module Animal
  grammar Rules
    rule parenthesized_conditionals
      parenthesized_conditional required_space boolean_join required_space parenthesized_conditionals {
        def conditions
          all_nodes = {}
          all_nodes[:conditions]  = []
          all_nodes[:conjunction] = boolean_join.conjunction
          all_nodes[:conditions] << parenthesized_conditional.conditions
          all_nodes[:conditions] << parenthesized_conditionals.conditions
          all_nodes
        end
      }
      / '(' parenthesized_conditionals ')' {
        def conditions
          parenthesized_conditionals.conditions
        end
      }
      / parenthesized_conditional
    end

    rule parenthesized_conditional
      '(' parenthesized_conditional ')' {
          def conditions
            parenthesized_conditional.conditions
          end
        }
        / conditional_items
    end

    rule conditional_items
      conditional_item required_space boolean_join required_space conditional_items {
        def conditions
          all_nodes = {}
          all_nodes[:conditions]  = []
          all_nodes[:conjunction] = boolean_join.conjunction
          all_nodes[:conditions] << conditional_item.conditions
          all_nodes[:conditions] << conditional_items.conditions
          all_nodes
        end
      }
      /
      conditional_item
    end

    rule boolean_join
      ( and_keyword / or_keyword ) {
        def conjunction
          text_value.downcase.to_sym
        end
      }
    end

    rule conditional_item
      plugin_class quoted_text close_bracket space conditional_operator space compared_value {
        def conditions
          {
            :operator => conditional_operator.value,
            :plugin => plugin_class.name,
            :key => quoted_text.content,
            :value => compared_value.content
          }
        end
      }
    end

    rule plugin_class
      ([A-Z] [a-zA-Z0-9]+) open_bracket {
        def name
          elements[0].text_value
        end
      }
    end

    rule compared_value
      (number / boolean / quoted_text)
    end

    rule open_bracket
      '['
    end

    rule close_bracket
      ']'
    end

    rule required_space
      [\s]+
    end

    rule space
      [\s]*
    end

    rule quoted_text
      '"' text '"' {
        def content
          elements[1].content
        end
      }
    end

    rule conditional_operator
      ('!=' / '>=' / '<=' / '=' / '>' / '<' / like_keyword) {
        def value
          text_value.downcase.to_sym
        end
      }
    end

    rule like_keyword
      [lL] [iI] [kK] [eE]
    end

    rule and_keyword
      [aA] [nN] [dD]
    end

    rule or_keyword
      [oO] [rR]
    end

    rule number
      ('-'? [1-9] [0-9]* / '0') {
        def content
          text_value.to_i
        end
      }
    end

    rule boolean
      ('true' / 'false') {
        def content
          text_value == 'true'
        end
      }
    end

    rule text
      [^"]* {
        def content
          text_value
        end
      }
    end
  end
end