ics2csv.rb

require 'time'

def convert_zone(orig, to_zone)
  original_zone = ENV["TZ"]
  utc_time = orig.gmtime
  ENV["TZ"] = to_zone
  to_zone_time = utc_time.localtime
  ENV["TZ"] = original_zone
  to_zone_time
end

raw_lines = File.read(ARGV[0]).each_line.map(&:strip).map{|l| l.split(":")}
tzid = raw_lines.select{|k,v| k == "X-WR-TIMEZONE" }[0][1]
begins = raw_lines.each_with_index.select{|e,i| e == ["BEGIN", "VEVENT"] }.map(&:last)

date_proc = Proc.new{|str| convert_zone(Time.parse(str), tzid).strftime("%Y/%m/%d") }
time_proc = Proc.new{|str| convert_zone(Time.parse(str), tzid).strftime("%H:%M") }
str_proc = Proc.new{|str| str }

convert_map = {
  "DTSTART"  => {"Start Date" => date_proc, "Start Time" => time_proc},
  "DTEND"    => {"End Date" => date_proc, "End Time" => time_proc},
  "LOCATION" => {"Location" => str_proc},
  "SUMMARY"  => {"Subject" => str_proc},
  # "DESCRIPTION"
}

events = []
begins.each do |i|
  tmp = {}
  j = i + 1
  loop do
    break if raw_lines[j] == ["END", "VEVENT"]
    k, v = raw_lines[j]
    tmp[k] = v
    j += 1
  end
  events << tmp
end

formatted_events = events.map{|e|
  e.map{|k,v|
    kk = k.split(";").first
    if convert_map[kk]
      convert_map[kk].map{|col,prc| [col, prc.call(v)] }
    end
  }.compact.flatten.each_slice(2).to_a.to_h
}.sort{|a,b|
  if Time.parse(a["Start Date"]) == Time.parse(b["Start Date"])
    a["Start Time"] <=> b["Start Time"]
  else
    Time.parse(a["Start Date"]) <=> Time.parse(b["Start Date"])
  end
}

sorted_header = [ "Start Date", "Start Time", "End Date", "End Time", "Location", "Subject" ]
puts sorted_header.join(", ")
formatted_events.each do |e|
  puts sorted_header.map{|k| e[k] }.join(", ")
end