# This module is only suitable to mix into Classes that use the OM::XML::Document Module
module Solrizer::XML::TerminologyBasedSolrizer
  
  def self.default_field_mapper
    @@default_field_mapper ||= Solrizer::FieldMapper::Default.new
  end
  
  # Module Methods
  
  # Build a solr document from +doc+ based on its terminology
  # @param [OM::XML::Document] doc  
  # @param [Hash] (optional) solr_doc (values hash) to populate
  def self.solrize(doc, solr_doc=Hash.new, field_mapper = nil)
    unless doc.class.terminology.nil?
      doc.class.terminology.terms.each_pair do |term_name,term|
        doc.solrize_term(term, solr_doc, field_mapper)
      end
    end

    return solr_doc
  end
  
  # Populate a solr document with fields based on nodes in +xml+ 
  # Values for a term are gathered by to +term_pointer+ using OM::XML::TermValueOperators.term_values 
  # and are deserialized by OM according to :type, as determined in its terminology.
  # The content of the actual field in solr is each +node+ of the +nodeset+ returned by OM,
  # rendered to a string.
  # @param [OM::XML::Document] doc xml document to extract values from
  # @param [OM::XML::Term] term corresponding to desired xml values
  # @param [Hash] (optional) solr_doc (values hash) to populate
  def self.solrize_term(doc, term, solr_doc = Hash.new, field_mapper = nil, opts={})
    parents = opts.fetch(:parents, [])
    term_pointer = parents+[term.name]
    nodeset = doc.term_values(*term_pointer)
    
    nodeset.each do |n|
      
      # TODO: Solrizer::FieldMapper::Default is supposed to translate dates into full ISO 8601 formatted strings.
      # However, there an integration issue with ActiveFedora using OM: it ignores the default field mapper given
      # in this gem that does this. So, the following is a workaround until it is fixed.
      node = n.is_a?(Date) ? DateTime.parse(n.to_s).to_time.utc.iso8601 : n.to_s
      
      doc.solrize_node(node.to_s, term_pointer, term, solr_doc, field_mapper)
      unless term.kind_of? OM::XML::NamedTermProxy
        term.children.each_pair do |child_term_name, child_term|
          doc.solrize_term(child_term, solr_doc, field_mapper, opts={:parents=>parents+[{term.name=>nodeset.index(node.to_s)}]})
        end
      end
    end
    solr_doc
  end
  
  # Populate a solr document with solr fields corresponding to the given xml node
  # Field names are generated using settings from the term in the +doc+'s terminology corresponding to +term_pointer+
  # If the supplied term does not have an index_as attribute, no indexing will be performed.
  # @param [Nokogiri::XML::Node] node to solrize
  # @param [OM::XML::Document] doc document the node came from
  # @param [Array] term_pointer Array pointing to the term that should be used for solrization settings
  # @param [Term] term the term to be solrized
  # @param [Hash] (optional) solr_doc (values hash) to populate
  # @return [Hash] the solr doc
  def self.solrize_node(node_value, doc, term_pointer, term, solr_doc = Hash.new, field_mapper = nil, opts = {})
    return solr_doc unless term.index_as && !term.index_as.empty?
    field_mapper ||= self.default_field_mapper
    
    generic_field_name_base = OM::XML::Terminology.term_generic_name(*term_pointer)
    
    field_mapper.solr_names_and_values(generic_field_name_base, node_value, term.type, term.index_as).each do |field_name, field_value|
      unless field_value.join("").strip.empty?
        ::Solrizer::Extractor.insert_solr_field_value(solr_doc, field_name, field_value)
      end
    end
    
    if term_pointer.length > 1
      hierarchical_field_name_base = OM::XML::Terminology.term_hierarchical_name(*term_pointer)
      field_mapper.solr_names_and_values(hierarchical_field_name_base, node_value, term.type, term.index_as).each do |field_name, field_value|
        unless field_value.join("").strip.empty?
          ::Solrizer::Extractor.insert_solr_field_value(solr_doc, field_name, field_value)
        end
      end
    end
    solr_doc
  end
  
  # Instance Methods
  
  attr_accessor :field_mapper
  
  def to_solr(solr_doc = Hash.new, field_mapper = self.field_mapper) # :nodoc:
    Solrizer::XML::TerminologyBasedSolrizer.solrize(self, solr_doc, field_mapper)
  end
  
  def solrize_term(term, solr_doc = Hash.new, field_mapper = self.field_mapper, opts={})
    Solrizer::XML::TerminologyBasedSolrizer.solrize_term(self, term, solr_doc, field_mapper, opts)    
  end
  
  def solrize_node(node, term_pointer, term, solr_doc = Hash.new, field_mapper = self.field_mapper, opts={})
    Solrizer::XML::TerminologyBasedSolrizer.solrize_node(node, self, term_pointer, term, solr_doc, field_mapper, opts)
  end
  
end