route subtitles through extension if installed

src/backend/helpers/subs.ts

@@ -5,6 +5,11 @@ import { convertSubtitlesToSrt } from "@/components/player/utils/captions";
 import { CaptionListItem } from "@/stores/player/slices/source";
 import { SimpleCache } from "@/utils/cache";
 
+import {
+  isExtensionActiveCached,
+  sendExtensionRequest,
+} from "../extension/messaging";
+
 export const subtitleTypeList = list().map((type) => `.${type}`);
 const downloadCache = new SimpleCache<string, string>();
 downloadCache.setCompare((a, b) => a === b);
@@ -21,7 +26,22 @@ export async function downloadCaption(
 
   let data: string | undefined;
   if (caption.needsProxy) {
+    if (isExtensionActiveCached()) {
+      const extensionResponse = await sendExtensionRequest({
+        url: caption.url,
+        method: "GET",
+      });
+      if (
+        !extensionResponse?.success ||
+        typeof extensionResponse.response.body !== "string"
+      ) {
+        throw new Error("failed to get caption data from extension");
+      }
+
+      data = extensionResponse.response.body;
+    } else {
       data = await proxiedFetch<string>(caption.url, { responseType: "text" });
+    }
   } else {
     data = await fetch(caption.url).then((v) => v.text());
   }