module ZCC
  #main search method
  def ZCC.zoomer(search_term, server, port, database )
    puts "\n-------------------------------------\n#{server} #{port} #{database} \n"
    
    conn = ZOOM::Connection.new
    conn.connect(server, port) #do |conn|
    conn.set_option('charset', 'UTF-8')
    conn.preferred_record_syntax = 'MARC21'
    conn.database_name = database
    
    # Determines kind of search and creates query
    full_search = ''
    if search_term =~ /\d+-\d+/
      search_term = ZCC.lccn_conversion(search_term)
      puts "converted lccn to #{search_term}"
      full_search = "@attr 1=9 #{search_term}"
    elsif search_term =~ /\d+[X||\d]/ and !(search_term.match( /[a-wyz]/i ))
      puts "Searching for ISBN: #{search_term}"
      full_search = "@attr 1=7 #{search_term}"
    elsif ( search_term[/[a-z]/i] ) #-- This check for a string could be better!
      puts "searching for title:#{search_term}"
      search_term = "\'#{search_term}\'"
      full_search = "@attr 1=4 \"#{search_term}\""
    else
      puts "What is this search? Does not compute."
      exit
    end
    
    #conducts search
    rset = conn.search(full_search)
    if ( rset.length == 0)
      return nil
    end
    puts "Number of results: #{rset.length}"
    #Grabs only as many records as are set to be shown
    rset_recs = rset[0,TO_SHOW]
    
    
    # Turns result set into MARC::Record objects which are returned
    xmlrecs = '' 
    rset_recs.each do |rsetrec|
      #puts rsetrec
      xmlrec = ZCC.convert_char(rsetrec)
      xmlrecs += xmlrec
    end
    return records = MARC::XMLReader.new(StringIO.new(string=xmlrecs))
    
  rescue Exception => except
    puts "Error! #{except}" 
    return nil
  end
  
  # Tests leader of MARC21 records for character encoding
  # If leader position 9 is ' ' then convert to UTF-8.
  # If leader position 9 is 'a' then the record is already UTF-8.
  # Finally converts to xml
  def ZCC.convert_char rsetrec
    rec = MARC::Record.new_from_marc(rsetrec.raw)
    ldr9 = rec.leader[9, 1]
    return_rec = ''
    if ldr9 == ' '
      return_rec = rsetrec.xml('MARC-8', 'UTF-8')
    elsif ldr9 == 'a'
      return_rec = rsetrec.xml
    else
      raise "Invalid value in leader 9 for MARC21"
    end
    return_rec
  end

end