
🔹 STEP 4: PAYMENTS
Milk Cost:
SELECT SUM(CALCULATEDAMOUNT)
FROM FA_DCSBILLDETAILS_T
WHERE BILLID = :billId
Headload:
SELECT SUM(HEADLOADAMOUNT)
FROM FA_DCSBILLDETAILS_T
WHERE BILLID = :billId
Payment Advice:
SELECT *
FROM CI_PAYMENTADVICE_T T
INNER JOIN PI_DCS_M D ON D.DCSCODE = T.DCSID
WHERE D.DCSDISPLAYCODE = :dcsCode
AND T.PAYMENTADVICEDATE BETWEEN :fromDate AND :toDate
🔹 STEP 5: DEDUCTIONS
Standard:
SELECT T.DEDUCTIONTRANSNAME, T.DEDUCTIONTRANSAMT
FROM FA_DEDUCTION_T T
INNER JOIN PI_DCS_M D ON D.DCSCODE = T.DCSCODE
WHERE DEDFROMDATE = :fromDate
AND DEDTODATE = :toDate
AND D.DCSDISPLAYCODE = :dcsCode
Other:
SELECT
T.AMOUNT,
M.DEDUCTIONHEADNAME
FROM FA_CIDEDUCTION_T T
INNER JOIN PI_DCS_M D ON D.DCSCODE = T.DCSCODE
INNER JOIN CI_DEDUCTIONHEAD_M M ON T.DEDUCTIONHEADID = M.DEDUCTIONHEADID
WHERE T.BILLFROMDATE = :fromDate
AND T.BILLTILLDATE = :toDate
AND D.DCSDISPLAYCODE = :dcsCode
Outstanding:
SELECT
T.DEDUCTIONHEADNAME,
T.DEDUCTEDAMOUNT
FROM FA_DCSWISEDEDHEADWISE_TEMP T
INNER JOIN PI_DCS_M M ON M.DCSCODE = T.DCSID
WHERE T.BILLFROMDATE = :prevFromDate
AND T.BILLTILLDATE = :prevToDate
AND M.DCSDISPLAYCODE = :dcsCode
🔹 STEP 6: PRICE DIFFERENCE
SELECT PRICEDIFFPERIODICALAMT
FROM FA_PRICEDIFFPERIODICAL_T T
INNER JOIN PI_DCS_M D ON D.DCSCODE = T.DCSCODE
WHERE D.DCSDISPLAYCODE = :dcsCode
AND T.MILKFROMDATE = :prevFromDate
AND T.MILKTODATE = :prevToDate
🔹 STEP 7: ADDITIONAL PAYMENTS
SELECT
M.SERVICENAME,
T.PAYMENTADVICEAMOUNT
FROM CI_PAYMENTADVICE_T T
INNER JOIN PI_DCS_M D ON D.DCSCODE = T.DCSID
INNER JOIN CI_SERVICE_M M ON T.SERVICEID = M.SERVICEID
WHERE D.DCSDISPLAYCODE = :dcsCode
AND T.PAYMENTADVICEDATE BETWEEN :fromDate AND :toDate
ORDER BY T.CREATIONDATE
🔹 STEP 8: FINAL CALCULATION

Compute:

netPayable =
  milkCost +
  headload +
  priceDiff +
  additionalPayments
  - totalDeductions
🧾 FINAL API RESPONSE FORMAT

Return structured response:

{
  header: {...},
  entries: [...],
  totals: {
    quantity,
    amount
  },
  payments: {
    milkCost,
    headload,
    additional
  },
  deductions: {
    standard: [],
    other: [],
    outstanding: []
  },
  priceDiff,
  netPayable
}
⚠️ IMPORTANT
Handle null values from Oracle
Do NOT expose raw DB column names
Keep response frontend-friendly
Use async/await properly
🎯 GOAL
Fully working Milk Bill API
Accurate calculation based on real business logic
Clean structured response for UI