addappointments

#!/usr/bin/env python3

# Copyright 2006-2024 Michael Cuffaro
#
# This file is part of mccal.
#
# mccal 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 3 of the License, or
# (at your option) any later version.
#
# mccal 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 mccal.  If not, see <http://www.gnu.org/licenses/>.

import argparse
import re
import sys
import time
from datetime import datetime, timedelta
from pathlib import Path


def save_appointment(calendar, appdate, remind, text, appt_id):
  # Assigning a date implies a copy operation:
  alarm = appdate
  alarm = alarm - timedelta(minutes=int(remind))
  if appt_id is None:
    appt_id = time.time()
  print(
    f'ID:{appt_id} {alarm.year}-{alarm.month}-{alarm.day} {alarm.hour}:{alarm.minute} '
    f'"{appdate.year}-{appdate.month}-{appdate.day} {appdate.hour}:{appdate.minute} {text}"',
    file=calendar
  )


def main(appointments, calendar, appt_id):
  for appointment in appointments:
    # Parse the next line:
    appointment = appointment.strip('\n')
    matches = re.fullmatch(r"((weekly|biweekly|monthly|yearly)\s+(\d+)\s+){0,1}"
                           r"(remind\s+(\d+)\s+){0,1}"
                           r"((\d{1,4})-(\d{1,2})-(\d{1,2})\s+){0,1}"
                           r"(\d{1,2}):(\d{1,2})"
                           r"(\s+(([\S\s])*)){0,1}",
                           appointment)
    if not matches:
      print(f"Ignoring appointment with invalid format: '{appointment}'. ", file=sys.stderr)
      continue
    matches = matches.groups()
    repeat, rep_val, remind, year, month, day, hour, minute, text = (
      matches[1], matches[2], matches[4], matches[6], matches[7],
      matches[8], matches[9], matches[10], matches[12]
    )

    # Determine the appointment date:
    if year is None:
      appt_date = datetime.today()
    else:
      try:
        appt_date = datetime(year=int(year), month=int(month), day=int(day))
      except ValueError:
        print(f"Ignoring appointment with invalid date: {year}-{month}-{day}", file=sys.stderr)
        continue
    try:
      appt_date = appt_date.replace(hour=int(hour), minute=int(minute))
    except ValueError:
      print(f"Ignoring appointment with invalid time: {hour}:{minute}", file=sys.stderr)
      continue

    # If no reminder has been provided it defaults to 0:
    remind = remind or 0

    # Save the appointment and then save it again as many times as needed at the proper times:
    this_appt_id = f"{appt_id}0" if appt_id else None
    save_appointment(calendar, appt_date, remind, text, this_appt_id)
    rep_val = None if not rep_val else int(rep_val)
    if repeat == "weekly":
      for i in range(1, rep_val):
        appt_date = appt_date + timedelta(days=7)
        this_appt_id = f"{appt_id}{i}" if appt_id else None
        save_appointment(calendar, appt_date, remind, text, this_appt_id)
    elif repeat == "biweekly":
      for i in range(1, rep_val):
        appt_date = appt_date + timedelta(days=14)
        this_appt_id = f"{appt_id}{i}" if appt_id else None
        save_appointment(calendar, appt_date, remind, text, this_appt_id)
    elif repeat == "monthly":
      for i in range(1, rep_val):
        appt_date = appt_date.replace(
          month=appt_date.month+1 if appt_date.month != 12 else 1,
          year=appt_date.year+1 if appt_date.month == 12 else appt_date.year
        )
        this_appt_id = f"{appt_id}{i}" if appt_id else None
        save_appointment(calendar, appt_date, remind, text, this_appt_id)
    elif repeat == "yearly":
      for i in range(1, rep_val):
        appt_date = appt_date.replace(year=appt_date.year+1)
        this_appt_id = f"{appt_id}{i}" if appt_id else None
        save_appointment(calendar, appt_date, remind, text, this_appt_id)

    print("OK")


if __name__ == "__main__":
  parser = argparse.ArgumentParser(
    formatter_class=argparse.RawTextHelpFormatter,
    description=(
      """Simple reminder calendar -- addappointments

      Adds the contents of APPOINTMENTS, which contains events specified in the format:

          <weekly|biweekly|monthly|yearly> <N>] [remind <M>] [yyyy-mm-dd] HH:mm [<text>]

          where N indicates how often to repeat the reminder, and M is the number of
          minutes before the reminder is due to notify the user of it,

      to the given CALENDAR.
      """
    )
  )
  default_cal = f"{str(Path.home())}/.mycalendar.txt"
  parser.add_argument(
    '--calendar', metavar='FILE',
    type=argparse.FileType('a'),
    help=f"use the given calendar file instead of '{default_cal}'"
  )
  parser.add_argument(
    '--id',
    help='use the given ID to identify new events instead of generating IDs randomly'
  )
  parser.add_argument(
    'APPOINTMENTS',
    nargs='?',
    type=argparse.FileType('r'),
    help=('the file from which the appointments are read, or STDIN if ommitted')
  )
  args = parser.parse_args()
  appointments = args.APPOINTMENTS or sys.stdin
  calendar = args.calendar or open(default_cal, mode='a')
  main(appointments, calendar, args.id)