"""
Small utilities for testing.
"""

import gc
import os
import sys
import sysconfig

from joblib._multiprocessing_helpers import mp
from joblib.testing import SkipTest, skipif

try:
    import lz4
except ImportError:
    lz4 = None

# TODO straight removal since in joblib.test.common?
IS_PYPY = hasattr(sys, "pypy_version_info")
IS_GIL_DISABLED = (
    sysconfig.get_config_var("Py_GIL_DISABLED") and not sys._is_gil_enabled()
)

# A decorator to run tests only when numpy is available
try:
    import numpy as np

    def with_numpy(func):
        """A decorator to skip tests requiring numpy."""
        return func

except ImportError:

    def with_numpy(func):
        """A decorator to skip tests requiring numpy."""

        def my_func():
            raise SkipTest("Test requires numpy")

        return my_func

    np = None

# TODO: Turn this back on after refactoring yield based tests in test_hashing
# with_numpy = skipif(not np, reason='Test requires numpy.')

# we use memory_profiler library for memory consumption checks
try:
    from memory_profiler import memory_usage

    def with_memory_profiler(func):
        """A decorator to skip tests requiring memory_profiler."""
        return func

    def memory_used(func, *args, **kwargs):
        """Compute memory usage when executing func."""
        gc.collect()
        mem_use = memory_usage((func, args, kwargs), interval=0.001)
        return max(mem_use) - min(mem_use)

except ImportError:

    def with_memory_profiler(func):
        """A decorator to skip tests requiring memory_profiler."""

        def dummy_func():
            raise SkipTest("Test requires memory_profiler.")

        return dummy_func

    memory_usage = memory_used = None


with_multiprocessing = skipif(mp is None, reason="Needs multiprocessing to run.")


with_dev_shm = skipif(
    not os.path.exists("/dev/shm"),
    reason="This test requires a large /dev/shm shared memory fs.",
)

with_lz4 = skipif(lz4 is None, reason="Needs lz4 compression to run")

without_lz4 = skipif(lz4 is not None, reason="Needs lz4 not being installed to run")