generate_ics.py

## Adds your timetable from `data.txt` to Google Calendar.
from __future__ import print_function
import os

import json
import datetime
import sys

# this script works only with Python 3
if sys.version_info[0] != 3:
    print("This script works only with Python 3")
    sys.exit(1)

import re
from icalendar import Calendar, Event

import dates

WORKING_DAYS = dates.get_dates()

import build_event
from update_subjects_json import update_sub_list

import argparse
import getpass

parser = argparse.ArgumentParser()
parser.add_argument("-i", "--input")
parser.add_argument("-o", "--output")
args = parser.parse_args()

DEBUG = False
GENERATE_ICS = True
TIMETABLE_DICT_RE = (
    "([0-9]{1,2}):([0-9]{1,2}):([AP])M-([0-9]{1,2}):([0-9]{1,2}):([AP])M"
)
timetable_dict_parser = re.compile(TIMETABLE_DICT_RE)

INPUT_FILENAME = args.input if args.input else "data.txt"
if not os.path.exists(INPUT_FILENAME):
    print("Input file", INPUT_FILENAME, "does not exist.")
    os._exit(1)

OUTPUT_FILENAME = "timetable.ics" if args.output is None else args.output

cal = Calendar()
cal.add("prodid", "-//Your Timetable generated by GYFT//mxm.dk//")
cal.add("version", "1.0")

"""
Given a starting timestamp d and a weekday number d (0-6), return the timestamp
of the next time this weekday is going to happen
"""


def next_weekday(d, weekday):
    days_ahead = weekday - d.weekday()
    if days_ahead < 0:  # Target day already happened this week
        days_ahead += 7
    return d + datetime.timedelta(days_ahead)


def get_stamp(argument, date):
    """
    argument is a 3-tuple such as
    ('10', '14', 'A') : 1014 HRS on date
    ('10', '4', 'P') : 2204 HRS on date
    """

    hours_24_format = int(argument[0])

    # Note:
    # 12 PM is 1200 HRS
    # 12 AM is 0000 HRS

    if argument[2] == "P" and hours_24_format != 12:
        hours_24_format = (hours_24_format + 12) % 24

    if argument[2] == "A" and hours_24_format == 12:
        hours_24_format = 0

    return build_event.generateIndiaTime(
        date.year, date.month, date.day, hours_24_format, int(argument[1])
    )


### days to number
days = {}
days["Monday"] = 0
days["Tuesday"] = 1
days["Wednesday"] = 2
days["Thursday"] = 3
days["Friday"] = 4
days["Saturday"] = 5
###

"""
Creates an ICS file `timetable.ics` with the timetable data present inside the
input file `data.txt`
"""


def main():

    # Get your timetable
    with open(INPUT_FILENAME) as data_file:
        data = json.load(data_file)
    # Get subjects code and their respective name
    with open("subjects.json") as data_file:
        subjects = json.load(data_file)

    found_missing_sub = False
    for day in data:
        startDates = [next_weekday(x[0], days[day]) for x in WORKING_DAYS]

        for time in data[day]:
            # parsing time from time_table dict
            # currently we only parse the starting time
            # duration of the event is rounded off to the closest hour
            # i.e 17:00 - 17:55 will be shown as 17:00 - 18:00

            parse_results = timetable_dict_parser.findall(time)[0]

            lectureBeginsStamps = [
                get_stamp(parse_results[:3], start) for start in startDates
            ]

            durationInHours = data[day][time][2]

            # Find the name of this course
            # Use subject name if available, else ask the user for the subject
            # name and use that
            # TODO: Add labs to `subjects.json`
            subject_code = data[day][time][0]
            summary = subject_code
            description = subject_code
            if subject_code in subjects.keys():
                summary = subjects[subject_code].title()
            else:
                print(
                    "ERROR: Our subjects database does not have %s in it."
                    % subject_code
                )
                summary = input(
                    "INPUT: Please input the name of the course %s: " % subject_code
                )

                subjects[subject_code] = str(summary)
                update_sub_list(subject_code, summary)

                summary = summary.title()
                found_missing_sub = True

            # Find location of this class
            location = data[day][time][1]

            for lectureBegin, [periodBegin, periodEnd] in zip(
                lectureBeginsStamps, WORKING_DAYS
            ):

                event = build_event.build_event_duration(
                    summary,
                    description,
                    lectureBegin,
                    durationInHours,
                    location,
                    "weekly",
                    periodEnd,
                )

                cal.add_component(event)

            if DEBUG:
                print(event)

    if found_missing_sub:
        print(
            "Subject list has been updated. Please commit, push and raise a pull request at github.com/metakgp/gyft."
        )

    with open(OUTPUT_FILENAME, "wb") as f:
        f.write(cal.to_ical())
        print("INFO: Your timetable has been written to %s" % OUTPUT_FILENAME)


if __name__ == "__main__":
    main()