# = sphinx_ex.rb - extend Sphinx Client API by Dmytro Shteflyuk
#
# Author::    Leonid S. Pavlov <mailto:leonid.pavlov at gmail dot com>.
# Copyright:: Copyright (c) 2008 Leonid S. Pavlov
# License::   Distributes under the same terms as Ruby


module Sphinx
  class Client

    SEARCHD_COMMAND_KEYWORDS = 3
    VER_COMMAND_KEYWORDS = 0x100
   
    # Keywords generation
    #
    # Connect to searchd server, and generate keyword list for a given query.
    #
    # * <tt>query</tt> is query string
    # * <tt>index</tt> is index name (or names) to query
    # * <tt>hits</tt> is the bool flag for counting words hits in indexed documents
    #
    # Returns an array of words on success.
    # Returns false on failure.
    #
    # Usage example:
    #    sphinx.BuildKeywords('test1', '*', true)
    #
    def BuildKeywords(query, index, hits)
      assert { query.instance_of? String }
      assert { index.instance_of? String }
      assert { hits.instance_of?(TrueClass) || hits.instance_of?(FalseClass) }

      sock = self.Connect

      # build request
      request = Request.new         # v.1.0 req  
      request.put_string query      # req query
      request.put_string index      # req index
      request.put_int hits ? 1 : 0  # req hits

      # send query, get response
      len = request.to_s.length
      request = [SEARCHD_COMMAND_KEYWORDS, VER_COMMAND_KEYWORDS, len].pack('nnN') + request.to_s     # add header
      sock.send(request, 0)    
      response = GetResponse(sock, VER_COMMAND_KEYWORDS)

      # parse response
      pos = 0
      res = []
      rlen = response.length
      nwords = response[pos, 4].unpack('N*').first
      pos += 4

      for i in 0...nwords do
        len = response[pos, 4].unpack('N*').first; pos += 4
        tokenized = response[pos, len]
        pos += len;

        len = response[pos, 4].unpack('N*').first; pos += 4
        normalized = response[pos, len]
        pos += len;

        res << { 'tokenized' => tokenized, 'normalized' => normalized }

        if (hits)
          ndocs, nhits = response[pos, 8].unpack('N*N*')
          pos += 8
          res[i].merge!('docs' => ndocs, 'hits' => nhits)
        end

        if pos > rlen
          @error = 'incomplete reply'
          raise SphinxResponseError, @error
        end
      end

      return res
    end

  end
end