module Compositor
  class MethodAlreadyDefinedError < RuntimeError; end

  class Base
    attr_reader :attrs
    attr_accessor :root, :context

    def initialize(view_context, attrs = {})
      @attrs = attrs
      self.context = view_context
      attrs.each_pair do |key, value|
        self.send("#{key}=", value)
      end
    end

    def to_hash
      raise NotImplementedError.new("Abstract method, should be implemented by subclasses")
    end

    def with_root_element
      include_root? ? {root => yield} : yield
    end

    def to_h
      to_hash
    end

    def to_json(options = {})
      Oj.dump(to_hash)
    end

    def include_root?
      self.root ? true : false
    end

    def root_class_name
      self.class.root_class_name(self.class)
    end

    def self.root_class_name(klazz)
      klazz.name.gsub(/(.*::)|(Compositor$)/, '').underscore
    end

    def self.inherited(subclass)
      method_name = root_class_name(subclass)
      unless method_name.eql?("base") || method_name.start_with?("abstract")
        # check if it's already defined
        if Compositor::DSL.instance_methods.include?(method_name.to_sym)
          raise MethodAlreadyDefinedError.new("Method #{method_name} is already defined on the DSL class.")
        end
        Compositor::DSL.send(:define_method, method_name) do |*args, &block|
          subclass.
            new(@context, *args).
            dsl(self, &block)
        end
      end
    end

    def dsl
      raise "Implement in subclasses"
    end
  end
end

require_relative 'dsl'
require_relative 'composite'
require_relative 'leaf'
require_relative 'literal'
require_relative 'list'
require_relative 'map'