# -*- coding: utf-8 -*-
"""
@file timestamp.py
@brief Extends the python datetime with functionality useful to the format recognized by ASF

@par History
     - Brian Helgans, Dec 17 2019, initial version
"""
import datetime as pydatetime
import re


class datetime(pydatetime.datetime):
    '''
    Extends datetime with fw patterned string output/input
    '''
    
    def __add__(self,other):
        result=super(datetime,self).__add__(other)
        result=datetime(result.year,
                        result.month,
                        result.day,
                        result.hour,
                        result.minute,
                        result.second,
                        result.microsecond,
                        result.tzinfo)        
        return result
    
    __radd__=__add__

    @property
    def as_fw_string(self):
        return as_fw_string(self)

    
    @staticmethod
    def from_fw_string(fw_string):
        ts_re = re.compile('^{year=(\d{4});month=(\d{1,2});day=(\d{1,2});hour=(\d{1,2});min=(\d{1,2});sec=(\d{1,2}.*[0-9]*)}')
        #print(fw_string)
        m = ts_re.match(fw_string).groups()
        seconds_f = float(m[5])
        seconds = int(seconds_f)
        micros = int ( (seconds_f - seconds ) * 1000000 )
        start_datetime = datetime(year=int(m[0]), month=int(m[1]), day=int(m[2]), 
                                  hour=int(m[3]), minute=int(m[4]), second=seconds, microsecond=micros)
        return start_datetime


def as_fw_string(datetime):
    '''
    Outputs a datetime as a fw format string.
    :param datetime:
    :type datetime.datetime:
    '''
    return '{year=%d;month=%d;day=%d;hour=%d;min=%d;sec=%f}' % (
            datetime.year,
            datetime.month,
            datetime.day,
            datetime.hour,
            datetime.minute,
            datetime.second + int(datetime.microsecond / 100000) / 10.0)