require 'deas/runner'

module Deas

  module ViewHandler

    def self.included(klass)
      klass.class_eval do
        extend ClassMethods
      end
    end

    def initialize(runner)
      @deas_runner = runner
    end

    def init
      self.run_callback 'before_init'
      self.init!
      self.run_callback 'after_init'
    end

    def init!
    end

    def run
      self.run_callback 'before_run'
      data = self.run!
      self.run_callback 'after_run'
      data
    end

    def run!
      raise NotImplementedError
    end

    def inspect
      reference = '0x0%x' % (self.object_id << 1)
      "#<#{self.class}:#{reference} @request=#{self.request.inspect}>"
    end

    protected

    # Helpers

    def halt(*args);        @deas_runner.halt(*args);        end
    def redirect(*args);    @deas_runner.redirect(*args);    end
    def redirect_to(*args); @deas_runner.redirect_to(*args); end

    def render(*args, &block)
      @deas_runner.render(*args, &block)
    end

    def logger;   @deas_runner.logger;   end
    def request;  @deas_runner.request;  end
    def response; @deas_runner.response; end
    def params;   @deas_runner.params;   end
    def session;  @deas_runner.session;  end

    def run_callback(callback)
      (self.class.send("#{callback}_callbacks") || []).each do |callback|
        self.instance_eval(&callback)
      end
    end

    module ClassMethods

      def before(&block)
        self.before_callbacks << block
      end

      def before_callbacks
        @before_callbacks ||= []
      end

      def after(&block)
        self.after_callbacks << block
      end

      def after_callbacks
        @after_callbacks ||= []
      end

      def before_init(&block)
        self.before_init_callbacks << block
      end

      def before_init_callbacks
        @before_init_callbacks ||= []
      end

      def after_init(&block)
        self.after_init_callbacks << block
      end

      def after_init_callbacks
        @after_init_callbacks ||= []
      end

      def before_run(&block)
        self.before_run_callbacks << block
      end

      def before_run_callbacks
        @before_run_callbacks ||= []
      end

      def after_run(&block)
        self.after_run_callbacks << block
      end

      def after_run_callbacks
        @after_run_callbacks ||= []
      end

      def layout(*args)
        @layouts = args unless args.empty?
        @layouts
      end
      alias :layouts :layout

    end

  end

end