rebase from live enviornment

wp/wp-content/mu-plugins/pantheon-mu-plugin/inc/pantheon-login-form-mods.php

@@ -0,0 +1,69 @@
+<?php
+/**
+ * Modify the WordPress login form for Pantheon
+ */
+
+/**
+ * Should we proceed with adding the return to Pantheon button?
+ *
+ * Only if we are on a Pantheon subdomain
+ */
+$show_return_to_pantheon_button = apply_filters( 'show_return_to_pantheon_button', (
+	(
+		false !== stripos( get_site_url(), 'pantheonsite.io' ) ||
+		( isset( $_SERVER['HTTP_HOST'] ) && false !== stripos( $_SERVER['HTTP_HOST'], 'pantheonsite.io' ) )
+	)
+) );
+
+if ( $show_return_to_pantheon_button ) {
+
+	/**
+	 * Enqueue Pantheon login styles
+	 *
+	 * @return void
+	 */
+	function Pantheon_Enqueue_Login_style() {
+		wp_enqueue_style( 'pantheon-login-mods', plugin_dir_url( __FILE__ ) . 'assets/css/return-to-pantheon-button.css', false, PANTHEON_MU_PLUGIN_VERSION );
+	}
+
+	add_action( 'login_enqueue_scripts', 'Pantheon_Enqueue_Login_style', 10 );
+
+	/**
+	 * Enqueue Pantheon login scripts
+	 *
+	 * @return void
+	 */
+	function Pantheon_Enqueue_Login_script() {
+		wp_enqueue_script( 'pantheon-login-mods', plugin_dir_url( __FILE__ ) . 'assets/js/return-to-pantheon-button.js', [ 'jquery' ], PANTHEON_MU_PLUGIN_VERSION, true );
+	}
+
+	add_action( 'login_enqueue_scripts', 'Pantheon_Enqueue_Login_script', 1 );
+
+	/**
+	 * Print return to Pantheon link HTML
+	 *
+	 * @return void
+	 */
+	function Return_To_Pantheon_Button_HTML() {
+		$pantheon_dashboard_url = 'https://dashboard.pantheon.io/sites/' . $_ENV['PANTHEON_SITE'] . '#' . $_ENV['PANTHEON_ENVIRONMENT'];
+
+		$pantheon_fist_icon_url = plugin_dir_url( __FILE__ ) . 'assets/images/pantheon-fist-icon-black.svg';
+		$login_message = apply_filters( 'pantheon_wp_login_text', esc_html__( 'Login to your WordPress Site', 'pantheon' ) );
+		?>
+		<div id="return-to-pantheon" style="display: none;">
+			<div class="left">
+					<?php echo $login_message; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?>
+			</div>
+			<div class="right">
+				<a href="<?php echo esc_url( $pantheon_dashboard_url ); ?>">
+					<img class="fist-icon"  src="<?php echo esc_url( $pantheon_fist_icon_url ); ?>">
+					<?php esc_html_e( 'Return to Pantheon', 'pantheon' ); ?>
+				</a>
+			</div>
+		</div>
+		<?php
+	}
+
+	add_action( 'login_header', 'Return_To_Pantheon_Button_HTML', 10 );
+
+}