"""Unpack or repack an OOXML document without shell-specific ZIP commands."""

import argparse
import os
import tempfile
import zipfile
from pathlib import Path, PurePosixPath


def unpack(source, destination):
    root = Path(destination).resolve()
    if root.exists() and any(root.iterdir()):
        raise ValueError("Unpack destination must be empty")
    with zipfile.ZipFile(source) as archive:
        for info in archive.infolist():
            name = PurePosixPath(info.filename.replace("\\", "/"))
            if name.is_absolute() or ".." in name.parts or any(":" in part for part in name.parts):
                raise ValueError(f"Unsafe ZIP entry: {info.filename}")
            if (info.external_attr >> 16) & 0o170000 == 0o120000:
                raise ValueError(f"ZIP symlink is not supported: {info.filename}")
        archive.extractall(root)


def pack(source, destination):
    root = Path(source).resolve()
    output = Path(destination).resolve()
    if output.is_relative_to(root):
        raise ValueError("Output must be outside the unpacked directory")
    if not (root / "[Content_Types].xml").is_file():
        raise ValueError("Source must be the package root containing [Content_Types].xml")
    output.parent.mkdir(parents=True, exist_ok=True)
    fd, temporary = tempfile.mkstemp(suffix=output.suffix, dir=output.parent)
    os.close(fd)
    try:
        with zipfile.ZipFile(temporary, "w", zipfile.ZIP_DEFLATED) as archive:
            for file in sorted(root.rglob("*")):
                if file.is_symlink():
                    raise ValueError(f"Package symlink is not supported: {file}")
                if file.is_file():
                    archive.write(file, file.relative_to(root).as_posix())
        os.replace(temporary, output)
    finally:
        Path(temporary).unlink(missing_ok=True)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("action", choices=("unpack", "pack"))
    parser.add_argument("input")
    parser.add_argument("output")
    args = parser.parse_args()
    {"unpack": unpack, "pack": pack}[args.action](args.input, args.output)