From e4266f908728e5aaf65d60149531880d2ec5c138 Mon Sep 17 00:00:00 2001
From: Tyler Hoang <tyler@tylerhoang.xyz>
Date: Mon, 29 Jun 2026 01:39:46 -0700
Subject: fix: remove erroneous frontend/ from gitignore

---
 .gitignore          |   1 -
 frontend/lib/dcf.ts | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 123 insertions(+), 3 deletions(-)

diff --git a/.gitignore b/.gitignore
index 6d60df3..2e35f21 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,7 +15,6 @@ backend/data/*.db-*
 node_modules/
 .next/
 .omo/
-frontend/
 out/
 dist/
 *.tsbuildinfo
diff --git a/frontend/lib/dcf.ts b/frontend/lib/dcf.ts
index 04f1d6c..51483a8 100644
--- a/frontend/lib/dcf.ts
+++ b/frontend/lib/dcf.ts
@@ -20,6 +20,24 @@ export type DcfComputed = {
   terminalValuePv: number;
 };
 
+export type AdvancedDcfInputs = {
+  baseRevenue: number;
+  revenueGrowth: number[];
+  ebitdaMargin: number[];
+  dnaPctRevenue: number[];
+  capexPctRevenue: number[];
+  nwcPctDeltaRev: number[];
+  taxRate: number[];
+};
+
+export type AdvancedDcfParams = {
+  wacc: number;
+  terminalGrowth: number;
+  projectionYears: number;
+  sharesOutstanding: number;
+  equityBridge: number;
+};
+
 export function computeDcf(
   inputs: DcfInputs,
   params: DcfParams
@@ -36,13 +54,13 @@ export function computeDcf(
     (_, i) => baseFcf * (1 + growthRate) ** (i + 1)
   );
   const fcfPvSum = projected.reduce(
-    (sum, fcf, i) => sum + fcf / (1 + wacc) ** (i + 1),
+    (sum, fcf, i) => sum + fcf / (1 + wacc) ** (i + 0.5),
     0
   );
 
   const terminalFcf = projected[projected.length - 1] * (1 + terminalGrowth);
   const terminalValue = terminalFcf / (wacc - terminalGrowth);
-  const terminalValuePv = terminalValue / (1 + wacc) ** projectionYears;
+  const terminalValuePv = terminalValue / (1 + wacc) ** (projectionYears - 0.5);
 
   const enterpriseValue = fcfPvSum + terminalValuePv;
   const equityValue = enterpriseValue - equityBridge;
@@ -50,3 +68,106 @@ export function computeDcf(
 
   return { intrinsicValuePerShare, enterpriseValue, equityValue, fcfPvSum, terminalValuePv };
 }
+
+export function computeAdvancedDcf(
+  inputs: AdvancedDcfInputs,
+  params: AdvancedDcfParams
+): DcfComputed | { error: string } {
+  const {
+    baseRevenue,
+    revenueGrowth,
+    ebitdaMargin,
+    dnaPctRevenue,
+    capexPctRevenue,
+    nwcPctDeltaRev,
+    taxRate,
+  } = inputs;
+  const { wacc, terminalGrowth, projectionYears, sharesOutstanding, equityBridge } = params;
+
+  if (wacc <= 0) return { error: "WACC must be greater than 0%." };
+  if (terminalGrowth >= wacc) return { error: "Terminal growth must be lower than WACC." };
+  if (baseRevenue <= 0) return { error: "Base revenue must be greater than 0." };
+  if (sharesOutstanding <= 0) return { error: "Shares outstanding must be greater than 0." };
+
+  const assumptions = [
+    revenueGrowth,
+    ebitdaMargin,
+    dnaPctRevenue,
+    capexPctRevenue,
+    nwcPctDeltaRev,
+    taxRate,
+  ];
+  if (assumptions.some((arr) => arr.length < projectionYears)) {
+    return { error: "Projection assumptions must cover every projection year." };
+  }
+
+  let revenue = baseRevenue;
+  const projectedFcf: number[] = [];
+  for (let year = 0; year < projectionYears; year++) {
+    const priorRevenue = revenue;
+    revenue = priorRevenue * (1 + revenueGrowth[year]);
+    const ebitda = revenue * ebitdaMargin[year];
+    const dna = revenue * dnaPctRevenue[year];
+    const ebit = ebitda - dna;
+    const nopat = ebit * (1 - taxRate[year]);
+    const capex = revenue * capexPctRevenue[year];
+    const deltaRev = year === 0 ? 0 : revenue - priorRevenue;
+    const nwcChange = deltaRev * nwcPctDeltaRev[year];
+    projectedFcf.push(nopat + dna - capex - nwcChange);
+  }
+
+  const fcfPvSum = projectedFcf.reduce(
+    (sum, fcf, i) => sum + fcf / (1 + wacc) ** (i + 0.5),
+    0
+  );
+
+  const terminalFcf = projectedFcf[projectedFcf.length - 1] * (1 + terminalGrowth);
+  const terminalValue = terminalFcf / (wacc - terminalGrowth);
+  const terminalValuePv = terminalValue / (1 + wacc) ** (projectionYears - 0.5);
+
+  const enterpriseValue = fcfPvSum + terminalValuePv;
+  const equityValue = enterpriseValue - equityBridge;
+  const intrinsicValuePerShare = equityValue / sharesOutstanding;
+
+  return { intrinsicValuePerShare, enterpriseValue, equityValue, fcfPvSum, terminalValuePv };
+}
+
+export type SensitivityGrid = {
+  wacc: number[];
+  terminalGrowth: number[];
+  impliedPrices: (number | null)[][];
+};
+
+export function computeSensitivityGrid(
+  baseWacc: number,
+  baseTerminalGrowth: number,
+  priceFor: (wacc: number, terminalGrowth: number) => number | null
+): SensitivityGrid {
+  const waccValues = [
+    Math.max(0.03, baseWacc - 0.02),
+    Math.max(0.03, baseWacc - 0.01),
+    baseWacc,
+    baseWacc + 0.01,
+    baseWacc + 0.02,
+  ];
+  const terminalGrowthValues = [
+    Math.max(0, baseTerminalGrowth - 0.015),
+    Math.max(0, baseTerminalGrowth - 0.01),
+    baseTerminalGrowth,
+    baseTerminalGrowth + 0.01,
+    baseTerminalGrowth + 0.015,
+  ];
+
+  const impliedPrices = waccValues.map((w) =>
+    terminalGrowthValues.map((g) => {
+      if (g >= w) return null;
+      try {
+        return priceFor(w, g);
+      } catch {
+        return null;
+      }
+    })
+  );
+
+  return { wacc: waccValues, terminalGrowth: terminalGrowthValues, impliedPrices };
+}
-- 
cgit v1.3-2-g0d8e