GP Nested Forms: Limit Entries Based on Another Field's Numeric Value

gpnf-limit-entry-min-max-from-field.php

<?php

class GP_Nested_Forms_Dynamic_Entry_Min_Max {

	public function __construct( $args = array() ) {

		// set our default arguments, parse against the provided arguments, and store for use throughout the class
		$this->_args = wp_parse_args( $args, array(
			'parent_form_id'       => false,
			'nested_form_field_id' => false,
			'default_max'          => 0, // Max to fallback to if the dependent field isn't populated
			'default_min'          => 0, // Min to fallback to if the dependent field isn't populated
			'max_field_id'         => null,
			'min_field_id'         => null, // (Optional)
		) );

		// do version check in the init to make sure if GF is going to be loaded, it is already loaded
		add_action( 'init', array( $this, 'init' ) );

	}

	public function init() {

		// make sure we're running the required minimum version of Gravity Forms
		if ( ! property_exists( 'GFCommon', 'version' ) || ! version_compare( GFCommon::$version, '1.8', '>=' ) ) {
			return;
		}

		// time for hooks
		add_filter( 'gform_pre_render', array( $this, 'load_form_script' ), 10, 2 );
		add_filter( 'gform_register_init_scripts', array( $this, 'add_init_script' ), 5, 2 );
		add_action( 'gform_validation', array( $this, 'validate' ) );

	}

	public function load_form_script( $form, $is_ajax_enabled ) {

		if ( $this->is_applicable_form( $form ) && ! has_action( 'wp_footer', array( $this, 'output_script' ) ) ) {
			add_action( 'wp_footer', array( $this, 'output_script' ) );
			add_action( 'gform_preview_footer', array( $this, 'output_script' ) );
		}

		return $form;
	}

	public function validate( $validation_result ) {

		if ( $validation_result['form']['id'] != $this->_args['parent_form_id'] ) {
			return $validation_result;
		}

		if ( ! $this->_args['max_field_id'] && ! $this->_args['min_field_id'] ) {
			return $validation_result;
		}

		$form                    = $validation_result['form'];
		$nested_form_field_id    = $this->_args['nested_form_field_id'];
		$nested_form_field_value = rgpost( "input_{$nested_form_field_id}" );
		$nested_form_field       = GFAPI::get_field( $form, $nested_form_field_id );

		$entry_ids   = explode( ',', $nested_form_field_value );
		$entry_count = empty( $nested_form_field_value ) ? 0 : count( $entry_ids );

		$raw_min = rgpost( "input_{$this->_args['min_field_id']}" );
		$raw_max = rgpost( "input_{$this->_args['max_field_id']}" );

		if ( empty( $raw_min ) ) {
			$raw_min = $this->_args['default_min'];
		}

		if ( empty( $raw_max ) ) {
			$raw_max = $this->_args['default_max'];
		}

		$min = apply_filters( 'gpnf_entry_limit_min', $raw_min, $entry_count, $entry_ids, null, $form );
		$max = apply_filters( 'gpnf_entry_limit_max', $raw_max, $entry_count, $entry_ids, null, $form );

		$has_validation_error = false;

		foreach ( $validation_result['form']['fields'] as &$field ) {

			if ( $field['failed_validation'] ) {
				$has_validation_error = true;
			}

			if ( $field['id'] !== $nested_form_field_id ) {
				continue;
			}

			if ( $min !== null && $min !== '' && $entry_count < $min ) {
				$field['failed_validation']  = true;
				$field['validation_message'] = sprintf( __( 'Please enter a minimum of %d %s', 'gp-nested-forms' ), $min, $min > 1 ? $nested_form_field->get_items_label() : $nested_form_field->get_item_label() );

				$has_validation_error = true;
			}

			if ( $max !== null && $max !== '' && $entry_count > $max ) {
				$field['failed_validation']  = true;
				$field['validation_message'] = sprintf( __( 'Please enter a maximum of %d %s', 'gp-nested-forms' ), $max, $max > 1 ? $nested_form_field->get_items_label() : $nested_form_field->get_item_label() );

				$has_validation_error = true;
			}

		}

		$validation_result['is_valid'] = ! $has_validation_error;

		return $validation_result;

	}

	public function output_script() {
		?>

        <script type="text/javascript">

            (function ($) {

                window.GPNFDynamicEntryMax = function (args) {

                    var self = this;

                    // copy all args to current object: (list expected props)
                    for (prop in args) {
                        if (args.hasOwnProperty(prop))
                            self[prop] = args[prop];
                    }

                    self.init = function () {

                        var $maxField = $('#input_' + self.parentFormId + '_' + self.maxFieldId);

                        gform.addFilter('gpnf_entry_limit_max', function (max, currentFormId, currentFieldId) {
                            if (self.parentFormId != currentFormId || self.nestedFormFieldId != currentFieldId) {
                                return max;
                            }

                            var value = parseInt($maxField.val());

                            return value ? value : self.defaultMax;
                        });

                        $maxField.on('change', function () {
                            // Force Knockout to recalculate the max when the number has changed
                            window['GPNestedForms_' + self.parentFormId + '_' + self.nestedFormFieldId].viewModel.entries.valueHasMutated();
                        });

                    };

                    self.init();

                }

            })(jQuery);

        </script>

		<?php
	}

	public function add_init_script( $form ) {

		if ( ! $this->is_applicable_form( $form ) ) {
			return;
		}

		$args = array(
			'parentFormId'      => $this->_args['parent_form_id'],
			'nestedFormFieldId' => $this->_args['nested_form_field_id'],
			'defaultMax'        => $this->_args['default_max'],
			'maxFieldId'        => $this->_args['max_field_id'],
		);

		$script = 'new GPNFDynamicEntryMax( ' . json_encode( $args ) . ' );';
		$slug   = implode( '_', array(
			'gpnf_dynamic_entry_max_template',
			$this->_args['parent_form_id'],
			$this->_args['nested_form_field_id']
		) );

		GFFormDisplay::add_init_script( $this->_args['parent_form_id'], $slug, GFFormDisplay::ON_PAGE_RENDER, $script );

	}

	public function is_applicable_form( $form ) {

		$form_id = isset( $form['id'] ) ? $form['id'] : $form;

		return empty( $this->_args['form_id'] ) || $form_id == $this->_args['form_id'];
	}

}

new GP_Nested_Forms_Dynamic_Entry_Min_Max( array(
	'parent_form_id'       => 4,
	'nested_form_field_id' => 3,
	'max_field_id'         => 1,
	'min_field_id'         => 2, // (Optional)
) );

I'm trying to get this to work on a paged form, but am having trouble. The "max field" is on the first page, and the nested form is on the second page. Any thoughts? (it works when they're on the same page, just not when on different ones)

👉 This Gist has been migrated to the Gravity Wiz Snippet Library:

https://github.com/gravitywiz/snippet-library/blob/master/gp-nested-forms/gpnf-limit-entry-min-max-from-field.php

Hi @jkyllonen,

Please send us an e-mail via https://gravitywiz.com/support and we'd be happy to help out with the snippet. 😃