import io
import tarfile

from jw.pkg.lib.TarIo import TarIoTarFile

def make_tar(files: dict[str, bytes]) -> bytes:
    buf = io.BytesIO()
    with tarfile.open(fileobj = buf, mode = 'w') as tf:
        for name, content in files.items():
            info = tarfile.TarInfo(name)
            info.size = len(content)
            tf.addfile(info, io.BytesIO(content))
    return buf.getvalue()

def members(blob: bytes) -> dict[str, bytes | None]:
    ret = {}
    with tarfile.open(fileobj = io.BytesIO(blob)) as tf:
        for info in tf.getmembers():
            f = tf.extractfile(info)
            ret[info.name] = f.read() if f is not None else None
    return ret

# -- Bypass the constructor: _filter_tar_file() and _match() do not use
# the copy contexts, so a bare instance is sufficient
tar = object.__new__(TarIoTarFile)

files = {
    'a.txt': b'AAA',
    'dir/b.txt': b'BBB',
    'c.txt': b'CCC',
}
blob = make_tar(files)

# -- _match is exact matching
assert tar._match('a.txt', ['a.txt', 'c.txt'])
assert not tar._match('a.txt', ['x.txt'])
assert not tar._match('a.txt', [])

# -- _filter_tar_file without a filter is a round trip
ret = tar._filter_tar_file(blob)
assert members(ret) == files

# -- With a filter, only the exact paths survive
matched: list[str] = []
ret = tar._filter_tar_file(blob, ['a.txt', 'c.txt'], matched = matched)
assert members(ret) == {'a.txt': b'AAA', 'c.txt': b'CCC'}
assert sorted(matched) == ['a.txt', 'c.txt']

# -- A filter without hits yields an empty tar
ret = tar._filter_tar_file(blob, ['nope.txt'])
assert members(ret) == {}

print('All TarIo tests passed')