gravityforms-date-selection-alt.php

<?php
/**
* Filters radio choices to include the next 14 days
*
* Place in the theme's functions.php file
* @link https://docs.gravityforms.com/dynamically-populating-drop-down-fields/
*/
add_filter( 'gform_pre_render_1', 'populate_dates' );
add_filter( 'gform_pre_validation_1', 'populate_dates' );
add_filter( 'gform_pre_submission_filter_1', 'populate_dates' );
add_filter( 'gform_admin_pre_render_1', 'populate_dates' );
function populate_dates( $form )
{
    foreach ( $form['fields'] as $field ) {
        if ( $field->type != 'radio' || strpos( $field->cssClass, 'date-radios' ) === false ) continue;
 		$dates = [];
 		for ( $i = 1; $i < 15; $i++ ){ // (change to 0 and < 14 to include today)
 			$date_label = ''; // Here, we're creating some custom HTML, so we can format as needed
 			$date_day = date('D', strtotime('+' . $i . ' day')); // ex: Thu
 			$date_date = date('jS M', strtotime('+' . $i . ' day')); // ex: 4th Jun
 			$date_label = '<strong>' . $date_day . '</strong><br>' . $date_date; // The HTML for the choice
 			$dates[$i] = [
 				'text' => $date_label, // The label
 				'value' => date('M d, Y', strtotime('+' . $i . ' day')) // The submitted value
 			];
 		}
 		$field->choices = $dates; 
    } 
    return $form;
}

/**
* The following function would replace the above in order to completely remove Sundays
* This still outputs 14 days, but skips sundays
*/
add_filter( 'gform_pre_render_1', 'populate_dates_remove_sundays' );
add_filter( 'gform_pre_validation_1', 'populate_dates_remove_sundays' );
add_filter( 'gform_pre_submission_filter_1', 'populate_dates_remove_sundays' );
add_filter( 'gform_admin_pre_render_1', 'populate_dates_remove_sundays' );
function populate_dates_remove_sundays( $form )
{
    foreach ( $form['fields'] as $field ) {
        if ( $field->type != 'radio' || strpos( $field->cssClass, 'date-radios' ) === false ) continue;
 		$dates = [];
 		$c = 15;
 		for ( $i = 1; $i < $c; $i++ ){ // (change to 0 and < 14 to include today)
 			$date_label = ''; // Here, we're creating some custom HTML, so we can format as needed'
 			$date_day = date('D', strtotime('+' . $i . ' day')); // ex: Thu
 			if ( $date_day == 'Sun' ) {
 				$c++;
 				continue;
 			}
 			$date_date = date('jS M', strtotime('+' . $i . ' day')); // ex: 4th Jun
 			$date_label = '<strong>' . $date_day . '</strong><br>' . $date_date; // The HTML for the choice
 			$dates[$i] = [
 				'text' => $date_label, // The label
 				'value' => date('M d, Y', strtotime('+' . $i . ' day')) // The submitted value
 			];
 		}
 		$field->choices = $dates; 
    } 
    return $form;
}


/**
* Disables "Sunday" choices in the dates 
* @link https://docs.gravityforms.com/gform_field_choice_markup_pre_render/
*/
add_filter( 'gform_field_choice_markup_pre_render_1', 'disable_sundays', 10, 4 );
function disable_sundays($choice_markup, $choice, $field, $value)
{
	if ( $field->type !== 'radio' ) return $choice_markup;
	if ( strpos($choice['text'], 'Sun') == false ) return $choice_markup;
	$choice_markup = str_replace( "type='radio'", "type='radio' disabled", $choice_markup );
	$choice_markup = str_replace( "class='", "class=' disabled ", $choice_markup );
	return str_replace( "type='radio'", "type='radio' disabled", $choice_markup );
}