class WelcomeController < ApplicationController
  # GET /
  def index
  end

  # GET /authenticate(/:token)
  # Discourse SSO Authentication
  def authenticate
    validate_token_format!

    # Try an ongoing SSO or create a new one
    @sso = SSO::FromDiscourse.new(token: params[:token], nonce: session[params[:token]])

    clear_current_session

    # Start SSO roundtrip if we're not passed a token
    if params[:token].nil?
      # Record this token and nonce in the session
      session[@sso.token] = @sso.nonce
      # Send to SSO authenticator
      redirect_to @sso.request_uri and return
    end

    # Validate authentication params from SSO
    begin
      @sso.parse(params)
    rescue ArgumentError => e
      Rails.logger.debug("SSO request failed: #{e.message}")
      return :forbidden
    end

    # Resolve SSO and finish authentication
    case @sso.status
    when :ok
      Rails.logger.info("Authentication succeeded!")
      find_or_create_current_user
      perform_background_jobs
      update_current_session
    when :unauthorized
      Rails.logger.info("Authentication failed!")
    end
    return :forbidden unless @current_user.present?

    # TODO add some memory of previously called URL and return there
    redirect_to '/my/dashboard'
  end

  # GET /dashboard
  def dashboard
    redirect_to '/authenticate' and return unless current_user.present?
  end

  # GET /logout
  def logout
    session.destroy
    render :index
  end

  private

  # Ensure nobody tries silly things with our session
  def validate_token_format!
    if params[:token].present? && !params[:token].match?(/[a-z0-9]{32}/)
      raise(ArgumentError, "Token invalid")
    end
  end

  # Remove any current session
  def clear_current_session
    Rails.logger.info("Removing current session (#{session[:current_user]})")
    session.destroy
    @current_user = nil
  end

  # Set @current_user to existing or new User record from SSO user info
  def find_or_create_current_user
    @current_user = User.find_by(external_id: @sso.user_info[:external_id]) ||
                    begin
                      Rails.logger.info('new user...')
                      u = User.create(
                        external_id: @sso.user_info[:external_id],
                        avatar_url: @sso.user_info[:avatar_url],
                        email: @sso.user_info[:email],
                        name: @sso.user_info[:name],
                        username: @sso.user_info[:username])
                      Rails.logger.info('created user %s' % u.inspect)
                      u
                    rescue Exception => e
                      Rails.logger.warning("#{e.type}: #{e.message}")
                    end
  end

  # Update user agents
  def perform_background_jobs
    if @current_user.present?
      AgencyWatcherJob.perform_later(@current_user, @sso.user_info[:groups].split(','))
    end
  end

  # Save User ID and current agent in session
  def update_current_session
    if @current_user.present?
      session[:current_user] = @current_user[:external_id]
      # TODO: make this a bit smarter
      session[:current_agent] = @current_user&.agents&.pluck(:name)&.last
    end
  end
end