"""Best-effort archive member extraction (filesystem-import aid).

zip/cbz via stdlib zipfile; rar via rarfile (needs an unrar/bsdtar
binary); 7z via py7zr (pure-Python). NEVER raises: on any failure the
context yields an empty list, and the caller still preserves the archive
file itself as a PostAttachment, so nothing is lost.
"""

import logging
import zipfile
from contextlib import contextmanager
from pathlib import Path
from tempfile import TemporaryDirectory

log = logging.getLogger(__name__)

ARCHIVE_EXTS = {".zip", ".cbz", ".rar", ".7z"}


def is_archive(path: Path) -> bool:
    return Path(path).suffix.lower() in ARCHIVE_EXTS


@contextmanager
def extract_archive(path: Path):
    """Context manager yielding a list of (member_name, extracted_path)
    for every regular-file member. Temp dir is removed on exit. Members
    are only ever under the temp dir (libs' safe extractall + rglob from
    base). Fail-soft: any error → yields []."""
    tmp = TemporaryDirectory(prefix="fc_arch_")
    base = Path(tmp.name)
    members: list[tuple[str, Path]] = []
    try:
        try:
            ext = Path(path).suffix.lower()
            if ext in (".zip", ".cbz"):
                with zipfile.ZipFile(path) as zf:
                    zf.extractall(base)
            elif ext == ".rar":
                import rarfile

                with rarfile.RarFile(path) as rf:
                    rf.extractall(base)
            elif ext == ".7z":
                import py7zr

                with py7zr.SevenZipFile(path, "r") as zf:
                    zf.extractall(base)
            for p in sorted(base.rglob("*")):
                if p.is_file():
                    members.append((str(p.relative_to(base)), p))
        except Exception as exc:
            log.warning("archive extract failed for %s: %s", path, exc)
            members = []
        yield members
    finally:
        tmp.cleanup()