"""章节封面是否可入队（与 Celery 任务共享，避免循环 import）。"""

from __future__ import annotations

from typing import Any

from app.features.memoir.asset_resolver import parse_asset_refs
from app.features.memoir.memoir_images.schema import (
    IMAGE_STATUS_FAILED,
    IMAGE_STATUS_PENDING,
)

# 正文内 ![...](asset://...) 数量需 **大于** 此值才生成/展示章节封面（与故事头图、正文配图任务独立）
MIN_INLINE_BODY_IMAGES_FOR_CHAPTER_COVER = 3


def chapter_has_story_links(chapter: Any) -> bool:
    return any(
        getattr(link, "story", None)
        for link in getattr(chapter, "story_links", None) or []
    )


def count_chapter_inline_body_images(chapter: Any) -> int:
    """统计章节 canonical_markdown 中正文插图（asset:// 图片引用）次数。"""
    md = getattr(chapter, "canonical_markdown", None) or ""
    return len(parse_asset_refs(md))


def chapter_eligible_for_cover_by_inline_body_image_count(chapter: Any) -> bool:
    """仅当正文内插图数量 > MIN_INLINE_BODY_IMAGES_FOR_CHAPTER_COVER 时才生成/展示章节封面。"""
    return (
        count_chapter_inline_body_images(chapter)
        > MIN_INLINE_BODY_IMAGES_FOR_CHAPTER_COVER
    )


def primary_chapter_memoir_image(chapter: Any) -> Any | None:
    """章节级 MemoirImage（封面槽位）：按 order_index 最小取第一条。"""
    imgs = sorted(
        getattr(chapter, "images", None) or [],
        key=lambda m: getattr(m, "order_index", 0),
    )
    return imgs[0] if imgs else None


def chapter_needs_cover_enqueue(chapter) -> bool:
    """尚无 cover_asset、有正文、且正文内 asset 插图多于阈值时，可派发 generate_chapter_cover。"""
    if not chapter:
        return False
    if not chapter_has_story_links(chapter):
        return False
    if getattr(chapter, "cover_asset_id", None):
        return False
    md = (getattr(chapter, "canonical_markdown", None) or "").strip()
    if not md:
        return False
    return chapter_eligible_for_cover_by_inline_body_image_count(chapter)


def chapter_has_cover_to_generate(chapter) -> bool:
    """章节是否有待生成的封面图（任一条 chapter 级 MemoirImage 为 pending/failed）。"""
    for m in getattr(chapter, "images", None) or []:
        status = (m.status or "").strip()
        if status in (IMAGE_STATUS_PENDING, IMAGE_STATUS_FAILED):
            return True
    return False


def cover_memoir_image_pending_or_failed(chapter: Any) -> Any | None:
    """用于补图任务：按 order_index 找到第一条 pending/failed 的章节配图行。"""
    images = sorted(
        getattr(chapter, "images", None) or [],
        key=lambda m: getattr(m, "order_index", 0),
    )
    for m in images:
        st = (m.status or "").strip()
        if st in (IMAGE_STATUS_PENDING, IMAGE_STATUS_FAILED):
            return m
    return None