"""Qwen-MT translation backend with cache support."""
  
  from __future__ import annotations
  
  import hashlib
  import logging
  import os
  import re
  import time
  from typing import List, Optional, Sequence, Union
  
  import redis
  from openai import OpenAI
  
  from config.env_config import DASHSCOPE_API_KEY, REDIS_CONFIG
  from config.services_config import get_translation_cache_config

  from translation.languages import QWEN_LANGUAGE_CODES

  
  logger = logging.getLogger(__name__)
  
  
  class QwenMTTranslationBackend:

      def __init__(
          self,

          capability_name: str,
          model: str,
          base_url: str,

          api_key: Optional[str] = None,
          use_cache: bool = True,
          timeout: int = 10,
          glossary_id: Optional[str] = None,

      ):

          self.capability_name = capability_name
          self.model = self._normalize_capability_name(capability_name)
          self.qwen_model_name = self._normalize_model_name(model)
          self.base_url = base_url

          self.timeout = int(timeout)
          self.use_cache = bool(use_cache)
          self.glossary_id = glossary_id

  
          cache_cfg = get_translation_cache_config()

          self.cache_prefix = str(cache_cfg["key_prefix"])
          self.expire_seconds = int(cache_cfg["ttl_seconds"])
          self.cache_sliding_expiration = bool(cache_cfg["sliding_expiration"])
          self.cache_include_scene = bool(cache_cfg["key_include_scene"])
          self.cache_include_source_lang = bool(cache_cfg["key_include_source_lang"])

          self._api_key = api_key or self._default_api_key(self.model)
          self._qwen_client: Optional[OpenAI] = None

          if self._api_key:
              try:

                  self._qwen_client = OpenAI(api_key=self._api_key, base_url=self.base_url)

              except Exception as exc:
                  logger.warning("Failed to initialize qwen-mt client: %s", exc, exc_info=True)
          else:
              logger.warning("DASHSCOPE_API_KEY not set; qwen-mt translation unavailable")
  
          self.redis_client = None

          if self.use_cache and bool(cache_cfg["enabled"]):

              self.redis_client = self._init_redis_client()
  
      @property
      def supports_batch(self) -> bool:
          return True
  
      @staticmethod

      def _normalize_capability_name(name: str) -> str:
          normalized = str(name or "").strip().lower()
          if normalized != "qwen-mt":
              raise ValueError(f"Qwen-MT backend capability must be 'qwen-mt', got '{name}'")
          return normalized

  
      @staticmethod

      def _normalize_model_name(model: str) -> str:
          normalized = str(model or "").strip()
          if not normalized:
              raise ValueError("qwen-mt backend model is required")
          return normalized

  
      @staticmethod
      def _default_api_key(model: str) -> Optional[str]:
          del model
          return DASHSCOPE_API_KEY or os.getenv("DASHSCOPE_API_KEY")
  
      def _init_redis_client(self):
          try:
              client = redis.Redis(
                  host=REDIS_CONFIG.get("host", "localhost"),
                  port=REDIS_CONFIG.get("port", 6479),
                  password=REDIS_CONFIG.get("password"),
                  decode_responses=True,
                  socket_timeout=REDIS_CONFIG.get("socket_timeout", 1),
                  socket_connect_timeout=REDIS_CONFIG.get("socket_connect_timeout", 1),
                  retry_on_timeout=REDIS_CONFIG.get("retry_on_timeout", False),
                  health_check_interval=10,
              )
              client.ping()
              return client
          except Exception as exc:
              logger.warning("Failed to initialize translation redis cache: %s", exc)
              return None
  
      def _build_cache_key(
          self,
          text: str,
          target_lang: str,
          source_lang: Optional[str],

          scene: Optional[str],

      ) -> str:
          src = (source_lang or "auto").strip().lower() if self.cache_include_source_lang else "-"
          tgt = (target_lang or "").strip().lower()

          scn = (scene or "").strip() if self.cache_include_scene else ""
          payload = f"model={self.model}\nsrc={src}\ntgt={tgt}\nscene={scn}\ntext={text}"

          digest = hashlib.sha256(payload.encode("utf-8")).hexdigest()
          return f"{self.cache_prefix}:{self.model}:{src}:{tgt}:{digest}"
  
      def translate(
          self,
          text: Union[str, Sequence[str]],
          target_lang: str,
          source_lang: Optional[str] = None,

          scene: Optional[str] = None,

      ) -> Union[Optional[str], List[Optional[str]]]:
          if isinstance(text, (list, tuple)):
              results: List[Optional[str]] = []
              for item in text:
                  if item is None or not str(item).strip():
                      results.append(item)  # type: ignore[arg-type]
                      continue
                  out = self.translate(
                      text=str(item),
                      target_lang=target_lang,
                      source_lang=source_lang,

                      scene=scene,

                  )
                  results.append(out)
              return results
  
          if not text or not str(text).strip():
              return text  # type: ignore[return-value]
  
          tgt = (target_lang or "").strip().lower()
          src = (source_lang or "").strip().lower() or None
          if tgt == "en" and self._is_english_text(text):
              return text
          if tgt == "zh" and (self._contains_chinese(text) or self._is_pure_number(text)):
              return text
  

          cached = self._get_cached_translation_redis(text, tgt, src, scene)

          if cached is not None:
              return cached
  
          result = self._translate_qwen(text, tgt, src)
  
          if result is not None:

              self._set_cached_translation_redis(text, tgt, result, src, scene)

          return result
  
      def _translate_qwen(
          self,
          text: str,
          target_lang: str,
          source_lang: Optional[str],
      ) -> Optional[str]:
          if not self._qwen_client:
              return None
          tgt_norm = (target_lang or "").strip().lower()
          src_norm = (source_lang or "").strip().lower()

          tgt_qwen = QWEN_LANGUAGE_CODES.get(tgt_norm, tgt_norm.capitalize())
          src_qwen = "auto" if not src_norm or src_norm == "auto" else QWEN_LANGUAGE_CODES.get(src_norm, src_norm.capitalize())

          start = time.time()
          try:
              completion = self._qwen_client.chat.completions.create(
                  model=self.qwen_model_name,
                  messages=[{"role": "user", "content": text}],
                  extra_body={
                      "translation_options": {
                          "source_lang": src_qwen,
                          "target_lang": tgt_qwen,
                      }
                  },
                  timeout=self.timeout,
              )
              content = (completion.choices[0].message.content or "").strip()
              if not content:
                  return None
              logger.info("[qwen-mt] Success | src=%s tgt=%s latency=%.1fms", src_qwen, tgt_qwen, (time.time() - start) * 1000)
              return content
          except Exception as exc:
              logger.warning(
                  "[qwen-mt] Failed | src=%s tgt=%s latency=%.1fms error=%s",
                  src_qwen,
                  tgt_qwen,
                  (time.time() - start) * 1000,
                  exc,
                  exc_info=True,
              )
              return None
  
      def _get_cached_translation_redis(
          self,
          text: str,
          target_lang: str,
          source_lang: Optional[str] = None,

          scene: Optional[str] = None,

      ) -> Optional[str]:
          if not self.redis_client:
              return None

          key = self._build_cache_key(text, target_lang, source_lang, scene)

          try:
              value = self.redis_client.get(key)
              if value and self.cache_sliding_expiration:
                  self.redis_client.expire(key, self.expire_seconds)
              return value
          except Exception as exc:
              logger.warning("Redis get translation cache failed: %s", exc)
              return None
  
      def _set_cached_translation_redis(
          self,
          text: str,
          target_lang: str,
          translation: str,
          source_lang: Optional[str] = None,

          scene: Optional[str] = None,

      ) -> None:
          if not self.redis_client:
              return

          key = self._build_cache_key(text, target_lang, source_lang, scene)

          try:
              self.redis_client.setex(key, self.expire_seconds, translation)
          except Exception as exc:
              logger.warning("Redis set translation cache failed: %s", exc)
  
      @staticmethod
      def _contains_chinese(text: str) -> bool:
          return bool(re.search(r"[\u4e00-\u9fff]", text or ""))
  
      @staticmethod
      def _is_english_text(text: str) -> bool:
          stripped = (text or "").strip()
          return bool(stripped) and bool(re.fullmatch(r"[A-Za-z0-9\s\W]+", stripped)) and not QwenMTTranslationBackend._contains_chinese(stripped)
  
      @staticmethod
      def _is_pure_number(text: str) -> bool:
          return bool(re.fullmatch(r"[\d.\-+%/,: ]+", (text or "").strip()))