feat(investment): deal time, interest cycle and charges on Purchase Entry

As per Jitendra Sir's review:
- Deal Time is now a mandatory field next to Deal Date.
- New Interest Cycle section: the two coupon days, last and next coupon,
  next coupon amount and days to it.
- Stamp duty, brokerage and other charges sit on the main form. They are
  expenses on their own GLs (500601/500602/500603), so they are added to
  the settlement amount but no longer to the book value, and each shows
  as its own debit line in the accounting preview.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/investment/bond-investment/bond-investment.component.html

@@ -214,6 +214,10 @@
             (ngModelChange)="onDealDateChange()"
           ></mifosx-date-ddmmyyyy
         ></label>
+        <label class="inv-form-field"
+          ><span>* Deal Time (HH:mm:ss)</span
+          ><input type="text" [(ngModel)]="purchaseForm.dealTime" placeholder="HH:mm:ss"
+        /></label>
         <label class="inv-form-field">
           <span>* Settlement Type</span>
           <select [(ngModel)]="purchaseForm.settlementType">
@@ -261,6 +265,15 @@
             }
           </select>
         </label>
+        <label class="inv-form-field"
+          ><span>Stamp Duty (₹)</span><input type="number" [(ngModel)]="purchaseForm.stampDuty" min="0"
+        /></label>
+        <label class="inv-form-field"
+          ><span>Brokerage (₹)</span><input type="number" [(ngModel)]="purchaseForm.brokerage" min="0"
+        /></label>
+        <label class="inv-form-field"
+          ><span>Other Charges (₹)</span><input type="number" [(ngModel)]="purchaseForm.otherCharges" min="0"
+        /></label>
       </div>
 
       <!-- 2. Calculated — filled by the system, read-only -->
@@ -316,12 +329,38 @@
           /></label>
           <label class="inv-form-field"><span>YTM %</span><input type="text" [value]="purchaseYtm" readonly /></label>
         }
+        <label class="inv-form-field"
+          ><span>Charges (expense)</span
+          ><input type="text" [value]="'₹' + (purchaseTotalCharges | number: '1.2-2')" readonly
+        /></label>
         <label class="inv-form-field"
           ><span>Total Settlement Amount</span
           ><input type="text" [value]="'₹' + (purchaseSettlementAmount | number: '1.2-2')" readonly
         /></label>
       </div>
 
+      @if (!isMutualFund && purchaseCouponDates) {
+        <div class="pos-section-label">Interest Cycle</div>
+        <div class="inv-form-grid">
+          <label class="inv-form-field"
+            ><span>Interest Dates (half-yearly)</span><input type="text" [value]="purchaseCouponDates" readonly
+          /></label>
+          <label class="inv-form-field"
+            ><span>Last Coupon</span><input type="text" [value]="purchaseForm.lastIntDt || '—'" readonly
+          /></label>
+          <label class="inv-form-field"
+            ><span>Next Coupon</span><input type="text" [value]="purchaseNextCouponDate || '—'" readonly
+          /></label>
+          <label class="inv-form-field"
+            ><span>Next Coupon Amount</span
+            ><input type="text" [value]="'₹' + (purchaseNextCouponAmount | number: '1.2-2')" readonly
+          /></label>
+          <label class="inv-form-field"
+            ><span>Days to Next Coupon</span><input type="text" [value]="purchaseDaysToNextCoupon" readonly
+          /></label>
+        </div>
+      }
+
       <!-- 3. Accounting preview -->
       <div class="pos-section-label">Accounting Preview (posted after checker approval)</div>
       @if (purchaseAccountingPreview.length) {
@@ -358,10 +397,6 @@
       @if (showMoreDetails) {
         <div class="pos-section-label">More Details (optional)</div>
         <div class="inv-form-grid">
-          <label class="inv-form-field"
-            ><span>Deal Time (HH:mm:ss)</span
-            ><input type="text" [(ngModel)]="purchaseForm.dealTime" placeholder="HH:mm:ss"
-          /></label>
           <label class="inv-form-field">
             <span>Sub Type</span>
             <select [(ngModel)]="purchaseForm.subType">
@@ -374,9 +409,6 @@
             <label class="inv-form-field"
               ><span>Trade Amt</span><input type="number" [(ngModel)]="purchaseForm.tradeAmt" min="0"
             /></label>
-            <label class="inv-form-field"
-              ><span>Stamp Duty</span><input type="number" [(ngModel)]="purchaseForm.stampDuty" min="0"
-            /></label>
             <label class="inv-form-field"
               ><span>Stamp Duty A/c</span><input type="text" [(ngModel)]="purchaseForm.stampDutyAc"
             /></label>
@@ -413,9 +445,6 @@
               ><span>TBill GL A/c</span><input type="text" [(ngModel)]="purchaseForm.tbillGlAc"
             /></label>
           }
-          <label class="inv-form-field"
-            ><span>Brokerage (₹)</span><input type="number" [(ngModel)]="purchaseForm.brokerage" min="0"
-          /></label>
           <label class="inv-form-field">
             <span>Broker</span>
             <select [(ngModel)]="purchaseForm.brokerName">

src/app/investment/bond-investment/bond-investment.component.ts

@@ -29,11 +29,16 @@ import {
   INVESTMENT_GL_BY_TYPE,
   INVESTMENT_GL_LOOKUP,
   INTEREST_RECEIVABLE_GL,
+  STAMP_DUTY_GL,
+  BROKERAGE_GL,
+  OTHER_CHARGES_GL,
   SETTLEMENT_BANK_GL_OPTIONS,
   periodBetween,
   parseDDMMYYYY,
   days360,
   lastHalfYearlyCouponDate,
+  nextHalfYearlyCouponDate,
+  couponDatesLabel,
   InvestmentHolding,
   InvestmentTxn,
   InstrumentType,
@@ -135,6 +140,7 @@ interface BondPurchaseForm {
   holdingDays: number | null;
   stampDuty: number | null;
   stampDutyAc: string;
+  otherCharges: number | null;
 }
 
 interface AccountingPreviewLine {
@@ -448,7 +454,8 @@ export class BondInvestmentComponent implements OnInit {
       nav: null,
       holdingDays: null,
       stampDuty: null,
-      stampDutyAc: ''
+      stampDutyAc: '',
+      otherCharges: null
     };
   }
 
@@ -518,14 +525,41 @@ export class BondInvestmentComponent implements OnInit {
     return this.isMutualFund ? this.purchaseForm.nav || 0 : 100;
   }
 
-  /** Book Value — what the investment is carried at, i.e. amount actually paid. */
+  /** Book Value — the price paid for the security. Charges are expenses and stay out of it (Jitendra Sir). */
   get purchaseBookValue(): number {
     const f = this.purchaseForm;
     if (this.isMutualFund) {
-      return this.purchaseBaseAmount + (f.stampDuty || 0) + (f.brokerage || 0);
+      return this.purchaseBaseAmount;
     }
     const rate = f.purchaseRate || 100;
-    return Math.round((this.purchaseBaseAmount * rate) / 100) + (f.brokerage || 0);
+    return Math.round((this.purchaseBaseAmount * rate) / 100);
+  }
+
+  /** Stamp duty + brokerage + other charges — paid with the settlement, booked to expense GLs. */
+  get purchaseTotalCharges(): number {
+    const f = this.purchaseForm;
+    return (f.stampDuty || 0) + (f.brokerage || 0) + (f.otherCharges || 0);
+  }
+
+  // Interest cycle of the security being bought: its two coupon days and the next coupon after the deal.
+  get purchaseCouponDates(): string {
+    return this.purchaseMaturityDate ? couponDatesLabel(this.purchaseMaturityDate) : '';
+  }
+
+  get purchaseNextCouponDate(): string {
+    const f = this.purchaseForm;
+    return this.purchaseMaturityDate && f.dealDate
+      ? nextHalfYearlyCouponDate(this.purchaseMaturityDate, f.dealDate)
+      : '';
+  }
+
+  get purchaseNextCouponAmount(): number {
+    const f = this.purchaseForm;
+    return f.intRate ? Math.round((this.purchaseBaseAmount * f.intRate) / 200) : 0;
+  }
+
+  get purchaseDaysToNextCoupon(): number {
+    return this.purchaseNextCouponDate ? days360(this.purchaseForm.dealDate, this.purchaseNextCouponDate) : 0;
   }
 
   get purchaseYtm(): number {
@@ -574,9 +608,9 @@ export class BondInvestmentComponent implements OnInit {
     }
   }
 
-  /** Settlement Amt of Purchase — book value plus accrued interest payable to the seller. */
+  /** Settlement Amt of Purchase — book value, accrued interest payable to the seller and the charges. */
   get purchaseSettlementAmount(): number {
-    return this.purchaseBookValue + this.purchaseAccruedInterest;
+    return this.purchaseBookValue + this.purchaseAccruedInterest + this.purchaseTotalCharges;
   }
 
   get purchaseMaturityAmount(): number {
@@ -683,6 +717,28 @@ export class BondInvestmentComponent implements OnInit {
         amount: accrued
       });
     }
+    const f = this.purchaseForm;
+    for (const [
+      gl,
+      amount
+    ] of [
+      [
+        STAMP_DUTY_GL,
+        f.stampDuty
+      ],
+      [
+        BROKERAGE_GL,
+        f.brokerage
+      ],
+      [
+        OTHER_CHARGES_GL,
+        f.otherCharges
+      ]
+    ] as const) {
+      if (amount && amount > 0) {
+        lines.push({ side: 'Dr', glCode: gl.glCode, glName: gl.glName, amount });
+      }
+    }
     lines.push({ side: 'Cr', glCode: crGl, glName: this.glNameOf(crGl), amount: total });
     return lines;
   }
@@ -693,6 +749,7 @@ export class BondInvestmentComponent implements OnInit {
     if (!f.scriptCode) missing.push('Script Code');
     if (!f.partyCode) missing.push('Party Code');
     if (!f.dealDate) missing.push('Deal Date');
+    if (!f.dealTime) missing.push('Deal Time');
     if (this.isMutualFund) {
       if (!f.considerAmt) missing.push('Consider Amt');
       if (!f.nav) missing.push('NAV');
@@ -726,9 +783,11 @@ export class BondInvestmentComponent implements OnInit {
       dealTime: f.dealTime || '',
       settlementType: f.settlementType,
       ...(this.isMutualFund
-        ? { considerAmt: f.considerAmt, nav: f.nav, stampDuty: f.stampDuty ?? null }
+        ? { considerAmt: f.considerAmt, nav: f.nav }
         : { faceValue: f.faceValue, purchaseRate: f.purchaseRate, lastIntDate: f.lastIntDt }),
+      stampDuty: f.stampDuty ?? null,
       brokerage: f.brokerage ?? null,
+      otherCharges: f.otherCharges ?? null,
       category: f.category,
       crGlAccountId,
       subType: f.subType || '',

src/app/investment/investment-data.ts

@@ -303,6 +303,35 @@ export function lastHalfYearlyCouponDate(maturityStr: string, onStr: string): st
   return best ? formatDDMMYYYY(best) : '';
 }
 
+/** First half-yearly coupon date after `onStr` (coupons fall on the maturity day/month and six months
+ *  either side), never later than maturity. */
+export function nextHalfYearlyCouponDate(maturityStr: string, onStr: string): string {
+  const last = lastHalfYearlyCouponDate(maturityStr, onStr);
+  const mat = parseDDMMYYYY(maturityStr);
+  if (!last || isNaN(mat.getTime())) {
+    return '';
+  }
+  const l = parseDDMMYYYY(last);
+  const year = l.getFullYear() + (l.getMonth() >= 6 ? 1 : 0);
+  const month = (l.getMonth() + 6) % 12;
+  const next = new Date(year, month, Math.min(mat.getDate(), new Date(year, month + 1, 0).getDate()));
+  return formatDDMMYYYY(next > mat ? mat : next);
+}
+
+/** The two coupon days of a half-yearly security, e.g. "14 Feb / 14 Aug". */
+export function couponDatesLabel(maturityStr: string): string {
+  const mat = parseDDMMYYYY(maturityStr);
+  if (isNaN(mat.getTime())) {
+    return '';
+  }
+  const label = (month: number): string => {
+    const day = Math.min(mat.getDate(), new Date(2001, month + 1, 0).getDate());
+    return `${day} ${new Date(2001, month, 1).toLocaleString('en-US', { month: 'short' })}`;
+  };
+  const first = mat.getMonth() % 6;
+  return `${label(first)} / ${label(first + 6)}`;
+}
+
 export function formatDDMMYYYY(d: Date): string {
   return `${String(d.getDate()).padStart(2, '0')}-${String(d.getMonth() + 1).padStart(2, '0')}-${d.getFullYear()}`;
 }
@@ -1480,6 +1509,11 @@ export const INVESTMENT_GL_BY_TYPE: Record<InstrumentType, string> = {
   SHARE: '100706'
 };
 
+/** Charges on an investment deal — expenses on their own GLs, not part of the book value (Jitendra Sir). */
+export const STAMP_DUTY_GL: InvestmentGlOption = { glCode: '500601', glName: 'STAMP DUTY ON INVESTMENTS' };
+export const BROKERAGE_GL: InvestmentGlOption = { glCode: '500602', glName: 'BROKERAGE ON INVESTMENTS' };
+export const OTHER_CHARGES_GL: InvestmentGlOption = { glCode: '500603', glName: 'OTHER CHARGES ON INVESTMENTS' };
+
 /** Interest receivable (the senior's "Provision A/c") — debited for interest bought from the seller. */
 export const INTEREST_RECEIVABLE_GL: InvestmentGlOption = {
   glCode: '100603',

src/app/investment/investment.service.ts

@@ -97,6 +97,7 @@ export interface InvestmentPurchaseDto {
   balanceUnits: number;
   brokerage?: number;
   stampDuty?: number;
+  otherCharges?: number;
   bookValue: number;
   premiumDiscount?: number;
   intRate?: number;