#!/usr/bin/env python
#03/21/2010 jcvernaleo (john@netpurgatory.com)
#$Id: read_ical.py,v 1.2 2010/03/31 01:29:27 john Exp $
#Copyright 2010 John C. Vernaleo
# read_ical v0.1
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# See the file gpl.txt in the same directory as this.
#
# This is a first pass at a python interface to ical files (specifically
# what Apple's iCal considers an ical file.  It only handle's todo items
# (VTODO) at the moment since that was all I wanted.
#
# The main purpose of it was to convert iCal todo's to a format I can use
# with emacs org-mode.  Thanks to this I was able to completely move my todo
# lists (and I really depend on todo lists) from iCal (which I never liked)
# to emacs (which I really like).
# I may try to improve this, but for now it does what I needed.

import sys
import re

class todo:
      """A simple class to hold a single TODO element from ical
      along with some routines to work with it.  The goal is to get
      data out of ical and into emacs org-mode.
      """
      def __init__(self):
            self.created=""
            self.UID=""
            self.summary=""
            self.completed=""
            self.due=""
            self.description=""
            return
      def get_item(self,line,item,name):
            if not item:
                  term=re.compile(name)
                  result=term.match(line)
                  if result:
                        return(term.split(line)[1])
                  else:
                        return
            else:
                  return(item)
      def read_ical_line(self,line):
            self.created=self.get_item(line,self.created,"CREATED:")
            self.UID=self.get_item(line,self.UID,"UID:")
            self.summary=self.get_item(line,self.summary,"SUMMARY:")
            self.completed=self.get_item(line,self.completed,"COMPLETED:")
            self.due=self.get_item(line,self.due,"DUE;VALUE=DATE:")
            self.description=self.get_item(line,self.description,"DESCRIPTION:")
            return
      def org_mode_date(self,date):
            """This is assuming that dates are always in the form
            YYYYMMDD followed by other stuff I don't care about.
            org mode allows for more precision for the completion dates
            but the extra info in the ical files doesn't look very helpful.
            """
            if date and (len(date)>=8):
                  corrected_date=date[0]+date[1]+date[2]+date[3]+"-"+date[4]+date[5]+"-"+date[6]+date[7]
                  return(corrected_date)
            else:
                  return
      def print_orgmode(self):
            line="**"
            if not (self.completed):
                  line=line+" TODO "+self.summary
            else:
                  line=line+" DONE "+self.summary
            print(line)
            line=""
            if self.due:
                  line="   DEADLINE: <"+self.org_mode_date(self.due)+">"
            if self.completed:
                  if not self.due:
                        line=line+"  "
                  line=line+" CLOSED: ["+self.org_mode_date(self.completed)+"]"
            if line:
                  print(line)
            line=""
            if self.description:
                  line="   "+self.description
                  print(line)
            return

def read_ical(filename):
      """This function reads a filename and put any VTODO items it finds
      in a list of TODO objects.
      """
      infile=open(filename)
      intodo=0
      i=0
      todo_list=[]
      for line in infile:
            line=line.rstrip()
            if line == "END:VTODO":
                  intodo=0
            if intodo:
                  todo_list[i-1].read_ical_line(line)
            if line == "BEGIN:VTODO":
                  intodo=1
                  todo_list.append(todo())
                  i+=1
      infile.close()
      return(todo_list)

if __name__ == "__main__":
      if not len(sys.argv)>1:   
            print("MUST SUPPLY A FILENAME")
            sys.exit()
      filename=sys.argv[1]
      todo_list=read_ical(filename)

      for item in todo_list:
            item.print_orgmode()