=begin
  Copyright (C) 2006 Sam Roberts

  This library is free software; you can redistribute it and/or modify it
  under the same terms as the ruby language itself, see the file COPYING for
  details.
=end

require 'vpim/dirinfo'
require 'vpim/field'
require 'vpim/rfc2425'
require 'vpim/vpim'
require 'vpim/property/base'
require 'vpim/property/common'
require 'vpim/property/priority'
require 'vpim/property/location'
require 'vpim/property/resources'
require 'vpim/property/recurrence'

module Vpim
  class Icalendar
    class Vevent
      include Vpim::Icalendar::Property::Base
      include Vpim::Icalendar::Property::Common
      include Vpim::Icalendar::Property::Priority
      include Vpim::Icalendar::Property::Location
      include Vpim::Icalendar::Property::Resources
      include Vpim::Icalendar::Property::Recurrence

      def initialize(fields) #:nodoc:
        outer, inner = Vpim.outer_inner(fields)

        @properties = Vpim::DirectoryInfo.create(outer)

        @elements = inner

        # See "TODO - fields" in dirinfo.rb
      end

      # Create a new Vevent object. All events must have a DTSTART field,
      # specify it as either a Time or a Date in +start+, it defaults to "now"
      # (is this useful?).
      #
      # If specified, +fields+ must be either an array of Field objects to
      # add, or a Hash of String names to values that will be used to build
      # Field objects. The latter is a convenient short-cut allowing the Field
      # objects to be created for you when called like:
      #
      #   Vevent.create(Date.today, 'SUMMARY' => "today's event")
      #
      # TODO - maybe events are usually created in a particular way? With a
      # start/duration or a start/end? Maybe I can make it easier. Ideally, I
      # would like to make it hard to encode an invalid Event.
      def Vevent.create(start = Time.now, fields=[])
        dtstart = DirectoryInfo::Field.create('DTSTART', start)
        di = DirectoryInfo.create([ dtstart ], 'VEVENT')

        Vpim::DirectoryInfo::Field.create_array(fields).each { |f| di.push_unique f }

        new(di.to_a)
      end

      # Creates a yearly repeating event, such as for a birthday.
      def Vevent.create_yearly(date, summary)
        create(
          date,
          'SUMMARY' => summary.to_str,
          'RRULE' => 'FREQ=YEARLY'
          )
      end

      # Accept an event invitation. The +invitee+ is the Address that wishes
      # to accept the event invitation as confirmed.
      def accept(invitee)
        # The event created is identical to this one, but
        # - without the attendees
        # - with the invitee added with a PARTSTAT of ACCEPTED
        invitee = invitee.copy
        invitee.partstat = 'ACCEPTED'

        fields = []

        @properties.each_with_index do
          |f,i|

          # put invitee in as field[1]
          fields << invitee.field if i == 1
          
          fields << f unless f.name? 'ATTENDEE'
        end

        Vevent.new(fields)
      end

=begin
      # Set the start time for the event to +start+, a Time object.
      # TODO - def dtstart=(start) ... start should be allowed to be Time/Date/DateTime
=end

      def transparency
        proptoken 'TRANSP', ["OPAQUE", "TRANSPARENT"], "OPAQUE"
      end

      # The duration in seconds of a Event, Todo, or Vfreebusy component, or
      # for Alarms, the delay period prior to repeating the alarm. The
      # duration is calculated from the DTEND and DTBEGIN fields if the
      # DURATION field is not present. Durations of zero seconds are possible.
      def duration
        dur = @properties.field 'DURATION'
        dte = @properties.field 'DTEND'
        if !dur
          return nil unless dte

          b = dtstart
          e = dtend

          return (e - b).to_i
        end

        Icalendar.decode_duration(dur.value_raw)
      end

      # The end time for this calendar component. For an Event, if there is no
      # end time, then nil is returned, and the event takes up no time.
      # However, the end time will be calculated from the event duration, if
      # present.
      def dtend
        dte = @properties.field 'DTEND'
        if dte
          dte.to_time.first
        elsif duration
            dtstart + duration
        else
          nil
        end
      end

    end
  end
end