WordPress plugin. Hot swap admin color scheme for probable local dev/stage sites

swap-admin-color.php

<?php
/**
 * Plugin Name: Swap color scheme on local dev/stage
 */

/**
 * Hotswap an alternate color scheme
 *
 * @param string $result Original value
 * @param string $option Option name
 * @param object $user WP_User object
 * @return string Color scheme handle
 */
function dsa_get_user_option_admin_color( $result, $option, $user ) {

	if ( dsa_is_dev_or_stage() ) {
		return dsa_get_swapped_color( $result );
	}

	return $result;

}
add_filter('get_user_option_admin_color', 'dsa_get_user_option_admin_color', 10, 3 );

/**
 * Calculate swapped color
 *
 * @param string $saved Current saved value
 * @return string New swapped value
 */
function dsa_get_swapped_color( $saved ) {
	$alternate = 'ocean';
	if ( $saved == $alternate ) {
		$alternate = 'sunrise';
	}
	// one of: fresh, light, blue, coffee, ectoplasm, midnight, ocean, sunrise
	return apply_filters( 'dsa_alternate_color', $alternate, $user );
}

/**
 * Unhook later so that actual saved value is properly shown to user when editing profile
 */
add_action('in_admin_header', function() {
	remove_filter('get_user_option_admin_color', 'dsa_get_user_option_admin_color', 10, 3 );
});

/**
 * Check if home_url() appears to be local dev or stage
 *
 * @return bool
 */
function dsa_is_dev_or_stage() {
	if ( // url
		// starts with...
		preg_match( '/^(stage|staging)\./', home_url() ) ||
		// ends with...
		preg_match( '/\.(dev|local|test|wp|localhost|10uplabs\.com)$/', home_url() )
		) {

		// one of: fresh, light, blue, coffee, ectoplasm, midnight, ocean, sunrise
		$return = true;
	} else {
		$return = false;
	}

	return apply_filters( 'is_dev_or_stage', $return );
}

/**
 * Notice under admin option to indicate change
 *
 * @return void
 */
function dsa_admin_color_scheme_picker( $user_id ) {
	if ( dsa_is_dev_or_stage() ) {

		$alternate = dsa_get_swapped_color( get_user_option( 'admin_color', $user_id ) );

		echo '<p>';
		printf( __( '<strong>Notice:</strong> This site appears to be dev or stage, an alternate color scheme (%s) is being swapped in', 'dev-stage-alert' ), $alternate );
		echo '</p>';

	}
}
add_action( 'admin_color_scheme_picker', 'dsa_admin_color_scheme_picker', 20 );