"""Portable process setup and classification for the native compiler driver.

MinGW maps different CreateProcess failures to ENOENT. That text does not prove
the compiler/subprogram is missing; never treat a C diagnostic as a launch retry.
"""
from __future__ import annotations

import os
from pathlib import Path
import re
import shutil

IS_WINDOWS = os.name == 'nt'
LAUNCH_RETRY_DELAYS = (0.05, 0.1, 0.2, 0.35, 0.5)


def command_environment(executable: str) -> dict[str, str] | None:
    if not IS_WINDOWS:
        return None  # Preserve the Linux toolchain and environment unchanged.
    env = os.environ.copy()
    path_key = next((key for key in env if key.upper() == 'PATH'), 'PATH')
    directory = str(Path(shutil.which(executable) or executable).resolve().parent)
    env[path_key] = directory + os.pathsep + env.get(path_key, '')
    return env


def is_driver_launch_failure(stderr: str) -> bool:
    # GCC 8 emits "gcc.exe: error: CreateProcess: ..."; other releases add
    # "cannot execute 'cc1':". Anchor the driver diagnostic, not source text.
    return IS_WINDOWS and bool(re.search(
        r'(?im)^(?:[^\r\n]*[/\\])?[\w.+-]*gcc(?:\.exe)?: (?:fatal )?error: (?:cannot execute [^\r\n]*: )?CreateProcess:', stderr))


def is_transient_process_error(exc: OSError) -> bool:
    return IS_WINDOWS and getattr(exc, 'winerror', None) in (5, 32, 1450, 1455)