gistfile1.rb

require 'icalendear'
require 'csv'

cal_file = File.open("iCal_export.ics")
outfile = File.open('hours.csv', 'wb')

# Initialize
sum = 0
week = 1
prev_week = nil

# Parse the calendar
cal = Icalendar.parse(cal_file).first

CSV::Writer.generate(outfile) do |csv|
  cal.events.sort_by{|x| x.dtstart}.each do |event|
    # %U because cweek considers Monday the start of the week
    # Right out this week's hours, unless we just started tossing data in
    if event.dtstart.strftime("%U") != prev_week
      unless prev_week.nil?
        csv << ["Total Hours",'','','',sum]
        csv << []
        sum = 0
      end
      csv << ["Week #{week}"]
      prev_week = event.dtstart.strftime("%U")
      week += 1
    end
    # Convert to hours and write out
    hours = (event.dtend-event.dtstart).to_f*24
    sum += hours
    csv << ['',event.summary, event.dtstart.strftime("%m/%d/%y %H:%M"), event.dtend.strftime("%m/%d/%y %H:%M"), hours]
  end
  
  # Write out the final total hours if we haven't already
  unless 0 == sum
    csv << ["Total Hours",'','','',sum]
  end
end

# Redundant, I know
cal_file.close
outfile.close