from __future__ import annotations

import subprocess
from typing import Callable


class CommandError(RuntimeError):
    pass


Runner = Callable[[list[str]], subprocess.CompletedProcess[str]]


def _default_runner(args: list[str]) -> subprocess.CompletedProcess[str]:
    return subprocess.run(args, capture_output=True, text=True, check=False)


class IpAddressManager:
    def __init__(self, runner: Runner | None = None):
        self._runner = runner or _default_runner

    def is_present(self, ip: str, cidr: int, device: str) -> bool:
        target = f"{ip}/{cidr}"
        result = self._runner(["ip", "-4", "-o", "addr", "show", "dev", device])
        if result.returncode != 0:
            raise CommandError(f"Failed to query addresses on {device}: {result.stderr.strip()}")

        for line in result.stdout.splitlines():
            tokens = line.split()
            if target in tokens:
                return True
        return False

    def ensure_present(self, ip: str, cidr: int, device: str) -> None:
        if self.is_present(ip, cidr, device):
            return

        result = self._runner(["ip", "addr", "add", f"{ip}/{cidr}", "dev", device])
        if result.returncode != 0 and "File exists" not in result.stderr:
            raise CommandError(f"Failed to add address {ip}/{cidr} on {device}: {result.stderr.strip()}")

    def ensure_absent(self, ip: str, cidr: int, device: str) -> None:
        if not self.is_present(ip, cidr, device):
            return

        result = self._runner(["ip", "addr", "del", f"{ip}/{cidr}", "dev", device])
        if result.returncode != 0 and "Cannot assign requested address" not in result.stderr:
            raise CommandError(f"Failed to remove address {ip}/{cidr} on {device}: {result.stderr.strip()}")