"""
    CLI argument handling; common stuff: logging
"""

import optparse
import logging

def parser (parser) :
    """
        Return an optparse.OptionGroup.
    """

    general = optparse.OptionGroup(parser, "General options")

    general.add_option('-q', '--quiet',     dest='loglevel', action='store_const', const=logging.ERROR, help="Less output")
    general.add_option('-v', '--verbose',   dest='loglevel', action='store_const', const=logging.INFO,  help="More output")
    general.add_option('-D', '--debug',     dest='loglevel', action='store_const', const=logging.DEBUG, help="Even more output")
    general.add_option('--debug-module',    action='append', metavar='MODULE', 
            help="Enable logging for the given logger/module name")

    # defaults
    parser.set_defaults(
        logname             = parser.prog,
        loglevel            = logging.WARN,
        debug_module        = [],
    )
 
    return general

def apply (options, logname=None) :
    """
        Apply the optparse options.
    """

    if logname :
        prefix = options.logname + ': '
    else :
        prefix = ''

    # configure
    logging.basicConfig(
        # XXX: log Class.__init__ as Class, not __init__?
        format  = prefix + '%(name)-20s: %(levelname)5s %(funcName)s: %(message)s',
        level   = options.loglevel,
    )

    # enable debugging for specific targets
    for logger in options.debug_module :
        logging.getLogger(logger).setLevel(logging.DEBUG)