oficinasuport-wp-plugin/includes/custom-field-ajuts-filter-function-frontend.php

<?php                                                                                                    
/**
 * Function to display the front end checkboxes for the ajut filter 
 *
 * references:
 * basic start
 * https://www.advancedcustomfields.com/resources/creating-wp-archive-custom-field-filter/
 * 
 * checkbox adaptation query
 * https://wordpress.stackexchange.com/a/102915
 *
 * form GET and POST
 * https://www.formget.com/php-checkbox/
 * 
 * @package Oficina_de_Suport_theme
 */

//function POST_look_values_to_submit() {
//          // look checked values to send
//          // https://stackoverflow.com/a/10808238
//          if( isset($_POST['submit-ajut']) ){
//             echo '<p style="color:#0b0;">$_POST[submit-ajut] set</p>';
//            if( !empty($_POST[ $fields['name'] ]) ){
//              echo '<p style="color:#0b0;">$_POST[$fields[name]] not empty</p>';
//              foreach( $_POST[ $fields['name'] ] as $post_fields_name ) {
//                $post_fields_name_value_checked[] = $post_fields_name;
//              };
//              $all_post_fields_name_values_selection[]  = $fields['name'] . '=' . implode(',',$post_fields_name_value_checked);
//              unset($post_fields_name_values_checked);
//            } else {
//              echo '<p style="color:#b00;">$_POST[$fields[name]] empty</p>';
//            };
//            //end look for checked values to send
//             echo '<p style="color:#0b0;">after $_POST:' . $url . '</p>';
//          };
//          // end look checked values to send
//}

if( ! function_exists( 'ofisuport_ajuts_filters_form' ) ):
  function ofisuport_ajuts_filters_form() {

    echo  '<div id="archive-filters" class="ofisuport-filters">';
    // output all possible values of a checkbox
    

    $groupkey = "group_63ab636898703"; // write here the key for the group of fields from acf
    if( $groupkey ) {
		
      // start the form 
      echo '<form name="search-ajuts" method="post" action="' . $url . '">';

      $groupkey_fields = acf_get_fields($groupkey);
      foreach( $groupkey_fields as $field_key ) {
		  
        if( $field_key['type'] == 'checkbox' ){

          //echo '<span style="color: #00b">' . ($field_key['key']) . '</span><br/>' . '<span style="color: #00b">' . ($field_key['label']) . '</span><br/>' .  '<span style="color: #00b">' . ($field_key['name']) . '</span><br/>';

          // https://wordpress.stackexchange.com/a/102915
          $fields = get_field_object($field_key['key']);
          if( $fields ) {

          // look checked values to send
          //POST_look_values_to_submit();
          // look checked values to send
          // https://stackoverflow.com/a/10808238
          if( isset($_POST['submit-ajut']) ){
             echo '<p style="color:#0b0;">$_POST[submit-ajut] set</p>';
            if( !empty($_POST[ $fields['name'] ]) ){
              echo '<p style="color:#0b0;">$_POST[$fields[name]] ' . $fields['name'] .  ' not empty</p>';
              foreach( $_POST[ $fields['name'] ] as $post_fields_name ) {
                $post_fields_name_value_checked[] = $post_fields_name;
              };
              $all_post_fields_name_values_selection[]  = $fields['name'] . '=' . implode(',',$post_fields_name_value_checked);
              unset($post_fields_name_values_checked);
            } else {
              echo '<p style="color:#b00;">$_POST[$fields[name]] ' . $fields['name'] .  ' empty</p>';
            };
            //end look for checked values to send
             echo '<p style="color:#0b0;">after $_POST:' . implode('?',$all_post_fields_name_values_selection) . '</p>';
          };
          // end look checked values to send

            // check for values from meta fields db in url
            foreach( $GLOBALS['my_query_filters'] as $key => $fieldname ) {

              // check for values in url
              // get value if available
              if( isset($_GET[ $fieldname ]) ) {

                $filteredvalues['value'] = explode(',', $_GET[ $fieldname ]);
		          };
		          //end check for values in url
  

                // construct the checkboxes
                if( $fieldname == $fields['name']) {
  
                  echo '<nav id="fund-filter" class="' . $fields['name'] .  '">' ;
                  echo '<h5>' . $fields['label'] . '</h5>';
                  echo '<ul>';
                  foreach( $fields['choices'] as $choicevalue => $choicelabel ) {
  
                    echo '<li>';
                    echo '<label for="' . $choicevalue  . '">';
                    echo '<input class="ofisuport-filter filter" type="checkbox" ';
                    echo ' value="' .  $choicevalue . '" ';
                   echo ' name="' .  $fields['name'] . '[]" ';
                    if( in_array($choicevalue,$filteredvalues['value']) ) {
  
                      echo ' checked="checked" ';
  
                    };
                    echo ' />';
                    echo $choicelabel;
                    echo '</label>';
                    echo '</li>';
  
                  };
                  echo '</ul>';
                  echo '</nav>';
                };
                // end of construct checkboxes
                
            };
            // end check for values from meta fields db in url


          };
          //end if field_key['key'] 
       
        };
        //end if type checkbox

      };
      //end foreach groupkey field

      $url = home_url('ajuts/?') . implode('&',$all_post_fields_name_values_selection);
      echo '<p>' . $url . '</p>';
      //header('Location:'. $url);
      echo '<button type="submit" name="submit-ajut" class="button-more">enviar</button>';
      echo '</form>'; 
      //close the form and subit
      //POST_look_values_to_submit();

    };
    //end if groupkey

    echo '</div>';
  };
  //end ofisuport_display_filters()
endif;
?>