fix(analysis): use last business day of previous month for 'Vs. mes anterior' card

apps/frontend/src/features/analysis/AnalysisPage.tsx

@@ -1,5 +1,5 @@
 import { Link, useNavigate } from "@tanstack/react-router";
-import { subDays } from "date-fns";
+import { subDays, subMonths } from "date-fns";
 import { ArrowLeft } from "lucide-react";
 import { useMemo, useState } from "react";
 import {
@@ -13,7 +13,12 @@ import {
   YAxis,
 } from "recharts";
 import { DatePicker } from "@/components/ui/date-picker";
-import { useDailyQuotes, useHistoricalMinMax, useQuotes } from "@/lib/queries";
+import {
+  useDailyQuotes,
+  useHistoricalMinMax,
+  useMonthlyLast,
+  useQuotes,
+} from "@/lib/queries";
 import { MonthlyVariationTable } from "./components/MonthlyVariationTable";
 
 const CURRENCIES = ["BELO", "BLUE", "BNA"] as const;
@@ -86,19 +91,13 @@ export function AnalysisPage({ currency }: { currency: string }) {
 
   const yesterday = subDays(today, 1);
   const yesterdayStr = formatDate(yesterday);
-  const firstOfMonth = new Date(today.getFullYear(), today.getMonth(), 1);
-  const firstOfMonthStr = formatDate(firstOfMonth);
 
   const { data: yesterdayQuote } = useDailyQuotes(
     currency,
     yesterdayStr,
     yesterdayStr,
   );
-  const { data: firstDayQuote } = useDailyQuotes(
-    currency,
-    firstOfMonthStr,
-    firstOfMonthStr,
-  );
+  const { data: monthlyLastData } = useMonthlyLast();
 
   const chartData = useMemo(() => {
     if (!daily) return [];
@@ -184,11 +183,21 @@ export function AnalysisPage({ currency }: { currency: string }) {
       ? (prevDayDiff / yesterdayBuy) * 100
       : null;
 
-  const firstMonthBuy = firstDayQuote?.[0]?.buy ?? null;
-  const monthDiff = firstMonthBuy !== null ? currentBuy - firstMonthBuy : null;
+  const previousMonthBuy = useMemo(() => {
+    if (!monthlyLastData || monthlyLastData.length === 0) return null;
+    const prevMonth = subMonths(today, 1);
+    const prevMonthKey = `${prevMonth.getFullYear()}-${String(prevMonth.getMonth() + 1).padStart(2, "0")}`;
+    const entry = monthlyLastData.find(
+      (e) => e.month === prevMonthKey && e.type === currency,
+    );
+    return entry?.buy ?? null;
+  }, [monthlyLastData, currency, today]);
+
+  const monthDiff =
+    previousMonthBuy !== null ? currentBuy - previousMonthBuy : null;
   const monthPct =
-    monthDiff !== null && firstMonthBuy !== null && firstMonthBuy !== 0
-      ? (monthDiff / firstMonthBuy) * 100
+    monthDiff !== null && previousMonthBuy !== null && previousMonthBuy !== 0
+      ? (monthDiff / previousMonthBuy) * 100
       : null;
 
   const backTo = currency === "BELO" ? "/quotes/belo" : "/quotes";
@@ -305,9 +314,7 @@ export function AnalysisPage({ currency }: { currency: string }) {
           <VariationValue value={prevDayDiff} pct={prevDayPct} />
         </div>
         <div className="rounded-lg border p-4">
-          <p className="text-sm text-muted-foreground mb-2">
-            Vs. primer día del mes
-          </p>
+          <p className="text-sm text-muted-foreground mb-2">Vs. mes anterior</p>
           <VariationValue value={monthDiff} pct={monthPct} />
         </div>
       </div>