#!/usr/bin/python3
import sys, os, re, datetime

eventTypes = {'APPOINTMENT' : {'hasTime': 1, 'numDates' : 2}, 'UNTIMED_EVENT' : {'hasTime' : 0, 'numDates' : 1}}
monthToIndex = {'jan' : 1, 'feb' : 2, 'mar' : 3, 'apr' : 4, 'may' : 5, 'jun' : 6, 'jul' : 7, 'aug' : 8, 'sep' : 9, 'oct' : 10, 'nov' : 11, 'dec' : 12}
dayToIndex = {'sun' : 0, 'mon' : 1, 'tue' : 2, 'wed' : 3, 'thu' : 4, 'fri' : 5, 'sat' : 6}
indexToDay = {0: 'sun', 1: 'mon', 2: 'tue', 3: 'wed', 4: 'thu', 5: 'fri', 6: 'sat'}

entries = []

class Repeat:
    def __init__(self):
        self.startDate = None
        self.endDate = None
        self.repeatType = ''
        self.repeatDays = []

    def __repr__(self):
        string = "Repeats from %s to %s" % (self.startDate, self.endDate)
        if (self.repeatType == 'weekly'):
            string = string + " on"
            for day in self.repeatDays:
                string = string + " %s" % indexToDay[day]
        return string

    def containsDate(self, date):
        if (date < self.startDate or self.endDate < date):
            return 0
        if (self.repeatType == 'daily'):
            return 1
        elif (self.repeatType == 'weekly'):
            return ((date.isoweekday() % 7) in self.repeatDays)
        else:
            print("Unknown repeat type: %s" % self.repeatType)
            return 0
            
class DatebookEntry:
    def __init__(self):
        self.entryType = ''
        self.hasTime = 0
        self.startDate = None
        self.endDate = None
        self.title = ''
        self.category = None
        self.repeat = None

    def __repr__(self):
        string = "%s (%s" % (self.title, self.startDate)
        if (self.endDate):
            string = string + " to %s" % self.endDate
        string = string + ")"
        if (self.category):
            string = string + " - %s" % self.category
        if (self.repeat):
            string = string + " %s" % self.repeat
        return string

    def containsDate(self, date):
        if (self.repeat):
            return self.repeat.containsDate(date)
        else:
            startDate = self.getStartDate()
            endDate = self.getEndDate()
            return (startDate == date or endDate == date)

    # TODO - make static?
    def getDateFromDateOrDatetime(self, dordt):
        toReturn = dordt
        # If we're a datetime, get a date
        if (isinstance(dordt, datetime.datetime)):
            toReturn = dordt.date()
        return toReturn

    def getStartDate(self):
        return self.getDateFromDateOrDatetime(self.startDate)

    def getEndDate(self):
        return self.getDateFromDateOrDatetime(self.endDate)

dateRE = re.compile(r'^(\d+)\s+(\w+)\s+(\d+)(?:\s+(\d+):(\d+))?$')
categoryRe = re.compile(r'^category=\d+\s+\((.*?)\)$', re.IGNORECASE)
def parseDate(text, hasTime):
    dateMatch = dateRE.match(text)
    if (dateMatch):
        if (hasTime):
            return datetime.datetime(int(dateMatch.group(3)), monthToIndex[dateMatch.group(2).lower()], int(dateMatch.group(1)), int(dateMatch.group(4)), int(dateMatch.group(5)))
        else:
            return datetime.date(int(dateMatch.group(3)), monthToIndex[dateMatch.group(2).lower()], int(dateMatch.group(1)))
    else:
        return None
    
def parseLines(lines):
    inEntry = 0
    curEntry = None
    for line in lines:
        if (not inEntry):
            for eventType in eventTypes:
                if (line.startswith(eventType)):
                    inEntry = 1
                    # Find all <> pairs after the first.
                    lessThanIndex = line.find('<') 
                    dates = []
                    for i in range(0, eventTypes[eventType]['numDates']):
                        lessThanIndex = line.find('<', lessThanIndex + 1)
                        greaterThanIndex = line.find('>', lessThanIndex)
                        dates.append(parseDate(line[lessThanIndex+1:greaterThanIndex], eventTypes[eventType]['hasTime']))
                    #print "got event with dates: "
                    #for date in dates:
                        #print str(date)
                    curEntry = DatebookEntry()
                    curEntry.entryType = eventType
                    curEntry.hasTime = len(dates) - 1
                    curEntry.startDate = dates[0]
                    if (curEntry.hasTime):
                        curEntry.endDate = dates[1]
                    #print repr(curEntry)
        else:
            if (line == '' or line == '\n'):
                #print "Adding %s" % repr(curEntry)
                entries.append(curEntry)
                curEntry = None
                inEntry = 0
            else:
                if (line.startswith('attributes=')):
                    # We don't care about attributes
                    pass
                elif (line.startswith('category=')):
                    categoryMatch = categoryRe.match(line)
                    if (categoryMatch):
                        curEntry.category = categoryMatch.group(1)
                    else:
                        print("ERROR - couldn't parse category line: %s" % line)
                elif (line.startswith('REPEAT from')):
                    repeatRe = re.compile("^REPEAT from <(.*?)> until <(.*?)>:\s*(.*)$")
                    repeatMatch = repeatRe.match(line)
                    if (repeatMatch):
                        startRepeatDate = parseDate(repeatMatch.group(1), 0)
                        endRepeatDate = parseDate(repeatMatch.group(2), 0)
                        intervalRe = re.compile(r"^<(.*?)>(?: on <(.*?)>)?$")
                        intervalMatch = intervalRe.match(repeatMatch.group(3))
                        if (intervalMatch):
                            repeat = Repeat()
                            repeat.startDate = startRepeatDate
                            repeat.endDate = endRepeatDate
                            repeat.repeatType = intervalMatch.group(1).lower()
                            if (repeat.repeatType == 'weekly'):
                                repeat.repeatDays = [dayToIndex[x] for x in intervalMatch.group(2).lower().split(',')]
                            # TODO - add other cases
                            curEntry.repeat = repeat    
                        else:
                            print("ERROR - couldn't parse interval line: %s" % repeatMatch.group(3))
                    else:
                        print("ERROR - couldn't parse repeat line: %s" % line)
                else:
                    curEntry.title = line[0:-1]

def getEntries(fileName, date, numDays):
    datebookFile = open(fileName, 'r')
    lines = datebookFile.readlines()
    datebookFile.close()
    parseLines(lines)
    curDate = date
    toReturn = {}
    for i in range(0, numDays):
        entriesToday = [e for e in entries if e.containsDate(curDate)]
        if (entriesToday):
            toReturn[curDate] = entriesToday
        curDate = curDate + datetime.timedelta(1)
    return toReturn

def main():
    if (len(sys.argv) > 1):
        datebookFileName = sys.argv[1]
    else:
        datebookFileName = 'datebook.txt'
    entries = getEntries(datebookFileName, datetime.date.today(), 40)
    for date in entries: 
        print("Entries for %s:" % date)
        for entry in entries[date]:
            print("   %s" % entry)

if (__name__ == '__main__'):
    main()