dreamweaver/backend/app/services/adapters/text/openai.py

"""OpenAI 文本生成适配器。"""

import json
import random
import re
import time
from typing import Literal

import httpx
from tenacity import (
    retry,
    retry_if_exception_type,
    stop_after_attempt,
    wait_exponential,
)

from app.core.logging import get_logger
from app.core.prompts import (
    RANDOM_ELEMENTS,
    SYSTEM_INSTRUCTION_ENHANCER,
    SYSTEM_INSTRUCTION_STORYTELLER,
    USER_PROMPT_ENHANCEMENT,
    USER_PROMPT_GENERATION,
)
from app.services.adapters.base import BaseAdapter
from app.services.adapters.registry import AdapterRegistry
from app.services.adapters.text.models import StoryOutput

logger = get_logger(__name__)

OPENAI_API_BASE = "https://api.openai.com/v1/chat/completions"




@AdapterRegistry.register("text", "openai")
class OpenAITextAdapter(BaseAdapter[StoryOutput]):
    """OpenAI 文本生成适配器。"""

    adapter_type = "text"
    adapter_name = "openai"

    async def execute(
        self,
        input_type: Literal["keywords", "full_story"],
        data: str,
        education_theme: str | None = None,
        memory_context: str | None = None,
        **kwargs,
    ) -> StoryOutput:
        """生成或润色故事。"""
        start_time = time.time()
        logger.info("openai_text_request_start", input_type=input_type, data_length=len(data))

        theme = education_theme or "成长"
        random_element = random.choice(RANDOM_ELEMENTS)

        if input_type == "keywords":
            system_instruction = SYSTEM_INSTRUCTION_STORYTELLER
            prompt = USER_PROMPT_GENERATION.format(
                keywords=data,
                education_theme=theme,
                random_element=random_element,
                memory_context=memory_context or "",
            )
        else:
            system_instruction = SYSTEM_INSTRUCTION_ENHANCER
            prompt = USER_PROMPT_ENHANCEMENT.format(
                full_story=data,
                education_theme=theme,
                random_element=random_element,
                memory_context=memory_context or "",
            )

        model = self.config.model or "gpt-4o-mini"
        payload = {
            "model": model,
            "messages": [
                {
                    "role": "system",
                    "content": system_instruction,
                },
                {"role": "user", "content": prompt},
            ],
            "response_format": {"type": "json_object"},
            "temperature": 0.95,
            "top_p": 0.9,
        }

        result = await self._call_api(payload)

        choices = result.get("choices") or []
        if not choices:
            raise ValueError("OpenAI 未返回内容")

        response_text = choices[0].get("message", {}).get("content", "")
        if not response_text:
            raise ValueError("OpenAI 响应缺少文本")

        clean_json = response_text
        if response_text.startswith("```json"):
            clean_json = re.sub(r"^```json\n|```$", "", response_text)

        try:
            parsed = json.loads(clean_json)
        except json.JSONDecodeError as exc:
            raise ValueError(f"OpenAI 输出 JSON 解析失败: {exc}")

        required_fields = ["mode", "title", "story_text", "cover_prompt_suggestion"]
        if any(field not in parsed for field in required_fields):
            raise ValueError("OpenAI 输出缺少必要字段")

        elapsed = time.time() - start_time
        logger.info(
            "openai_text_request_success",
            elapsed_seconds=round(elapsed, 2),
            title=parsed["title"],
            mode=parsed["mode"],
        )

        return StoryOutput(
            mode=parsed["mode"],
            title=parsed["title"],
            story_text=parsed["story_text"],
            cover_prompt_suggestion=parsed["cover_prompt_suggestion"],
        )

    @retry(
        stop=stop_after_attempt(3),
        wait=wait_exponential(multiplier=1, min=4, max=10),
        retry=retry_if_exception_type(httpx.HTTPStatusError),
    )
    async def _call_api(self, payload: dict) -> dict:
        """调用 OpenAI API，带重试机制。"""
        url = self.config.api_base or OPENAI_API_BASE

        # 智能补全: 如果用户只填了 Base URL，自动补全路径
        if self.config.api_base and not url.endswith("/chat/completions"):
            base = url.rstrip("/")
            url = f"{base}/chat/completions"

        timeout = self.config.timeout_ms / 1000

        async with httpx.AsyncClient(timeout=timeout) as client:
            response = await client.post(
                url,
                json=payload,
                headers={
                    "Authorization": f"Bearer {self.config.api_key}",
                    "Content-Type": "application/json",
                },
            )
            response.raise_for_status()
            return response.json()

    async def health_check(self) -> bool:
        """检查 OpenAI API 是否可用。"""
        try:
            payload = {
                "model": self.config.model or "gpt-4o-mini",
                "messages": [{"role": "user", "content": "Hi"}],
                "max_tokens": 5,
            }
            await self._call_api(payload)
            return True
        except Exception:
            return False

    @property
    def estimated_cost(self) -> float:
        """预估文本生成成本 (USD)。"""
        return 0.01