require "thor"

module UcbRailsCli
  class Cli < Thor
    ## error messages
    INSTALL_RAILS = "Unable to find rails - please make sure you've installed Rails 5.1 or greater"
    GEMFILE_ERROR = "Unable to add new gems to Gemfile - check the console output for more info"
    LAYOUT_FILES = "Unable to copy view templates - check the console output for more info"
    HELPER_FILES = "Unable to copy helpers - check the console output for more info"
    ASSETS = "Unable to copy app assets - check the console output for more info"
    ROUTES = "Unable to copy routes file - check the console output for more info"
    MIGRATIONS = "Unable to copy migrations from ucb_rails_user gem - check the console output for more info"
    CONTROLLERS = "Unable to copy controllers - check the console output for more info"
    CONFIG_FILES = "Unable to copy config files - check the console output for more info"
    GITIGNORE = "Unable to update .gitignore - check the console output for more info"
    RSPEC = "Unable to install RSpec - check the console output for more info"

    desc "new APP_NAME", "generate a new UCB Rails app called NAME"
    option :rails_options
    def new(app_name)
      puts "Generating #{app_name}..."

      verify_rails or exit_with_error(INSTALL_RAILS)

      create_rails_app(app_name) or exit_with_error

      add_to_gemfile(app_name) or exit_with_error(GEMFILE_ERROR)

      add_layout_files(app_name) or exit_with_error(LAYOUT_FILES)

      add_helpers(app_name) or exit_with_error(HELPER_FILES)

      add_assets(app_name) or exit_with_error(ASSETS)

      add_routes(app_name) or exit_with_error(ROUTES)

      add_controllers(app_name) or exit_with_error(CONTROLLERS)

      add_config_files(app_name) or exit_with_error(CONFIG_FILES)

      update_gitignore(app_name) or exit_with_error(GITIGNORE)

      install_migrations(app_name) or exit_with_error(MIGRATIONS)

      setup_rspec(app_name) or exit_with_error(RSPEC)

      puts <<-END

********************************************************************
Finished! Your new app is in ./#{app_name}

From here, you should set up the database:

  cd #{app_name}
  bin/rake db:create
  bin/rake db:migrate

then add the missing values in config/config.yml - you can get the
credentials from another developer.

At that point, you can start the server as usual:

  bin/rails server

then access the homepage at http://localhost:3000. You should be able
to login with your usual UCB credentials.

Enjoy!

      END
    end

    private

    def exit_with_error(msg="")
      puts msg
      exit -1
    end

    def verify_rails
      begin
        `rails --version` =~ /Rails 5\./
      rescue Exception => e
        return false
      end
    end

    def create_rails_app(app_name)
      result = system("rails new #{app_name} #{options[:rails_options]}")
      return true if result

      puts "Unable to run \"rails new\" to create a new app - check the console output \n" +
        "for more details about what went wrong"
      false
    end

    def add_to_gemfile(app_name)
      puts "Adding gems to Gemfile..."
      if system("cat #{template_dir}/Gemfile_additions >> #{app_name}/Gemfile")
        puts "Installing new gems..."
        system "cd #{app_name} && bundle install"
      end
    end

    def add_layout_files(app_name)
      puts "Installing template files..."
      if system("cp #{template_dir}/views/* #{app_name}/app/views/layouts")
        system "rm -f #{app_name}/app/views/layouts/application.html.erb"
      else
        false
      end
    end

    def add_helpers(app_name)
      puts "Installing helpers..."
      file_contents = `cat #{template_dir}/helpers/application_helper.rb`
        .gsub("%APP_NAME", humanize(app_name))
      system "echo '#{file_contents}' > #{app_name}/app/helpers/application_helper.rb"
      true
    end

    def add_assets(app_name)
      puts "Installing assets..."
      result =
        system("cp #{template_dir}/stylesheets/main.sass #{app_name}/app/assets/stylesheets") &&
        system("cp -R #{template_dir}/stylesheets/themes #{app_name}/app/assets/stylesheets") &&
        system("cp #{template_dir}/images/* #{app_name}/app/assets/images")
      if result
        # don't clobber the default file until we're sure everything else went through
        system "cp #{template_dir}/stylesheets/application.css #{app_name}/app/assets/stylesheets"
        system "cp #{template_dir}/javascripts/application.js #{app_name}/app/assets/javascripts"
      else
        false
      end
    end

    def add_routes(app_name)
      puts "Installing routes..."
      system "cp #{template_dir}/config/routes.rb #{app_name}/config/routes.rb"
    end

    def add_controllers(app_name)
      puts "Installing controllers..."
      system "cp #{template_dir}/controllers/* #{app_name}/app/controllers/"
    end

    def add_config_files(app_name)
      puts "Installing config files..."
      system("cp #{template_dir}/config/config.yml #{app_name}/config") &&
        system("cp #{template_dir}/config/initializers/ucb_rails_user.rb #{app_name}/config/initializers")
    end

    def update_gitignore(app_name)
      puts "Updating .gitignore..."
      system "echo 'config/config.yml' >> #{app_name}/.gitignore"
    end

    def install_migrations(app_name)
      puts "Installing migrations from ucb_rails_user..."
      system "cd #{app_name} && bin/rails railties:install:migrations"
    end

    def setup_rspec(app_name)
      puts "Setting up rspec..."
      system("cd #{app_name} && bin/spring stop && bin/rails generate rspec:install") &&
        system("rm -rf #{app_name}/test")
    end

    def template_dir
      "#{File.dirname(__dir__)}/ucb_rails_cli/templates"
    end

    def humanize(str)
      str
        .gsub("_", " ")
        .split
        .map(&:capitalize)
        .join(" ")
    end

  end
end