# This is a set of functions (some erroneous) which I wrote to make it
# easy to use dates in some programs.  Some material is borrowed from
# calendar and some from some Zope file (I forgot which).  The most
# interesting function is DateSerial() which takes a date and returns a
# serial number, with 1/1/1900 being 1 (note that MS Excel and Lotus123
# missed or added one leap year early on and are off by one for recent
# dates.  There is an explanation that used to be on the MS website
# somewhere.)  I am trying to learn how to do python classes, so the class
# DateInfo: is probably defective.  Using a serial number date allows more
# flexibility with dates and makes financial calculations such as
# interest, days360, weekDay, and other such stuff easier, but all my
# functions must be checked for correctness and any improvements,
# additions, etc. are quite welcome.  I would hope that this could be part
# of a useful financial analysis or calendar class (if I ever figure out
# how to use classes).

# Hoping you find this interesting...
# Thanks! 


#
#
import string
from types import *
import calendar


yearbase = 1900
monthLength = (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31)
daysToMonth = (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334)
monthNames = ('January','February','March','April','May','June','July',
              'August', 'September', 'October', 'November', 'December')
dayNames = ('Sunday','Monday','Tuesday','Wednesday', 'Thursday','Friday','Saturday')

dytmoD = {'M1':0, 'M2':31, 'M3':59, 'M4':90, 'M5':120, 'M6':151, 'M7':181,
          'M8':212, 'M9':243, 'M10':273, 'M11':304, 'M12':334 }
molenD = {'M1':31, 'M2':28, 'M3':31, 'M4':30, 'M5':31, 'M6':30, 'M7':31,
          'M8':31, 'M9':30, 'M10':31, 'M11':30, 'M12':31 }
monameD = {'M1':'January', 'M2':'February', 'M3':'March', 'M4':'April',
           'M5':'May', 'M6':'June', 'M7':'July','M8':'August',
'M9':'September',
           'M10':'October', 'M11':'November', 'M12':'December' }
#=========
class DateInfo(yr, mo, dy):
    """
    Intended to take a date and provide information such as
    serial number (1900 base), day of week (Sunday begins),
    year to date days, days 360
    """

    if yr < baseYear:
        raise ValueError, 'year: ' + repr(yr) + ' less than ' +
repr(baseYear)
    if mo > 12:
        raise ValueError, 'month: ' + repr(mo) + ' greater than 12'
    if yr < baseYear:
        raise ValueError, 'year: ' + repr(yr) + ' less than ' +
repr(baseYear)
    
    #date = dateMDY 
    if yr < 1900:
        if yr > 35:
            year = 1900 + yr
        else:
            year = 2000 + yr
        
    month = int(mo)
    day = dy

    moId = 'M%d' % month
    
    baseYear = 1900
    dSep = '/'

    dytmoD = {'M1':0, 'M2':31, 'M3':59, 'M4':90, 'M5':120, 'M6':151, 'M7':181,
              'M8':212, 'M9':243, 'M10':273, 'M11':304, 'M12':334 }
    molenD = {'M1':31, 'M2':28, 'M3':31, 'M4':30, 'M5':31, 'M6':30, 'M7':31,
              'M8':31, 'M9':30, 'M10':31, 'M11':30, 'M12':31 }
    monameD = {'M1':'January', 'M2':'February', 'M3':'March', 'M4':'April',
               'M5':'May', 'M6':'June', 'M7':'July','M8':'August', 'M9':'September',
               'M10':'October', 'M11':'November', 'M12':'December' }
    moKeys = dytmoD.keys()
    moKeys.sort()
    
    dayNames = ((1, 'Sun', 'Sunday'),(2, 'Mon', 'Monday'),
                (3, 'Tue', 'Tuesday'),(4, 'Wed', 'Wednesday'),
                (5, 'Thur', 'Thursday'),(6, 'Fri', 'Friday'),
                (7, 'Sat', 'Saturday'))
    
    serial = dateSerial(year, month, day)

    def isLeapYear(yr):
        return (0 == (yr % 4))
            
    def dateSerial(yr, mo, dy):
        # assume base year of 1900 so that 1-1-1900 is day 1
        sy = (yr - baseYear) * 365  # 365 days to a year
        # Leap Year occurs every four years, except for years ending in 00,
        # in which case only if the year is divisible by 400.
        # for any year add: - (yr/100 - baseYear/100) + (yr/400 - baseYear/400)
        # but since this is for centuries 1900 and 2000, it is superfluous
        sly = (yr/4 - baseYear/4)
        #
        sm = dtymoD[moId]
        if isLeapYear(yr) and mo < 3:
            sm = sm - 1 

        return sy + sly + sm + dy

    def serialDate(dSerial):
        """verify the correction for leap years"""
        sy = (dSerial / 365) + baseYear
        sly = (yr - baseYear) / 4
        sd = dSerial - sy - sly
        mo = 0
        for ky in moKeys:
            if sd < dytmoD[ky]:
                mo = mo + 1
            else:
                break
            
        dy = sd - dytmoD[ky]            
        if isLeapYear(sy) and mo < 3:
            dy = dy - 1

        return (yr, mo, dy)    
    
    def DayOfWeek(dSerial, Onum1abrev2word=0):
        """
        Argument is a serial number date.
        Onum1abrev2word -> 0=integer, 1=abbreviation, 2=word
        Returns the day of the week where Sunday=1, Monday=2, ..., Saturday = 7
        """
        try:
            rt = int(Onum1abrev2word)
        except ValueError:
            print 'Onum1abrev2word: %s must be an integer 0, 1, or 2' % Onum1abrev2word
        try:
            dNum = int(dSerial)
        except ValueError:
           print 'dSerial: %s must be an integer as from dateSerial()' % dSerial
        
        # assuming that 1/1/1900 was a Monday
        firstDay = 1
        if dSerial < 7:
            dw = dNum
        else:
            dw = dNum % 7

        return dayNames[dw][rt]
    
#=========
def tupleYMD(sYYMMDD, yearLen=2, delimiter='/', isTuple=0):
    dType = type(sYYMMDD)
    
    if dType is types.StringType:
        # we want a string here
        strDate = sYYMMDD
    else:
        strDate = repr(sYYMMDD) 		# convert dateYMD to a string
    
    if yrLen == 2:
        yr = int(strDate(:yearLen))
        if yr < 35:
            yr = yr + 2000
        else:
            yr = yr + 1900
    else:
        yr = int(strDate(:yearLen)
        
    mo = int(strDate(yearLen:yearLen+2))
    dy = int(strDate(-2:))
                    
    if isTuple:
    	return (yr, mo, dy)
    else:
    	return %d + delimiter + %d % strMo + delimiter + %d % strYr
	
#===========
def dateSerial(year, month, day):
    # assume base year of 1900 so that 1-1-1900 is day 1
    yr = int(year)
    mo = int(month)
    dy = int(day)
    moKy = 'M%d' % mo
    
    if yr < baseYear:
        raise ValueError, 'year: ' + repr(yr) + ' less than ' +
repr(baseYear)
    if mo > 12:
        raise ValueError, 'month: ' + repr(mo) + ' greater than 12'
    if yr < baseYear:
        raise ValueError, 'year: ' + repr(yr) + ' less than ' +
repr(baseYear)    
    moIdx = mo - 1
    #Leap Year occurs every four years, except for years ending in 00,
    #in which case only if the year is divisible by 400.
    sy = (yr - baseYear) * 365
    sly = (yr/4 - baseYear/4) - (yr/100 - baseYear/100) + (yr/400 -
baseYear/400)
    sm = daysToMonth[moIdx]
    sm = dtymoD['M%' % mo]

    if isLeapYear(yr):
        if moIdx <= 1:
            sly = sly - 1 

    return sy + sly + sm + dy
    
#===========
def serialDate(dSerial):
    """verify the correction for leap years"""
    sly = dSerial / (365 * 4)
    dS = dSerial - sly
    yr = dS / 365
    dy1 = dS % 365
    for i in range(len(daysToMonth)):
        if dy1 < daysToMonth[i]:
            mo = i + 1
            break

    dy = dy1 - daysToMonth[mo-1]

    return (yr, mo, dy)    

#==========
def dayOfWeek(dSerial):
    """Argument is a serial number date.
       Returns the integer value for the day of the week
       where Sunday = 1, Monday = 2, ... Saturday = 7"""
    # assuming that 1/1/1900 was a Monday
    firstDay = 1
    id dSerial < 7:
        dw = dSerial + firstDay
    else:
        dw = dSerial % 7 + firstDay

    return dw
    
#===========
def isLeapYear(yr):
    isLY = (0 == (yr % 4)
    return isLY
            
def isleap(year):
    """Return 1 for leap years, 0 for non-leap years."""
    return year % 4 == 0 and (year % 100 <> 0 or year % 400 == 0)

def leapdays(y1, y2):
    """Return number of leap years in range [y1, y2).
       Assume y1 <= y2."""
    y1 -= 1
    y2 -= 1
    return (y2/4 - y1/4) - (y2/100 - y1/100) + (y2/400 - y1/400)

#===========
def getInfo(getWhat='help'):
    """Returns different information based on getWhat"""
    
    argsL = ('monthLength -> int tuple', 'monthNames -> string tuple',
             'dayNames -> string tuple', 'daysToMonth -> int tuple')

    
    argsR = { 'help': argsL, 'monthLength': monthLength, 'monthNames': monthNames,
              'dayNames': dayNames, 'daysToMonth': daysToMonth}
    rVal = 'help'
    for itm in argsR.keys():
        if getWhat == itm:
            rVal = itm
            break

    return argsR[rVal]

##    # known separators are / - .
##    def FindSeparator(dateMDY):
##        sep = ('/','-','.')
##        for s in sep:
##            try:
                  
##    DateTimeError='DateTimeError'
##    SyntaxError  ='Invalid Date-Time String'
##    DateError    ='Invalid Date Components'
##    int_pattern  =ts_regex.compile('\([0-9]+\)') #TS
##    flt_pattern  =ts_regex.compile(':\([0-9]+\.[0-9]+\)') #TS
##    name_pattern =ts_regex.compile('\([a-z][a-z]+\)', ts_regex.casefold) #TS
##    space_chars  =' \t\n'
##    delimiters   ='-/.:,'
##    _month_len  =((0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31), 
##                  (0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31))
##    _until_month=((0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334),
##                  (0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335))
##    _months    =['','January','February','March','April','May','June','July',
##                     'August', 'September', 'October', 'November', 'December']
##    _months_a   =['','Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
##                     'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
##    _months_p   =['','Jan.', 'Feb.', 'Mar.', 'Apr.', 'May', 'June',
##                     'July', 'Aug.', 'Sep.', 'Oct.', 'Nov.', 'Dec.']
##    _monthmap   ={'january': 1,   'jan': 1,
##                  'february': 2,  'feb': 2,
##                  'march': 3,     'mar': 3,
##                  'april': 4,     'apr': 4,
##                  'may': 5,
##                  'june': 6,      'jun': 6,
##                  'july': 7,      'jul': 7,
##                  'august': 8,    'aug': 8,
##                  'september': 9, 'sep': 9, 'sept': 9,
##                  'october': 10,  'oct': 10,
##                  'november': 11, 'nov': 11,
##                  'december': 12, 'dec': 12}
##    _days       =['Sunday','Monday','Tuesday','Wednesday',
##                  'Thursday','Friday','Saturday']
##    _days_a     =['Sun',  'Mon',  'Tue',  'Wed',  'Thu',  'Fri', 'Sat' ]
##    _days_p     =['Sun.', 'Mon.', 'Tue.', 'Wed.', 'Thu.', 'Fri.', 'Sat.']
##    _daymap     ={'sunday': 1,    'sun': 1,
##                  'monday': 2,    'mon': 2,
##                  'tuesday': 3,   'tues': 3,  'tue': 3,
##                  'wednesday': 4, 'wed': 4,
##                  'thursday': 5,  'thurs': 5, 'thur': 5, 'thu': 5,
##                  'friday': 6,    'fri': 6,
##                  'saturday': 7,  'sat': 7}