wp-m365-login/includes/class-m365-login-button.php

<?php
/**
 * Login page button.
 *
 * @package M365_Login
 */

defined( 'ABSPATH' ) || exit;

/**
 * Renders the "Sign in with Microsoft" button on wp-login.php.
 */
class M365_Login_Button {

	/**
	 * Settings.
	 *
	 * @var M365_Login_Settings
	 */
	private $settings;

	/**
	 * Constructor.
	 *
	 * @param M365_Login_Settings $settings Settings.
	 */
	public function __construct( M365_Login_Settings $settings ) {
		$this->settings = $settings;

		add_action( 'login_enqueue_scripts', array( $this, 'enqueue' ) );
		add_filter( 'login_body_class', array( $this, 'body_class' ) );
		add_filter( 'login_message', array( $this, 'render_above' ), 20 );
		add_action( 'login_footer', array( $this, 'render_below' ) );
		add_shortcode( 'm365_login_button', array( $this, 'shortcode' ) );

		// Custom login pages built with wp_login_form().
		add_filter( 'login_form_top', array( $this, 'form_top' ), 10, 2 );
		add_filter( 'login_form_bottom', array( $this, 'form_bottom' ), 10, 2 );
	}

	/**
	 * Whether the plugin should hook into wp_login_form() output.
	 *
	 * @return bool
	 */
	private function inject_into_forms() {
		return $this->settings->is_configured() && (bool) $this->settings->get( 'inject_form' ) && ! is_user_logged_in();
	}

	/**
	 * wp_login_form(): messages above the fields; in button-only mode the fields are wrapped and hidden.
	 *
	 * @param string $content Existing content.
	 * @param array  $args    wp_login_form() arguments.
	 * @return string
	 */
	public function form_top( $content, $args = array() ) {
		if ( ! $this->inject_into_forms() ) {
			return $content;
		}
		$this->enqueue_frontend();
		$content .= $this->messages_markup();
		if ( $this->password_login_hidden() ) {
			$content .= '<div class="m365-login__hidden-fields" hidden>';
		}
		return $content;
	}

	/**
	 * wp_login_form(): closes the wrapper and appends the button.
	 *
	 * @param string $content Existing content.
	 * @param array  $args    wp_login_form() arguments.
	 * @return string
	 */
	public function form_bottom( $content, $args = array() ) {
		if ( ! $this->inject_into_forms() ) {
			return $content;
		}
		$hidden      = $this->password_login_hidden();
		$redirect_to = isset( $args['redirect'] ) ? (string) $args['redirect'] : '';
		if ( $hidden ) {
			$content .= '</div>';
		}
		$divider = $hidden ? '' : $this->divider_markup();
		return $content . '<div class="m365-login m365-login--form">' . $divider . $this->button( $redirect_to ) . '</div>';
	}

	/**
	 * Whether password fields should be hidden right now (button-only mode without fallback).
	 *
	 * @return bool
	 */
	private function password_login_hidden() {
		return $this->settings->button_only() && ! M365_Login::instance()->auth->fallback_active();
	}

	/**
	 * Enqueues the stylesheet on the front end (custom login pages).
	 */
	public function enqueue_frontend() {
		wp_enqueue_style( 'm365-login', M365_LOGIN_URL . 'assets/css/login.css', array(), M365_LOGIN_VERSION );
		wp_add_inline_style( 'm365-login', $this->css_variables() );
	}

	/**
	 * Divider line markup ('' when the divider text is empty).
	 *
	 * @return string
	 */
	private function divider_markup() {
		$divider = (string) $this->settings->get( 'divider_text' );
		return '' === trim( $divider ) ? '' : '<div class="m365-login__divider" aria-hidden="true"><span>' . esc_html( $divider ) . '</span></div>';
	}

	/**
	 * Error / info messages for custom login pages.
	 *
	 * @return string
	 */
	public function messages_markup() {
		$html = '';
		foreach ( M365_Login::instance()->auth->current_messages() as $msg ) {
			$html .= '<div class="m365-login__notice m365-login__notice--' . esc_attr( $msg['type'] ) . '" role="' . ( 'error' === $msg['type'] ? 'alert' : 'status' ) . '">' . esc_html( $msg['text'] ) . '</div>';
		}
		return $html;
	}

	/**
	 * Full markup for templates and shortcodes.
	 *
	 * @param array $args {
	 *     @type string $redirect      Destination after login.
	 *     @type bool   $show_messages Show error/info messages. Default true.
	 *     @type bool   $show_divider  Show the divider line. Default false.
	 * }
	 * @return string
	 */
	public function standalone( $args = array() ) {
		if ( ! $this->settings->is_configured() || is_user_logged_in() ) {
			return '';
		}
		$args = wp_parse_args(
			$args,
			array(
				'redirect'      => '',
				'show_messages' => true,
				'show_divider'  => false,
			)
		);
		$this->enqueue_frontend();

		$html = '<div class="m365-login m365-login--shortcode">';
		if ( $args['show_messages'] ) {
			$html .= $this->messages_markup();
		}
		if ( $args['show_divider'] && ! $this->password_login_hidden() ) {
			$html .= $this->divider_markup();
		}
		$html .= $this->button( esc_url_raw( (string) $args['redirect'] ) );
		return $html . '</div>';
	}

	/**
	 * Whether the button should be shown for the current login screen.
	 *
	 * @return bool
	 */
	private function should_render() {
		if ( ! $this->settings->is_configured() || ! $this->is_login_action() ) {
			return false;
		}
		/**
		 * Filters whether the Microsoft button is displayed on the login screen.
		 *
		 * @param bool $show Show the button.
		 */
		return (bool) apply_filters( 'm365_login_show_button', true );
	}

	/**
	 * Whether the current wp-login.php request shows the sign-in form (not interim login or another action).
	 *
	 * @return bool
	 */
	private function is_login_action() {
		// phpcs:disable WordPress.Security.NonceVerification.Recommended -- read-only routing check.
		$action  = isset( $_REQUEST['action'] ) ? sanitize_key( wp_unslash( $_REQUEST['action'] ) ) : 'login';
		$interim = ! empty( $_REQUEST['interim-login'] );
		// phpcs:enable WordPress.Security.NonceVerification.Recommended
		return ! $interim && in_array( $action, array( '', 'login' ), true );
	}

	/**
	 * Whether the password form is hidden for this request.
	 *
	 * Also while the connection is broken: password sign-in is refused anyway, the fields would only mislead.
	 *
	 * @return bool
	 */
	private function form_hidden() {
		if ( ! $this->settings->button_only() || M365_Login::instance()->auth->fallback_active() || ! $this->is_login_action() ) {
			return false;
		}
		return $this->should_render() || ! $this->settings->is_configured();
	}

	/**
	 * Adds a body class while the password form is hidden.
	 *
	 * @param string[] $classes Body classes.
	 * @return string[]
	 */
	public function body_class( $classes ) {
		if ( $this->should_render() ) {
			$classes[] = 'm365-login-page';
		}
		if ( $this->form_hidden() ) {
			$classes[] = 'm365-button-only';
		}
		return $classes;
	}

	/**
	 * Enqueues login styles and the small positioning script.
	 */
	public function enqueue() {
		// Also when only the form is hidden (e.g. broken connection): the stylesheet hides the password form and links.
		if ( ! $this->should_render() && ! $this->form_hidden() ) {
			return;
		}
		wp_enqueue_style( 'm365-login', M365_LOGIN_URL . 'assets/css/login.css', array(), M365_LOGIN_VERSION );
		wp_add_inline_style( 'm365-login', $this->css_variables() );

		if ( 'below' === $this->settings->get( 'button_position' ) ) {
			wp_enqueue_script( 'm365-login', M365_LOGIN_URL . 'assets/js/login.js', array(), M365_LOGIN_VERSION, true );
		}
	}

	/**
	 * CSS custom properties derived from the settings.
	 *
	 * @return string
	 */
	public function css_variables() {
		$s = $this->settings->all();
		return sprintf(
			'.m365-login{--m365-bg:%1$s;--m365-bg-hover:%2$s;--m365-color:%3$s;--m365-border:%4$s;--m365-radius:%5$dpx;}',
			sanitize_hex_color( $s['button_bg'] ),
			sanitize_hex_color( $s['button_bg_hover'] ),
			sanitize_hex_color( $s['button_color'] ),
			sanitize_hex_color( $s['button_border'] ),
			absint( $s['button_radius'] )
		);
	}

	/**
	 * Output above the form (via login_message).
	 *
	 * @param string $message Existing message HTML.
	 * @return string
	 */
	public function render_above( $message ) {
		if ( 'above' !== $this->settings->get( 'button_position' ) || ! $this->should_render() ) {
			return $message;
		}
		return $message . $this->markup( 'above' );
	}

	/**
	 * Output below the form (moved into place by login.js).
	 */
	public function render_below() {
		if ( 'below' !== $this->settings->get( 'button_position' ) || ! $this->should_render() ) {
			return;
		}
		echo $this->markup( 'below' ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- markup() escapes everything.
	}

	/**
	 * Shortcode for placing the button on custom login pages.
	 *
	 * @param array $atts Attributes.
	 * @return string
	 */
	public function shortcode( $atts ) {
		$atts = shortcode_atts(
			array(
				'redirect' => '',
				'messages' => 'yes',
				'divider'  => 'no',
			),
			$atts,
			'm365_login_button'
		);
		return $this->standalone(
			array(
				'redirect'      => $atts['redirect'],
				'show_messages' => 'no' !== strtolower( (string) $atts['messages'] ),
				'show_divider'  => 'yes' === strtolower( (string) $atts['divider'] ),
			)
		);
	}

	/**
	 * Full block: divider + button.
	 *
	 * @param string $position 'above' or 'below'.
	 * @return string
	 */
	public function markup( $position ) {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- passed through to the flow, validated there.
		$redirect_to = isset( $_REQUEST['redirect_to'] ) ? esc_url_raw( wp_unslash( $_REQUEST['redirect_to'] ) ) : '';

		$divider = $this->form_hidden() ? '' : $this->divider_markup();

		$html  = '<div class="m365-login m365-login--' . esc_attr( $position ) . '" id="m365-login-block">';
		$html .= 'above' === $position ? $this->button( $redirect_to ) . $divider : $divider . $this->button( $redirect_to );
		$html .= '</div>';
		return $html;
	}

	/**
	 * Button markup.
	 *
	 * @param string $redirect_to Post-login destination.
	 * @return string
	 */
	public function button( $redirect_to = '' ) {
		$auth = M365_Login::instance()->auth;
		$url  = $auth->start_url( $redirect_to );

		$icon = '';
		if ( $this->settings->get( 'button_show_icon' ) ) {
			$custom = (string) $this->settings->get( 'button_icon' );
			if ( '' !== $custom && M365_Login_Settings::is_safe_image_url( $custom ) ) {
				$icon = '<img class="m365-login__icon" src="' . esc_url( $custom ) . '" alt="" width="20" height="20" loading="lazy" />';
			} else {
				$icon = self::microsoft_logo();
			}
		}

		return '<a class="m365-login__button" href="' . esc_url( $url ) . '" rel="nofollow">'
			. $icon
			. '<span class="m365-login__label">' . esc_html( $this->settings->get( 'button_text' ) ) . '</span>'
			. '</a>';
	}

	/**
	 * Bundled Microsoft logo (inline SVG, four coloured squares).
	 *
	 * @return string
	 */
	public static function microsoft_logo() {
		return '<svg class="m365-login__icon" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 23 23" width="20" height="20" aria-hidden="true" focusable="false">'
			. '<path fill="#f25022" d="M1 1h10v10H1z"/>'
			. '<path fill="#7fba00" d="M12 1h10v10H12z"/>'
			. '<path fill="#00a4ef" d="M1 12h10v10H1z"/>'
			. '<path fill="#ffb900" d="M12 12h10v10H12z"/>'
			. '</svg>';
	}
}