module Opener
  class OpinionDetectorBasic
    class Term
      attr_reader :node, :sentence, :is_conjunction
      attr_accessor :use, :accumulated_strength, :list_ids

      # Map of conjunctions per language code
      CONJUNCTIONS = {
        'nl' => %w{, en},
        'en' => %w{, and},
        'es' => %w{, y e},
        'it' => %w{, e ed},
        'de' => %w{, und},
        'fr' => %w{, et}
      }

      def initialize(node, document, language)
        @node                 = node
        @sentence             = get_sentence(document)
        @use                  = true
        @accumulated_strength = strength
        @list_ids             = [id]
        @is_conjunction       = is_conjunction?(language)
      end

      ##
      # Returns the term id.
      #
      # @return [String]
      #
      def id
        @id ||= node.get('tid')
      end

      ##
      # Returns the lemma of the term.
      #
      # @return [String]
      #
      def lemma
        @lemma ||= node.get('lemma')
      end

      ##
      # Returns the part of speech of the term.
      #
      # @return [String]
      #
      def pos
        @pos ||= node.get('pos')
      end

      ##
      # Returns the sentiment modifier type if it exists.
      #
      # @return [String|NilClass]
      #
      def sentiment_modifier
        @sentiment_modifier ||=
          first_sentiment ? first_sentiment.get('sentiment_modifier') : nil
      end

      ##
      # Returns the polarity of the term if it exists.
      #
      # @return [String|NilClass]
      #
      def polarity
        @polarity ||= first_sentiment ? first_sentiment.get('polarity') : nil
      end

      ##
      # Returns the actual word ids that construct the lemma.
      #
      # @return [Array]
      #
      def target_ids
        @target_ids ||= node.xpath('span/target')
          .map { |target| target.get('id') }
      end

      ##
      # Returns the strength of the term depending on its type.
      #
      # @return [Integer]
      #
      def strength
        if polarity == "positive"
          return 1
        elsif polarity == "negative"
          return -1
        end

        if is_intensifier?
          return 2
        elsif is_shifter?
          return -1
        end

        return 0
      end

      ##
      # Returns the sentence id that the term belongs to in the document.
      #
      # @return [String]
      #
      def get_sentence(document)
        document
        .xpath("KAF/text/wf[@wid='#{target_ids.first}']")
        .first
        .get('sent')
      end

      ##
      # Checks if a term is an intensifier.
      #
      # @return [TrueClass|FalseClass]
      #
      def is_intensifier?
        sentiment_modifier == "intensifier"
      end

      ##
      # Checks if a term is a shifter.
      #
      # @return [TrueClass|FalseClass]
      #
      def is_shifter?
        sentiment_modifier == "shifter"
      end

      ##
      # Checks if a term is an expression.
      #
      # @return [TrueClass|FalseClass]
      #
      def is_expression?
        use && !!polarity
      end

      ##
      # Checks if a term is a conjunction.
      #
      # @return [TrueClass|FalseClass]
      #
      def is_conjunction?(language)
        pos == 'J' || CONJUNCTIONS[language]&.include?(lemma)
      end

      private

      # @return [Oga::XML::Element]
      def first_sentiment
        @first_sentiment ||= node.xpath('sentiment').first
      end
    end # Term
  end # OpinionDetectorBasic
end # Opener