pyUnixtime2UTC

# Convert Unix Time to current UTC data and time, without using Datetime module
# Mike Kerry - 28-Jan-2021 - [email protected]
# **BUG FIXED 28-Jan 14:00 UTC !!

# Unix Time is the number of seconds that have elapsed since 00:00:00 UTC on 01-Jan-1970
# Because year 2000 is a leap year (unlike 1900 or 2100 etc.) this code will work from 1970 to 2099
# (or until some time in year 2038 when 32-bit Unix timestamps overflow - if we are not all on 64-bit by then!)

import time         # Unix Time is available from the "time" module


def n2(n):
    # A little function to format an integer 0 to 99 into a 2-character string with leading zero where needed
    return str(n + 100)[1:]


secs_per_day = 86400                                # A useful constant
unix_now = int(time.time())                         # Unix time is seconds since 1-Jan-1970
days_per_4years = 365 * 4 + 1                       # a span of 4 years has 1461 days (365 * 3 + 366)
secs_per_4years = days_per_4years * secs_per_day
count_of_4years = unix_now // secs_per_4years       # compute number of 4-year spans that have elapsed since 1970

secs_into_4years = unix_now - count_of_4years * secs_per_4years
days_into_4years = secs_into_4years // secs_per_day

year = int(1970 + count_of_4years * 4)

days_into_year = 1 + days_into_4years       # Plus 1 because the base date is 1st Jan, not day zero
if days_into_year > 365:
    days_into_year -= 365       # count a non-leap year e.g. 1970
    year += 1
if days_into_year > 365:
    days_into_year -= 365       # count a non-leap year e.g. 1971
    year += 1
if days_into_year > 366:
    days_into_year -= 366       # count a leap year e.g. 1972
    year += 1

feb_days = 28
if not year & 3:          # is year divisible by 4? (faster and neater than year % 4)
    feb_days = 29         # year is a leap year
days_by_month = [0, 31, feb_days, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]     # table of days by month (Jan is month 1)
day = days_into_year
# Convert days_into_year into month and day
for mon, num in enumerate(days_by_month):
    if day <= num:              # BUG FIX !!
        break
    day -= num

# Compute time of day in hours, minutes, and seconds
secs_into_day = unix_now % secs_per_day
hours = secs_into_day // 3600
mins = (secs_into_day // 60) % 60
secs = (secs_into_day - (hours * 3600) - (mins * 60))

print(str(year) + "-" + n2(mon) + "-" + n2(day) + " " + n2(hours) + ":" + n2(mins) + ":" + n2(secs))