mandatory-product-categories-field-on-vendor-registration-form

add_action( 'end_wcfm_membership_registration_form', function() {
    $selected_categories = array();

    $product_categories   = get_terms( 'product_cat', 'orderby=name&hide_empty=0&parent=0' );
    $p_category_options   = array();
    foreach ( $product_categories as $cat ) {
        $p_category_options[$cat->term_id] = array( 'name' => $cat->name, 'parent' => 0 );
    }

    if( !empty( $p_category_options ) ) showRegistrationCategoryHierarchySelector( $p_category_options, $selected_categories );
    ?>
    <script>
    jQuery(document).ready(function($) {
        $('.wcfm_category_hierarchy').each(function() {
            $(this).change(function() {
                $level = parseInt($(this).data('level'));
                $value = $(this).val();
                if( $('.p_category_'+($level+1)).length > 0 ) {
                    $('.p_category_'+($level+1)).addClass('wcfm_custom_hide');
                    $('.p_category_label_'+($level+1)).addClass('wcfm_custom_hide');
                    if( $value ) {
                        $.each($value, function( $i, $svalue ) {
                            if( $('.p_category_'+($level+1)).find('.cat_parent_'+$svalue).length > 0 ) {
                                $('.p_category_'+($level+1)).removeClass('wcfm_custom_hide');
                                $('.p_category_label_'+($level+1)).removeClass('wcfm_custom_hide');
                            }
                        });
                    }
                    $level_1 = $('.p_category_'+($level+1)).val();
                    $('.p_category_'+($level+1)).val('');
                    $('.p_category_'+($level+1)).find('option').addClass('wcfm_custom_hide');
                    if( $value ) {
                        $.each($value, function( $i, $svalue ) {
                            $('.p_category_'+($level+1)).find('.cat_parent_'+$svalue).removeClass('wcfm_custom_hide');
                        });
                    }
                    if( $level_1 ) {
                        if( !$('.p_category_'+($level+1)).find('option[value="'+$level_1+'"]').hasClass('wcfm_custom_hide') ) {
                            $('.p_category_'+($level+1)).val($level_1);
                        }
                    }
                    $('.p_category_'+($level+1)).change();
                }
            }).change();

        });
    });
    </script>
    <?php
});

function showRegistrationCategoryHierarchySelector( $p_category_options, $selected_categories, $level = 0 ) {
    global $WCFM, $WCFMch;

    $p_category_child_options = array();
    $ptax_custom_arrtibutes = apply_filters( 'wcfm_taxonomy_custom_attributes', array(), 'product_cat' );
    ?>
    <p class="wcfm_title p_category_label_<?php echo $level; ?>">
        <strong>
            <?php
            echo apply_filters( 'wcfm_taxonomy_custom_label', '', 'product_cat' );
            if( $level ) _e( 'Sub-', 'wcfm-category-hierarchy' );
            _e( 'Categories', 'wc-frontend-manager' );
            ?>
            <span class="required">*</span>
        </strong>
    </p>
    <label class="screen-reader-text" for="product_cats">
        <?php
        if( $level ) echo __( 'Sub-', 'wcfm-category-hierarchy' );
        echo apply_filters( 'wcfm_taxonomy_custom_label', __( 'Categories', 'wc-frontend-manager' ), 'product_cat' );
        ?>
    </label>
    <select id="p_category_<?php echo $level; ?>" style="height: auto;" multiple name="reg_category[<?php echo $level; ?>][]" class="wcfm-select wcfm_category_hierarchy p_category_<?php echo $level; ?>" data-level="<?php echo $level; ?>" data-catlimit="1" <?php echo implode( ' ', $ptax_custom_arrtibutes ); ?>>
        <option value=""><?php _e( '-- Select Category --', 'wcfm-category-hierarchy' ); ?></option>
        <?php
        foreach( $p_category_options as $term_id => $term_details ) {
            $cat_group_class = 'cat_parent_' . $term_details['parent'];
            echo '<option class="' . $cat_group_class . '" value="' . esc_attr( $term_id ) . '"' . selected( in_array( $term_id, $selected_categories ), true, false ) . '>' . __( esc_html( $term_details['name'] ), 'wcfm-category-hierarchy' ) . '</option>';

            $product_child_taxonomies   = get_terms( 'product_cat', 'orderby=name&hide_empty=0&parent=' . absint( $term_id ) );
            if ( $product_child_taxonomies ) {
                foreach ( $product_child_taxonomies as $cat ) {
                    $p_category_child_options[$cat->term_id] = array( 'name' => $cat->name, 'parent' => $term_id );
                }
            }
        }
        ?>
    </select>
    <?php
    $level++;
    if( !empty( $p_category_child_options ) ) showRegistrationCategoryHierarchySelector( $p_category_child_options, $selected_categories, $level );
}

add_filter('wcfm_taxonomy_custom_attributes', function($attributes, $taxonomy) {
    if( 'product_cat' === $taxonomy ) {
        $attributes[] = 'data-required="1"';
        $attributes[] = 'data-required_message="Please select at least one category."';
    }
    return $attributes;
}, 10, 2);

add_action( 'wcfm_membership_registration', function( $member_id, $wcfm_membership_registration_form_data ) {
    if( isset( $wcfm_membership_registration_form_data['reg_category'] ) ) {
        update_user_meta( $member_id, 'wcfm_vendor_reg_category', $wcfm_membership_registration_form_data['reg_category'] );
    }
}, 50, 2 );

add_filter('wcfm_allowed_taxonomies', function($is_allowed, $taxonomy, $term_id) {
    global $wp;
    $vendor_id = 0;
    if($taxonomy === 'product_cat') {
        if(wcfm_is_vendor()) {
            $vendor_id = apply_filters( 'wcfm_current_vendor_id', get_current_user_id() );
        } else if(isset( $wp->query_vars['wcfm-products-manage'] ) && !empty( $wp->query_vars['wcfm-products-manage'] ) ) {
            $vendor_id = wcfm_get_vendor_id_by_post($wp->query_vars['wcfm-products-manage']);
        }
        if($vendor_id) {
            $allowed_cat = get_user_meta($vendor_id, 'wcfm_vendor_reg_category', true);
            $allowed_parent_cat = empty($allowed_cat) ? $allowed_cat : reset($allowed_cat);
            if(!empty($allowed_parent_cat)) {
                return in_array($term_id, $allowed_parent_cat);
            }
        }
    }
    return $is_allowed;
}, 10, 3);

add_action('end_wcfm_membership_registration_form', function() {
    ?>
    <script>
        jQuery(function($) {
            $( document.body ).on( 'wcfm_form_validate', function(event, form) {
                $form = $(form);
                $elems = $form.find('select.wcfm_category_hierarchy:visible');
                $elems.each( function() {
                    $elem = $(this);
                    var data_val = [];
                    if($elem.length && $elem.data('required')==1) {
                        data_val = $elem.val();
                        if(data_val.length === 0 || (data_val.length === 1 && data_val[0] === "")) {
                            if( $wcfm_is_valid_form ) {
                                $('#' + $form.attr('id') + ' .wcfm-message').html( '<span class="wcicon-status-cancelled"></span>' + $elem.data('required_message') ).addClass('wcfm-error').slideDown();
                            } else {
                                $('#' + $form.attr('id') + ' .wcfm-message').append( '<br /><span class="wcicon-status-cancelled"></span>' + $elem.data('required_message') );
                            }
                            $wcfm_is_valid_form = false;
                            $elem.removeClass('wcfm_validation_success').addClass('wcfm_validation_failed');
                        }
                    }
                });
            });
        });
    </script>
    <?php
});