Disable USA Holidays for Gravity Forms Gravity Wiz Limit Dates.

functions.php

<?php
/**
 * Disable USA Holidays for Gravity Forms Gravity Wiz Limit Dates.
 *
 * @link https://gravitywiz.com/documentation/gravity-forms-limit-dates/
 * @link https://gist.github.com/cliffordp/38892bbfe30702d4623c9c13e17a1b09 This snippet.
 *
 * DOES NOT appear in the form editor's UI but DOES take effect when filling the form.
 * If you add your own Exception within form editor's UI, that will take precedence over these rules.
 *
 * TODO: ADD YOUR OWN FORM#s AND FIELD#s AT THE BOTTOM!
 */

if ( ! class_exists( 'GW_Limit_Dates_Federal_Holidays' ) ) {

	class GW_Limit_Dates_Federal_Holidays {

		// Set how many years in advance to generate
		private int $years_to_generate = 2;
		
		// Internal cache so we only calculate dates once per page load
		private ?array $generated_holidays = null;

		/**
		 * Constructor
		 * @param array $targets Array of strings in "formId_fieldId" format.
		 */
		public function __construct( array $targets ) {
			foreach ( $targets as $target ) {
				add_filter( "gpld_limit_dates_options_{$target}", [ $this, 'apply_holiday_exceptions' ], 10, 3 );
			}
		}

		/**
		 * The callback that intercepts the field options and applies the dates.
		 */
		public function apply_holiday_exceptions( $field_options, $form, $field ) {
			if ( $this->generated_holidays === null ) {
				$this->generated_holidays = $this->generate_dates();
			}

			// Safely merge our federal holidays with any exceptions you clicked in the UI
			$existing_exceptions = $field_options['exceptions'] ?? [];
			$field_options['exceptions'] = array_values( array_unique( array_merge( $existing_exceptions, $this->generated_holidays ) ) );

			return $field_options;
		}

		/**
		 * The math engine that figures out the US Federal Holidays & Observations.
		 */
		private function generate_dates(): array {
			$federal_holidays = [];
			$current_year     = (int) wp_date( 'Y' );

			for ( $i = 0; $i <= $this->years_to_generate; $i++ ) {
				$year = $current_year + $i;

				// 1. Fixed Dates (Require observation math)
				$fixed_dates = [
					"$year-01-01", // New Year's Day
					"$year-06-19", // Juneteenth
					"$year-07-04", // Independence Day
					"$year-11-11", // Veterans Day
					"$year-12-25", // Christmas Day 
				];

				foreach ( $fixed_dates as $date_string ) {
					$timestamp   = strtotime( $date_string );
					$day_of_week = (int) gmdate( 'w', $timestamp ); // 0 = Sunday, 6 = Saturday

					// Shift weekends to observed Federal weekdays
					if ( $day_of_week === 0 ) {
						// Sunday -> Observe on Monday
						$timestamp = strtotime( '+1 day', $timestamp );
					} elseif ( $day_of_week === 6 ) {
						// Saturday -> Observe on Friday
						$timestamp = strtotime( '-1 day', $timestamp );
					}

					$federal_holidays[] = gmdate( 'm/d/Y', $timestamp );
				}

				// 2. Floating Dates (Always land on a weekday natively)
				$floating_dates = [
					"third monday of january $year",   // Martin Luther King Jr. Day
					"third monday of february $year",  // Washington's Birthday / Presidents' Day
					"last monday of may $year",        // Memorial Day
					"first monday of september $year", // Labor Day
					"second monday of october $year",  // Columbus Day / Indigenous Peoples' Day
					"fourth thursday of november $year"// Thanksgiving Day
				];

				foreach ( $floating_dates as $date_string ) {
					$federal_holidays[] = gmdate( 'm/d/Y', strtotime( $date_string ) );
				}
			}

			return $federal_holidays;
		}
	}
}

// --------------------------------------------------------
// USAGE: Instantiate the class and pass in your targets
// Format: "formId_fieldId"
// --------------------------------------------------------
new GW_Limit_Dates_Federal_Holidays( [
	'5_15', // Applies to Form 5, Field 15
	'1_15', // Applies to Form 1, Field 15
] );