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#
#   See COPYING file distributed along with the NiBabel package for the
#   copyright and license terms.
#
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""" Defaults for images and headers

error_level is the problem level (see BatteryRunners) at which an error will be
raised, by the batteryrunners ``log_raise`` method.  Thus a level of 0 will
result in an error for any problem at all, and a level of 50 will mean no errors
will be raised (unless someone's put some strange problem_level > 50 code in).

``logger`` is the default logger (python log instance)

To set the log level (log message appears for problem of level >= log level),
use e.g. ``logger.level = 40``.

As for most loggers, if ``logger.level == 0`` then a default log level is used -
use ``logger.getEffectiveLevel()`` to see what that default is.

Use ``logger.level = 1`` to see all messages.
"""

import logging

error_level = 40
logger = logging.getLogger('nibabel.global')
logger.addHandler(logging.StreamHandler())


class ErrorLevel(object):
    """ Context manager to set log error level
    """

    def __init__(self, level):
        self.level = level

    def __enter__(self):
        global error_level
        self._original_level = error_level
        error_level = self.level

    def __exit__(self, exc, value, tb):
        global error_level
        error_level = self._original_level
        return False


class LoggingOutputSuppressor(object):
    """Context manager to prevent global logger from printing"""

    def __enter__(self):
        self.orig_handlers = logger.handlers
        for handler in self.orig_handlers:
            logger.removeHandler(handler)

    def __exit__(self, exc, value, tb):
        for handler in self.orig_handlers:
            logger.addHandler(handler)
