# functions related to Date-fields
# -----------------------------------------------------
"""
additionally functions for calculating date with formulas like [DATE+2M] and for comparison of date related on two reference-dates
"""
import datetime
#from dateutil.relativedelta import relativedelta
import re
import utils.data_const as D


F_DIR = "%Y-%m-%d_%H-%M-%S"
F_DE = "%d.%m.%Y"
F_N8 = "%Y%m%d"

def getActdate(format):
    return getFormatdate(datetime.datetime.now(), format)


def getFormatdate(date, format):
    """ it return the date as string in the format """
    return date.strftime(format)


def getFormatDatetupel(dtupel, format):
    """ it return the date as string in the format """
    if format == F_N8:
        return f'{dtupel[0]:04}'+f'{dtupel[1]:02}'+f'{dtupel[2]:02}'
    return getFormatdate(datetime.datetime(dtupel[0], dtupel[1], dtupel[2],
                                           dtupel[3], dtupel[4], dtupel[5]) ,format)


def parseFormula(instring):
    """
    the function parses the string as a formula. In the formula the input-date - actdate or explicite date -
    will be added resp. subtracted with years, months or dates which are specified in the formula.
    The structure of the formula: DATE +/- mY +/-nM +/-qD
    :param instring:
    :return:
    """
    instring = instring.upper()
    if instring[2:6] == "DATE":
        refdate = datetime.datetime.today()
        formula = instring[7:-2].upper()
    else:
        dstring = instring[2:instring.find(" ")]
        res = parseDate(dstring)
        refdate = datetime.datetime(res[0], res[1], res[2], res[3], res[4], res[5])
        formula = instring[2+len(dstring):-2]
    formula = re.sub(r' ', '', formula)
    year = refdate.year
    mon = refdate.month
    day = refdate.day
    hour = refdate.hour
    min = refdate.minute
    sec = refdate.second
    if re.match(r"[-+]\d+[JYMDT]", formula):
        ress = re.compile(r"([-+])(\d+)([JYMDT])")
        for res in ress.finditer(formula):
            summand = int(res.group(2))
            if res.group(1) == "-":
                summand = summand * (-1)
            if res.group(3) in "JY":
                year = year + summand
            if res.group(3) in "M":
                mon = mon + summand
                while mon <= 0:
                    mon = mon + 12
                    year = year - 1
                while mon > 12:
                    mon = mon - 12
                    year = year + 1
            if res.group(3) in "DT":
                refdate = datetime.datetime(year, mon, day, hour, min, sec)
                refdate = refdate + datetime.timedelta(days=summand)
                year = refdate.year
                mon = refdate.month
                day = refdate.day
                hour = refdate.hour
                min = refdate.minute
                sec = refdate.second
        return (year, mon, day, hour, min, sec)
    else:
        print("re matcht nicht")
        return (year, mon, day, hour, min, sec)


def parseDate(instring):
    """
    the function parses the string as a date or timestamp which is formed in one of the typical formates
    :param the string to be parse:
    :return timestamp as tupel (y, m, d, H, M ,S):
    """
    year = 0
    mon = 0
    day = 0
    hour = 0
    min = 0
    sec = 0
    if instring[0:2] == "{(" and instring[-2:] == ")}":
        return parseFormula(instring)
    for d in ["_", " "]:
        if d in instring and instring.find(d) > 8:
            dstring = instring[0:instring.find(d)]
            tstring = instring[instring.find(d)+1:]
            dres = parseDate(dstring)
            tres = parseDate(tstring)
            return (dres[0], dres[1], dres[2], tres[3], tres[4], tres[5])
    if re.match(r"\d{4}[-./]\d{2}[-./]\d{2}", instring):
        res = re.match(r"(\d{4})[-./](\d{2})[-./](\d{2})", instring)
        year = int(res.group(1))
        mon = int(res.group(2))
        day = int(res.group(3))
        return (year, mon, day, hour, min, sec)
    if re.match(r"\d{1,2}[-./]\d{1,2}[-./]\d{1,2}", instring):
        res = re.match(r"(\d{1,2})[-./](\d{1,2})[-./](\d{4})", instring)
        year = int(res.group(3))
        mon = int(res.group(2))
        day = int(res.group(1))
        return (year, mon, day, hour, min, sec)
    if re.match(r"\d{8}", instring):
        year = instring[0:4]
        mon = instring[4:6]
        day = instring[6:8]
        return (year, mon, day, hour, min, sec)
    if re.match(r"\d{2}[-:]\d{2}[-:/]\d{2}", instring):
        res = re.match(r"(\d{2})[-:/](\d{2})[-:/](\d{2})", instring)
        hour = int(res.group(1))
        min = int(res.group(2))
        sec = int(res.group(3))
        return (year, mon, day, hour, min, sec)