"""模板 → 有序章节规格映射（Phase 5）。

真实 ParsedTemplate.sections 为 ChapterMarker 列表；章节由 type=="heading" 起，
紧随其后的 type=="placeholder" 且形如 `section:<id>` 的标记归属该章，
用于确定 chapter_id 与 section_placeholder（语言无关、按文档顺序）。
"""
from __future__ import annotations

import re

from genesis.data_models import ParsedTemplate
from genesis.writer.models import ChapterSpec

_SECTION_RE = re.compile(r"^section:(.+)$", re.IGNORECASE)


def map_template(parsed: ParsedTemplate) -> list[ChapterSpec]:
    specs: list[ChapterSpec] = []
    idx = 0
    current: ChapterSpec | None = None
    for ch in getattr(parsed, "sections", []):
        t = getattr(ch, "type", None)
        if t == "heading":
            idx += 1
            current = ChapterSpec(
                chapter_id=f"chapter_{idx}", title=getattr(ch, "name", ""), section_placeholder=None
            )
            specs.append(current)
        elif t == "placeholder" and current is not None:
            m = _SECTION_RE.match(getattr(ch, "name", ""))
            if m:
                sid = m.group(1)
                current.section_placeholder = getattr(ch, "name", "")
                if current.chapter_id.startswith("chapter_"):
                    current.chapter_id = sid
    return specs