mastodon/app/controllers/remote_follow_controller.rb

# frozen_string_literal: true

class RemoteFollowController < ApplicationController
  layout 'public'

  before_action :set_account
  before_action :gone, if: :suspended_account?

  def new
    @remote_follow = RemoteFollow.new(session_params)
  end

  def create
    @remote_follow = RemoteFollow.new(resource_params)

    if @remote_follow.valid?
      session[:remote_follow] = @remote_follow.acct
      redirect_to @remote_follow.subscribe_address_for(@account)
    else
      render :new
    end
  end

  private

  def resource_params
    params.require(:remote_follow).permit(:acct)
  end

  def session_params
    { acct: session[:remote_follow] }
  end

  def set_account
    @account = Account.find_local!(params[:account_username])
  end

  def suspended_account?
    @account.suspended?
  end
end