# Use this with
# validates :your_province_field, province: { country: :your_country_field }

class ProvinceValidator < ActiveModel::EachValidator
  def validate_each(object, attribute, value)
    provinces = PROV_STATE[object.send(options[:country])]
    if !provinces.try(:include?, value)
      object.errors[attribute] << (options[:message] || 'Province/State is in selected country.')
    end
  end

  PROV_STATE = {
      canada: ['Alberta', 'British Columbia', 'Manitoba', 'New Brunswick', 'Newfoundland', 'Nova Scotia',
               'Northwest Territories', 'Nunavut', 'Ontario', 'Prince Edward Island', 'Saskatchewan',
               'Quebec', 'Yukon'],
      usa: ['Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California', 'Colorado', 'Connecticut', 'Delaware',
            'Florida', 'Georgia', 'Hawaii', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky',
            'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi',
            'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico',
            'New York', 'North Carolina', 'North Dakota', 'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania',
            'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont',
            'Virginia', 'Washington', 'Washington, D.C', 'West Virginia', 'Wisconsin', 'Wyoming']
  }
end