require 'digest'

module Ecoportal
  module API
    module Common
      module Content
        module StringDigest
          MAX_HASH_LABEL = 64

          def indexable_label(str)
            return nil unless str
            lbl = str.downcase.gsub(/[^A-Za-z]+/,"-").slice(0, MAX_HASH_LABEL)
            return nil unless lbl.length >= 3
            lbl
          end

          # Calculates the Hash of the field based on label
          def hash_label(str)
            return nil unless lbl = indexable_label(str)
            "z" +  Digest::MD5.hexdigest(lbl).slice(0, 8);
          end

        end
      end
    end
  end
end