State taxes added to simulation

src/utils/FinancialProjectionService.js

@@ -3,16 +3,11 @@ import moment from 'moment';
 /**
  * Single-filer federal tax calculation (2023).
  * Includes standard deduction ($13,850). 
- * If you need to update the brackets/deduction, edit here.
  */
 function calculateAnnualFederalTaxSingle(annualIncome) {
-  // 1. Subtract standard deduction
   const STANDARD_DEDUCTION_SINGLE = 13850;
   const taxableIncome = Math.max(0, annualIncome - STANDARD_DEDUCTION_SINGLE);
 
-  // 2. Define bracket thresholds & rates for single filers (2023)
-  // The 'limit' is the upper bound for that bracket segment.
-  // Use Infinity for the top bracket.
   const brackets = [
     { limit: 11000,    rate: 0.10 },
     { limit: 44725,    rate: 0.12 },
@@ -26,23 +21,37 @@ function calculateAnnualFederalTaxSingle(annualIncome) {
   let tax = 0;
   let lastLimit = 0;
 
-  // 3. Accumulate tax across brackets
   for (let i = 0; i < brackets.length; i++) {
     const { limit, rate } = brackets[i];
     if (taxableIncome <= limit) {
-      // only tax the portion within this bracket
       tax += (taxableIncome - lastLimit) * rate;
       break;
     } else {
-      // tax the entire bracket range, then continue
       tax += (limit - lastLimit) * rate;
       lastLimit = limit;
     }
   }
-
   return tax;
 }
 
+/**
+ * Example state tax calculation. 
+ * Currently a simple flat rate based on `stateCode` from a small dictionary. 
+ * You can replace with bracket-based logic if desired.
+ */
+function calculateAnnualStateTax(annualIncome, stateCode) {
+  // Example dictionary of flat rates (not real data!)
+  const stateTaxInfo = {
+    CA: 0.08, // 8%
+    NY: 0.06, // 6%
+    TX: 0.00, 
+    FL: 0.00,
+    GA: 0.05
+  };
+  const rate = stateTaxInfo[stateCode] ?? 0.05; // default 5% if not found
+  return annualIncome * rate;
+}
+
 /**
  * Calculate the standard monthly loan payment for principal, annualRate (%) and term (years).
  */
@@ -53,7 +62,6 @@ function calculateLoanPayment(principal, annualRate, years) {
   const numPayments = years * 12;
 
   if (monthlyRate === 0) {
-    // no interest
     return principal / numPayments;
   }
   return (
@@ -63,7 +71,7 @@ function calculateLoanPayment(principal, annualRate, years) {
 }
 
 /**
- * Main projection function with bracket-based tax logic for single filers.
+ * Main projection function with bracket-based FEDERAL + optional STATE tax logic.
  */
 export function simulateFinancialProjection(userProfile) {
   const {
@@ -107,10 +115,13 @@ export function simulateFinancialProjection(userProfile) {
     surplusRetirementAllocation = 50,
 
     // Potential override
-    programLength
+    programLength,
+
+    // NEW: user’s state code (e.g. 'CA', 'NY', 'TX', etc.)
+    stateCode = 'TX', // default to TX (no state income tax)
   } = userProfile;
 
-  // 1. Calculate standard monthly loan payment (if not deferring)
+  // 1. Monthly loan payment if not deferring
   let monthlyLoanPayment = loanDeferralUntilGraduation
     ? 0
     : calculateLoanPayment(studentLoanAmount, interestRate, loanTerm);
@@ -137,13 +148,12 @@ export function simulateFinancialProjection(userProfile) {
   const dynamicProgramLength = Math.ceil(remainingCreditHours / creditHoursPerYear);
   const finalProgramLength = programLength || dynamicProgramLength;
 
-  // 3. Net annual tuition after financial aid
+  // 3. Net annual tuition after aid
   const netAnnualTuition = Math.max(0, calculatedTuition - annualFinancialAid);
   const totalTuitionCost = netAnnualTuition * finalProgramLength;
 
-  // 4. Setup lumps per year based on academicCalendar
+  // 4. Setup lumps per year
-  let lumpsPerYear = 12; // monthly fallback
+  let lumpsPerYear, lumpsSchedule;
-  let lumpsSchedule = []; 
   switch (academicCalendar) {
     case 'semester':
       lumpsPerYear = 2;
@@ -160,41 +170,39 @@ export function simulateFinancialProjection(userProfile) {
     case 'monthly':
     default:
       lumpsPerYear = 12;
-      lumpsSchedule = [...Array(12).keys()]; // 0..11
+      lumpsSchedule = [...Array(12).keys()];
       break;
   }
   const totalAcademicMonths = finalProgramLength * 12;
   const lumpAmount = totalTuitionCost / (lumpsPerYear * finalProgramLength);
 
-  // 5. Simulation loop up to 20 years
+  // 5. Simulation loop
   const maxMonths = 240;
   let date = startDate ? new Date(startDate) : new Date();
 
   let loanBalance = Math.max(studentLoanAmount, 0);
   let loanPaidOffMonth = null;
-
   let currentEmergencySavings = emergencySavings;
   let currentRetirementSavings = retirementSavings;
 
   let projectionData = [];
   let wasInDeferral = inCollege && loanDeferralUntilGraduation;
-
-  // If gradDate is provided, parse it to Date
   const graduationDate = gradDate ? new Date(gradDate) : null;
 
-  // Keep a map of year => { ytdGross, ytdTaxSoFar } for bracket-based taxes
+  // YTD tracking for each year (federal + state)
+  // e.g. taxStateByYear[2025] = { federalYtdGross, federalYtdTaxSoFar, stateYtdGross, stateYtdTaxSoFar }
   const taxStateByYear = {};
 
   for (let month = 0; month < maxMonths; month++) {
     date.setMonth(date.getMonth() + 1);
     const currentYear = date.getFullYear();
 
-    // If loan is fully paid, record if not already done
+    // Check if loan is fully paid
     if (loanBalance <= 0 && !loanPaidOffMonth) {
       loanPaidOffMonth = `${currentYear}-${String(date.getMonth() + 1).padStart(2, '0')}`;
     }
 
-    // Determine if user is still in college (trusted gradDate or approximate)
+    // Are we still in college?
     let stillInCollege = false;
     if (inCollege) {
       if (graduationDate) {
@@ -208,7 +216,7 @@ export function simulateFinancialProjection(userProfile) {
       }
     }
 
-    // 6. Check if we owe tuition lumps this month
+    // 6. Tuition lumps
     let tuitionCostThisMonth = 0;
     if (stillInCollege && lumpsPerYear > 0) {
       const simStart = startDate ? new Date(startDate) : new Date();
@@ -224,10 +232,10 @@ export function simulateFinancialProjection(userProfile) {
       }
     }
 
-    // 7. Detect if we are now exiting college this month
+    // 7. Exiting college?
     const nowExitingCollege = (wasInDeferral && !stillInCollege);
 
-    // 8. If in deferral, lumps get added to the loan principal
+    // 8. Deferral lumps get added to loan
     if (stillInCollege && loanDeferralUntilGraduation) {
       if (tuitionCostThisMonth > 0) {
         loanBalance += tuitionCostThisMonth;
@@ -235,60 +243,68 @@ export function simulateFinancialProjection(userProfile) {
       }
     }
 
-    // 9. Gross monthly income depends on college status
+    // 9. Gross monthly income
     let grossMonthlyIncome = 0;
     if (!inCollege || !stillInCollege) {
-      // Graduated or never was in college => use expectedSalary if given
       grossMonthlyIncome = (expectedSalary > 0 ? expectedSalary : currentSalary) / 12;
     } else {
-      // Still in college => currentSalary + part-time
       grossMonthlyIncome = (currentSalary / 12) + (partTimeIncome / 12);
     }
 
-    /**
+    // 10. Tax calculations
-     * 10. Calculate monthly TAX via bracket-based approach:
-     *     We track year-to-date (YTD) for the current calendar year.
-     */
     if (!taxStateByYear[currentYear]) {
-      taxStateByYear[currentYear] = { ytdGross: 0, ytdTaxSoFar: 0 };
+      taxStateByYear[currentYear] = {
+        federalYtdGross: 0,
+        federalYtdTaxSoFar: 0,
+        stateYtdGross: 0,
+        stateYtdTaxSoFar: 0
+      };
     }
 
-    // Add this month’s gross to YTD
+    // Update YTD gross for federal + state
-    taxStateByYear[currentYear].ytdGross += grossMonthlyIncome;
+    taxStateByYear[currentYear].federalYtdGross += grossMonthlyIncome;
+    taxStateByYear[currentYear].stateYtdGross += grossMonthlyIncome;
 
-    // Calculate total tax for YTD
+    // Compute total fed tax for the year so far
-    const annualTaxSoFar = calculateAnnualFederalTaxSingle(
+    const newFedTaxTotal = calculateAnnualFederalTaxSingle(
-      taxStateByYear[currentYear].ytdGross
+      taxStateByYear[currentYear].federalYtdGross
     );
+    // Monthly fed tax = difference
+    const monthlyFederalTax = newFedTaxTotal - taxStateByYear[currentYear].federalYtdTaxSoFar;
+    taxStateByYear[currentYear].federalYtdTaxSoFar = newFedTaxTotal;
 
-    // This month’s tax = (new YTD tax) - (old YTD tax)
+    // Compute total state tax for the year so far
-    const monthlyTax = annualTaxSoFar - taxStateByYear[currentYear].ytdTaxSoFar;
+    const newStateTaxTotal = calculateAnnualStateTax(
+      taxStateByYear[currentYear].stateYtdGross,
+      stateCode
+    );
+    const monthlyStateTax = newStateTaxTotal - taxStateByYear[currentYear].stateYtdTaxSoFar;
+    taxStateByYear[currentYear].stateYtdTaxSoFar = newStateTaxTotal;
 
-    // Update YTD tax
+    // Combined monthly tax
-    taxStateByYear[currentYear].ytdTaxSoFar = annualTaxSoFar;
+    const combinedTax = monthlyFederalTax + monthlyStateTax;
 
-    // Net monthly income after tax
+    // Net monthly income after taxes
-    const netMonthlyIncome = grossMonthlyIncome - monthlyTax;
+    const netMonthlyIncome = grossMonthlyIncome - combinedTax;
 
-    // 11. Monthly expenses (excluding student loan if deferring)
+    // 11. Expenses & loan
     let thisMonthLoanPayment = 0;
     let totalMonthlyExpenses = monthlyExpenses + monthlyDebtPayments + tuitionCostThisMonth;
 
-    // Re-amortize if we're just now exiting college
+    // Re-amortize if just exited college
     if (nowExitingCollege) {
       monthlyLoanPayment = calculateLoanPayment(
         loanBalance,
         interestRate,
-        10 // fresh 10-year term post-college
+        10
       );
     }
 
-    // 12. If still deferring, just accrue interest
+    // If not deferring, we do normal payments
     if (stillInCollege && loanDeferralUntilGraduation) {
       const interestForMonth = loanBalance * (interestRate / 100 / 12);
       loanBalance += interestForMonth;
     } else {
-      // Normal repayment if loan > 0
       if (loanBalance > 0) {
         const interestForMonth = loanBalance * (interestRate / 100 / 12);
         const principalForMonth = Math.min(
@@ -303,11 +319,11 @@ export function simulateFinancialProjection(userProfile) {
       }
     }
 
-    // 13. leftover after mandatory expenses
+    // 12. leftover after mandatory expenses
     let leftover = netMonthlyIncome - totalMonthlyExpenses;
     if (leftover < 0) leftover = 0;
 
-    // Baseline monthly contributions
+    // Baseline contributions
     const baselineContributions = monthlyRetirementContribution + monthlyEmergencyContribution;
     let effectiveRetirementContribution = 0;
     let effectiveEmergencyContribution = 0;
@@ -317,48 +333,44 @@ export function simulateFinancialProjection(userProfile) {
       effectiveEmergencyContribution = monthlyEmergencyContribution;
       leftover -= baselineContributions;
     } else {
-      // Not enough leftover => zero out contributions
       effectiveRetirementContribution = 0;
       effectiveEmergencyContribution = 0;
     }
 
-    // Check for shortfall vs. mandatory expenses
+    // Check shortfall
     const totalWantedContributions = effectiveRetirementContribution + effectiveEmergencyContribution;
     const actualExpensesPaid = totalMonthlyExpenses + totalWantedContributions;
     let shortfall = actualExpensesPaid - netMonthlyIncome;
     if (shortfall > 0) {
-      // Attempt to cover from emergency savings
       const canCover = Math.min(shortfall, currentEmergencySavings);
       currentEmergencySavings -= canCover;
       shortfall -= canCover;
       if (shortfall > 0) {
-        // Even after emergency, we can't cover => break (bankrupt scenario)
+        // bankrupt scenario
         break;
       }
     }
 
-    // 14. Surplus allocation if leftover > 0
+    // 13. Surplus
-    const newLeftover = leftover;
+    if (leftover > 0) {
-    if (newLeftover > 0) {
-      // Allocate by percentage
       const totalPct = surplusEmergencyAllocation + surplusRetirementAllocation;
-      const emergencyPortion = newLeftover * (surplusEmergencyAllocation / totalPct);
+      const emergencyPortion = leftover * (surplusEmergencyAllocation / totalPct);
-      const retirementPortion = newLeftover * (surplusRetirementAllocation / totalPct);
+      const retirementPortion = leftover * (surplusRetirementAllocation / totalPct);
 
       currentEmergencySavings += emergencyPortion;
       currentRetirementSavings += retirementPortion;
     }
 
-    // 15. netSavings for the month (could be leftover minus contributions, etc.)
+    // netSavings for display
-    // But we already subtracted everything from netMonthlyIncome except what ended up surplus
     const finalExpensesPaid = totalMonthlyExpenses + totalWantedContributions;
     const netSavings = netMonthlyIncome - finalExpensesPaid;
 
-    // Record in the projection data
     projectionData.push({
       month: `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, '0')}`,
       grossMonthlyIncome: Math.round(grossMonthlyIncome * 100) / 100,
-      monthlyTax: Math.round(monthlyTax * 100) / 100,
+      monthlyFederalTax: Math.round(monthlyFederalTax * 100) / 100,
+      monthlyStateTax: Math.round(monthlyStateTax * 100) / 100,
+      combinedTax: Math.round(combinedTax * 100) / 100,
       netMonthlyIncome: Math.round(netMonthlyIncome * 100) / 100,
       totalExpenses: Math.round(finalExpensesPaid * 100) / 100,
       effectiveRetirementContribution: Math.round(effectiveRetirementContribution * 100) / 100,
@@ -370,11 +382,9 @@ export function simulateFinancialProjection(userProfile) {
       loanPaymentThisMonth: Math.round(thisMonthLoanPayment * 100) / 100
     });
 
-    // Update deferral flag for next iteration
     wasInDeferral = (stillInCollege && loanDeferralUntilGraduation);
   }
 
-  // Return the final output
   return {
     projectionData,
     loanPaidOffMonth,