"""Synthetic operations, imported only by isolated tests; no application effects."""
from __future__ import annotations

import json
import os
import re
import subprocess
import sys
import time


def echo(payload: bytes) -> bytes:
    return payload


def wait(payload: bytes) -> bytes:
    time.sleep(float(payload))
    return b"done"


def regex_stall(_payload: bytes) -> bytes:
    re.fullmatch(r"(a+)+$", "a" * 100 + "!")
    return b"unreachable"


def allocate(_payload: bytes) -> bytes:
    return b"x" * (256 * 1024 * 1024)


def too_much_stdout(_payload: bytes) -> bytes:
    while True:
        os.write(1, b"x" * 65536)


def too_much_stderr(_payload: bytes) -> bytes:
    while True:
        os.write(2, b"sensitive synthetic log" * 4096)


def fail(_payload: bytes) -> bytes:
    raise ValueError("private synthetic data must not become an error response")


def close_pipes_then_wait(_payload: bytes) -> bytes:
    os.close(1)
    os.close(2)
    time.sleep(30)
    return b""


def observe(_payload: bytes) -> bytes:
    import resource

    return json.dumps({
        "pid": os.getpid(), "pgid": os.getpgrp(), "sid": os.getsid(0),
        "cpu": resource.getrlimit(resource.RLIMIT_CPU),
        "memory": resource.getrlimit(resource.RLIMIT_AS),
        "file": resource.getrlimit(resource.RLIMIT_FSIZE),
        "core": resource.getrlimit(resource.RLIMIT_CORE),
        "env": sorted(os.environ), "cwd": os.getcwd(),
    }).encode()


def child_with_closed_pipes(_payload: bytes) -> bytes:
    child = subprocess.Popen(
        [sys.executable, "-I", "-c", "import time; time.sleep(30)"],
        stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
    )
    return str(child.pid).encode()