require 'erb'
require 'moblues/reader/type'

module Moblues
  module Generator
    class Base
      def initialize(params)
        @output_dir = params.fetch(:output_dir)
      end

      protected
      attr_reader :output_dir

      def write_header(entity)
        write_file(header_file(entity), header(entity))
      end

      def write_implementation(entity)
        write_file(implementation_file(entity), implementation(entity))
      end

      def write_file(file, text)
        File.open(file, 'w+') do |f|
          f.write(text)
        end
      end

      def header_file(entity)
        File.join(output_dir, format_name(entity, 'h'))
      end

      def implementation_file(entity)
        File.join(output_dir, format_name(entity, 'm'))
      end

      def format_name(entity, extension)
        raise NotImplemented
      end

      def header(entity)
        render(header_template, entity)
      end

      def implementation(entity)
        render(implementation_template, entity)
      end

      def render(template, entity)
        ERB.new(template, 0, '-').result(entity.send(:binding))
      end

      def header_template
        raise NotImplemented
      end

      def implementation_template
        raise NotImplemented
      end

      def file_template(name)
        File.read(File.expand_path("../#{name}.erb", __FILE__))
      end
    end
  end
end