from settings import hours, language
from datetime import timedelta, datetime, timezone

first_occurrence_char = '['
middle_occurrence_char = '|'
last_occurrence_char = ']'
multiday_begin_character = ' >'
multiday_end_character = '< '
until_character = ' - '
allday_character = "•"

allday_lang = {
    "en" : "All day",
    "de" : "Ganztägig"
}
allday_detailed = allday_lang[language]

multiday_lang = {
    "en" : "Multi-day",
    "de" : "Mehrtägig"
}
multiday_detailed = multiday_lang[language]

def time_str (dt):
    if hours is "12":
        return dt.strftime("%I:%M%p")
    elif hours is "24":
        return dt.strftime("%H:%M")
    else:
        return str(dt)

def event_prefix_str_md_dif (event, relative_date=None):
    if relative_date is None:
        relative_date = event.begin_datetime.date()

    if __is_multiday__(event) is False:
        return event_time_summary(event)
    
    #Relative to
    #First day
    elif __equal__(event.begin_datetime, relative_date):
        return event_time_summary(event) + multiday_begin_character

    #Last day
    elif __equal__(event.end_datetime, relative_date) or \
        (__day_duration__(event.end_datetime) == timedelta(0) and __equal__(relative_date + timedelta(1), event.end_datetime)):
        return multiday_end_character + event_time_summary(event)

    #Some day
    else:
        event.allday = True
        return multiday_end_character + event_time_summary(event) + multiday_begin_character

def event_prefix_str (event, relative_date=None):
    if relative_date is None:
        relative_date = event.begin_datetime.date()

    if __is_multiday__(event):
        return multiday_detailed
    else:
        return event_time_detailed(event)

def event_time_summary (event):
    if event.allday:
        return allday_character
    else:
        return time_str(event.begin_datetime)

def event_time_detailed (event):
    if event.allday:
        return allday_detailed
    else:
        return time_str(event.begin_datetime) + until_character + time_str(event.end_datetime)

def date_str(dt):
    return remove_leading_zero(dt.strftime('%d. %b'))

def remove_leading_zero (text):
        while text[0] is '0':
            text = text[1:]
        return text

def date_summary_str(dt):
    day = remove_leading_zero(dt.strftime("%d"))
    if language is "en":
        return dt.strftime('%a ' + day + '. %b')
    elif language is "de":
        return dt.strftime(day + '. %b., %a')
    else:
        return dt.strftime('%a ' + day + '. %b')

def __is_multiday__ (event):
    if event.allday and event.duration == timedelta(1):
        return False

    return event.begin_datetime.day != event.end_datetime.day or \
        event.begin_datetime.month != event.end_datetime.month or \
        event.begin_datetime.year != event.end_datetime.year

def __equal__(dt1, dt2):
    return dt1.day == dt2.day and \
        dt1.month == dt2.month and \
        dt1.year == dt2.year

def __day_duration__(dt):
    day_begin = datetime(dt.year, dt.month, dt.day, 0, 0, 0, 0, timezone.utc)
    return dt - day_begin