completness_analyzer.rb

# See if an object is "complete" and give it a score.  Example useage
# would look like this.
CompletenessAnalyzer.new(object: Event.find(1), criteria: [
  Criterion.new({
    name:      'Audience',
    message:   'Whom is your event is intended for?',
    condition: ->(event) { event.audiences.empty? }
    }),
  Criterion.new({
    name:      'Contact Info',
    message:   'Who is the event contact person?',
    condition: ->(event) { [event.contact_name, event.contact_email, event.contact_phone].reject(&:blank?).length == 0 }
    }),
  ])


# A simple class that has a name, a message, and a
# callable object that returns either truthy or falsey.
class Criterion
  attr_accessor :name, :message, :condition

  def initialize(args)
    @name, @message, @condition = args[:name], args[:message], args[:condition]
  end
end

# Analyze the completeness of an object.
class CompletenessAnalyzer
  attr_accessor :object, :criteria, :incomplete_criteria

  def initialize(args)
    @object              = args[:object]
    @criteria            = args[:criteria] || []
    @incomplete_criteria = []
    analyze
  end

  def complete?
    score.to_i == 1
  end

  def score
    if criteria.empty?
      0.0
    else
      (criteria.length - incomplete_criteria.length) / criteria.length.to_f
    end
  end

  def score_message
    case score
    when 0.0...0.2
      'Not too good'
    when 0.2...0.4
      'Could use some improvment'
    when 0.4...0.6
      'About half way there'
    when 0.6...0.8
      'Pretty good'
    when 0.8...0.99
      'Great job'
    when 0.99..1.0
      'Perfect score'
    end
  end

  def each_criterion
    criteria.each do |criterion|
      result = criterion.condition.call(object)
      yield(criterion, result)
    end
  end

  private
    def analyze
      incomplete_criteria.clear
      criteria.each do |criterion|
        incomplete_criteria << criterion if criterion.condition.call(object)
      end
    end
end