From 198a0b2a0dc84fec5c809f9de067ce0272bd94ec Mon Sep 17 00:00:00 2001
From: Benjamin Admin <benjaminadmin@MacBook-Pro.local>
Date: Sun, 26 Apr 2026 23:46:40 +0200
Subject: [PATCH] Fix: Use /synthesize-direct for correct language selection

/synthesize always used the German model. /synthesize-direct uses
Edge TTS (with language-aware voice selection) and falls back to
Piper with the correct model (Thorsten DE / Lessac EN).

Also cleared audio cache to purge wrongly-generated files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 backend-lehrer/services/audio.py | 46 ++------------------------------
 1 file changed, 2 insertions(+), 44 deletions(-)

diff --git a/backend-lehrer/services/audio.py b/backend-lehrer/services/audio.py
index c022517..a3f1e1b 100644
--- a/backend-lehrer/services/audio.py
+++ b/backend-lehrer/services/audio.py
@@ -56,56 +56,14 @@ async def synthesize_word(
     if os.path.exists(cached):
         return cached
 
-    # Call Piper TTS service
+    # Call Piper TTS service via /synthesize-direct (returns MP3, selects language correctly)
     try:
         async with httpx.AsyncClient(timeout=30.0) as client:
             resp = await client.post(
-                f"{TTS_SERVICE_URL}/synthesize",
+                f"{TTS_SERVICE_URL}/synthesize-direct",
                 json={
                     "text": text,
                     "language": language,
-                    "voice": "thorsten-high" if language == "de" else "lessac-high",
-                    "module_id": "vocabulary",
-                    "content_id": word_id or _cache_key(text, language),
-                },
-            )
-            if resp.status_code != 200:
-                logger.warning(f"TTS service returned {resp.status_code} for '{text}'")
-                return None
-
-            data = resp.json()
-            bucket = data.get("bucket")
-            object_key = data.get("object_key")
-
-            if bucket and object_key:
-                # Get presigned URL to download the audio
-                url_resp = await client.post(
-                    f"{TTS_SERVICE_URL}/presigned-url",
-                    json={"bucket": bucket, "object_key": object_key, "expires": 300},
-                )
-                if url_resp.status_code == 200:
-                    audio_url = url_resp.json().get("url")
-                    if audio_url:
-                        audio_resp = await client.get(audio_url)
-                        if audio_resp.status_code == 200:
-                            with open(cached, "wb") as f:
-                                f.write(audio_resp.content)
-                            logger.info(f"TTS cached: '{text}' ({language}) → {cached}")
-                            return cached
-
-    except Exception as e:
-        logger.warning(f"TTS service unavailable: {e}")
-
-    # Fallback: try direct MP3 endpoint
-    try:
-        async with httpx.AsyncClient(timeout=30.0) as client:
-            resp = await client.post(
-                f"{TTS_SERVICE_URL}/synthesize/mp3",
-                json={
-                    "text": text,
-                    "language": language,
-                    "voice": "thorsten-high" if language == "de" else "lessac-high",
-                    "module_id": "vocabulary",
                 },
             )
             if resp.status_code == 200 and resp.headers.get("content-type", "").startswith("audio"):