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<?php
/**
 * WARNING! THIS SNIPPET MAY BE OUTDATED.
 * The latest version of this snippet can be found in the Gravity Wiz Snippet Library:
 * https://github.com/gravitywiz/snippet-library/blob/master/gravity-forms/gw-minimum-order-qty.php
 */
/**
 * Gravity Wiz // Gravity Forms // Minimum Order Quantity
 * http://gravitywiz.com/set-a-minimum-order-quantity/
 */
add_filter('gform_validation_123', function( $result ) {

	$result = gw_validate_minimum_quantity( $result, array(
		'min_qty' => 20,
		'min_qty_message' => 'Customized messaged for this group.',
		'min_qty_fields'  => array( 1, 2, 3 ),
	) );

	$result = gw_validate_minimum_quantity( $result, array(
		'min_qty' => 15,
		'min_qty_fields' => array( 4, 5, 6 ),
	) );

	return $result;
} );

function gw_validate_minimum_quantity( $result, $args = array() ) {

	$args = wp_parse_args( $args, array(
		'min_qty'         => 1,
		'min_qty_message' => 'You must order a minimum of %1$d tickets. Order %2$d more tickets to complete your order.',
		'min_qty_fields'  => array(),
		'validate_empty_fields' => false,
	) );

	$min_qty = $args['min_qty'];
	$min_qty_message = $args['min_qty_message'];
	$min_qty_fields = $args['min_qty_fields'];

	/* no need to edit below this line */

	$form = $result['form'];
	$quantity = 0;
	$qty_fields = array();
	$has_entered_value = false;

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

		// if $min_qty_fields specified, make sure only applicable quantity fields are totaled
		if(!empty($min_qty_fields) && !in_array($field['id'], $min_qty_fields))
			continue;

		if(in_array(RGFormsModel::get_input_type($field), array('singleproduct', 'calculation'))) {

			// check if product field has separate quantity field, if so skip
			if(sizeof(GFCommon::get_product_fields_by_type($form, array("quantity"), $field['id'])) > 0)
				continue;

			$value = rgpost( "input_{$field['id']}_3" );
			if( ! rgblank( $value ) ) {
				$has_entered_value = true;
			}

			$quantity += floatval( GFCommon::clean_number( $value ) );
			$qty_fields[] =& $field;

		} else if($field['type'] == 'quantity') {

			$value = rgpost( "input_{$field['id']}" );
			if( ! rgblank( $value ) ) {
				$has_entered_value = true;
			}

			$quantity += floatval( GFCommon::clean_number( $value ) );
			if( ! rgblank( $value ) || $args['validate_empty_fields'] ) {
				$qty_fields[] =& $field;
			}

		}

	}

	if( ! $has_entered_value || $quantity >= $min_qty ) {
		return $result;
	}

	for($i = 0; $i < count($qty_fields); $i++) {
		$qty_fields[$i]['failed_validation'] = true;
		$qty_fields[$i]['validation_message'] = sprintf($min_qty_message, $min_qty, $min_qty - $quantity);
	}

	$result['is_valid'] = false;
	$result['form'] = $form;

	return $result;
}

<?php

/**
 * WARNING! THIS SNIPPET MAY BE OUTDATED.
 * The latest version of this snippet can be found in the Gravity Wiz Snippet Library:
 * https://github.com/gravitywiz/snippet-library/blob/master/gravity-forms/gw-minimum-order-qty.php
 */
/**
 * Gravity Wiz // Gravity Forms // Minimum Order Quantity
 * http://gravitywiz.com/set-a-minimum-order-quantity/
 */
function gw_validate_minimum_quantity( $result, $args = array() ) {

	$args = wp_parse_args( $args, array(
		'min_qty'         => 1,
		'min_qty_message' => 'You must order a minimum of %1$d tickets. Order %2$d more tickets to complete your order.',
		'min_qty_fields'  => array(),
		'validate_empty_fields' => false,
	) );

	$min_qty = $args['min_qty'];
	$min_qty_message = $args['min_qty_message'];
	$min_qty_fields = $args['min_qty_fields'];

	/* no need to edit below this line */

	$form = $result['form'];
	$quantity = 0;
	$qty_fields = array();
	$has_entered_value = false;

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

		// if $min_qty_fields specified, make sure only applicable quantity fields are totaled
		if(!empty($min_qty_fields) && !in_array($field['id'], $min_qty_fields))
			continue;

		if(in_array(RGFormsModel::get_input_type($field), array('singleproduct', 'calculation'))) {

			// check if product field has separate quantity field, if so skip
			if(sizeof(GFCommon::get_product_fields_by_type($form, array("quantity"), $field['id'])) > 0)
				continue;

			$value = rgpost( "input_{$field['id']}_3" );
			if( ! rgblank( $value ) ) {
				$has_entered_value = true;
			}

			$quantity += floatval( GFCommon::clean_number( $value ) );
			$qty_fields[] =& $field;

		} else if($field['type'] == 'quantity') {

			$value = rgpost( "input_{$field['id']}" );
			if( ! rgblank( $value ) ) {
				$has_entered_value = true;
			}

			$quantity += floatval( GFCommon::clean_number( $value ) );
			if( ! rgblank( $value ) || $args['validate_empty_fields'] ) {
				$qty_fields[] =& $field;
			}

		}

	}

	if( ! $has_entered_value || $quantity >= $min_qty ) {
		return $result;
	}

	for($i = 0; $i < count($qty_fields); $i++) {
		$qty_fields[$i]['failed_validation'] = true;
		$qty_fields[$i]['validation_message'] = sprintf($min_qty_message, $min_qty, $min_qty - $quantity);
	}

	$result['is_valid'] = false;
	$result['form'] = $form;

	return $result;
}