# ------------------------------------------------------------------------------
# Formatting weeks
# Use "Monday" as the first day of the week following European convention
# and ISO 8601, OR use "Sunday" as the first day of the week following Jewish
# tradition
# https://en.wikipedia.org/wiki/Week#Week_numbering
# http://www.cjvlang.com/Dow/SunMon.html
# Keep this the same as the JQueryDatePicker to avoid confusion
# see http://xdsoft.net/jqplugins/datetimepicker
# TODO: support other first day of week options (e.g. Saturday) and other
# date within first week options (e.g. sixth_jan)
# ------------------------------------------------------------------------------
import datetime as dt
import calendar
from django.conf import settings
from django.utils.formats import get_format
from .names import (MONDAY_TO_SUNDAY, MON_TO_SUN,
SUNDAY_TO_SATURDAY, SUN_TO_SAT)
# ------------------------------------------------------------------------------
# Start weeks on Monday
# https://stackoverflow.com/questions/304256/
def _iso_year_start(iso_year):
"The gregorian calendar date of the first day of the given ISO year"
fourth_jan = dt.date(iso_year, 1, 4)
delta = dt.timedelta(fourth_jan.isoweekday()-1)
return fourth_jan - delta
def _iso_to_gregorian(iso_year, iso_week, iso_day):
"Gregorian calendar date for the given ISO year, week and day"
year_start = _iso_year_start(iso_year)
return year_start + dt.timedelta(days=iso_day-1, weeks=iso_week-1)
def _iso_num_weeks(iso_year):
"Get the number of ISO-weeks in this year"
year_start = _iso_year_start(iso_year)
next_year_start = _iso_year_start(iso_year+1)
year_num_weeks = ((next_year_start - year_start).days) // 7
return year_num_weeks
def _iso_info(iso_year, iso_week):
"Give all the iso info we need from one calculation"
prev_year_start = _iso_year_start(iso_year-1)
year_start = _iso_year_start(iso_year)
next_year_start = _iso_year_start(iso_year+1)
first_day = year_start + dt.timedelta(weeks=iso_week-1)
last_day = first_day + dt.timedelta(days=6)
prev_year_num_weeks = ((year_start - prev_year_start).days) // 7
year_num_weeks = ((next_year_start - year_start).days) // 7
return (first_day, last_day, prev_year_num_weeks, year_num_weeks)
def _gregorian_to_iso(date_value):
"ISO year, week and day for the given Gregorian calendar date"
return date_value.isocalendar()
def _iso_week_of_month(date_value):
"0-starting index which ISO-week in the month this date is"
weekday_of_first = date_value.replace(day=1).weekday()
return (date_value.day + weekday_of_first - 1) // 7
# ------------------------------------------------------------------------------
# Start weeks on Sunday
def _ssweek_year_start(ssweek_year):
"The gregorian calendar date of the first day of the given Sundaystarting-week year"
fifth_jan = dt.date(ssweek_year, 1, 5)
delta = dt.timedelta(fifth_jan.weekday()+1)
return fifth_jan - delta
def _ssweek_to_gregorian(ssweek_year, ssweek_week, ssweek_day):
"Gregorian calendar date for the given Sundaystarting-week year, week and day"
year_start = _ssweek_year_start(ssweek_year)
return year_start + dt.timedelta(days=ssweek_day-1, weeks=ssweek_week-1)
def _ssweek_num_weeks(ssweek_year):
"Get the number of Sundaystarting-weeks in this year"
year_start = _ssweek_year_start(ssweek_year)
next_year_start = _ssweek_year_start(ssweek_year+1)
year_num_weeks = ((next_year_start - year_start).days) // 7
return year_num_weeks
def _ssweek_info(ssweek_year, ssweek_week):
"Give all the ssweek info we need from one calculation"
prev_year_start = _ssweek_year_start(ssweek_year-1)
year_start = _ssweek_year_start(ssweek_year)
next_year_start = _ssweek_year_start(ssweek_year+1)
first_day = year_start + dt.timedelta(weeks=ssweek_week-1)
last_day = first_day + dt.timedelta(days=6)
prev_year_num_weeks = ((year_start - prev_year_start).days) // 7
year_num_weeks = ((next_year_start - year_start).days) // 7
return (first_day, last_day, prev_year_num_weeks, year_num_weeks)
def _gregorian_to_ssweek(date_value):
"Sundaystarting-week year, week and day for the given Gregorian calendar date"
nextYear = date_value.year + 1
nextYearStart = _ssweek_year_start(nextYear)
if date_value >= nextYearStart:
year = nextYear
yearStart = nextYearStart
else:
yearStart = _ssweek_year_start(date_value.year)
if date_value >= yearStart:
year = date_value.year
else:
year = date_value.year - 1
yearStart = _ssweek_year_start(year)
weekNum = ((date_value - yearStart).days) // 7 + 1
dayOfWeek = date_value.weekday() + 1
return (year, weekNum, dayOfWeek)
def _ssweek_of_month(date_value):
"0-starting index which Sundaystarting-week in the month this date is"
weekday_of_first = (date_value.replace(day=1).weekday() + 1) % 7
return (date_value.day + weekday_of_first - 1) // 7
# ------------------------------------------------------------------------------
def getFirstDayOfWeek():
return getattr(settings, "JOYOUS_FIRST_DAY_OF_WEEK",
get_format("FIRST_DAY_OF_WEEK"))
if getFirstDayOfWeek() == 1:
calendar.setfirstweekday(calendar.MONDAY)
#: Give all the info we need from one calculation
#: (first_day, last_day, prev_year_num_weeks, year_num_weeks)
week_info = _iso_info
#: Get the number of weeks in this year
num_weeks_in_year = _iso_num_weeks
#: year, week and day for the given Gregorian calendar date
gregorian_to_week_date = _gregorian_to_iso
#: Returns a 0-starting index of which week in the month this date is
week_of_month = _iso_week_of_month
#: Abbreviations of the days of the week
weekday_abbr = MON_TO_SUN
#: Names of the days of the week
weekday_name = MONDAY_TO_SUNDAY
else:
calendar.setfirstweekday(calendar.SUNDAY)
week_info = _ssweek_info
num_weeks_in_year = _ssweek_num_weeks
gregorian_to_week_date = _gregorian_to_ssweek
week_of_month = _ssweek_of_month
weekday_abbr = SUN_TO_SAT
weekday_name = SUNDAY_TO_SATURDAY
# ------------------------------------------------------------------------------
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