# frozen_string_literal: true

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController

  ##
  # Dynamically build a handler for each omniauth provider
  # -------------------------------------------------------------
  IdentifierScheme.where(active: true).each do |scheme|
    define_method(scheme.name.downcase) do
      handle_omniauth(scheme)
    end
  end

  # Processes callbacks from an omniauth provider and directs the user to
  # the appropriate page:
  #   Not logged in and uid had no match ---> Sign Up page
  #   Not logged in and uid had a match ---> Sign In and go to Home Page
  #   Signed in and uid had no match --> Save the uid and go to the Profile Page
  #   Signed in and uid had a match --> Go to the Home Page
  #
  # scheme - The IdentifierScheme for the provider
  #
  def handle_omniauth(scheme)
    if request.env["omniauth.auth"].nil?
      user = User.from_omniauth(request.env)
    else
      user = User.from_omniauth(request.env["omniauth.auth"])
    end

    # If the user isn't logged in
    if current_user.nil?
      # If the uid didn't have a match in the system send them to register
      if user.nil?
        session["devise.#{scheme.name.downcase}_data"] = request.env["omniauth.auth"]
        redirect_to new_user_registration_url

      # Otherwise sign them in
      else
        # Until ORCID becomes supported as a login method
        if scheme.name == "shibboleth"
          if is_navigational_format?
            set_flash_message(:notice, :success, kind: scheme.description)
          end
          sign_in_and_redirect user, event: :authentication
        else
          flash[:notice] = _("Successfully signed in")
          redirect_to new_user_registration_url
        end
      end

    # The user is already logged in and just registering the uid with us
    else
      # If the user could not be found by that uid then attach it to their record
      if user.nil?
        if UserIdentifier.create(identifier_scheme: scheme,
                                 identifier: request.env["omniauth.auth"].uid,
                                 user: current_user)
          # rubocop:disable Metrics/LineLength
          flash[:notice] = _("Your account has been successfully linked to %{scheme}.") % {
            scheme: scheme.description
          }
          # rubocop:enable Metrics/LineLength
        else
          flash[:alert] = _("Unable to link your account to %{scheme}.") % {
            scheme: scheme.description
          }
        end

      else
        # If a user was found but does NOT match the current user then the identifier has
        # already been attached to another account (likely the user has 2 accounts)
        identifier = UserIdentifier.where(
          identifier: request.env["omniauth.auth"].uid
        ).first
        if identifier.user.id != current_user.id
          # rubocop:disable Metrics/LineLength
          flash[:alert] = _("The current #{scheme.description} iD has been already linked to a user with email #{identifier.user.email}")
          # rubocop:enable Metrics/LineLength
        end

        # Otherwise, the identifier was found and it matches the one already associated
        # with the current user so nothing else needs to be done
      end

      # Redirect to the User Profile page
      redirect_to edit_user_registration_path
    end
  end

  def failure
    redirect_to root_path
  end

end