protected function auth_endpoint( $route ) {
		ob_start();

		$consumer_data = array();

		try {
			$route = strtolower( wc_clean( $route ) );
			$this->make_validation();

			$data = wp_unslash( $_REQUEST ); // WPCS: input var ok, CSRF ok.

			// Login endpoint.
			if ( 'login' === $route && ! is_user_logged_in() ) {
				wc_get_template(
					'auth/form-login.php', array(
						'app_name'     => wc_clean( $data['app_name'] ),
						'return_url'   => add_query_arg(
							array(
								'success' => 0,
								'user_id' => wc_clean( $data['user_id'] ),
							), $this->get_formatted_url( $data['return_url'] )
						),
						'redirect_url' => $this->build_url( $data, 'authorize' ),
					)
				);
				exit;

			} elseif ( 'login' === $route && is_user_logged_in() ) {
				// Redirect with user is logged in.
				wp_redirect( esc_url_raw( $this->build_url( $data, 'authorize' ) ) );
				exit;

			} elseif ( 'authorize' === $route && ! is_user_logged_in() ) {
				// Redirect with user is not logged in and trying to access the authorize endpoint.
				wp_redirect( esc_url_raw( $this->build_url( $data, 'login' ) ) );
				exit;

			} elseif ( 'authorize' === $route && current_user_can( 'manage_woocommerce' ) ) {
				// Authorize endpoint.
				wc_get_template(
					'auth/form-grant-access.php', array(
						'app_name'    => wc_clean( $data['app_name'] ),
						'return_url'  => add_query_arg(
							array(
								'success' => 0,
								'user_id' => wc_clean( $data['user_id'] ),
							), $this->get_formatted_url( $data['return_url'] )
						),
						'scope'       => $this->get_i18n_scope( wc_clean( $data['scope'] ) ),
						'permissions' => $this->get_permissions_in_scope( wc_clean( $data['scope'] ) ),
						'granted_url' => wp_nonce_url( $this->build_url( $data, 'access_granted' ), 'wc_auth_grant_access', 'wc_auth_nonce' ),
						'logout_url'  => wp_logout_url( $this->build_url( $data, 'login' ) ),
						'user'        => wp_get_current_user(),
					)
				);
				exit;

			} elseif ( 'access_granted' === $route && current_user_can( 'manage_woocommerce' ) ) {
				// Granted access endpoint.
				if ( ! isset( $_GET['wc_auth_nonce'] ) || ! wp_verify_nonce( sanitize_key( wp_unslash( $_GET['wc_auth_nonce'] ) ), 'wc_auth_grant_access' ) ) { // WPCS: input var ok.
					throw new Exception( __( 'Invalid nonce verification', 'woocommerce' ) );
				}

				$consumer_data = $this->create_keys( $data['app_name'], $data['user_id'], $data['scope'] );
				$response      = $this->post_consumer_data( $consumer_data, $this->get_formatted_url( $data['callback_url'] ) );

				if ( $response ) {
					wp_redirect(
						esc_url_raw(
							add_query_arg(
								array(
									'success' => 1,
									'user_id' => wc_clean( $data['user_id'] ),
								), $this->get_formatted_url( $data['return_url'] )
							)
						)
					);
					exit;
				}
			} else {
				throw new Exception( __( 'You do not have permission to access this page', 'woocommerce' ) );
			}
		} catch ( Exception $e ) {
			$this->maybe_delete_key( $consumer_data );

			/* translators: %s: error message */
			wp_die( sprintf( esc_html__( 'Error: %s.', 'woocommerce' ), esc_html( $e->getMessage() ) ), esc_html__( 'Access denied', 'woocommerce' ), array( 'response' => 401 ) );
		}
	}