Calendar Generator class prototype

README

## NOTE
Class assumes event model includes start_date and end_date, 
both of type 'datetime'.

You can init the class with a hash of options. 
There are two options options at this point, 'month_format', 
and 'date_format' which accept Ruby's 'strftime' style strings. 

calendar_generator.rb

class Calendar

  TODAY = {
    :year => DateTime.now.year, 
    :month => DateTime.now.month,
    :day => DateTime.now.day,
    :wday => DateTime.now.wday
  }

  attr_accessor :events

  def initialize events, options={}
    @events = sort_events(events)
    @month_format = options[:month_format] || "%B %Y"
    @date_format = options[:date_format] || "%a %-d"
  end

  def generate
    month_range.collect do |month|
      st = calendar_start_day(month)
      en = calendar_end_day(month)
      dates = (st..en).collect do |date|
        events = @events.select do |e|
          e.start_date.strftime("%F") == date.to_s
        end
        { :name => date.strftime(@date_format), 
          :events => events, 
          :date => date }
      end
      { :name => month.strftime(@month_format), 
        :dates => dates }
    end
  end

  def month_range
    events = @events.uniq_by do |event| 
      event.start_date.month 
    end
    events.collect! do |e| 
      Date.new(e.start_date.year, e.start_date.month) 
    end
  end

  def sort_events events
    events.sort do |a,b| 
      a.start_date <=> b.start_date 
    end
  end

  def days_in_month month, year
    (Date.new(year, 12, 31) << (12-month)).day
  end

  def calendar_start_day date
    day = Date.new(date.year, date.month)
    day -= day.wday
  end

  def calendar_end_day date
    day = Date.new(date.year, date.month, days_in_month(date.month, date.year))
    day += (6 - day.wday)
  end

  def full
    generate
  end

end

example.rb

# Example

def index
  respond_to do |format|
    format.json do
      @events = Event.all
      @cal = Calendar.new @events
      render :json => @cal.full
    end
end