"""
按 chapter_story_links 顺序将各 story 正文物化为单一 markdown（无 LLM）。
保留 story 内 asset:// 引用不变。
"""

from typing import Any


def compose_ordered_stories_to_markdown(
    ordered: list[tuple[str, str]],
) -> str:
    """
    :param ordered: (story_title, canonical_markdown) 已按阅读顺序排好
    :return: 章节级 markdown；每个故事为 ## 标题 + 正文，故事之间用 markdown 水平线 --- 分隔
      （配图在 story 正文中，自然落在该故事块内、--- 之前）
    """
    parts: list[str] = []
    for title, md in ordered:
        title = (title or "").strip() or "故事"
        body = (md or "").strip()
        parts.append(f"## {title}\n\n{body}" if body else f"## {title}")
    return "\n\n---\n\n".join(parts)


def materialize_chapter_markdown_from_loaded_chapter(chapter: Any) -> str:
    """要求 chapter.story_links 已 eager-load，且各 link.story 可用。"""
    links = sorted(
        list(getattr(chapter, "story_links", None) or []),
        key=lambda x: getattr(x, "order_index", 0),
    )
    pairs: list[tuple[str, str]] = []
    for link in links:
        st = getattr(link, "story", None)
        if st is None:
            continue
        title = (getattr(st, "title", None) or "").strip()
        body = (getattr(st, "canonical_markdown", None) or "").strip()
        pairs.append((title, body))
    return compose_ordered_stories_to_markdown(pairs)