#!/usr/bin/env ruby
#
# Copyright (C) 2004 Hiroyuki KUROSAKI <noir@st.rim.or.jp>
# 
# This program 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 2 of the License, or
# (at your option) any later version.
# 
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

$KCODE = 'UTF-8'

module ICalendar
  class ICalendarObject
    def initialize
      @properties = Hash.new
      @components = Array.new
    end
    attr_accessor :properties, :components
  end

  class Component
    def initialize(name = '', properties = {})
      @name = name
      @properties = properties
    end
    attr_accessor :name, :properties

    def [](property_name)
      @properties[property_name]
    end

    def []=(property_name, other)
      @properties[property_name] = other
    end
  end

  class Property
    def initialize(name = '', parameters = {}, value = nil)
      @name = name
      if parameters.is_a?(String) then
        @parameters = Hash.new
        parameters.scan(/([^;=]+)=([^;=]+)/) {|key, val|
          @parameters[key] = val
        }
      else
        @parameters = parameters
      end
      @value = value
    end
    attr_accessor :name, :parameters, :value
  end

  class Text
    def Text.unescape(str)
      str.gsub(/\\(.)/) { |s|
        case $1
        when '\\', ';'
          $1
        when 'n', 'N'
          "\n"
        else
          s
        end
      }
    end
  end

  class Reader
    def initialize
      @doc = nil
    end

    def parse(io)
      @doc = nil
      curr = ''
      prev = nil
      currp = nil
      io.each {|line|
        line.sub!(/\r?\n\z/, '')
        if m = /^\s+/.match(line) then
          curr << m.post_match
        else
          curr = line
          if prev then
            if /^([^:;]+)((;([^:]+))*):(.*)$/ =~ prev then
              name = $1; param = $2; value = $5
              if name == "BEGIN" then
                case value
                when "VCALENDAR"
                  @doc = currp = ICalendarObject.new
                when "VEVENT", "VTODO"
                  currp = Component.new(value)
                  @doc.components.push currp
                end
              elsif name == "END" then
                currp = nil
              else
                if currp then
                  currp.properties[name] = Property.new(name, param, Text::unescape(value))
                  if name == 'RRULE' then
                    value_hash = Hash.new
                    value.scan(/([^;=]+)=([^;=]+)/) {|key, val|
                      value_hash[key] = val
                    }
                    currp.properties[name].value = value_hash
                  end
                end
              end
            end
          end
        end
        prev = curr
      }
      @doc
    end
  end
end

class ISO8601
  class Date
    def Date.to_utc(str, timezone = nil)
      if /\A(\d{4})-?(\d{2})-?(\d{2})/ =~ str then
	year = $1.to_i; month = $2.to_i; day = $3.to_i
	Time.gm(year, month, day).to_i
      else
	nil
      end
    end
  end
  class DateTime
    def DateTime.to_utc(str, timezone = nil)
      if /\A(\d{4})-?(\d{2})-?(\d{2})T(\d{2}):?(\d{2}):?(\d{2})(.*)\z/ =~ str then
	year = $1.to_i; month = $2.to_i; day = $3.to_i
	hour = $4.to_i; min = $5.to_i; sec = $6.to_i
	tzstr = $7
	if tzstr && tzstr == 'Z' then
	  Time.gm(year, month, day, hour, min, sec).to_i
	else
	  Time.local(year, month, day, hour, min, sec).utc.to_i
	end
      else
	ISO8601::Date.to_utc(str, timezone)
      end
    end
  end
end

module Zdbat

  class NotSupportedError <StandardError
  end

  class Record
    HEADER = %w(CARDID)

    def initialize(cardid = 0)
      @fields = Hash.new
      @fields['CARDID'] = cardid.to_s
    end

    attr_accessor :fields

    def cardid
      @fields['CARDID'].to_i
    end

    def [](field_name)
      @fields[field_name]
    end

    def []=(field_name, other)
      @fields[field_name] = other
    end

    def header
      self.class::HEADER.join(',') + "\n"
    end

    def to_s
      self.class::HEADER.map {|h| ((self[h] && ('"' + self[h].gsub(/"/, '""') + '"')) || '') } .join(',') + "\n"
    end
  end

  class Event<Record
    HEADER = %w(CARDID DSRP PLCE MEM1 TIM1 TIM2 ADAY ARON ARMN ARSD RTYP RFRQ RPOS RDYS REND REDT ALSD ALED MDAY)

    RDYS_VALUE = {'MO' => 1, 'TU' => 2, 'WE' => 4, 'TH' => 8, 'FR' => 16, 'SA' => 32, 'SU' => 64 }

    def fromVEvent(vevent)
      self['DSRP'] = vevent['SUMMARY'].value
      self['PLCE'] = vevent['LOCATION'] && vevent['LOCATION'].value
      self['MEM1'] = vevent['DESCRIPTION'] && vevent['DESCRIPTION'].value
      self['ARON'] = '1' # not supported
      self['ARMN'] = '0' # not supported
      dateval = vevent['DTSTART'].parameters['VALUE']
      if dateval && dateval == 'DATE'
        self['ADAY'] = '1'
        self['ALSD'] = vevent['DTSTART'].value
        self['ALED'] = vevent['DTEND'] && vevent['DTEND'].value
	if self['ALED'] then
	  self['ALED'] = Time.at(ISO8601::DateTime.to_utc(self['ALED'] + 'Z') - 60 * 60 * 24).strftime("%Y%m%d")
	end
	self['TIM1'] = self['ALSD']
	self['TIM2'] = self['ALED']
      else
        self['ADAY'] = '0'
	self['TIM1'] = Time.at(ISO8601::DateTime.to_utc(vevent['DTSTART'].value)).utc.strftime("%Y%m%dT%H%M%S")
	self['TIM2'] = vevent['DTEND'] && vevent['DTEND'].value
	if self['TIM2'] then
	  self['TIM2'] = Time.at(ISO8601::DateTime.to_utc(self['TIM2'])).utc.strftime("%Y%m%dT%H%M%S")
	end
      end
      if self['ALSD'] != self['ALED'] then
        self['MDAY'] = '1'
      else
        self['MDAY'] = '0'
      end
      if vevent['DURATION'] then
	if /^([+\-])?P(?:(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?|(\d+)W)/ =~ vevent['DURATION'].value then
	  sign = $1; day = $2; hour = $3; min = $4; sec = $5; week = $6
	  dtend_time = ISO8601::DateTime.to_utc(self['TIM1'] + 'Z')
	  if day then
	    dtend_time += day.to_i * 60 * 60 * 24
	  end
	  if hour then
	    dtend_time += hour.to_i * 60 * 60
	  end
	  if min then
	    dtend_time += min.to_i * 60
	  end
	  if sec then
	    dtend_time += sec.to_i
	  end
	  if week then
	    dtend_time += week.to_i * 60 * 60 * 24 * 7
	  end
	  if self['ADAY'] == '1' then
	    self['TIM2'] = Time.at(dtend_time - 60 * 60 * 24).utc.strftime("%Y%m%d")
	    self['ALED'] = self['TIM2']
	  else
	    self['TIM2'] = Time.at(dtend_time).utc.strftime("%Y%m%dT%H%M%S")
	  end
	end
      end
      self['RPOS'] = '0'
      rrule = vevent['RRULE']
      if rrule then
	self['RFRQ'] = rrule.value['INTERVAL']
	if rrule.value['UNTIL'] then
	  self['REND'] = '1'
	  self['REDT'] = rrule.value['UNTIL'].sub(/Z\z/, '')
	else
	  self['REND'] = '0'
	end
        case rrule.value['FREQ']
        when 'DAILY'
	  self['RTYP'] = '0'
	  if rrule.value['COUNT'] then
	    self['REND'] = '1'
	    self['REDT'] = Time.at(ISO8601::DateTime.to_utc(vevent['DTSTART'].value) + rrule.value['COUNT'].to_i * 60 * 60 * 24 * self['RFRQ'].to_i).utc.strftime('%Y%m%dT%H%M%S')
	  end
        when 'WEEKLY'
          self['RTYP'] = '1'
          if rrule.value['BYDAY'] then
            rdys_val = 0
            rrule.value['BYDAY'].split(/,/).each{|w|
              rdys_val += RDYS_VALUE[w]
            }
            self['RDYS'] = rdys_val.to_s
          end
        when 'MONTHLY'
	  if rrule.value['BYDAY'] then
	    self['RTYP'] = '2'
	    if /\A\+?(\d)([A-Z][A-Z])\z/ =~ rrule.value['BYDAY'] then
	      self['RPOS'] = $1
	      self['RDYS'] = RDYS_VALUE[$2].to_s
	    else
	      raise Zdbat::NotSupportedError
	    end
	  else
	    self['RTYP'] = '3'
	    if rrule.value['BYMONTHDAY'] then
	      raise Zdbat::NotSupportedError
	    end
	  end
        when 'YEARLY'
	  self['RTYP'] = '4'
        end
      else
        self['RTYP'] = '255'
      end
    end
  end

  class ToDo<Record
    HEADER = %w(CARDID ETDY LTDY FNDY MARK PRTY TITL MEM1)

    def fromVToDo(vtodo)
      self['ETDY'] = vtodo['DTSTART'] && vtodo['DTSTART'].value
      self['LTDY'] = vtodo['DUE'] && vtodo['DUE'].value
      if vtodo['STATUS'] && vtodo['STATUS'].value == 'COMPLETED' then
	self['MARK'] = '0'
      else
	self['MARK'] = '1'
      end
      if vtodo['COMPLETED'] then
	self['FNDY'] = vtodo['COMPLETED'].value
	self['MARK'] = '0'
      end
      self['TITL'] = vtodo['SUMMARY'].value
      self['MEM1'] = vtodo['DESCRIPTION'] && vtodo['DESCRIPTION'].value
      self['PRTY'] = vtodo['PRIORITY'] && vtodo['PRIORITY'].value
    end
  end
end

if $0 == __FILE__ then

  if ARGV.size != 1 then
    puts "Usage: ruby ics2csv.rb filename"
    exit 1
  end

  events_csv = File.open('events.csv', 'w')
  todos_csv = File.open('todos.csv', 'w')

  events_csv.puts Zdbat::Event.new.header
  todos_csv.puts Zdbat::ToDo.new.header

  File.open(ARGV[0], 'r') do |f|
    reader = ICalendar::Reader.new
    cal = reader.parse(f)
    cal.components.each {|c|
      if c.name == 'VEVENT' then
	zdbat_event = Zdbat::Event.new
	zdbat_event.fromVEvent(c)
	events_csv.puts zdbat_event.to_s
      elsif c.name == 'VTODO' then
	zdbat_todo = Zdbat::ToDo.new
	zdbat_todo.fromVToDo(c)
	todos_csv.puts zdbat_todo.to_s
      end
    }
  end

  events_csv.close
  todos_csv.close
end