life-echo/api/app/agents/image_prompt/orchestrator.py

"""
ImagePromptOrchestrator：图片提示词生成编排器。
根据调用方（封面/正文）选择 build_prompt 或 build_cover_prompt；
统一异常处理和回退；内部委托 PromptGenerationAgent。
"""

from __future__ import annotations

from typing import Any, Optional

from app.agents.image_prompt.prompt_agent import PromptGenerationAgent
from app.core.config import settings
from app.core.logging import get_logger
from app.features.memoir.memoir_images.settings import MemoirImageSettings

logger = get_logger(__name__)


class ImagePromptOrchestrator:
    """
    图片提示词编排器。
    区分封面 vs 正文配图，统一调用 PromptGenerationAgent；
    异常与回退由 PromptGenerationAgent（底层 MemoirImagePromptService）处理。
    """

    def __init__(self, llm: Optional[Any], settings: MemoirImageSettings) -> None:
        self._agent = PromptGenerationAgent(llm=llm, settings=settings)

    def build_prompt(
        self,
        chapter_title: str,
        chapter_category: str,
        description: str,
        context_excerpt: str,
    ) -> dict[str, str]:
        """
        生成正文配图的 prompt。
        委托 PromptGenerationAgent，已含 LLM 调用失败时的 fallback 逻辑。
        """
        return self._agent.build_prompt(
            chapter_title=chapter_title,
            chapter_category=chapter_category,
            description=description,
            context_excerpt=context_excerpt,
        )

    def build_cover_prompt(
        self,
        chapter_title: str,
        chapter_category: str,
        context_excerpt: str,
    ) -> dict[str, str]:
        """
        生成章节封面的 prompt。
        委托 PromptGenerationAgent，已含 LLM 调用失败时的 fallback 逻辑。
        """
        return self._agent.build_cover_prompt(
            chapter_title=chapter_title,
            chapter_category=chapter_category,
            context_excerpt=context_excerpt,
        )

    def build_story_primary_prompt(
        self,
        story_title: str,
        story_stage: str | None,
        prompt_brief: str,
        style_profile: str | None,
    ) -> dict[str, str]:
        """生成 story 主插图的 prompt。"""
        return self._agent.build_story_primary_prompt(
            story_title=story_title,
            story_stage=story_stage,
            prompt_brief=prompt_brief,
            style_profile=style_profile,
        )


def get_image_prompt_orchestrator() -> ImagePromptOrchestrator:
    """Celery / 后台任务入口：统一装配 LLM 与 MemoirImageSettings。"""
    from app.core.llm_gateway import LlmGateway, LlmUseCase

    image_settings = MemoirImageSettings.from_env()
    try:
        llm = LlmGateway().langchain_llm_for(LlmUseCase("image_prompt"))
    except Exception as e:
        if settings.image_prompt_fallback_disabled:
            raise
        logger.warning(
            "ImagePromptOrchestrator LLM 初始化失败，使用确定性 fallback: {}",
            e,
        )
        llm = None
    return ImagePromptOrchestrator(llm=llm, settings=image_settings)