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_message', array( $this, 'render_above' ), 20 );
		add_action( 'login_footer', array( $this, 'render_below' ) );
		add_shortcode( 'm365_login_button', array( $this, 'shortcode' ) );
	}

	/**
	 * Whether the button should be shown for the current login screen.
	 *
	 * @return bool
	 */
	private function should_render() {
		if ( ! $this->settings->is_configured() ) {
			return false;
		}
		// 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
		if ( $interim || ! in_array( $action, array( '', 'login' ), true ) ) {
			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 );
	}

	/**
	 * Enqueues login styles and the small positioning script.
	 */
	public function enqueue() {
		if ( ! $this->should_render() ) {
			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 ) {
		if ( ! $this->settings->is_configured() || is_user_logged_in() ) {
			return '';
		}
		$atts = shortcode_atts( array( 'redirect' => '' ), $atts, 'm365_login_button' );

		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() );

		return '<div class="m365-login m365-login--shortcode">' . $this->button( esc_url_raw( $atts['redirect'] ) ) . '</div>';
	}

	/**
	 * 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 = (string) $this->settings->get( 'divider_text' );
		$divider = '' === trim( $divider ) ? '' : '<div class="m365-login__divider" aria-hidden="true"><span>' . esc_html( $divider ) . '</span></div>';

		$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>';
	}
}