topics_controller.rb

class TopicsController < ApplicationController
  before_action :require_sign_in, except: [:index, :show]
  before_action :authorize!, except: [:index, :show]

  def index
    @topics = Topic.all
  end

  def new
    @topic = Topic.new
  end

  def create
    @topic = Topic.new(topic_params)

    if @topic.save
      flash[:notice] = "Topic was saved successfully."
      redirect_to @topic
    else
      flash.now[:alert] = "Error creating topic. Please try again."
      render :new
    end
  end

  def show
    @topic = Topic.find(params[:id])
  end

  def update
    @topic = Topic.find(params[:id])
    @topic.assign_attributes(topic_params)

    if @topic.save
      flash[:notice] = "Topic was updated successfully."
      redirect_to @topic
    else
      flash.now[:alert] = "Error saving topic. Please try again."
      render :edit
    end
  end


  def edit
    @topic = Topic.find(params[:id])
  end

  def destroy
    @topic = Topic.find(params[:id])

    if @topic.destroy
      flash[:notice] = "\"#{@topic.name}\" was deleted successfully."
      redirect_to action: :index
    else
      flash.now[:alert] = "There was an error deleting the topic."
      render :show
    end
  end

  private

  def topic_params
    params.require(:topic).permit(:name, :description, :public)
  end

  def authorize!
    case action_name
    when :edit, :update
      unless current_user.admin? || current_user.moderator?
        redirect_to topics_path, alert: 'You are not authorized to do that'
      end
    when :new, :create, :destroy
      unless current_user.admin?
        redirect_to topics_path, alert: 'You are not authorized to do that'
      end
    end
  end
k
end