##############################################################################
# Copyright (c) 2016 Huawei Technologies Co.,Ltd and others.
#
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Apache License, Version 2.0
# which accompanies this distribution, and is available at
# http://www.apache.org/licenses/LICENSE-2.0
##############################################################################


import datetime
import re
import sys


def format_datetime(date_time):
    """Generate string from datetime object."""
    return date_time.strftime("%Y-%m-%d %H:%M:%S")


def parse_time_interval(time_interval_str):
    """parse string of time interval to time interval.

    supported time interval unit: ['d', 'w', 'h', 'm', 's']
    Examples:
       time_interval_str: '3d 2h' time interval to 3 days and 2 hours.
    """
    if not time_interval_str:
        return 0

    time_interval_tuple = [
        time_interval_element
        for time_interval_element in time_interval_str.split(' ')
        if time_interval_element
    ]
    time_interval_dict = {}
    time_interval_unit_mapping = {
        'd': 'days',
        'w': 'weeks',
        'h': 'hours',
        'm': 'minutes',
        's': 'seconds'
    }
    for time_interval_element in time_interval_tuple:
        mat = re.match(r'^([+-]?\d+)(w|d|h|m|s).*', time_interval_element)
        if not mat:
            continue

        time_interval_value = int(mat.group(1))
        time_interval_unit = time_interval_unit_mapping[mat.group(2)]
        time_interval_dict[time_interval_unit] = (
            time_interval_dict.get(time_interval_unit, 0) + time_interval_value
        )

    time_interval = datetime.timedelta(**time_interval_dict)
    if sys.version_info[0:2] > (2, 6):
        return time_interval.total_seconds()
    else:
        return (
            time_interval.microseconds + (
                time_interval.seconds + time_interval.days * 24 * 3600
            ) * 1e6
        ) / 1e6


def pretty_print(*contents):
    """pretty print contents."""
    if len(contents) == 0:
        print ""
    else:
        print "\n".join(content for content in contents)