module Solrizer
  
# Provides utilities for extracting solr fields from a variety of objects and/or creating solr documents from a given object
# Note: These utilities are optional.  You can implement .to_solr directly on your classes if you want to bypass using Extractors.
#
# Each of the Solrizer implementations (ie. solrizer-fedora) provides its own Extractor module that extends the behaviors of Solrizer::Extractor
# with methods specific to that implementation (ie. extract_tag, extract_rels_ext, xml_to_solr, html_to_solr).  
# By convention, the solrizer implementations will mix their own Extractors' behaviors into this class when you load them into an application.
#
class Extractor
  
  class << self
    # Insert +field_value+ for +field_name+ into +solr_doc+
    # Handles inserting new values into a Hash while ensuring that you don't destroy or overwrite any existing values in the hash.
    # Ensures that field values are always appended to arrays within the values hash.
    # Also ensures that values are run through format_node_value
    # @param [Hash] solr_doc
    # @param [String] field_name
    # @param [String] field_value
    def insert_solr_field_value(solr_doc, field_name, field_value)
      formatted_value = format_node_value(field_value)
      if solr_doc[field_name]
        solr_doc[field_name] = Array(solr_doc[field_name]) << formatted_value
      else
        solr_doc[field_name] = formatted_value
      end
      return solr_doc
    end

    # Strips the majority of whitespace from the values array and then joins them with a single blank delimitter
    # Returns an empty string if values argument is nil
    #
    # @param [Array] values Array of strings representing the values to be formatted
    # @return [String]
    def format_node_value values
      if values.nil?
        ""
      else
        Array(values).map{|val| val.gsub(/\s+/,' ').strip}.join(" ")
      end
    end
  end
  
  # Instance Methods
  
  # Alias for Solrizer::Extractor#insert_solr_field_value
  def insert_solr_field_value(solr_doc, field_name, field_value)
    Solrizer::Extractor.insert_solr_field_value(solr_doc, field_name, field_value)
  end
  
  # Alias for Solrizer::Extractor#format_node_value
  def format_node_value values
    Solrizer::Extractor.format_node_value(values)
  end
  
  # Deprecated.
  # merges input_hash into solr_hash
  # @param [Hash] input_hash the input hash of values
  # @param [Hash] solr_hash the solr values hash to add the values into
  # @return [Hash] the populated Solr values hash
  # 
  def extract_hash( input_hash, solr_hash=Hash.new )   
    warn "[DEPRECATION] `extract_hash` is deprecated.  Just pass values directly into your solr values hash" 
    return solr_hash.merge!(input_hash)
  end
  
end
end