require 'yamler'



class Configuration

	def self.load_yaml(path, opts = {})

		yml = Yamler.load(path)

		

		config = build_inheritance_chain yml, opts[:hash].to_s, opts[:inherit].to_s unless opts[:hash].nil? or opts[:inherit].nil?

		apply_overrides yml, config, opts[:override_with].to_s unless opts[:override_with].nil?



		config

	end

	

	def self.build_inheritance_chain(everything, selector, inheritance_attr)

		selection = everything[selector]

		

		if not selection[inheritance_attr].nil?

			puts "Settings for '#{selector}' inherit '#{selection[inheritance_attr]}' via attribute '#{inheritance_attr}'"

			

			inherited = build_inheritance_chain everything, selection[inheritance_attr], inheritance_attr

			selection = inherited.recursive_merge(selection)

			selection.delete(inheritance_attr)

		end

		

		selection

	end

	

	def self.apply_overrides(everything, config, selector)

		overrides = everything[selector] 

		

		return if overrides.nil?



		puts "Applying configuration overrides from #{selector}"

		config.recursive_merge(overrides)

	end

end



class Hash

	def recursive_merge(h)

		self.merge!(h) do |key, _old, _new|

			if _old.class == Hash

				_old.recursive_merge(_new)

			else

				_new

			end

		end

	end

end