require 'csv'

# == Report
#
# An initialized Report expects to be passed a block that supplies an array
# suitable for CSV conversion.
class Report
  def initialize(title, &block)
    @title    = title
    @data_ary = yield
    @data_csv = String.new
  
    CSV::Writer.generate(@data_csv) do |csv|
      @data_ary.each { |data| csv << data }
    end
  end
  
  # Create a new report
  def self.create(*args, &block)
    puts "Building report for #{args.first}..."
    self.send(:new, args.first, &block).write!
  end

  private

    def write!
      file_name = @title.gsub(/ /, '_').downcase
      file_path = File.join( File.dirname(__FILE__),"reports", "#{file_name}.csv")
      File.open(file_path, "w") do |file|
        @data_csv.each_line { |line| file << line }
      end
    end

end

# == Array
#
# Some utility extentions to the Array class
class Array
  def extract(method)
    map { |e| e.send(method) }
  end
  
  # The sum of all elements in the array.
  def sum
    inject( 0 ) { |sum, x| sum + (x.nil? ? 0 : x) }
  end
  
  # The mean of all elements in the array.
  def mean
    (size > 0) ? sum.to_f / size : 0
  end
end