calendar_ical.rb

# calendar_ical.rb

# Todo - date string format
def get_date_format(time_obj)
    # Convert standard ruby datetime obj to ISO 8601 format
    # time_obj - should be datetime object

    # Time format: 
    # timestring.to_time.iso8601    # Incorrect format! We need 19970610T172345Z 
    # 1997 06 10 T 17 23 45 Z
    # year mo da T hr mi se Z

    fmt = '%Y%m%dT%H%M%SZ'
    return time_obj.strftime(fmt)

end


# Create iCal format for events
def calendar_format_ical(start_date, end_date, title, description)
# def calendar_format_ical(start_date, end_date, title, description, client_id: "bobs_english", username: 'Ruzuku', email: 'calendar@ruzuku.com')

    # Returns:
    #  event.ics    (plaintext file)

    # Start date and end date should be in ISO 8601 format
    # ie.: 19970714T170000Z

    # Parameters:
    # username = 'Ruzuku'
    # client_id = "bobs_english"
    # email = 'calendar@ruzuku.com'
    # uid = uid1@ruzuku.com

    # Questions:
    # - what's PRODID?
    #   -> specifies the identifier for the product that created the iCalendar object. (?)
    #   ? See https://www.kanzaki.com/docs/ical/prodid.html
    # - what's UID? User id? -> Unique identifier: MUST be unique.
    # - what should be the email/organizer? (defaulting to calendar@ruzuku.com)

    # Todo:
    #  [X] Get timestamp
    #  [ ] Get client id?
    #  [ ] Get email address?
    #  [X] Figure out prod_id (?)
    #  [ ] uid - combine hash of timestamp and organization name
    #  [X] write to file
    #  [ ] escape string sequences / html

    # Placeholder params
    prod_id = '-//Ruzuku.com/calendar_event//NONSGML v1.0//EN'
    client_id = "bobs_english"
    location = "ruzuku.com"
    username = 'Ruzuku'
    email = 'calendar@ruzuku.com'

    # Combine uid
    timestamp = get_date_format(Time.now)       # Timestamp now (string)
    uid = timestamp + client_id + '@ruzuku.com' # Combined UID - [timestamp][client_id]@ruzuku.com
    
    template = """
        BEGIN:VCALENDAR
        VERSION:2.0
        PRODID:#{prod_id}
        BEGIN:VEVENT
        UID:#{uid}
        LOCATION:#{location}
        DTSTAMP:#{timestamp}
        SEQUENCE:0
        ORGANIZER:CN=#{username}:MAILTO:#{email}
        DTSTART:#{start_date}
        DTEND:#{end_date}
        SUMMARY:#{description}
        END:VEVENT
        END:VCALENDAR
    """
    # Print
    puts template

    # Write to file
    fd = 'event.ics'

    open(fd, 'w') do |f|
        f.puts template
        puts 'Event written to file: #{fd}'
    end
    
    return fd

end