"""The `GatewayTransport` for the gateway running in the gateway microVM
(PRD 0070).

How the launcher stages files + runs commands in the running gateway: the
docker exec/cp equivalents over SSH (dropbear + the stable infra key). The
backend-neutral provisioning logic that drives it lives in
`backend.gateway_provision`.
"""

from __future__ import annotations

import os
import shlex
import stat
import subprocess
from pathlib import Path

from ...gateway import GatewayProvisionError
from . import util


class FirecrackerGatewayTransport:
    """`GatewayTransport` for the gateway running in the gateway VM — the docker
    exec/cp equivalents over SSH (dropbear + the stable infra key)."""

    def __init__(self, private_key: Path, guest_ip: str) -> None:
        self._key = private_key
        self._ip = guest_ip

    def exec(self, argv: list[str]) -> None:
        proc = subprocess.run(
            util.ssh_base_argv(self._key, self._ip) + [shlex.join(argv)],
            capture_output=True, text=True, timeout=60, check=False,
        )
        if proc.returncode != 0:
            raise GatewayProvisionError(
                f"infra gateway exec {argv!r} failed: {proc.stderr.strip()}")

    def cp_into(self, src: str, dest: str) -> None:
        # Preserve the source mode (docker cp does): the access-hook is staged
        # 0700 and git-http execs it directly — a plain `cat >` would land it
        # 0644 and the exec fails with EACCES; keys stay 0600.
        mode = stat.S_IMODE(os.stat(src).st_mode)
        q = shlex.quote(dest)
        proc = subprocess.run(
            util.ssh_base_argv(self._key, self._ip)
            + [f"cat > {q} && chmod {mode:o} {q}"],
            input=Path(src).read_bytes(), capture_output=True, timeout=30, check=False,
        )
        if proc.returncode != 0:
            raise GatewayProvisionError(
                f"infra gateway cp {src} -> {dest} failed: "
                f"{proc.stderr.decode(errors='replace').strip()}")


__all__ = ["FirecrackerGatewayTransport"]