feat: add extensive test suite

app/api/tts/route.ts

@@ -1,119 +1,23 @@
 import { GoogleGenAI } from "@google/genai";
-import { hash } from "bun";
-import { PassThrough, Readable } from "stream";
-import wav from "wav";
-import z from "zod";
 import { redis } from "@/lib/db/redis";
+import { createTtsHandler } from "./handler";
 
-const { DONATE_WIDGET_KEY, GEMINI_TTS_API_KEY } = process.env as Record<
-  string,
-  string
->;
-
-const MODELS = [
-  "gemini-2.5-flash-preview-tts",
-  // "gemini-3.1-flash-preview-tts",
-] as const;
-const API_KEYS = GEMINI_TTS_API_KEY.split(",")
-  .map((k) => k.trim())
-  .filter(Boolean);
-const POSSIBLE_CHOICES = MODELS.flatMap((m) =>
-  API_KEYS.map((k) => `${k}:${m}` as `${string}:${(typeof MODELS)[number]}`),
-);
-const MAX_TRIES = 10;
-
-const Schema = z.object({
-  message: z.string().max(1000),
-  key: z.literal(DONATE_WIDGET_KEY),
-});
-
-const voices = ["Zephyr", "Charon", "Fenrir", "Kore", "Sulafat"];
-
-export async function GET(request: Request) {
-  const data = Schema.safeParse(
-    Object.fromEntries(new URL(request.url).searchParams.entries()),
-  );
-  if (data.error)
-    return new Response(z.prettifyError(data.error), { status: 400 });
-  const {
-    data: { message },
-  } = data;
-
-  const textHash = hash(message).toString(36);
-  const cached = await redis!.get(`tts:${textHash}`);
-  console.log(
-    `[TTS] ${textHash}:${cached ? "cached" : "fresh"} "${message.slice(0, 200)}${message.length > 200 ? "..." : ""}"`,
-  );
-  if (cached)
-    return new Response(pcmToWav(cached), {
-      headers: { "Content-Type": "audio/wav" },
-    });
-
-  let audioData: string | undefined;
-  let currentRotation = await redis!
-    .get("tts_key_rotation")
-    .then((e) => (e ? Number(e) : 0))
-    .catch(() => 0);
-  for (
-    let i = 0;
-    i < MAX_TRIES;
-    i++, currentRotation = (currentRotation + 1) % POSSIBLE_CHOICES.length
-  ) {
-    const [apiKey, model] = POSSIBLE_CHOICES[currentRotation].split(":");
-    console.log(
-      `[TTS] Trying key ${apiKey.slice(0, 8)}:${model} (${currentRotation}/${POSSIBLE_CHOICES.length} #${i + 1})...`,
-    );
+export const GET = createTtsHandler({
+  redis: redis!,
+  widgetKey: process.env.DONATE_WIDGET_KEY,
+  apiKeys: process.env.GEMINI_TTS_API_KEY,
+  async generateContent({ apiKey, model, message, voice }) {
     const client = new GoogleGenAI({ apiKey });
-
-    try {
-      const response = await client.models.generateContent({
-        model,
-        contents: [{ parts: [{ text: message }] }],
-        config: {
-          responseModalities: ["AUDIO"],
-          speechConfig: {
-            voiceConfig: {
-              prebuiltVoiceConfig: {
-                voiceName: voices[Math.floor(Math.random() * voices.length)],
-              },
-            },
-          },
+    const response = await client.models.generateContent({
+      model,
+      contents: [{ parts: [{ text: message }] }],
+      config: {
+        responseModalities: ["AUDIO"],
+        speechConfig: {
+          voiceConfig: { prebuiltVoiceConfig: { voiceName: voice } },
         },
-      });
-
-      audioData = response.candidates?.[0].content?.parts?.[0].inlineData?.data;
-      if (audioData) break;
-    } catch (e) {
-      console.error(`TTS API key failed: ${apiKey.slice(0, 8)}...`, e);
-    }
-  }
-  console.log("[TTS] Got response?", audioData ? "yes" : "no");
-
-  if (!audioData)
-    return Response.json({ error: "Response is empty" }, { status: 500 });
-  queueMicrotask(() => {
-    redis!.setex(`tts:${textHash}`, 604800, audioData);
-    redis!.setex("tts_key_rotation", 604800, `${currentRotation}`);
-  });
-  return new Response(pcmToWav(audioData), {
-    headers: { "Content-Type": "audio/wav" },
-  });
-}
-
-function pcmToWav(audioData: string) {
-  const audioBuffer = Buffer.from(audioData, "base64");
-  const pcmStream = Readable.from([audioBuffer]);
-  const writer = new wav.Writer({
-    channels: 1,
-    sampleRate: 24000,
-    bitDepth: 16,
-  });
-
-  const out = new PassThrough();
-
-  pcmStream.pipe(writer);
-  writer.on("data", (chunk) => out.write(chunk));
-  writer.on("end", () => out.end());
-  writer.on("error", () => out.end());
-  return Readable.toWeb(out) as unknown as globalThis.ReadableStream;
-}
+      },
+    });
+    return response.candidates?.[0].content?.parts?.[0].inlineData?.data;
+  },
+});