import os
import warnings
from functools import wraps

from pytorch_lightning import _logger as log


def rank_zero_only(fn):

    @wraps(fn)
    def wrapped_fn(*args, **kwargs):
        if rank_zero_only.rank == 0:
            return fn(*args, **kwargs)

    return wrapped_fn


# add the attribute to the function but don't overwrite in case Trainer has already set it
rank_zero_only.rank = getattr(rank_zero_only, 'rank', int(os.environ.get('LOCAL_RANK', 0)))


def _warn(*args, **kwargs):
    warnings.warn(*args, **kwargs)


def _info(*args, **kwargs):
    log.info(*args, **kwargs)


def _debug(*args, **kwargs):
    log.info(*args, **kwargs)


rank_zero_debug = rank_zero_only(_debug)
rank_zero_info = rank_zero_only(_info)
rank_zero_warn = rank_zero_only(_warn)