module ResqueAdmin
  module Plugin
    extend self

    LintError = Class.new(RuntimeError)

    # Ensure that your plugin conforms to good hook naming conventions.
    #
    #   ResqueAdmin::Plugin.lint(MyResquePlugin)
    def lint(plugin)
      hooks = before_hooks(plugin) + around_hooks(plugin) + after_hooks(plugin)

      hooks.each do |hook|
        if hook.to_s.end_with?("perform")
          raise LintError, "#{plugin}.#{hook} is not namespaced"
        end
      end

      failure_hooks(plugin).each do |hook|
        if hook.to_s.end_with?("failure")
          raise LintError, "#{plugin}.#{hook} is not namespaced"
        end
      end
    end

    @job_methods = {}
    def job_methods(job)
      @job_methods[job] ||= job.methods.collect{|m| m.to_s}
    end

    # Given an object, and a method prefix, returns a list of methods prefixed
    # with that name (hook names).
    def get_hook_names(job, hook_method_prefix)
      methods = (job.respond_to?(:hooks) && job.hooks) || job_methods(job)
      methods.select{|m| m.start_with?(hook_method_prefix)}.sort
    end

    # Given an object, returns a list `before_perform` hook names.
    def before_hooks(job)
      get_hook_names(job, 'before_perform')
    end

    # Given an object, returns a list `around_perform` hook names.
    def around_hooks(job)
      get_hook_names(job, 'around_perform')
    end

    # Given an object, returns a list `after_perform` hook names.
    def after_hooks(job)
      get_hook_names(job, 'after_perform')
    end

    # Given an object, returns a list `on_failure` hook names.
    def failure_hooks(job)
      get_hook_names(job, 'on_failure')
    end

    # Given an object, returns a list `after_enqueue` hook names.
    def after_enqueue_hooks(job)
      get_hook_names(job, 'after_enqueue')
    end

    # Given an object, returns a list `before_enqueue` hook names.
    def before_enqueue_hooks(job)
      get_hook_names(job, 'before_enqueue')
    end

    # Given an object, returns a list `after_dequeue` hook names.
    def after_dequeue_hooks(job)
      get_hook_names(job, 'after_dequeue')
    end

    # Given an object, returns a list `before_dequeue` hook names.
    def before_dequeue_hooks(job)
      get_hook_names(job, 'before_dequeue')
    end
  end
end