From 40b5b94102a0edeccfc681b469d919dcce080555 Mon Sep 17 00:00:00 2001
From: Horizontal42 <75383519+Horizontal42@users.noreply.github.com>
Date: Wed, 8 Jul 2026 14:06:00 +0300
Subject: [PATCH] fetch historical rates for multiple dates concurrently
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

fetchNeededHistoricalRates awaited each date's fetch sequentially even
though they're independent requests — a sheet referencing several
historical dates paid for that latency serially instead of in parallel.
---
 src/main.ts | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/main.ts b/src/main.ts
index a11994a..e3360f8 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -568,11 +568,20 @@ const HIST_DATE_RE = /(?:on|на)\s+(\d{4}-\d{2}-\d{2})/gi;
 async function fetchNeededHistoricalRates(text: string): Promise<void> {
   const dates = new Set<string>();
   for (const m of text.matchAll(HIST_DATE_RE)) dates.add(m[1]!);
+  const datesToFetch = Array.from(dates).filter((date) => !engine.hasHistoricalRates(date));
   let fetched = false;
-  for (const date of dates) {
-    if (!engine.hasHistoricalRates(date)) {
-      const rates = await fetchHistoricalRates(date);
-      if (rates) { engine.setHistoricalRates(date, rates); fetched = true; }
+  if (datesToFetch.length > 0) {
+    const results = await Promise.all(
+      datesToFetch.map(async (date) => {
+        const rates = await fetchHistoricalRates(date);
+        return { date, rates };
+      })
+    );
+    for (const { date, rates } of results) {
+      if (rates) {
+        engine.setHistoricalRates(date, rates);
+        fetched = true;
+      }
     }
   }
   if (fetched) { workspace.invalidateAll(); editor.refresh(); }