import os
import subprocess

from typing import Any, List


def get_self_dir() -> str:
    """ Get the path to the directory where this script lives. """
    return os.path.dirname(os.path.abspath(__file__))


def mkdir_if_needed(path: str) -> None:
    """ Create a directory if it doesn't already exist

    Note this won't try to create intermediate directories.
    """
    try:
        os.mkdir(path)
    except FileExistsError:
        pass
    assert os.path.isdir(path)


def subprocess_capture(capture_dir: str, cmd: List[str], **kwargs: Any) -> None:
    """ Run a process and capture its output

    Output will go to files named "cmd_NNN.stdout" and "cmd_NNN.stderr"
    where "cmd" is the name of the program and NNN is an incrementing
    counter.

    If those files already exist, we will overwrite them.
    """
    assert type(cmd) is list
    base = os.path.basename(cmd[0]) + '_{}'.format(global_counter())
    basepath = os.path.join(capture_dir, base)
    stdout_filename = basepath + '.stdout'
    stderr_filename = basepath + '.stderr'

    with open(stdout_filename, 'w') as stdout_f:
        with open(stderr_filename, 'w') as stderr_f:
            print('(capturing output to "{}.stdout")'.format(base))
            subprocess.run(cmd, **kwargs, stdout=stdout_f, stderr=stderr_f)


_global_counter = 0


def global_counter() -> int:
    """ A really dumb global counter.

    This is useful for giving output files a unique number, so if we run the
    same command multiple times we can keep their output separate.
    """
    global _global_counter
    _global_counter += 1
    return _global_counter

def debug_print(*args, **kwargs) -> None:
    """ Print to the console if TEST_DEBUG_PRINT is set in env.
    
    All parameters are passed to print().
    """
    if os.environ.get('TEST_DEBUG_PRINT') is not None:
        print(*args, **kwargs)