marcy-terui / rapis

  class Converter

    include Rapis::TemplateFunctions

    CHANGE_SETS = {

      'x-amazon-apigateway-integration' => 'amazon_apigateway_integration',

      '$ref' => 'ref'

    }

    def to_dsl(hash)

      dsl = Dslh.deval(

        hash,

        exclude_key: to_dsl_exclude_key,

        key_conv: to_dsl_key_conv,

        value_conv: to_dsl_value_conv

      )

      dsl.gsub!(/^/, '  ').strip!

      <<-EOS

rest_api do

  #{dsl}

end

EOS

    end

    def to_h(dsl)

      instance_eval(dsl)

      @apis

    end

    private

    def to_dsl_exclude_key

      proc do |k|

        if !k.is_a?(String)

          false

        elsif ['in'].include?(k)

          true

        elsif k.include?('/')

          if k =~ %r{^\/}

            false

          else

            true

          end

        elsif ['-', '.'].any? { |i| k.include?(i) } && k != 'x-amazon-apigateway-integration'

          true

        else

          false

        end

      end

    end

    def to_dsl_key_conv

      proc do |k|

        k = k.to_s

        case k

        when %r{^\/}

          item_key_proc k

        when /^\d{3}$/

          code_key_proc k

        when 'parameters', 'api_key'

          parameters_key_proc k

        else

          CHANGE_SETS.each { |f, t| k = k.gsub(f, t) }

          k

        end

      end

    end

    def code_key_proc(k)

      proc do |v, nested|

        if nested

          "code #{k.to_s.inspect} #{v}"

        else

          "code #{k.to_s.inspect}, #{v}"

        end

      end

    end

    def parameters_key_proc(k)

      proc do |v, _|

        if v =~ /\n(\s+)/

          indent = Regexp.last_match(1)

          v = instance_eval(v)

          dsl = "#{k} do\n"

          if v.is_a?(Array)

            v.each do |param|

              dsl << param_to_dsl(param, indent)

            end

          else

            dsl << param_to_dsl(v, indent)

          end

          dsl << indent[2..-1] + "end\n"

        else

          "#{k} #{v}"

        end

      end

    end

    def param_to_dsl(param, indent)

      dsl = indent + "#{param['in']} #{param['name'].inspect} do\n"

      param.each do |pk, pv|

        next if %w(in name).include?(pk)

        dsl << indent

        dsl += pv.is_a?(String) ? "  #{pk} #{pv.inspect}\n" : "  #{pk} #{pv}\n"

      end

      dsl << indent + "end\n"

    end

    def to_dsl_value_conv

      proc do |v|

        if v.is_a?(String) && v =~ /\A(?:0|[1-9]\d*)\Z/

          v.to_i

        else

          v

        end

      end

    end

    def to_h_exclude_key

      proc do |_|

        false

      end

    end

    def to_h_key_conv

      proc do |k|

        k = k.to_s

        CHANGE_SETS.each { |f, t| k = k.gsub(t, f) }

        k

      end

    end

    def to_h_value_conv

      proc do |v|

        case v

        when Hash, Array, TrueClass, FalseClass

          v

        else

          v.to_s

        end

      end

    end

    def rest_api(&block)

      @apis = Dslh.eval(

        exclude_key: to_h_exclude_key,

        key_conv: to_h_key_conv,

        value_conv: to_h_value_conv,

        allow_empty_args: true,

        scope_hook: proc { |scope| define_template_func(scope) },

        &block

      )

    end

    def define_template_func(scope)

      scope.instance_eval(<<-EOS)

        #{template_code_func}

        #{template_item_func}

        #{template_api_key_func}

        #{template_params_func}

        #{template_include_func}

        EOS

    end

  end

end