from md2gost.renderable import Renderable
from md2gost.renderable.heading import Heading
from md2gost.renderable.toc import ToC
from md2gost.util import create_element


def _enable_update_fields_on_open(document) -> None:
    """Ask Word to refresh fields (TOC) when the document is opened."""
    settings = document.settings.element
    # Remove existing updateFields if any
    for child in list(settings):
        if child.tag.endswith("}updateFields"):
            settings.remove(child)
    settings.append(create_element("w:updateFields", {"w:val": "true"}))


class TocProcessor:
    def process(self, renderables: list[Renderable]):
        renderables_iter = iter(renderables)

        toc = None
        for renderable in renderables_iter:
            if isinstance(renderable, ToC):
                toc = renderable
                break

        if not toc:
            return

        if toc.toc_mode == "native":
            # Field already in body from render; ensure dirty + updateFields
            toc.fill()
            try:
                doc = toc._paragraph._docx_paragraph.part.document
                _enable_update_fields_on_open(doc)
            except Exception:
                pass
            return

        for renderable in renderables_iter:
            if isinstance(renderable, Heading):
                title = (renderable.text or "").strip()
                if title.upper() == "СОДЕРЖАНИЕ":
                    continue
                toc.add_item(
                    renderable.level,
                    renderable.text,
                    renderable.rendered_page,
                    renderable.is_numbered,
                )
        toc.fill()