feat: interest posting

src/app/tds-reports/tds-reports.compute.ts

@@ -56,6 +56,25 @@ export interface TdsReportFilter {
   nearThresholdOnly: boolean;
 }
 
+/**
+ * One of the customer's accounts as the report sees it: whether its interest is being counted
+ * toward the deduction, and if not, why not. A customer can hold savings, fixed and recurring
+ * accounts together, and the branch has to see which of them the deduction is actually watching.
+ */
+export interface TdsAccountLine {
+  accountNo: string;
+  type: 'FD' | 'RD' | 'SB' | 'OTHER';
+  /** True when the account's interest counts toward this customer's threshold. */
+  tracked: boolean;
+  /** Plain-language reason, shown beside the account. */
+  reason: string;
+  /** Interest credited in the year. */
+  interest: number;
+  /** How many interest postings made up that figure. */
+  postings: number;
+  lastPostedOn: string | null;
+}
+
 /** How close to the trigger counts as "worth chasing a declaration for". */
 export const NEAR_THRESHOLD_BAND = 6_000;
 
@@ -101,6 +120,10 @@ export interface TdsInterestRow {
   paidWithoutDeduction: number;
   panOnRecord: boolean;
   rateApplied: number;
+  /** Every account the customer holds, tracked or not. */
+  accounts: TdsAccountLine[];
+  /** How many of them count toward the deduction. */
+  trackedAccounts: number;
 }
 
 function emptyQuarters(): Record<Quarter, number> {
@@ -154,14 +177,35 @@ export function tdsInterestRowsForFy(fy: string): TdsInterestRow[] {
 
     let exemptInterest = 0;
     let jointHeldInterest = 0;
+    const accountLines: TdsAccountLine[] = [];
     for (const account of deductee.accounts) {
-      const inYear = account.credits.filter((c) => fyOf(c.date) === fy).reduce((s, c) => s + c.amount, 0);
+      const yearCredits = account.credits.filter((c) => fyOf(c.date) === fy);
+      const inYear = yearCredits.reduce((s, c) => s + c.amount, 0);
+      const type = accountTypeOf(account.depositTypeCode);
+      let tracked = false;
+      let reason: string;
       if (!isTdsApplicable(account)) {
         exemptInterest += inYear;
+        reason = type === 'SB' ? 'Savings account — no TDS on savings interest' : 'Not a time deposit — no TDS';
       } else if (tdsDeducteeOf(account) !== deductee.clientId) {
         jointHeldInterest += inYear;
+        reason = 'Joint deposit — counted under the first-named holder';
+      } else {
+        tracked = true;
+        reason = 'Counted toward the TDS limit';
       }
+      accountLines.push({
+        accountNo: account.accountNo || '',
+        type,
+        tracked,
+        reason,
+        interest: inYear,
+        postings: yearCredits.length,
+        lastPostedOn: yearCredits.reduce<string | null>((last, c) => (!last || c.date > last ? c.date : last), null)
+      });
     }
+    // Tracked accounts first, so the deposits that drive the figure lead the list.
+    accountLines.sort((a, b) => Number(b.tracked) - Number(a.tracked));
 
     const crossedLine = schedule.lines.find((l) => l.thresholdCrossedHere);
     const headroom = Math.max(0, schedule.threshold - schedule.totalInterest);
@@ -190,7 +234,9 @@ export function tdsInterestRowsForFy(fy: string): TdsInterestRow[] {
       tdsSaved: declaration ? Math.max(0, withoutDeclaration.totalTds - schedule.totalTds) : 0,
       paidWithoutDeduction: schedule.shieldedInterest,
       panOnRecord: isWellFormedPan(deductee.pan),
-      rateApplied: schedule.rateApplied
+      rateApplied: schedule.rateApplied,
+      accounts: accountLines,
+      trackedAccounts: accountLines.filter((a) => a.tracked).length
     });
   }
 
@@ -210,10 +256,29 @@ function overallModeFor(deductee: TdsDeductee): TdsMode {
   return applicable.some((a) => tdsModeFor(a) === 'QUARTERLY') ? 'QUARTERLY' : 'ANNUAL';
 }
 
+function accountTypeOf(code: string | undefined): TdsAccountLine['type'] {
+  const c = (code || '').toLowerCase();
+  if (c.includes('fixeddeposit')) {
+    return 'FD';
+  }
+  if (c.includes('recurringdeposit')) {
+    return 'RD';
+  }
+  if (c.includes('savings')) {
+    return 'SB';
+  }
+  return 'OTHER';
+}
+
+/** Branches are compared by office name, case and spacing aside — the platform and the session both carry the name. */
+function sameBranch(a: string, b: string): boolean {
+  return (a || '').trim().toLowerCase() === (b || '').trim().toLowerCase();
+}
+
 export function tdsInterestRows(filter: TdsReportFilter): TdsInterestRow[] {
   const needle = filter.search.trim().toLowerCase();
   return tdsInterestRowsForFy(filter.fy).filter((row) => {
-    if (filter.branchCode && row.branchCode !== filter.branchCode) {
+    if (filter.branchCode && !sameBranch(row.branchCode, filter.branchCode)) {
       return false;
     }
     if (filter.band && row.band !== filter.band) {
@@ -254,6 +319,8 @@ export interface TdsInterestSummary {
   tdsSaved: number;
   paidWithoutDeduction: number;
   noPan: number;
+  /** Customers holding at least one account whose interest counts toward the deduction. */
+  trackedCustomers: number;
   byQuarter: { quarter: Quarter; interest: number; tds: number }[];
 }
 
@@ -280,7 +347,10 @@ export function tdsInterestSummary(filter: TdsReportFilter): TdsInterestSummary
     declarations: rows.filter((r) => r.hasDeclaration).length,
     tdsSaved: rows.reduce((s, r) => s + r.tdsSaved, 0),
     paidWithoutDeduction: rows.reduce((s, r) => s + r.paidWithoutDeduction, 0),
-    noPan: rows.filter((r) => !r.panOnRecord).length,
+    // Only customers with a deposit the deduction watches: a savings-only customer without a PAN
+    // is never deducted at the higher rate, so counting them overstated the problem.
+    noPan: rows.filter((r) => !r.panOnRecord && r.trackedAccounts > 0).length,
+    trackedCustomers: rows.filter((r) => r.trackedAccounts > 0).length,
     byQuarter
   };
 }