from __future__ import annotations

import io
import tarfile

from tarfile import TarFile
from typing import TYPE_CHECKING, Callable

from ....lib.ExecContext import ExecContext
from ....lib.log import DEBUG, log

if TYPE_CHECKING:
    from typing import Iterable

    from ....lib.FileContext import FileContext

def filter(
    blob: bytes,
    path_filter: Callable[[str], bool] | None,
    matched: list[str] | None = None,
) -> bytes:
    ret = io.BytesIO()
    with tarfile.open(fileobj = ret, mode = 'w') as tf_out:
        tf_in = TarFile(fileobj = io.BytesIO(blob))
        for info in tf_in.getmembers():
            if path_filter is not None and not path_filter(info.name):
                continue
            log(DEBUG, f'Adding {info.name}')
            if matched is not None:
                matched.append(info.name)
            buf = tf_in.extractfile(info)
            tf_out.addfile(info, buf)
    return ret.getvalue()

def rewrite(blob: bytes, rewrite_filter: Callable[[str], str]) -> bytes:
    ret = io.BytesIO()
    with tarfile.open(fileobj = ret, mode = 'w') as tf_out:
        tf_in = TarFile(fileobj = io.BytesIO(blob))
        for info in tf_in.getmembers():
            new_name = rewrite_filter(info.name)
            log(DEBUG, f'Rewriting {info.name} -> {new_name}')
            info.name = new_name
            buf = tf_in.extractfile(info)
            tf_out.addfile(info, buf)
    return ret.getvalue()

def merge(blobs: Iterable[bytes], overwrite: bool = False) -> bytes:
    ret = io.BytesIO()
    with tarfile.open(fileobj = ret, mode = 'w') as tf_out:
        for blob in blobs:
            tf_in = TarFile(fileobj = io.BytesIO(blob))
            existing_names = tf_out.getnames()
            for info in tf_in.getmembers():
                if not overwrite and info.name in existing_names:
                    continue
                buf = tf_in.extractfile(info)
                tf_out.addfile(info, buf)
    return ret.getvalue()

async def extract(
    dst: FileContext,
    blob: bytes,
    root: str | None = None,
    verbose: bool = False
) -> None:
    cmd = ['tar']
    if root is not None:
        cmd += ['-C', root]
    if verbose:
        cmd += '-v'
    cmd += ['-x', '-f', '-']
    if not isinstance(dst, ExecContext):
        raise NotImplementedError(
            'Extracting tar files to a non-executable '
            f'context is not yet implemented: {dst}'
        )
    await dst.run(cmd, verbose = verbose, cmd_input = blob)