module ExpressTemplates
  class Component

    attr_accessor :children

    INDENT = '  '

    def initialize(*children_or_options)
      @children = []
      @options = {}.with_indifferent_access
      _process(*children_or_options)
    end

    def self.macro_name
      @macro_name ||= to_s.split('::').last.underscore
    end

    def macro_name ; self.class.macro_name end

    def html_options
      @options.each_pair.map do |name, value|
        %Q(#{name}=\\"#{value}\\")
      end.join(" ")
    end

    def start_tag
      "<#{macro_name}#{html_options.empty? ? '' : ' '+html_options}>"
    end

    def close_tag
      "</#{macro_name}>"
    end

    def add_css_class(css_class)
      @options['class'] ||= ''
      @options['class'] = (@options['class'].split + [css_class]).join(" ")
    end

    def method_missing(name, *args)
      add_css_class(name)
      _process(*args) unless args.empty?
      return self
    end

    def compile
      ruby_fragments = @children.map do |child|
        if child.respond_to?(:compile)
          child.compile
        else
          %Q("#{child}")
        end
      end
      ruby_fragments.unshift %Q("#{start_tag}")
      ruby_fragments.push %Q("#{close_tag}")
      ruby_fragments.reject {|frag| frag.empty? }.join("+")
    end

    def to_template(depth = 0)
      template_fragments = @children.map do |child|
        if child.kind_of?(ExpressTemplates::Component)
          child.to_template(depth+1)
        else
          child
        end
      end
      indent = INDENT*(depth+1)
      macro_name + _blockify(template_fragments.join("\n#{indent}"), depth)
    end

    private
      def _indent(code)
        code.split("\n").map {|line| INDENT + line }.join("\n")
      end

      def _blockify(code, depth)
        indent = INDENT*depth
        code.empty? ? code : " {\n#{_indent(code)}\n}\n"
      end

      def _process(*children_or_options)
        children_or_options.each do |child_or_option|
          if child_or_option.kind_of?(Hash)
            @options.merge!(child_or_option)
          else
            @children << child_or_option
          end
        end
      end


  end
end