module OpenToken
  class KeyValueSerializer
    LINE_START = 0
    EMPTY_SPACE = 1
    VALUE_START = 2
    LINE_END = 3
    IN_KEY = 4
    IN_VALUE = 5
    IN_QUOTED_VALUE = 6

    class << self
      def serialize(hashmap)
        result = String.new
        count = 0;
        hashmap.each_pair do |key,value|
          if (count != 0)
            result = result + "\n"
          end
          count +=1
          result += key + "="
          result += escape_value(value)
        end
        result
      end
      def deserialize(string)
        result = OpenToken::Token.new
        state = LINE_START
        open_quote_char = 0.chr
        currkey = ""
        token = ""
        nextval = ""
      
        string.split(//).each do |c|
          nextval = c

          case c
          when "\t"
            if state == IN_KEY
              # key ends
              currkey = token
              token = ""
              state = EMPTY_SPACE
            elsif state == IN_VALUE
              # non-quoted value ends
              result[currkey] = self.deserialize(token)
              token = ""
              state = LINE_END
            elsif state == IN_QUOTED_VALUE
              token += c
            end
          when " "
            if state == IN_KEY
              # key ends
              currkey = token
              token = ""
              state = EMPTY_SPACE
            elsif state == IN_VALUE
              # non-quoted value ends
              result[currkey] = self.deserialize(token)
              token = ""
              state = LINE_END
            elsif state == IN_QUOTED_VALUE
              token += c
            end
          when "\n"
            # newline
            if (state == IN_VALUE) || (state == VALUE_START)
              result[currkey] = unescape_value(token)
              token = ""
              state = LINE_START
            elsif state == LINE_END
              token = ""
              state = LINE_START
            elsif state == IN_QUOTED_VALUE
              token += c
            end
          when "="
            if state == IN_KEY
              currkey = token
              token = ""
              state = VALUE_START
            elsif (state == IN_QUOTED_VALUE) || (state == IN_VALUE)
              token += c
            end
          when "\""
            if state == IN_QUOTED_VALUE
              if (c == open_quote_char) && (token[token.size-1] != "\\"[0])
                result[currkey] = unescape_value(token)
                token = ""
                state = LINE_END
              else
                token += c
              end
            elsif state == VALUE_START
              state = IN_QUOTED_VALUE
              open_quote_char = c
            end
          when "'"
            if state == IN_QUOTED_VALUE
              if (c == open_quote_char) && (token[token.size-1] != "\\"[0])
                result[currkey] = unescape_value(token)
                token = ""
                state = LINE_END
              else
                token += c
              end
            else state == VALUE_START
              state = IN_QUOTED_VALUE
              open_quote_char = c
            end
          else
            if state == LINE_START
              state = IN_KEY
            elsif state == VALUE_START
              state = IN_VALUE
            end
            token += c
          end
        
          if (state == IN_QUOTED_VALUE) || (state == IN_VALUE)
            result[currkey] = unescape_value(token)
          end
        end
        result
      end
      private
      def unescape_value(value)
        value.gsub("\\\"", "\"").gsub("\\\'", "'")
      end
      def escape_value(value)
        value.each_byte do |b|
          c = b.chr
          if c == "\n" or c == "\t" or c == " " or c == "'" or c == "\""
            value = "'" + value.gsub("'", "\'").gsub("\"", "\\\"") + "'"
            break
          end
        end
        value
      end
    end
  end
end