"""A simple log mechanism styled after PEP 282."""

# The class here is styled after PEP 282 so that it could later be
# replaced with a standard Python logging implementation.

DEBUG = 1
INFO = 2
WARN = 3
ERROR = 4
FATAL = 5

import sys

class Log:

 def __init__(self, threshold=WARN):
 self.threshold = threshold

 def _log(self, level, msg, args):
 if level not in (DEBUG, INFO, WARN, ERROR, FATAL):
 raise ValueError('%s wrong log level' % str(level))

 if level >= self.threshold:
 if args:
 msg = msg % args
 if level in (WARN, ERROR, FATAL):
 stream = sys.stderr
 else:
 stream = sys.stdout
 if stream.errors == 'strict':
 # emulate backslashreplace error handler
 encoding = stream.encoding
 msg = msg.encode(encoding, "backslashreplace").decode(encoding)
 stream.write('%s\n' % msg)
 stream.flush()

 def log(self, level, msg, *args):
 self._log(level, msg, args)

 def debug(self, msg, *args):
 self._log(DEBUG, msg, args)

 def info(self, msg, *args):
 self._log(INFO, msg, args)

 def warn(self, msg, *args):
 self._log(WARN, msg, args)

 def error(self, msg, *args):
 self._log(ERROR, msg, args)

 def fatal(self, msg, *args):
 self._log(FATAL, msg, args)

_global_log = Log()
log = _global_log.log
debug = _global_log.debug
info = _global_log.info
warn = _global_log.warn
error = _global_log.error
fatal = _global_log.fatal

def set_threshold(level):
 # return the old threshold for use from tests
 old = _global_log.threshold
 _global_log.threshold = level
 return old

def set_verbosity(v):
 if v <= 0:
 set_threshold(WARN)
 elif v == 1:
 set_threshold(INFO)
 elif v >= 2:
 set_threshold(DEBUG)