require 'thread'
require 'treetop'
require 'flydata-core/table_def'

module Mysql
  class ParserProvider

    @@mutex = Mutex.new
    @@parsers = {}

    def self.parser(db_type, parser_type)
      key = [db_type.to_s, parser_type.to_s].join("::").to_s
      @@mutex.synchronize do
        if @@parsers[key]
          return @@parsers[key]
        else
          # lazy load
          treetop_path = File.join(
            File.expand_path(File.dirname(__FILE__)),
            "parser/#{db_type}/#{parser_type}.treetop")
          Treetop.load treetop_path
          @@parsers[key] = "#{parser_type}_parser".camelize.constantize
        end
      end
    end
  end
end