class Settings:
    """
    Settings manager
    """

    def version( self ):
        return '1.0.0'

    def __init__( self , arguments ):
        # Default configuration
        self.cache    = None
        self.filename = None
        self.inte_cal = None
        self.no_cache = False
        self.output   = 'data.fits'
        self.verbose  = False
        self.wave_cal = None

        # configuration change
        if len( arguments ) < 2:
            raise Exception(
                'type \'' + __file__ + ' -h\' for more information'
            )

        index = 0
        while index < len( arguments ):
            argument = arguments[ index ]
            if argument[0] == '-':
                if len( argument ) < 2:
                    raise Exception(
                        'unknown argument, type \' + __file__ + \' -h' +
                        ' for more information'
                    )
                if argument[1] != '-':
                    if argument == '-h':
                        argument = '--help'
                    elif argument == '-V':
                        argument = '--version'
                    elif argument == '-v':
                        argument = '--verbose'
                    elif argument == '-n':
                        argument = '--no-cache'
                    elif argument == '-c':
                        if index == len( arguments ) - 1:
                            raise Exception(
                                'cache have to take a value'
                            )
                        arguments[ index + 1 ] = '--cache=' + \
                        arguments[ index + 1 ]
                        index += 1
                        continue
                    elif argument == '-o':
                        if index == len( arguments ) - 1:
                            raise Exception(
                                'output have to take a value'
                            )
                        arguments[ index + 1 ] = '--output=' + \
                        arguments[ index + 1 ]
                        index += 1
                        continue
                    elif argument == '-w':
                        if index == len( arguments ) - 1:
                            raise Exception(
                                'wavelength calibration have to take a value'
                            )
                        arguments[ index + 1 ] = '--wavelength=' + \
                        arguments[ index + 1 ]
                        index += 1
                        continue
                    elif argument == '-i':
                        if index == len( arguments ) - 1:
                            raise Exception(
                                'intensity calibration have to take a value'
                            )
                        arguments[ index + 1 ] = '--intensity=' + \
                        arguments[ index + 1 ]
                        index += 1
                        continue
                    else:
                        raise Exception(
                            'unknown argument "' + argument + \
                            '", type \'' + __file__ + \
                            ' -h\' for more information'
                        )
                if argument[1] == '-': # not elif because argument
                                       # can change in the last if
                    if argument == '--help':
                        print( self.help() )
                        exit()
                    elif argument == '--version':
                        print( self.version() )
                        exit()
                    elif argument == '--verbose':
                        self.verbose = True
                    elif argument == '--no-cache':
                        self.no_cache = True
                    elif (
                        len( argument ) > 8 and
                        argument[ : 8 ] == '--cache='
                    ):
                        self.cache = argument[ 8 : ]
                    elif (
                        len( argument ) > 9 and
                        argument[ : 9 ] == '--output='
                    ):
                        self.output = argument[ 9 : ]
                    elif (
                        len( argument ) > 13 and
                        argument[ : 13 ] == '--wavelength='
                    ):
                        self.wave_cal = argument[ 13 : ]
                    elif (
                        len( argument ) > 12 and
                        argument[ : 12 ] == '--intensity='
                    ):
                        self.inte_cal = argument[ 12 : ]
                    else:
                        raise Exception(
                            'unknown argument "' + argument + \
                            '", type \'' + __file__ + ' -h\' ' + \
                            'for more information'
                        )
            else:
                self.filename = argument
            index += 1

        if self.filename == None:
            raise Exception( 'filename should be given' )

    def help( self ):
        return '\
naroo_reader [options...] filename\
\n    -w wavelength  wavelength calibration file, default to None.\
\n                   None means no wavelength interpolation\
\n    -i intensity   intensity calibration file, default to None.\
\n                   None means no intensity interpolation\
\n    -c --cache     use given cache file to store new temporary\
\n                   data or use old ones.\
\n    -h --help      show this help and quit\
\n    -n --no-cache  do not use already existing cache file.\
\n                   If cache is defined, the cache file will be\
\n                   overwrited.\
\n                   If cache is None, it does nothing\
\n    -o --output    Output file. Default to data.fits\
\n    -V --version   show version number and quit\
\n    -v --verbose   show more information to help debugging\
        '