"""Interpret user-curated date folders without guessing dates from image files."""

import re
from datetime import date
from pathlib import PurePosixPath

_DATE = r"(?P<year>\d{4})(?:[-._年]?)(?P<month>\d{2})(?:[-._月]?)(?P<day>\d{2})(?:日)?(?!\d)"
_PREFIX = re.compile(r"^" + _DATE)


def folder_caption(name: str) -> dict[str, str] | None:
    match = _PREFIX.match(name.strip())
    if not match:
        return None
    try:
        captured = date(int(match["year"]), int(match["month"]), int(match["day"]))
    except ValueError:
        return None
    remainder = name.strip()[match.end() :].strip(" _-—–:：")
    title, separator, place = remainder.replace("＠", "@").partition("@")
    return {
        "title": " ".join(title.split()),
        "date": captured.isoformat(),
        "place": " ".join(place.split()) if separator else "",
    }


def path_caption(path: str) -> dict[str, str] | None:
    # Children inherit their nearest date folder, rather than their filename.
    for component in reversed(PurePosixPath(path).parent.parts):
        caption = folder_caption(component)
        if caption is not None:
            return caption
    return None