module Opener
  class OpinionDetectorBasic
    module Kaf
      class Document

        attr_accessor :document, :timestamp, :opinion_strength, :pretty

        def initialize file, options = {}
          @document = Nokogiri.XML file

          @timestamp        = options[:timestamp]
          @opinion_strength = options[:opinion_strength]
          @pretty           = options[:pretty] || false

          raise 'Error parsing input. Input is required to be KAF' unless is_kaf?
        end

        def terms
          @terms ||= document.xpath('KAF/terms/term').map do |term|
            Term.new term, self, language
          end
        end

        def language
          @language ||= document.at_xpath('KAF').attr('xml:lang')
        end

        ##
        # Get terms grouped by sentence.
        #
        def sentences
          @sentences ||= terms.group_by{ |t| t.sentence }
        end

        ##
        # Adds the entire opinion in the KAF file.
        #
        def add_opinion opinion, index
          opinion_node = new_node 'opinion', 'KAF/opinions'
          opinion_node['oid'] = "o#{index.to_s}"

          if opinion.holders.present?
            opinion_holder_node = new_node 'opinion_holder', opinion_node
            add_opinion_element opinion_holder_node, opinion.holders
          end

          opinion_target_node = new_node 'opinion_target', opinion_node

          if opinion.target_ids.present?
            add_opinion_element opinion_target_node, opinion.target_ids
          end

          expression_node = new_node 'opinion_expression', opinion_node
          expression_node['polarity'] = opinion.polarity
          expression_node['strength'] = opinion.strength.to_s
          expression_node['lexicon-id'] = opinion.lexicon_id if opinion.lexicon_id

          add_opinion_element expression_node, opinion.ids
        end

        ##
        # Remove the opinions layer from the KAF file if it exists and add a new
        # one.
        def add_opinions_layer
          existing = document.at_xpath('KAF/opinions')

          existing.remove if existing

          new_node 'opinions', 'KAF'
        end

        ##
        # Method for adding opinion holders, targets and expressions.
        #
        def add_opinion_element node, ids
          lemmas    = terms.select{|t| ids.include?(t.id)}.map(&:lemma).join(' ')
          comment   = Nokogiri::XML::Comment.new(document, lemmas)
          node.add_child comment

          span_node = new_node('span', node)

          ids.each do |id|
            target_node       = new_node('target', span_node)
            target_node['id'] = id.to_s
          end
        end

        ##
        # Add linguistic processor layer with basic information
        # (version, timestamp, description etc) in the KAF file.
        #
        def add_linguistic_processor
          description = 'Basic opinion detector with Pos'
          last_edited = '13may2015'
          version     = '2.0'

          node = new_node('linguisticProcessors', 'KAF/kafHeader')
          node['layer'] = 'opinions'

          lp_node = new_node('lp', node)

          lp_node['version'] = "#{last_edited}-#{version}"
          lp_node['name'] = description

          if timestamp
            format = '%Y-%m-%dT%H:%M:%S%Z'

            lp_node['timestamp'] = Time.now.strftime(format)
          else
            lp_node['timestamp'] = '*'
          end
        end

        ##
        # Creates a new node in the KAF file.
        #
        def new_node tag, parent
          if parent.is_a?(String)
            parent_node = document.at_xpath(parent)
          else
            parent_node = parent
          end

          node = Nokogiri::XML::Element.new(tag, document)

          parent_node.add_child node

          node
        end

        ##
        # Check if input is a KAF file.
        # @return [Boolean]
        #
        def is_kaf?
          !!document.at_xpath('KAF')
        end

        def method_missing method, *args, &block
          @document.send method, *args, &block
        end

      end
    end
  end
end