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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 THIS SNIPPET MAY BE OUTDATED.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-disable-submit-button-until-required-fields-are-filled-out.php
 */
/**
* Gravity Wiz // Gravity Forms // Disable Submit Button Until Required Fields are Field Out
*
* Disable submit buttones until all required fields have been filled out. Currently only supports single-page forms.
*
* @version	 1.0
* @author    David Smith <david@gravitywiz.com>
* @license   GPL-2.0+
* @link      http://gravitywiz.com/...
* @copyright 2013 Gravity Wiz
*/
class GW_Disable_Submit {

    public static $script_output = false;

    public function __construct( $form_id ) {

        add_action( "gform_pre_render_{$form_id}", array( $this, 'maybe_output_script' ) );
        add_action( "gform_register_init_scripts_{$form_id}", array( $this, 'add_init_script' ) );

    }

    public function maybe_output_script( $form ) {

        if( ! self::$script_output ) {
            $this->script();
            self::$script_output = true;
        }

        return $form;
    }

    public function script() {
        ?>

        <script type="text/javascript">

            var GWDisableSubmit;

            (function($){

                GWDisableSubmit = function( args ) {

                    var self = this;

                    // copy all args to current object: formId, fieldId
                    for( prop in args ) {
                        if( args.hasOwnProperty( prop ) )
                            self[prop] = args[prop];
                    }

                    self.init = function() {

                        $( args.inputHtmlIds.join( ', ' ) ).change( function() {
                            self.runCheck();
                        } );

                        self.runCheck();

                    }

                    self.runCheck = function() {

                        var submitButton = $( '#gform_submit_button_' + self.formId );

                        if( self.areRequiredPopulated() ) {
                            submitButton.attr( 'disabled', false ).removeClass( 'gwds-disabled' );
                        } else {
                            submitButton.attr( 'disabled', true ).addClass( 'gwds-disabled' );
                        }

                    }

                    self.areRequiredPopulated = function() {

                        var inputs     = $( args.inputHtmlIds.join( ', ' ) ),
                            inputCount = inputs.length,
                            fullCount  = 0;

                        $( inputs ).each( function() {

                            var input   = $( this ),
                                fieldId = input.attr( 'id' ).split( '_' )[2];

                            // don't count fields hidden via conditional logic towards the inputCount
                            if( window['gf_check_field_rule'] && gf_check_field_rule( self.formId, fieldId, null, null ) == 'hide' ) {
                                inputCount -= 1;
                                return;
                            }

                            if( $.trim( $( this ).val() ) ) {
                                fullCount += 1;
                            } else {
                                return false;
                            }

                        } );

                        return fullCount == inputCount;
                    }

                    self.init();

                }

            })(jQuery);

        </script>

        <?php
    }

    public function add_init_script( $form ) {

        $args = array(
            'formId'       => $form['id'],
            'inputHtmlIds' => $this->get_required_input_html_ids( $form )
        );

        $script = '; new GWDisableSubmit( ' . json_encode( $args ) . ' );';
        $slug = "gw_disable_submit_{$form['id']}";

        GFFormDisplay::add_init_script( $form['id'], $slug, GFFormDisplay::ON_PAGE_RENDER, $script );

    }

    public function get_required_input_html_ids( $form ) {

        $html_ids = '';

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

            if( ! $field['isRequired'] )
                continue;

            $input_ids = false;

            switch( GFFormsModel::get_input_type( $field ) ) {

                case 'address':
                    $input_ids = array( 1, 3, 4, 5, 6 );
                    break;

                case 'name':
                    $input_ids = array( 1, 2, 3, 4, 5, 6 );
                    break;

                default:
                    $html_ids[] = "#input_{$form['id']}_{$field['id']}";
                    break;

            }

            if( ! $input_ids )
                continue;

            foreach( $input_ids as $input_id ) {
                $html_ids[] = "#input_{$form['id']}_{$field['id']}_{$input_id}";
            }

        }

        return $html_ids;
    }

}

# Configuration

new GW_Disable_Submit( 534 );