feat/tts (#15)

Co-authored-by: Kevin <kevin@brighteng.org>

api/app/adapters/tts/tencent_tts.py

@@ -0,0 +1,144 @@
+"""Tencent Cloud TTS adapter — implements TTSProvider port."""
+
+import asyncio
+import base64
+import re
+import uuid
+
+from app.core.logging import get_logger
+
+logger = get_logger(__name__)
+
+# OpenAI voice name -> Tencent VoiceType ID
+VOICE_MAP: dict[str, int] = {
+    "alloy": 1001,
+    "echo": 1002,
+    "fable": 1003,
+    "onyx": 1004,
+    "nova": 1005,
+    "shimmer": 1006,
+}
+
+# 中文 150 字 / 英文 500 字母，取保守值
+MAX_CHARS_PER_REQUEST = 150
+
+
+def _chunk_text(text: str, max_chars: int = MAX_CHARS_PER_REQUEST) -> list[str]:
+    """Split text into chunks within API limit."""
+    text = text.strip()
+    if not text:
+        return []
+    if len(text) <= max_chars:
+        return [text]
+
+    chunks: list[str] = []
+    # Split by sentence boundaries first
+    pattern = r"[。！？.!?\n]+"
+    parts = re.split(f"({pattern})", text)
+    current = ""
+    for i, p in enumerate(parts):
+        if re.match(pattern, p):
+            current += p
+            if current.strip():
+                chunks.append(current.strip())
+                current = ""
+        else:
+            if len(current) + len(p) <= max_chars:
+                current += p
+            else:
+                if current.strip():
+                    chunks.append(current.strip())
+                    current = ""
+                # Single part exceeds limit, split by length
+                while p:
+                    chunk = p[:max_chars]
+                    p = p[max_chars:]
+                    chunks.append(chunk)
+    if current.strip():
+        chunks.append(current.strip())
+    return chunks
+
+
+class TencentTTSProvider:
+    def __init__(
+        self,
+        secret_id: str,
+        secret_key: str,
+        voice_type: int = 1001,
+        codec: str = "mp3",
+    ):
+        self._secret_id = secret_id
+        self._secret_key = secret_key
+        self._voice_type = voice_type
+        self._codec = codec
+        self._client = None
+
+    def _get_client(self):
+        if self._client is not None:
+            return self._client
+        try:
+            from tencentcloud.common import credential
+            from tencentcloud.common.profile.client_profile import ClientProfile
+            from tencentcloud.common.profile.http_profile import HttpProfile
+            from tencentcloud.tts.v20190823 import tts_client
+
+            cred = credential.Credential(self._secret_id, self._secret_key)
+            http_profile = HttpProfile()
+            http_profile.endpoint = "tts.tencentcloudapi.com"
+            client_profile = ClientProfile()
+            client_profile.httpProfile = http_profile
+            self._client = tts_client.TtsClient(cred, "", client_profile)
+            return self._client
+        except Exception as e:
+            logger.error("Tencent TTS client init failed: %s", e)
+            return None
+
+    def _synthesize_sync(self, text: str, voice_type: int) -> bytes:
+        client = self._get_client()
+        if not client:
+            return b""
+        try:
+            from tencentcloud.common.exception.tencent_cloud_sdk_exception import (
+                TencentCloudSDKException,
+            )
+            from tencentcloud.tts.v20190823 import models
+
+            req = models.TextToVoiceRequest()
+            req.Text = text
+            req.SessionId = uuid.uuid4().hex
+            req.VoiceType = voice_type
+            req.PrimaryLanguage = 1
+            req.SampleRate = 16000
+            req.Codec = self._codec
+
+            resp = client.TextToVoice(req)
+            if not resp or not resp.Audio:
+                return b""
+            return base64.b64decode(resp.Audio)
+        except TencentCloudSDKException as e:
+            logger.error("Tencent TTS SDK error: %s", e)
+            return b""
+        except Exception as e:
+            logger.error("Tencent TTS synthesize failed: %s", e)
+            return b""
+
+    async def synthesize(self, text: str, voice: str = "alloy") -> bytes:
+        if not self._secret_id or not self._secret_key:
+            logger.error("Tencent TTS credentials not configured")
+            return b""
+
+        voice_type = VOICE_MAP.get(voice.lower(), self._voice_type)
+        chunks = _chunk_text(text)
+        if not chunks:
+            return b""
+
+        results: list[bytes] = []
+        for chunk in chunks:
+            audio = await asyncio.to_thread(
+                self._synthesize_sync, chunk, voice_type
+            )
+            if not audio:
+                return b""
+            results.append(audio)
+
+        return b"".join(results)