translator.py

import hashlib, hmac, json, os, random, time
from datetime import datetime
from typing import List, Sequence, Optional, Dict, Any

import requests

TRANSLATOR_ACCESS_KEY = os.environ.get("TRANSLATOR_ACCESS_KEY")

TENCENT_SECRET_ID = os.environ.get("TENCENT_SECRET_ID")
TENCENT_SECRET_KEY = os.environ.get("TENCENT_SECRET_KEY")
TENCENT_TRANSLATE_URL = os.environ.get("TENCENT_TRANSLATE_URL", "https://tmt.tencentcloudapi.com")

BAIDU_TRANSLATE_URL = os.environ.get("BAIDU_TRANSLATE_URL", "https://fanyi-api.baidu.com/api/trans/vip/translate")
try:
    BAIDU_CREDENTIALS_DEFAULT = json.loads(os.environ.get("BAIDU_CREDENTIALS_JSON", "[]"))
except json.JSONDecodeError:
    BAIDU_CREDENTIALS_DEFAULT = []

def _sign(key: bytes, msg: str) -> bytes:
    return hmac.new(key, msg.encode("utf-8"), hashlib.sha256).digest()

def _tc3_signature(secret_key: str, date: str, service: str, string_to_sign: str) -> str:
    secret_date = _sign(("TC3" + secret_key).encode(), date)
    secret_service = _sign(secret_date, service)
    secret_signing = _sign(secret_service, "tc3_request")
    return hmac.new(secret_signing, string_to_sign.encode("utf-8"), hashlib.sha256).hexdigest()

def _translate_with_tencent(texts: Sequence[str], src: str, tgt: str, secret_id: str, secret_key: str) -> Optional[List[str]]:
    if not (secret_id and secret_key): return None

    service, host, action, version, region = "tmt", "tmt.tencentcloudapi.com", "TextTranslate", "2018-03-21", "ap-beijing"
    ts = int(time.time())
    date = datetime.utcfromtimestamp(ts).strftime("%Y-%m-%d")
    
    payload = {"SourceText": "\n".join(texts), "Source": src, "Target": tgt, "ProjectId": 0}
    payload_str = json.dumps(payload, ensure_ascii=False)
    
    canonical_request = "POST\n/\n\n" + \
                        f"content-type:application/json; charset=utf-8\nhost:{host}\nx-tc-action:{action.lower()}\n\n" + \
                        "content-type;host;x-tc-action\n" + \
                        hashlib.sha256(payload_str.encode()).hexdigest()
    
    credential_scope = f"{date}/{service}/tc3_request"
    string_to_sign = "TC3-HMAC-SHA256\n" + str(ts) + "\n" + credential_scope + "\n" + \
                     hashlib.sha256(canonical_request.encode()).hexdigest()
    
    signature = _tc3_signature(secret_key, date, service, string_to_sign)
    
    authorization = f"TC3-HMAC-SHA256 Credential={secret_id}/{credential_scope}, " + \
                    f"SignedHeaders=content-type;host;x-tc-action, Signature={signature}"
    
    headers = {
        "Authorization": authorization, "Content-Type": "application/json; charset=utf-8",
        "Host": host, "X-TC-Action": action, "X-TC-Timestamp": str(ts),
        "X-TC-Version": version, "X-TC-Region": region,
    }

    try:
        resp = requests.post(TENCENT_TRANSLATE_URL, headers=headers, data=payload_str, timeout=8)
        resp.raise_for_status()
        data = resp.json()
        if "Response" in data and "TargetText" in data["Response"]:
            return data["Response"]["TargetText"].split("\n")
        else:
            print(f"[translator] Tencent API abnormal response: {data}")
            return None
    except Exception as e:
        print(f"[translator] Tencent API error → {e}")
        return None

def _translate_with_baidu(texts: Sequence[str], src: str, tgt: str, baidu_credentials: List[Dict[str, str]]) -> Optional[List[str]]:
    if not baidu_credentials: return None

    cred = random.choice(baidu_credentials)
    app_id, secret_key = cred.get("app_id"), cred.get("secret_key")

    if not (app_id and secret_key): return None
    
    salt = random.randint(32768, 65536)
    query = "\n".join(texts)
    sign = hashlib.md5((app_id + query + str(salt) + secret_key).encode()).hexdigest()
    params = {"q": query, "from": src, "to": tgt, "appid": app_id, "salt": salt, "sign": sign}

    try:
        resp = requests.get(BAIDU_TRANSLATE_URL, params=params, timeout=8)
        resp.raise_for_status()
        data = resp.json()
        if "trans_result" in data:
            return [item["dst"] for item in data["trans_result"]]
        else:
            print(f"[translator] Baidu API abnormal response: {data}")
            return None
    except Exception as e:
        print(f"[translator] Baidu API error → {e}")
        return None


def translate_texts(texts: Sequence[str],
                    src_lang: str = "auto",
                    tgt_lang: str = "zh",
                    system_key_input: Optional[str] = None,
                    tencent_id: Optional[str] = None,
                    tencent_key: Optional[str] = None,
                    baidu_creds_json_str: Optional[str] = None) -> List[str]:
    if not texts:
        return []

    use_tencent_id, use_tencent_key = None, None
    use_baidu_creds = []

    if tencent_id and tencent_key:
        use_tencent_id, use_tencent_key = tencent_id, tencent_key
        print("[translator] Using custom Tencent API key.")
    if baidu_creds_json_str:
        try:
            creds = json.loads(baidu_creds_json_str)
            if isinstance(creds, list) and all(isinstance(d, dict) for d in creds):
                use_baidu_creds = creds
                print("[translator] Using custom Baidu API key(s).")
            else:
                 print("[translator] Warning: Custom Baidu credentials format is incorrect.")
        except json.JSONDecodeError:
            print("[translator] Warning: Failed to parse custom Baidu credentials JSON.")

    elif TRANSLATOR_ACCESS_KEY and system_key_input == TRANSLATOR_ACCESS_KEY:
        print("[translator] System access key validated. Using system-configured API keys.")
        use_tencent_id, use_tencent_key = TENCENT_SECRET_ID, TENCENT_SECRET_KEY
        use_baidu_creds = BAIDU_CREDENTIALS_DEFAULT
    
    else:
        print("[translator] Translation disabled: No valid API keys or system key provided.")
        return list(texts)

    translated_texts = None
    if use_tencent_id and use_tencent_key:
        translated_texts = _translate_with_tencent(texts, src_lang, tgt_lang, use_tencent_id, use_tencent_key)
    
    if translated_texts is None and use_baidu_creds:
        translated_texts = _translate_with_baidu(texts, src_lang, tgt_lang, use_baidu_creds)

    return translated_texts or list(texts)