add_pagination_by_day_to_will_paginate.rb

require_dependency 'will_paginate'
require_dependency 'will_paginate/finder'


unless Time.instance_methods.include? 'at_end_of_day'
	Time.class_eval do
		def at_end_of_day
			self.at_beginning_of_day + 1.day
		end
	end
end

module AddPaginationByDayToWillPaginate
	# warning, you cannot pass this conditions, it has to be simple
	def paginate_by_day *args, &block
		options = args.pop
		page = options[:page].to_i || 1
		total_entries = options[:total_entries]

		day = (page-1).days.ago

		WillPaginate::Collection.create(page, 1) do |pager|
			count_options = options.except :page, :total_entries, :finder
			find_options = count_options.except(:count).update(:conditions => [ "#{table_name}.created_at BETWEEN ? AND ? ", day.at_beginning_of_day, day.at_end_of_day ])

			args << find_options

			pager.replace send(:all, *args, &block)

			# magic counting for user convenience:
			pager.total_entries = 365 # user can go back one year?
		end

	end
end

ActiveRecord::Base.extend AddPaginationByDayToWillPaginate