Validation spike

class Result
  attr_reader :failure_details

  def initialize(successful, failure_details = nil)
    @failure_details = failure_details
  end

  def failure?
    @failure_details != nil
  end
end

class CompositeValidation < Validation
  def initialize
    @sub_validations = []
  end

  def test(params)
    @sub_validations.each do |sub_validation|
      result = sub_validation.test(params)
      result.failure?
        return result
      end
    end
    create_success
  end

  def <<(sub_validation)
    @sub_validations << sub_validation
  end
end

class PresenceValidation < Validation
  def initialize(name)
    @name = name
  end

  def test(params)
    if params[@name].blank?
      create_failure("no_#{@name}".to_sym)
    else
      create_success
    end
  end
end

# Andre Validation-klasser man kunne lave
# PositiveIntegerValidation # fx til limit
# 


class RidesController
  INDEX_VALIDATION = create_index_validation

  def index
    result = INDEX_VALIDATION.test(params)
    if result.failure?
      render_failure(:bad_request, result.failure_details)
    end

    # do usual business
  end  

  def self.create_index_validation
    validation = CompositeValidation.new
    [:limit, :properties].each do |n|
      validation << PresenceValidation.new(n)
    end

    validation << PositiveIntegerValidation.new(:limit)

    [:origin_latitude, :origin_longitude, :destination_latitude, :origin_longitude].each do |n|
      validation << FloatValidation.new(n)
    end
    
    validation
  end
end